driver core: Introduce device_link_wait_removal()

The commit 80dd33cf72d1 ("drivers: base: Fix device link removal")
introduces a workqueue to release the consumer and supplier devices used
in the devlink.
In the job queued, devices are release and in turn, when all the
references to these devices are dropped, the release function of the
device itself is called.

Nothing is present to provide some synchronisation with this workqueue
in order to ensure that all ongoing releasing operations are done and
so, some other operations can be started safely.

For instance, in the following sequence:
1) of_platform_depopulate()
2) of_overlay_remove()

During the step 1, devices are released and related devlinks are removed
(jobs pushed in the workqueue).
During the step 2, OF nodes are destroyed but, without any
synchronisation with devlink removal jobs, of_overlay_remove() can raise
warnings related to missing of_node_put():
ERROR: memory leak, expected refcount 1 instead of 2

Indeed, the missing of_node_put() call is going to be done, too late,
from the workqueue job execution.

Introduce device_link_wait_removal() to offer a way to synchronize
operations waiting for the end of devlink removals (i.e. end of
workqueue jobs).
Also, as a flushing operation is done on the workqueue, the workqueue
used is moved from a system-wide workqueue to a local one.

Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20240325152140.198219-2-herve.codina@bootlin.com
Signed-off-by: Rob Herring <robh@kernel.org>

driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link

A fwnode link between specific supplier-consumer fwnodes can be added
multiple times for multiple reasons. If that dependency doesn't exist,
deleting the fwnode link once doesn't guarantee that it won't get created
again.

So, add FWLINK_FLAG_IGNORE flag to mark a fwnode link as one that needs to
be completely ignored. Since a fwnode link's flags is an OR of all the
flags passed to all the fwnode_link_add() calls to create that specific
fwnode link, the FWLINK_FLAG_IGNORE flag is preserved and can be used to
mark a fwnode link as on that need to be completely ignored until it is
deleted.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20240305050458.1400667-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Adds flags param to fwnode_link_add()

Allow the callers to set fwnode link flags when adding fwnode links.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20240305050458.1400667-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Move fw_devlink stuff to where it belongs

A few APIs, i.e. fwnode_is_ancestor_of(), fwnode_get_next_parent_dev(),
and get_dev_from_fwnode(), that belong specifically to the fw_devlink APIs,
may be static, but they are not.

Resolve this mess by moving them to the driver/base/core where the all
users are being resided and make static.

No functional changes intended.

Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240301180138.271590-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Improve logs for cycle detection

The links in a cycle are not all logged in a consistent manner or not
logged at all. Make them consistent by adding a "cycle:" string and log all
the link in the cycles (even the child ==> parent dependency) so that it's
easier to debug cycle detection code. Also, mark the start and end of a
cycle so it's easy to tell when multiple cycles are logged back to back.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20240202095636.868578-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Improve detection of overlapping cycles

fw_devlink can detect most overlapping/intersecting cycles. However it was
missing a few corner cases because of an incorrect optimization logic that
tries to avoid repeating cycle detection for devices that are already
marked as part of a cycle.

Here's an example provided by Xu Yang (edited for clarity):

usb
+-----+
tcpc | |
+-----+ | +--|
| |----------->|EP|
|--+ | | +--|
|EP|<-----------| |
|--+ | | B |
| | +-----+
| A | |
+-----+ |
^ +-----+ |
| | | |
+-----| C |<--+
| |
+-----+
usb-phy

Node A (tcpc) will be populated as device 1-0050.
Node B (usb) will be populated as device 38100000.usb.
Node C (usb-phy) will be populated as device 381f0040.usb-phy.

The description below uses the notation:
consumer --> supplier
child ==> parent

1. Node C is populated as device C. No cycles detected because cycle
detection is only run when a fwnode link is converted to a device link.

2. Node B is populated as device B. As we convert B --> C into a device
link we run cycle detection and find and mark the device link/fwnode
link cycle:
C--> A --> B.EP ==> B --> C

3. Node A is populated as device A. As we convert C --> A into a device
link, we see it's already part of a cycle (from step 2) and don't run
cycle detection. Thus we miss detecting the cycle:
A --> B.EP ==> B --> A.EP ==> A

Looking at it another way, A depends on B in one way:
A --> B.EP ==> B

But B depends on A in two ways and we only detect the first:
B --> C --> A
B --> A.EP ==> A

To detect both of these, we remove the incorrect optimization attempt in
step 3 and run cycle detection even if the fwnode link from which the
device link is being created has already been marked as part of a cycle.

Reported-by: Xu Yang <xu.yang_2@nxp.com>
Closes: https://lore.kernel.org/lkml/DU2PR04MB8822693748725F85DC0CB86C8C792@DU2PR04MB8822.eurprd04.prod.outlook.com/
Fixes: 3fb16866b51d ("driver core: fw_devlink: Make cycle detection more robust")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20240202095636.868578-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix device_link_flag_is_sync_state_only()

device_link_flag_is_sync_state_only() correctly returns true on the flags
of an existing device link that only implements sync_state() functionality.
However, it incorrectly and confusingly returns false if it's called with
DL_FLAG_SYNC_STATE_ONLY.

This bug doesn't manifest in any of the existing calls to this function,
but fix this confusing behavior to avoid future bugs.

Fixes: 67cad5c67019 ("driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20240202095636.868578-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Better advertise dev_err_probe()

Describing the usage of dev_err_probe() as being (only?) "deemed
acceptable" has a bad connotation. In fact dev_err_probe() fulfills
three tasks:

- handling of EPROBE_DEFER (even more than degrading to dev_dbg())
- symbolic output of the error code
- return err for compact error code paths

Advertise these better and claim the usage to be "fine" to get rid of
the bad connotation.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231215174540.2438601-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Enable fw_devlink=rpm by default

fw_devlink=on has stabilized and is working correctly. Let's start using
device links created by fw_devlink to also enforce runtime PM ordering.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20231113220948.80089-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: make device_is_dependent() static

The function device_is_dependent() is only called by the driver core
internally and should not, at this time, be called by anyone else
outside of it, so mark it as static so as not to give driver authors the
wrong idea.

Cc: Saravana Kannan <saravanak@google.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/2023112815-faculty-thud-add8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Export device_is_dependent() to modules"

This reverts commit 1d5e8f4bf06da86b71cc9169110d1a0e1e7af337.

Greg says: "why exactly is this needed? Nothing outside of
the driver core should be needing this function, it shouldn't
be public at all (I missed that before.)

So please, revert it for now, let's figure out why DRM thinks
this is needed for it's devices, and yet no other bus/subsystem
does."

Link: https://lore.kernel.org/dri-devel/2023112739-willing-sighing-6bdd@gregkh/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231128-revert-panel-fix-v1-1-69bb05048dae@linaro.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231128-revert-panel-fix-v1-1-69bb05048dae@linaro.org

driver core: Export device_is_dependent() to modules

Export device_is_dependent() since the drm_kms_helper module is starting
to use it.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127051414.3783108-2-victor.liu@nxp.com

driver core: Add missing parameter description to __fwnode_link_add()

The kernel documentation validator is not happy with:

drivers/base/core.c:67: warning: Function parameter or member 'flags' not described in '__fwnode_link_add'

Add missing parameter description.

Fixes: 6a6dfdf8b3ff ("driver core: fw_devlink: Allow marking a fwnode link as being part of a cycle")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230919195048.3197551-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: return an error when dev_set_name() hasn't happened

The commit d21fdd07cea4 ("driver core: Return proper error code when
dev_set_name() fails") rewrote the logic of handling the dev_set_name()
error codes, but missed the point that initially set error value to
-EINVAL might be rewritten and hence the error path can't be triggered
at some circumstances. To fix this, make sure that error variable is
set to -EINVAL when other conditionals are false.

Reported-by: syzbot+bdfb03b1ec8b342c12cb@syzkaller.appspotmail.com
Fixes: d21fdd07cea4 ("driver core: Return proper error code when dev_set_name() fails")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230828145824.3895288-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Call in reversed order in device_platform_notify_remove()

It's logically correct to call the removal notifiers in the reversed order
as it might be dependent to each other. Luckily, platform_notify_remove()
currently is not used and the others have no dependency use, but theoretically
it's still possible.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230818133654.767986-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Return proper error code when dev_set_name() fails

Whe device_add() tries to assign a device name with help of
dev_set_name() the error path explicitly uses -EINVAL, while
the function may return something different.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230817091221.463721-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: base: Free devm resources when unregistering a device

In the current code, devres_release_all() only gets called if the device
has a bus and has been probed.

This leads to issues when using bus-less or driver-less devices where
the device might never get freed if a managed resource holds a reference
to the device. This is happening in the DRM framework for example.

We should thus call devres_release_all() in the device_del() function to
make sure that the device-managed actions are properly executed when the
device is unregistered, even if it has neither a bus nor a driver.

This is effectively the same change than commit 2f8d16a996da ("devres:
release resources on device_del()") that got reverted by commit
a525a3ddeaca ("driver core: free devres in device_release") over
memory leaks concerns.

This patch effectively combines the two commits mentioned above to
release the resources both on device_del() and device_release() and get
the best of both worlds.

Fixes: a525a3ddeaca ("driver core: free devres in device_release")
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20230720-kunit-devm-inconsistencies-test-v3-3-6aa7e074f373@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Replace kstrdup() + strreplace() with kstrdup_and_replace()

Replace open coded functionality of kstrdup_and_replace() with a call.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230804143910.15504-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

swiotlb: make io_tlb_default_mem local to swiotlb.c

SWIOTLB implementation details should not be exposed to the rest of the
kernel. This will allow to make changes to the implementation without
modifying non-swiotlb code.

To avoid breaking existing users, provide helper functions for the few
required fields.

As a bonus, using a helper function to initialize struct device allows to
get rid of an #ifdef in driver core.

Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

driver core: update comments in device_rename()

Document that some subsystems are still going to use device_rename for
the time being, so it is not a good idea to assume it's not used. Also
remove mentions of a plan to stop renaming net devices.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230406045435.19452-1-wedsonaf@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: class: remove struct class_interface * from callbacks

The add_dev and remove_dev callbacks in struct class_interface currently
pass in a pointer back to the class_interface structure that is calling
them, but none of the callback implementations actually use this pointer
as it is pointless (the structure is known, the driver passed it in in
the first place if it is really needed again.)

So clean this up and just remove the pointer from the callbacks and fix
up all callback functions.

Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Kurt Schwemmer <kurt.schwemmer@microsemi.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: John Stultz <jstultz@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wang Weiyang <wangweiyang2@huawei.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Cc: Jakob Koschel <jakobkoschel@gmail.com>
Cc: Cai Xinchen <caixinchen1@huawei.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Logan Gunthorpe <logang@deltatee.com>
Link: https://lore.kernel.org/r/2023040250-pushover-platter-509c@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: remove incorrect comment for device_create*

The device_create() and device_create_with_groups() function comments
incorrectly state that they only work with a struct class that was
created using class_create(), but that is not true now and I am not sure
if it ever was. So just remove the comment as it's not needed now.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/2023040218-scouts-unplowed-24d2@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: make sysfs_dev_char_kobj static

Nothing outside of drivers/base/core.c uses sysfs_dev_char_kobj, so
make it static and document what it is used for so we remember it the
next time we touch it 15 years from now.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-7-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: make sysfs_dev_block_kobj static

Nothing outside of drivers/base/core.c uses sysfs_dev_block_kobj, so
make it static and document what it is used for so we remember it the
next time we touch it 15 years from now.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-6-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: clean up the logic to determine which /sys/dev/ directory to use

When a dev_t is set in a struct device, an symlink in /sys/dev/ is
created for it either under /sys/dev/block/ or /sys/dev/char/ depending
on the device type.

The logic to determine this would trigger off of the class of the
object, and the kobj_type set in that location. But it turns out that
this deep nesting isn't needed at all, as it's either a choice of block
or "everything else" which is a char device. So make the logic a lot
more simple and obvious, and remove the incorrect comments in the code
that tried to document something that was not happening at all (it is
impossible to set class->dev_kobj to NULL as the class core prevented
that from happening.

This removes the only place that class->dev_kobj was being used, so
after this, it can be removed entirely.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: core: move to use class_to_subsys()

There are a number of places in core.c that need access to the private
subsystem structure of struct class, so move them to use
class_to_subsys() instead of accessing it directly.

This requires exporting class_to_subsys() out of class.c, but keeping it
local to the driver core.

Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230331093318.82288-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT

Add a build time equivalent of fw_devlink.sync_state=timeout so that
board specific kernels could enable it and not have to deal with setting
or cluttering the kernel commandline.

Cc: Doug Anderson <dianders@chromium.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230317205134.964098-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add a comment to set_primary_fwnode() on nullifying

Explain what parent && fn == parent->fwnode conditional does.
With this refactor the code a bit.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230323182640.61085-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: device: make device_create*() take a const struct class *

The functions device_create() and device_create_with_groups() do not
modify the struct class passed into it, so enforce this by changing the
function parameters to be struct const class.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-12-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: device: mark struct class in struct device as constant

The pointer to a struct class in a struct device should never be used to
change anything in that class. So mark it as constant to enforce this
requirement.

This requires a few minor changes to some internal driver core functions
to enforce the const * being used here now.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-11-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: device: make device_destroy() take a const class *

device_destroy() does not modify the struct class passed into it, so
mark it as const to enforce this rule.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-9-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: remove struct module * setting from struct class

There is no need to manually set the owner of a struct class, as the
registering function does it automatically, so remove all of the
explicit settings from various drivers that did so as it is unneeded.

This allows us to remove this pointer entirely from this structure going
forward.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Make state_synced device attribute writeable

If the file is written to and sync_state() hasn't been called for the
device yet, then call sync_state() for the device independent of the
state of its consumers.

This is useful for supplier devices that have one or more consumers that
don't have a driver but the consumers are in a state that don't use the
resources supplied by the supplier device.

This gives finer grained control than using the
fw_devlink.sync_state=timeout kernel commandline parameter.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230304005355.746421-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add fw_devlink.sync_state command line param

When all devices that could probe have finished probing (based on
deferred_probe_timeout configuration or late_initcall() when
!CONFIG_MODULES), this parameter controls what to do with devices that
haven't yet received their sync_state() calls.

fw_devlink.sync_state=strict is the default and the driver core will
continue waiting on all consumers of a device to probe successfully
before sync_state() is called for the device. This is the default
behavior since calling sync_state() on a device when all its consumers
haven't probed could make some systems unusable/unstable. When this
option is selected, we also print the list of devices that haven't had
sync_state() called on them by the time all devices the could probe have
finished probing.

fw_devlink.sync_state=timeout will cause the driver core to give up
waiting on consumers and call sync_state() on any devices that haven't
yet received their sync_state() calls. This option is provided for
systems that won't become unusable/unstable as they might be able to
save power (depends on state of hardware before kernel starts) if all
devices get their sync_state().

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230304005355.746421-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: remove CONFIG_SYSFS_DEPRECATED and CONFIG_SYSFS_DEPRECATED_V2

CONFIG_SYSFS_DEPRECATED was added in commit 88a22c985e35
("CONFIG_SYSFS_DEPRECATED") in 2006 to allow systems with older versions
of some tools (i.e. Fedora 3's version of udev) to boot properly. Four
years later, in 2010, the option was attempted to be removed as most of
userspace should have been fixed up properly by then, but some kernel
developers clung to those old systems and refused to update, so we added
CONFIG_SYSFS_DEPRECATED_V2 in commit e52eec13cd6b ("SYSFS: Allow boot
time switching between deprecated and modern sysfs layout") to allow
them to continue to boot properly, and we allowed a boot time parameter
to be used to switch back to the old format if needed.

Over time, the logic that was covered under these config options was
slowly removed from individual driver subsystems successfully, removed,
and the only thing that is now left in the kernel are some changes in
the block layer's representation in sysfs where real directories are
used instead of symlinks like normal.

Because the original changes were done to userspace tools in 2006, and
all distros that use those tools are long end-of-life, and older
non-udev-based systems do not care about the block layer's sysfs
representation, it is time to finally remove this old logic and the
config entries from the kernel.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: linux-block@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Acked-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20230223073326.2073220-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Print full path and name of fwnode

Some of the log messages were printing just the fwnode name. While it's
short, it's not always uniquely identifiable in system. So print the
full path and name to make debugging easier.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230225065443.278284-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Avoid spurious error message

fw_devlink can sometimes try to create a device link with the consumer
and supplier as the same device. These attempts will fail (correctly),
but are harmless. So, avoid printing an error for these cases. Also, add
more detail to the error message.

Fixes: 3fb16866b51d ("driver core: fw_devlink: Make cycle detection more robust")
Reported-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reported-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230225064148.274376-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: add error handling for devtmpfs_create_node()"

This reverts commit 31b4b6730fd4f5d503c9f23619c920ce7b794754 as it is
reported to cause boot regressions.

Link: https://lore.kernel.org/r/Y+rSXg14z1Myd8Px@dev-arch.thelio-3990X
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Longlong Xia <xialonglong1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: add error handling for devtmpfs_create_node()

In some cases, devtmpfs_create_node() can return error value.
So, make use of it.

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230210095444.4067307-2-xialonglong1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: bus: add bus_get_dev_root() function

Instead of poking around in the struct bus_type directly for the
dev_root pointer, provide a function to return it properly reference
counted, if it is present in the bus. This will be needed to move the
pointer out of struct bus_type in the future.

Use the function in the driver core code at the same time it is
introduced to verify that it works properly.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230209093556.19132-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Make cycle detection more robust

fw_devlink could only detect a single and simple cycle because it relied
mainly on device link cycle detection code that only checked for cycles
between devices. The expectation was that the firmware wouldn't have
complicated cycles and multiple cycles between devices. That expectation
has been proven to be wrong.

For example, fw_devlink could handle:

+-+ +-+
|A+------> |B+
+-+ +++
^ |
| |
+----------+

But it couldn't handle even something as "simple" as:

+---------------------+
| |
v |
+-+ +-+ +++
|A+------> |B+------> |C|
+-+ +++ +-+
^ |
| |
+----------+

But firmware has even more complicated cycles like:

+---------------------+
| |
v |
+-+ +---+ +++
+--+A+------>| B +-----> |C|<--+
| +-+ ++--+ +++ |
| ^ | ^ | |
| | | | | |
| +---------+ +---------+ |
| |
+------------------------------+

And this is without including parent child dependencies or nodes in the
cycle that are just firmware nodes that'll never have a struct device
created for them.

The proper way to treat these devices it to not force any probe ordering
between them, while still enforce dependencies between node in the
cycles (A, B and C) and their consumers.

So this patch goes all out and just deals with all types of cycles. It
does this by:

1. Following dependencies across device links, parent-child and fwnode
links.
2. When it find cycles, it mark the device links and fwnode links as
such instead of just deleting them or making the indistinguishable
from proxy SYNC_STATE_ONLY device links.

This way, when new nodes get added, we can immediately find and mark any
new cycles whether the new node is a device or firmware node.

Fixes: 2de9d8e0d2fe ("driver core: fw_devlink: Improve handling of cyclic dependencies")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Luca Weiss <luca.weiss@fairphone.com> # qcom/sm7225-fairphone-fp4
Link: https://lore.kernel.org/r/20230207014207.1678715-9-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Consolidate device link flag computation

Consolidate the code that computes the flags to be used when creating a
device link from a fwnode link.

Fixes: 2de9d8e0d2fe ("driver core: fw_devlink: Improve handling of cyclic dependencies")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Luca Weiss <luca.weiss@fairphone.com> # qcom/sm7225-fairphone-fp4
Link: https://lore.kernel.org/r/20230207014207.1678715-8-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Allow marking a fwnode link as being part of a cycle

To improve detection and handling of dependency cycles, we need to be
able to mark fwnode links as being part of cycles. fwnode links marked
as being part of a cycle should not block their consumers from probing.

Fixes: 2de9d8e0d2fe ("driver core: fw_devlink: Improve handling of cyclic dependencies")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Luca Weiss <luca.weiss@fairphone.com> # qcom/sm7225-fairphone-fp4
Link: https://lore.kernel.org/r/20230207014207.1678715-7-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Add DL_FLAG_CYCLE support to device links

fw_devlink uses DL_FLAG_SYNC_STATE_ONLY device link flag for two
purposes:

1. To allow a parent device to proxy its child device's dependency on a
supplier so that the supplier doesn't get its sync_state() callback
before the child device/consumer can be added and probed. In this
usage scenario, we need to ignore cycles for ensure correctness of
sync_state() callbacks.

2. When there are dependency cycles in firmware, we don't know which of
those dependencies are valid. So, we have to ignore them all wrt
probe ordering while still making sure the sync_state() callbacks
come correctly.

However, when detecting dependency cycles, there can be multiple
dependency cycles between two devices that we need to detect. For
example:

A -> B -> A and A -> C -> B -> A.

To detect multiple cycles correct, we need to be able to differentiate
DL_FLAG_SYNC_STATE_ONLY device links used for (1) vs (2) above.

To allow this differentiation, add a DL_FLAG_CYCLE that can be use to
mark use case (2). We can then use the DL_FLAG_CYCLE to decide which
DL_FLAG_SYNC_STATE_ONLY device links to follow when looking for
dependency cycles.

Fixes: 2de9d8e0d2fe ("driver core: fw_devlink: Improve handling of cyclic dependencies")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Luca Weiss <luca.weiss@fairphone.com> # qcom/sm7225-fairphone-fp4
Link: https://lore.kernel.org/r/20230207014207.1678715-6-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Improve check for fwnode with no device/driver

fw_devlink shouldn't defer the probe of a device to wait on a supplier
that'll never have a struct device or will never be probed by a driver.
We currently check if a supplier falls into this category, but don't
check its ancestors. We need to check the ancestors too because if the
ancestor will never probe, then the supplier will never probe either.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Luca Weiss <luca.weiss@fairphone.com> # qcom/sm7225-fairphone-fp4
Link: https://lore.kernel.org/r/20230207014207.1678715-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Don't purge child fwnode's consumer links

When a device X is bound successfully to a driver, if it has a child
firmware node Y that doesn't have a struct device created by then, we
delete fwnode links where the child firmware node Y is the supplier. We
did this to avoid blocking the consumers of the child firmware node Y
from deferring probe indefinitely.

While that a step in the right direction, it's better to make the
consumers of the child firmware node Y to be consumers of the device X
because device X is probably implementing whatever functionality is
represented by child firmware node Y. By doing this, we capture the
device dependencies more accurately and ensure better
probe/suspend/resume ordering.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Luca Weiss <luca.weiss@fairphone.com> # qcom/sm7225-fairphone-fp4
Link: https://lore.kernel.org/r/20230207014207.1678715-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: make kobj_type structures constant

Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definitions to prevent
modification at runtime.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230204-kobj_type-driver-core-v1-1-b9f809419f2c@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kobject: kset_uevent_ops: make uevent() callback take a const *

The uevent() callback in struct kset_uevent_ops does not modify the
kobject passed into it, so make the pointer const to enforce this
restriction. When doing so, fix up all existing uevent() callbacks to
have the correct signature to preserve the build.

Cc: Christine Caulfield <ccaulfie@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-17-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: device_get_devnode() should take a const *

device_get_devnode() should take a constant * to struct device as it
does not modify it in any way, so modify the function definition to do
this and move it out of device.h as it does not need to be exposed to
the whole kernel tree.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Won Chung <wonchung@google.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-8-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fix resource leak in device_add()

When calling kobject_add() failed in device_add(), it will call
cleanup_glue_dir() to free resource. But in kobject_add(),
dev->kobj.parent has been set to NULL. This will cause resource leak.

The process is as follows:
device_add()
get_device_parent()
class_dir_create_and_add()
kobject_add() //kobject_get()
...
dev->kobj.parent = kobj;
...
kobject_add() //failed, but set dev->kobj.parent = NULL
...
glue_dir = get_glue_dir(dev) //glue_dir = NULL, and goto
//"Error" label
...
cleanup_glue_dir() //becaues glue_dir is NULL, not call
//kobject_put()

The preceding problem may cause insmod mac80211_hwsim.ko to failed.
sysfs: cannot create duplicate filename '/devices/virtual/mac80211_hwsim'
Call Trace:
<TASK>
dump_stack_lvl+0x8e/0xd1
sysfs_warn_dup.cold+0x1c/0x29
sysfs_create_dir_ns+0x224/0x280
kobject_add_internal+0x2aa/0x880
kobject_add+0x135/0x1a0
get_device_parent+0x3d7/0x590
device_add+0x2aa/0x1cb0
device_create_groups_vargs+0x1eb/0x260
device_create+0xdc/0x110
mac80211_hwsim_new_radio+0x31e/0x4790 [mac80211_hwsim]
init_mac80211_hwsim+0x48d/0x1000 [mac80211_hwsim]
do_one_initcall+0x10f/0x630
do_init_module+0x19f/0x5e0
load_module+0x64b7/0x6eb0
__do_sys_finit_module+0x140/0x200
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
kobject_add_internal failed for mac80211_hwsim with -EEXIST, don't try to
register things with the same name in the same directory.

Fixes: cebf8fd16900 ("driver core: fix race between creating/querying glue dir and its cleanup")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20221123012042.335252-1-shaozhengchao@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: bus: move bus notifier logic into bus.c

The logic to touch the bus notifier was open-coded in numberous places
in the driver core. Clean that up by creating a local bus_notify()
function and have everyone call this function instead, making the
reading of the caller code simpler and easier to maintain over time.

Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230111092331.3946745-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fix potential null-ptr-deref in device_add()

I got the following null-ptr-deref report while doing fault injection test:

BUG: kernel NULL pointer dereference, address: 0000000000000058
CPU: 2 PID: 278 Comm: 37-i2c-ds2482 Tainted: G B W N 6.1.0-rc3+
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
<TASK>
klist_remove+0xf1/0x1c0
device_release_driver_internal+0x196/0x210
bus_remove_device+0x1bd/0x240
device_add+0xd3d/0x1100
w1_add_master_device+0x476/0x490 [wire]
ds2482_probe+0x303/0x3e0 [ds2482]

This is how it happened:

w1_alloc_dev()
// The dev->driver is set to w1_master_driver.
memcpy(&dev->dev, device, sizeof(struct device));
device_add()
bus_add_device()
dpm_sysfs_add() // It fails, calls bus_remove_device.

// error path
bus_remove_device()
// The dev->driver is not null, but driver is not bound.
__device_release_driver()
klist_remove(&dev->p->knode_driver) <-- It causes null-ptr-deref.

// normal path
bus_probe_device() // It's not called yet.
device_bind_driver()

If dev->driver is set, in the error path after calling bus_add_device()
in device_add(), bus_remove_device() is called, then the device will be
detached from driver. But device_bind_driver() is not called yet, so it
causes null-ptr-deref while access the 'knode_driver'. To fix this, set
dev->driver to null in the error path before calling bus_remove_device().

Fixes: 57eee3d23e88 ("Driver core: Call device_pm_add() after bus_add_device() in device_add()")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221205034904.2077765-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base: Remove CONFIG_SRCU

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in conditional compilation based on CONFIG_SRCU.
Therefore, remove the #ifdef and throw away the #else clause.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>

kobject: kset_uevent_ops: make name() callback take a const *

The name() callback in struct kset_uevent_ops does not modify the
kobject passed into it, so make the pointer const to enforce this
restriction. When doing so, fix up the single existing name() callback
to have the correct signature to preserve the build.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20221121094649.1556002-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kobject: kset_uevent_ops: make filter() callback take a const *

The filter() callback in struct kset_uevent_ops does not modify the
kobject passed into it, so make the pointer const to enforce this
restriction. When doing so, fix up all existing filter() callbacks to
have the correct signature to preserve the build.

Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Christian König <christian.koenig@amd.com> for the changes to
Link: https://lore.kernel.org/r/20221121094649.1556002-3-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kobject: make kobject_get_ownership() take a constant kobject *

The call, kobject_get_ownership(), does not modify the kobject passed
into it, so make it const. This propagates down into the kobj_type
function callbacks so make the kobject passed into them also const,
ensuring that nothing in the kobject is being changed here.

This helps make it more obvious what calls and callbacks do, and do not,
modify structures passed to them.

Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: linux-nfs@vger.kernel.org
Cc: bridge@lists.linux-foundation.org
Cc: netdev@vger.kernel.org
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20221121094649.1556002-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Use kstrtobool() instead of strtobool()

strtobool() is the same as kstrtobool().
However, the latter is more used within the kernel.

In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.

While at it, include the corresponding header file (<linux/kstrtox.h>)

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/02ba683a5c0716638ad8ca11e8b0fdca97c4f294.1667336095.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: remove devm_device_remove_group()

There is no in-kernel user of this function, so it is not needed anymore
and can be removed.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20221109140711.105222-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: remove devm_device_remove_groups()

There is no in-kernel user of this function, so it is not needed anymore
and can be removed.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20221109140711.105222-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: class: make namespace and get_ownership take const *

The callbacks in struct class namespace() and get_ownership() do not
modify the struct device passed to them, so mark the pointer as constant
and fix up all callbacks in the kernel to have the correct function
signature.

This helps make it more obvious what calls and callbacks do, and do not,
modify structures passed to them.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20221001165426.2690912-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: use IS_ERR_OR_NULL() helper in device_create_groups_vargs()

Use IS_ERR_OR_NULL() helper in device_create_groups_vargs() to simplify code
and improve readiblity. No functional change.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220914140753.3799982-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: base: Print error code on synthetic uevent failure

If we're going to log the failure, we might as well log the return code
too.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Link: https://lore.kernel.org/r/20220824165213.1.Ifdb98af3d0c23708a11d8d5ae5697bdb7e96a3cc@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Set fw_devlink.strict=1 by default"

This reverts commit 71066545b48e4259f89481199a0bbc7c35457738.

It causes boot problems on some systems, so revert it for now until it
is worked out.

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Saravana Kannan <saravanak@google.com>
Fixes: 71066545b48e ("driver core: Set fw_devlink.strict=1 by default")
Reported-by: Olof Johansson <olof@lixom.net>
Link: https://lore.kernel.org/r/CAOesGMjQHhTUMBGHQcME4JBkZCof2NEQ4gaM1GWFgH40+LN9AQ@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Allow firmware to mark devices as best effort

When firmware sets the FWNODE_FLAG_BEST_EFFORT flag for a fwnode,
fw_devlink will do a best effort ordering for that device where it'll
only enforce the probe/suspend/resume ordering of that device with
suppliers that have drivers. The driver of that device can then decide
if it wants to defer probe or probe without the suppliers.

This will be useful for avoid probe delays of the console device that
were caused by commit 71066545b48e ("driver core: Set
fw_devlink.strict=1 by default").

Fixes: 71066545b48e ("driver core: Set fw_devlink.strict=1 by default")
Reported-by: Sascha Hauer <sha@pengutronix.de>
Reported-by: Peng Fan <peng.fan@nxp.com>
Tested-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20220623080344.783549-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Introduce device_find_any_child() helper

There are several places in the kernel where this kind of functionality is
being used. Provide a generic helper for such cases.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220610120219.18988-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Set fw_devlink.strict=1 by default

Now that deferred_probe_timeout is non-zero by default, fw_devlink will
never permanently block the probing of devices. It'll try its best to
probe the devices in the right order and then finally let devices probe
even if their suppliers don't have any drivers.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20220601070707.3946847-8-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add wait_for_init_devices_probe helper function

Some devices might need to be probed and bound successfully before the
kernel boot sequence can finish and move on to init/userspace. For
example, a network interface might need to be bound to be able to mount
a NFS rootfs.

With fw_devlink=on by default, some of these devices might be blocked
from probing because they are waiting on a optional supplier that
doesn't have a driver. While fw_devlink will eventually identify such
devices and unblock the probing automatically, it might be too late by
the time it unblocks the probing of devices. For example, the IP4
autoconfig might timeout before fw_devlink unblocks probing of the
network interface.

This function is available to temporarily try and probe all devices that
have a driver even if some of their suppliers haven't been added or
don't have drivers.

The drivers can then decide which of the suppliers are optional vs
mandatory and probe the device if possible. By the time this function
returns, all such "best effort" probes are guaranteed to be completed.
If a device successfully probes in this mode, we delete all fw_devlink
discovered dependencies of that device where the supplier hasn't yet
probed successfully because they have to be optional dependencies.

This also means that some devices that aren't needed for init and could
have waited for their optional supplier to probe (when the supplier's
module is loaded later on) would end up probing prematurely with limited
functionality. So call this function only when boot would fail without
it.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20220601070707.3946847-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: runtime: Fix supplier device management during consumer probe

Because pm_runtime_get_suppliers() bumps up the rpm_active counter
of each device link to a supplier of the given device in addition
to bumping up the supplier's PM-runtime usage counter, a runtime
suspend of the consumer device may case the latter to go down to 0
when pm_runtime_put_suppliers() is running on a remote CPU. If that
happens after pm_runtime_put_suppliers() has released power.lock for
the consumer device, and a runtime resume of that device takes place
immediately after it, before pm_runtime_put() is called for the
supplier, that pm_runtime_put() call may cause the supplier to be
suspended even though the consumer is active.

To prevent that from happening, modify pm_runtime_get_suppliers() to
call pm_runtime_get_sync() for the given device's suppliers without
touching the rpm_active counters of the involved device links
Accordingly, modify pm_runtime_put_suppliers() to call pm_runtime_put()
for the given device's suppliers without looking at the rpm_active
counters of the device links at hand. [This is analogous to what
happened before commit 4c06c4e6cf63 ("driver core: Fix possible
supplier PM-usage counter imbalance").]

Since pm_runtime_get_suppliers() sets supplier_preactivated for each
device link where the supplier's PM-runtime usage counter has been
incremented and pm_runtime_put_suppliers() calls pm_runtime_put() for
the suppliers whose device links have supplier_preactivated set, the
PM-runtime usage counter is balanced for each supplier and this is
independent of the runtime suspend and resume of the consumer device.

However, in case a device link with DL_FLAG_PM_RUNTIME set is dropped
during the consumer device probe, so pm_runtime_get_suppliers() bumps
up the supplier's PM-runtime usage counter, but it cannot be dropped by
pm_runtime_put_suppliers(), make device_link_release_fn() take care of
that.

Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance")
Reported-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+

PM: runtime: Redefine pm_runtime_release_supplier()

Instead of passing an extra bool argument to pm_runtime_release_supplier(),
make its callers take care of triggering a runtime-suspend of the
supplier device as needed.

No expected functional impact.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+

driver core: Add sysfs support for physical location of a device

When ACPI table includes _PLD fields for a device, create a new
directory (physical_location) in sysfs to share _PLD fields.

Currently without PLD information, when there are multiple of same
devices, it is hard to distinguish which device corresponds to which
physical device at which location. For example, when there are two Type
C connectors, it is hard to find out which connector corresponds to the
Type C port on the left panel versus the Type C port on the right panel.
With PLD information provided, we can determine which specific device at
which location is doing what.

_PLD output includes much more fields, but only generic fields are added
and exposed to sysfs, so that non-ACPI devices can also support it in
the future. The minimal generic fields needed for locating a device are
the following.
- panel
- vertical_position
- horizontal_position
- dock
- lid

Signed-off-by: Won Chung <wonchung@google.com>
Link: https://lore.kernel.org/r/20220314195458.271430-1-wonchung@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

device-core: Kill the lockdep_mutex

Per Peter [1], the lockdep API has native support for all the use cases
lockdep_mutex was attempting to enable. Now that all lockdep_mutex users
have been converted to those APIs, drop this lock.

Link: https://lore.kernel.org/r/Ylf0dewci8myLvoW@hirez.programming.kicks-ass.net [1]
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/165055522548.3745911.14298368286915484086.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

block: remove genhd.h

There is no good reason to keep genhd.h separate from the main blkdev.h
header that includes it. So fold the contents of genhd.h into blkdev.h
and remove genhd.h entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

genirq/msi: Move descriptor list to struct msi_device_data

It's only required when MSI is in use.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211206210747.650487479@linutronix.de

PCI/MSI: Move msi_lock to struct pci_dev

It's only required for PCI/MSI. So no point in having it in every struct
device.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210224.925241961@linutronix.de

headers/uninline: Uninline single-use function: kobject_has_children()

This was the only usage of <linux/kref_api.h> in <linux/kobject_api.h>,
so we'll able to decouple the two after this change.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kobject: remove kset from struct kset_uevent_ops callbacks

There is no need to pass the pointer to the kset in the struct
kset_uevent_ops callbacks as no one uses it, so just remove that pointer
entirely.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Wedson Almeida Filho <wedsonaf@google.com>
Link: https://lore.kernel.org/r/20211227163924.3970661-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: make kobj_type constant.

This way instances of kobj_type (which contain function pointers) can be
stored in .rodata, which means that they cannot be [easily/accidentally]
modified at runtime.

Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Link: https://lore.kernel.org/r/20211224231345.777370-1-wedsonaf@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: runtime: Add safety net to supplier device release

Because refcount_dec_not_one() returns true if the target refcount
becomes saturated, it is generally unsafe to use its return value as
a loop termination condition, but that is what happens when a device
link's supplier device is released during runtime PM suspend
operations and on device link removal.

To address this, introduce pm_runtime_release_supplier() to be used
in the above cases which will check the supplier device's runtime
PM usage counter in addition to the refcount_dec_not_one() return
value, so the loop can be terminated in case the rpm_active refcount
value becomes invalid, and update the code in question to use it as
appropriate.

This change is not expected to have any visible functional impact.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

driver core: Don't call device_remove_properties() from device_del()

All the drivers that relied on device_del() to call
device_remove_properties() have now been converted to either
use device_create_managed_software_node() instead of
device_add_properties(), or to register the software node
completely separately from the device.

This will make it finally possible to share and reuse the
software nodes that hold the additional device properties.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

driver core: Provide device_match_acpi_handle() helper

We have a couple of users of this helper, make it available for them.

The prototype for the helper is specifically crafted in order to be
easily used with bus_find_device() call. That's why its location is
in the driver core rather than ACPI.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211014134756.39092-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: use NUMA_NO_NODE during device_initialize

Don't use (-1) constant for setting initial device node. Instead, use
the generic NUMA_NO_NODE definition to indicate that "no node id
specified".

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Link: https://lore.kernel.org/r/20211004133453.18881-1-mgurtovoy@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix possible memory leak in device_link_add()

I got memory leak as follows:

unreferenced object 0xffff88801f0b2200 (size 64):
comm "i2c-lis2hh12-21", pid 5455, jiffies 4294944606 (age 15.224s)
hex dump (first 32 bytes):
72 65 67 75 6c 61 74 6f 72 3a 72 65 67 75 6c 61 regulator:regula
74 6f 72 2e 30 2d 2d 69 32 63 3a 31 2d 30 30 31 tor.0--i2c:1-001
backtrace:
[<00000000bf5b0c3b>] __kmalloc_track_caller+0x19f/0x3a0
[<0000000050da42d9>] kvasprintf+0xb5/0x150
[<000000004bbbed13>] kvasprintf_const+0x60/0x190
[<00000000cdac7480>] kobject_set_name_vargs+0x56/0x150
[<00000000bf83f8e8>] dev_set_name+0xc0/0x100
[<00000000cc1cf7e3>] device_link_add+0x6b4/0x17c0
[<000000009db9faed>] _regulator_get+0x297/0x680
[<00000000845e7f2b>] _devm_regulator_get+0x5b/0xe0
[<000000003958ee25>] st_sensors_power_enable+0x71/0x1b0 [st_sensors]
[<000000005f450f52>] st_accel_i2c_probe+0xd9/0x150 [st_accel_i2c]
[<00000000b5f2ab33>] i2c_device_probe+0x4d8/0xbe0
[<0000000070fb977b>] really_probe+0x299/0xc30
[<0000000088e226ce>] __driver_probe_device+0x357/0x500
[<00000000c21dda32>] driver_probe_device+0x4e/0x140
[<000000004e650441>] __device_attach_driver+0x257/0x340
[<00000000cf1891b8>] bus_for_each_drv+0x166/0x1e0

When device_register() returns an error, the name allocated in dev_set_name()
will be leaked, the put_device() should be used instead of kfree() to give up
the device reference, then the name will be freed in kobject_cleanup() and the
references of consumer and supplier will be decreased in device_link_release_fn().

Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20210930085714.2057460-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Clarify that dev_err_probe() is OK even w/out -EPROBE_DEFER

There is some debate about whether it's deemed acceptable to call
dev_err_probe() if you know that the error code can never be
-EPROBE_DEFER. Clarify in the function comments that this is
OK. Specifically this makes us able to transform code like this:

ret = do_something_that_cant_defer();
if (ret < 0) {
dev_err(dev, "The foo failed to bar (%pe)\n", ERR_PTR(ret));
return ret;
}

to code like this:
ret = do_something_that_cant_defer();
if (ret < 0)
return dev_err_probe(dev, ret, "The foo failed to bar\n");

It is also possible that in the future folks might want a CONFIG
option to strip out all probe error strings to save space (keeping
non-probe errors) with the argument that probe errors rarely happen
after bringup. Having probe errors reported with a consistent function
would allow that.

Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20210916161931.1.I32bea713bd6c6fb419a24da73686145742b6c117@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Reject pointless SYNC_STATE_ONLY device links

SYNC_STATE_ONLY device links intentionally allow cycles because cyclic
sync_state() dependencies are valid and necessary.

However a SYNC_STATE_ONLY device link where the consumer and the supplier
are the same device is pointless because the device link would be deleted
as soon as the device probes (because it's also the consumer) and won't
affect when the sync_state() callback is called. It's a waste of CPU cycles
and memory to create this device link. So reject any attempts to create
such a device link.

Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Cc: stable <stable@vger.kernel.org>
Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210929190549.860541-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add debug logs when fwnode links are added/deleted

This will help with debugging fw_devlink issues.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210915172808.620546-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Create __fwnode_link_del() helper function

The same code is repeated in multiple locations. Create a helper
function for it.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210915172808.620546-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Set deferred probe reason when deferred by driver core

When the driver core defers the probe of a device, set the deferred
probe reason so that it's easier to debug. The deferred probe reason is
available in debugfs under devices_deferred.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210915172808.620546-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Add support for FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD

If a parent device is also a supplier to a child device, fw_devlink=on by
design delays the probe() of the child device until the probe() of the
parent finishes successfully.

However, some drivers of such parent devices (where parent is also a
supplier) expect the child device to finish probing successfully as soon as
they are added using device_add() and before the probe() of the parent
device has completed successfully. One example of such a case is discussed
in the link mentioned below.

Add a flag to make fw_devlink=on not enforce these supplier-consumer
relationships, so these drivers can continue working.

Link: https://lore.kernel.org/netdev/CAGETcx_uj0V4DChME-gy5HGKTYnxLBX=TH2rag29f_p=UcG+Tg@mail.gmail.com/
Fixes: ea718c699055 ("Revert "Revert "driver core: Set fw_devlink=on by default""")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210915170940.617415-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Improve handling of cyclic dependencies

When we have a dependency of the form:

Device-A -> Device-C
Device-B

Device-C -> Device-B

Where,
* Indentation denotes "child of" parent in previous line.
* X -> Y denotes X is consumer of Y based on firmware (Eg: DT).

We have cyclic dependency: device-A -> device-C -> device-B -> device-A

fw_devlink current treats device-C -> device-B dependency as an invalid
dependency and doesn't enforce it but leaves the rest of the
dependencies as is.

While the current behavior is necessary, it is not sufficient if the
false dependency in this example is actually device-A -> device-C. When
this is the case, device-C will correctly probe defer waiting for
device-B to be added, but device-A will be incorrectly probe deferred by
fw_devlink waiting on device-C to probe successfully. Due to this, none
of the devices in the cycle will end up probing.

To fix this, we need to go relax all the dependencies in the cycle like
we already do in the other instances where fw_devlink detects cycles.
A real world example of this was reported[1] and analyzed[2].

[1] - https://lore.kernel.org/lkml/0a2c4106-7f48-2bb5-048e-8c001a7c3fda@samsung.com/
[2] - https://lore.kernel.org/lkml/CAGETcx8peaew90SWiux=TyvuGgvTQOmO4BFALz7aj0Za5QdNFQ@mail.gmail.com/

Fixes: f9aa460672c9 ("driver core: Refactor fw_devlink feature")
Cc: stable <stable@vger.kernel.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210915170940.617415-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

swiotlb: Convert io_default_tlb_mem to static allocation

Since commit 69031f500865 ("swiotlb: Set dev->dma_io_tlb_mem to the
swiotlb pool used"), 'struct device' may hold a copy of the global
'io_default_tlb_mem' pointer if the device is using swiotlb for DMA. A
subsequent call to swiotlb_exit() will therefore leave dangling pointers
behind in these device structures, resulting in KASAN splats such as:

| BUG: KASAN: use-after-free in __iommu_dma_unmap_swiotlb+0x64/0xb0
| Read of size 8 at addr ffff8881d7830000 by task swapper/0/0
|
| CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc3-debug #1
| Hardware name: HP HP Desktop M01-F1xxx/87D6, BIOS F.12 12/17/2020
| Call Trace:
| <IRQ>
| dump_stack+0x9c/0xcf
| print_address_description.constprop.0+0x18/0x130
| kasan_report.cold+0x7f/0x111
| __iommu_dma_unmap_swiotlb+0x64/0xb0
| nvme_pci_complete_rq+0x73/0x130
| blk_complete_reqs+0x6f/0x80
| __do_softirq+0xfc/0x3be

Convert 'io_default_tlb_mem' to a static structure, so that the
per-device pointers remain valid after swiotlb_exit() has been invoked.
All users are updated to reference the static structure directly, using
the 'nslabs' field to determine whether swiotlb has been initialised.
The 'slots' array is still allocated dynamically and referenced via a
pointer rather than a flexible array member.

Cc: Claire Chang <tientzu@chromium.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Fixes: 69031f500865 ("swiotlb: Set dev->dma_io_tlb_mem to the swiotlb pool used")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Claire Chang <tientzu@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>

swiotlb: Set dev->dma_io_tlb_mem to the swiotlb pool used

Always have the pointer to the swiotlb pool used in struct device. This
could help simplify the code for other pools.

Signed-off-by: Claire Chang <tientzu@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Stefano Stabellini <sstabellini@kernel.org>
Tested-by: Will Deacon <will@kernel.org>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

scsi: ufshcd: Fix device links when BOOT WLUN fails to probe

Managed device links are deleted by device_del(). However it is possible to
add a device link to a consumer before device_add(), and then discovering
an error prevents the device from being used. In that case normally
references to the device would be dropped and the device would be deleted.
However the device link holds a reference to the device, so the device link
and device remain indefinitely (unless the supplier is deleted).

For UFSHCD, if a LUN fails to probe (e.g. absent BOOT WLUN), the device
will not have been registered but can still have a device link holding a
reference to the device. The unwanted device link will prevent runtime
suspend indefinitely.

Amend device link removal to accept removal of a link with an unregistered
consumer device (suggested by Rafael), and fix UFSHCD by explicitly
deleting the device link when SCSI destroys the SCSI device.

Link: https://lore.kernel.org/r/a1c9bac8-b560-b662-f0aa-58c7e000cbbd@intel.com
Fixes: b294ff3e3449 ("scsi: ufs: core: Enable power management for wlun")
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

printk: index: Add indexing support to dev_printk

While for most kinds of issues we have counters, tracepoints, or metrics
with a stable interface which can reliably be used to indicate issues,
in order to react to production issues quickly we sometimes need to work
with the interface which most kernel developers naturally use when
developing: printk, and printk-esques like dev_printk.

dev_printk is by far the most likely custom subsystem printk to benefit
from the printk indexing infrastructure, since niche device issues
brought about by production changes, firmware upgrades, and the like are
one of the most common things that we need printk infrastructure's
assistance to monitor.

Often these errors were never expected to practically manifest in
reality, and exhibit in code without extensive (or any) metrics present.
As such, there are typically very few options for issue detection
available to those with large fleets at the time the incident happens,
and we thus benefit strongly from monitoring netconsole in these
instances.

As such, add the infrastructure for dev_printk to be indexed in the
printk index. Even on a minimal kernel config, the coverage of the base
kernel's printk index is significantly improved:

Before:

[root@ktst ~]# wc -l /sys/kernel/debug/printk/index/vmlinux
4497 /sys/kernel/debug/printk/index/vmlinux

After:

[root@ktst ~]# wc -l /sys/kernel/debug/printk/index/vmlinux
5573 /sys/kernel/debug/printk/index/vmlinux

In terms of implementation, in order to trivially disambiguate them,
dev_printk is now a macro which wraps _dev_printk.

Signed-off-by: Chris Down <chris@chrisdown.name>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/959c7aed1017cb2c9de922e0a820d397e29c6a5a.1623775748.git.chris@chrisdown.name

driver core: Split device_platform_notify()

Split device_platform_notify_remove) out of device_platform_notify()
and call the latter on device addition and the former on device
removal.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

software nodes: Split software_node_notify()

Split software_node_notify_remove) out of software_node_notify()
and make device_platform_notify() call the latter on device addition
and the former on device removal.

While at it, put the headers of the above functions into base.h,
because they don't need to be present in a global header file.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

ACPI: glue: Eliminate acpi_platform_notify()

Get rid of acpi_platform_notify() which is redundant and
make device_platform_notify() in the driver core call
acpi_device_notify() and acpi_device_notify_remove() directly.

No functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

PCI/MSI: Protect msi_desc::masked for multi-MSI

Multi-MSI uses a single MSI descriptor and there is a single mask register
when the device supports per vector masking. To avoid reading back the mask
register the value is cached in the MSI descriptor and updates are done by
clearing and setting bits in the cache and writing it to the device.

But nothing protects msi_desc::masked and the mask register from being
modified concurrently on two different CPUs for two different Linux
interrupts which belong to the same multi-MSI descriptor.

Add a lock to struct device and protect any operation on the mask and the
mask register with it.

This makes the update of msi_desc::masked unconditional, but there is no
place which requires a modification of the hardware register without
updating the masked cache.

msi_mask_irq() is now an empty wrapper which will be cleaned up in follow
up changes.

The problem goes way back to the initial support of multi-MSI, but picking
the commit which introduced the mask cache is a valid cut off point
(2.6.30).

Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.726833414@linutronix.de

driver core: Prevent warning when removing a device link from unregistered consumer

sysfs_remove_link() causes a warning if the parent directory does not
exist. That can happen if the device link consumer has not been registered.
So do not attempt sysfs_remove_link() in that case.

Fixes: 287905e68dd29 ("driver core: Expose device link details in sysfs")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # 5.9+
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20210716114408.17320-2-adrian.hunter@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Move the "removable" attribute from USB to core

Move the "removable" attribute from USB to core in order to allow it to be
supported by other subsystem / buses. Individual buses that want to support
this attribute can populate the removable property of the device while
enumerating it with the 3 possible values -
- "unknown"
- "fixed"
- "removable"
Leaving the field unchanged (i.e. "not supported") would mean that the
attribute would not show up in sysfs for that device. The UAPI (location,
symantics etc) for the attribute remains unchanged.

Move the "removable" attribute from USB to the device core so it can be
used by other subsystems / buses.

By default, devices do not have a "removable" attribute in sysfs.

If a subsystem or bus driver wants to support a "removable" attribute, it
should call device_set_removable() before calling device_register() or
device_add(), e.g.:

device_set_removable(dev, DEVICE_REMOVABLE);
device_register(dev);

The possible values and the resulting sysfs attribute contents are:

DEVICE_REMOVABLE_UNKNOWN -> "unknown"
DEVICE_REMOVABLE -> "removable"
DEVICE_FIXED -> "fixed"

Convert the USB "removable" attribute to use this new device core
functionality. There should be no user-visible change in the location or
semantics of attribute for USB devices.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rajat Jain <rajatja@google.com>
Link: https://lore.kernel.org/r/20210524171812.18095-1-rajatja@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: replace open-coded device_lock_assert()

Using the right wrapper makes it easier to associate this assert
statement with the device_[un]lock() helpers.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Link: https://lore.kernel.org/r/20210512141054.2180373-1-jwi@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: add a helper to setup both the of_node and fwnode of a device

There are many places where both the fwnode_handle and the of_node of a
device need to be populated. Add a function which does both so that we
have consistency.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers: base: Reduce device link removal code duplication

Reduce device link removal code duplication between the cases when
SRCU is enabled and when it is disabled by moving the only differing
piece of it (which is the removal of the link from the consumer and
supplier lists) into a separate wrapper function (defined differently
for each of the cases in question).

No intentional functional impact.

Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/4326215.LvFx2qVVIh@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: base: Fix device link removal

When device_link_free() drops references to the supplier and
consumer devices of the device link going away and the reference
being dropped turns out to be the last one for any of those
device objects, its ->release callback will be invoked and it
may sleep which goes against the SRCU callback execution
requirements.

To address this issue, make the device link removal code carry out
the device_link_free() actions preceded by SRCU synchronization from
a separate work item (the "long" workqueue is used for that, because
it does not matter when the device link memory is released and it may
take time to get to that point) instead of using SRCU callbacks.

While at it, make the code work analogously when SRCU is not enabled
to reduce the differences between the SRCU and non-SRCU cases.

Fixes: 843e600b8a2b ("driver core: Fix sleeping in invalid context during device link deletion")
Cc: stable <stable@vger.kernel.org>
Reported-by: chenxiang (M) <chenxiang66@hisilicon.com>
Tested-by: chenxiang (M) <chenxiang66@hisilicon.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/5722787.lOV4Wx5bFT@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: typec: tcpm: Don't block probing of consumers of "connector" nodes

fw_devlink expects DT device nodes with "compatible" property to have
struct devices created for them. Since the connector node might not be
populated as a device, mark it as such so that fw_devlink knows not to
wait on this fwnode being populated as a struct device.

Without this patch, USB functionality can be broken on some boards.

Fixes: f7514a663016 ("of: property: fw_devlink: Add support for remote-endpoint")
Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210506004423.345199-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Improve fw_devlink & deferred_probe_timeout interaction

deferred_probe_timeout kernel commandline parameter allows probing of
consumer devices if the supplier devices don't have any drivers.

fw_devlink=on will indefintely block probe() calls on a device if all
its suppliers haven't probed successfully. This completely skips calls
to driver_deferred_probe_check_state() since that's only called when a
.probe() function calls framework APIs. So fw_devlink=on breaks
deferred_probe_timeout.

deferred_probe_timeout in its current state also ignores a lot of
information that's now available to the kernel. It assumes all suppliers
that haven't probed when the timer expires (or when initcalls are done
on a static kernel) will never probe and fails any calls to acquire
resources from these unprobed suppliers.

However, this assumption by deferred_probe_timeout isn't true under many
conditions. For example:
- If the consumer happens to be before the supplier in the deferred
probe list.
- If the supplier itself is waiting on its supplier to probe.

This patch fixes both these issues by relaxing device links between
devices only if the supplier doesn't have any driver that could match
with (NOT bound to) the supplier device. This way, we only fail attempts
to acquire resources from suppliers that truly don't have any driver vs
suppliers that just happen to not have probed yet.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210402040342.2944858-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: remove kernel-doc warnings

remove make W=1 warning:

drivers/base/core.c:1670: warning: Function parameter or member
'flags' not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1670: warning: Function parameter or member 'con'
not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1670: warning: Function parameter or member
'sup_handle' not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1670: warning: Function parameter or member
'flags' not described in 'fw_devlink_create_devlink'

drivers/base/core.c:1763: warning: Function parameter or member 'dev'
not described in '__fw_devlink_link_to_consumers'

drivers/base/core.c:1844: warning: Function parameter or member 'dev'
not described in '__fw_devlink_link_to_suppliers'

drivers/base/core.c:1844: warning: Function parameter or member
'fwnode' not described in '__fw_devlink_link_to_suppliers'

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210331232614.304591-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "Revert "driver core: Set fw_devlink=on by default""

This reverts commit 3e4c982f1ce75faf5314477b8da296d2d00919df.

Since all reported issues due to fw_devlink=on should be addressed by
this series, revert the revert. fw_devlink=on Take II.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210302211133.2244281-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Update device link status properly for device_bind_driver()

Device link status was not getting updated correctly when
device_bind_driver() is called on a device. This causes a warning[1].
Fix this by updating device links that can be updated and dropping
device links that can't be updated to a sensible state.

[1] - https://lore.kernel.org/lkml/56f7d032-ba5a-a8c7-23de-2969d98c527e@nvidia.com/

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210302211133.2244281-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Set fw_devlink=on by default"

This reverts commit e590474768f1cc04852190b61dec692411b22e2a.

While things are _almost_ there and working for almost all systems,
there are still reported regressions happening, so let's revert this
default for 5.12. We can bring it back in linux-next after 5.12-rc1 is
out to get more testing and hopefully solve the remaining different
subsystem and driver issues that people are running into.

Cc: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210219074549.1506936-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Handle suppliers that don't use driver core

Device links only work between devices that use the driver core to match
and bind a driver to a device. So, add an API for frameworks to let the
driver core know that a fwnode has been initialized by a driver without
using the driver core.

Then use this information to make sure that fw_devlink doesn't make the
consumers wait indefinitely on suppliers that'll never bind to a driver.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210205222644.2357303-6-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add fw_devlink.strict kernel param

This param allows forcing all dependencies to be treated as mandatory.
This will be useful for boards in which all optional dependencies like
IOMMUs and DMAs need to be treated as mandatory dependencies.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210205222644.2357303-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Detect supplier devices that will never be added

During the initial parsing of firmware by fw_devlink, fw_devlink might
infer that some supplier firmware nodes would get populated as devices.
But the inference is not always correct. This patch tries to logically
detect and fix such mistakes as boot progresses or more devices probe.

fw_devlink makes a fundamental assumption that once a device binds to a
driver, it will populate (i.e: add as struct devices) all the child
firmware nodes that could be populated as devices (if they aren't
populated already).

So, whenever a device probes, we check all its child firmware nodes. If
a child firmware node has a corresponding device populated, we don't
modify the child node or its descendants. However, if a child firmware
node has not been populated as a device, we delete all the fwnode links
where the child node or its descendants are suppliers. This ensures that
no other device is blocked on a firmware node that will never be
populated as a device. We also mark such fwnodes as NOT_DEVICE, so that
no new fwnode links are created with these nodes as suppliers.

Fixes: e590474768f1 ("driver core: Set fw_devlink=on by default")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210205222644.2357303-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "drivers: core: Detach device from power domain on shutdown"

This reverts commit 0fab972eef49ef8d30eb91d6bd98861122d083d1 as it is
reported by users to cause problems.

Reported-by: Dmitry Osipenko <digetx@gmail.com>
Fixes: 0fab972eef49 ("drivers: core: Detach device from power domain on shutdown")
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Furquan Shaikh <furquan@google.com>
Link: https://lore.kernel.org/r/CAJZ5v0jhniqG43F6hCqXdxQiQZRc67GdkdP0BXcRut=P7k7BVQ@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: core: Detach device from power domain on shutdown

When the system is powered off or rebooted, devices are not detached
from their PM domain. This results in ACPI PM not being invoked and
hence PowerResouce _OFF method not being invoked for any of the
devices. Because the ACPI power resources are not turned off in case
of poweroff and reboot, it violates the power sequencing requirements
which impacts the reliability of the devices over the lifetime of the
platform. This is currently observed on all Chromebooks using ACPI.

In order to solve the above problem, this change detaches a device
from its PM domain whenever it is shutdown. This action is basically
analogous to ->remove() from driver model perspective. Detaching the
device from its PM domain ensures that the ACPI PM gets a chance to
turn off the power resources for the device thus complying with its
power sequencing requirements.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Furquan Shaikh <furquan@google.com>
Link: https://lore.kernel.org/r/20201201213019.1558738-1-furquan@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Set fw_devlink=on by default

Cyclic dependencies in some firmware was one of the last remaining
reasons fw_devlink=on couldn't be set by default. Now that cyclic
dependencies don't block probing, set fw_devlink=on by default.

Setting fw_devlink=on by default brings a bunch of benefits (currently,
only for systems with device tree firmware):
* Significantly cuts down deferred probes.
* Device probe is effectively attempted in graph order.
* Makes it much easier to load drivers as modules without having to
worry about functional dependencies between modules (depmod is still
needed for symbol dependencies).

If this patch prevents some devices from probing, it's very likely due
to the system having one or more device drivers that "probe"/set up a
device (DT node with compatible property) without creating a struct
device for it. If we hit such cases, the device drivers need to be
fixed so that they populate struct devices and probe them like normal
device drivers so that the driver core is aware of the devices and their
status. See [1] for an example of such a case.

[1] - https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201218031703.3053753-6-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink_relax_cycle() can be static

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20201218063934.GA66003@e60698be8304
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Handle cycles in device links created by fw_devlink

Sometimes, firmware can have cyclic dependencies between devices. But
one or more of those dependencies in the cycle are false dependencies
that don't affect the probing of the device.

fw_devlink can detect some of these false dependencies using logic. But
when it can't, we don't want to block probing of the devices in this
cyclic dependency.

So, instead of using normal device links for the devices in this cycle,
we need to switch to SYNC_STATE_ONLY device links between these devices.
This is so that sync_state() callback correctness is still maintained
while we allow these device to probe.

This is functionally similar to switching to fw_devlink=permissive just
for the devices in the cycle.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201218031703.3053753-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Have fw_devlink use DL_FLAG_INFERRED

This will be useful in identifying device links created only due to
fw_devlink when we need to break cyclic dependencies due to fw_devlink.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201218031703.3053753-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add device link support for INFERRED flag

This flag can never be added to a device link that already exists and
doesn't have the flag set. It can only be added when a device link is
created for the first time or it can be maintained if the device link
already has the it set.

This flag will be used for marking device links created ONLY by
inferring dependencies from data and NOT from explicit action by device
drivers/frameworks. This will be useful in the future when we need to
deal with cycles in dependencies inferred from firmware.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201218031703.3053753-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add debug logs for device link related probe deferrals

There's insufficient logging when device links or fw_devlink (waiting to
create device links) cause probe deferrals. This makes it hard to debug
devices not getting probed. So, add debug logs to make it easy to debug.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201218031703.3053753-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: lift dma_default_coherent into common code

Lift the dma_default_coherent variable from the mips architecture code
to the driver core. This allows an architecture to sdefault all device
to be DMA coherent at run time, even if the kernel is build with support
for DMA noncoherent device. By allowing device_initialize to set the
->dma_coherent field to this default the amount of arch hooks required
for this behavior can be greatly reduced.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

driver core: Fix device link device name collision

The device link device's name was of the form:
<supplier-dev-name>--<consumer-dev-name>

This can cause name collision as reported here [1] as device names are
not globally unique. Since device names have to be unique within the
bus/class, add the bus/class name as a prefix to the device names used to
construct the device link device name.

So the devuce link device's name will be of the form:
<supplier-bus-name>:<supplier-dev-name>--<consumer-bus-name>:<consumer-dev-name>

[1] - https://lore.kernel.org/lkml/20201229033440.32142-1-michael@walle.cc/

Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
Cc: stable@vger.kernel.org
Reported-by: Michael Walle <michael@walle.cc>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210110175408.1465657-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Extend device_is_dependent()

If the device passed as the target (second argument) to
device_is_dependent() is not completely registered (that is, it has
been initialized, but not added yet), but the parent pointer of it
is set, it may be missing from the list of the parent's children
and device_for_each_child() called by device_is_dependent() cannot
be relied on to catch that dependency.

For this reason, modify device_is_dependent() to check the ancestors
of the target device by following its parent pointer in addition to
the device_for_each_child() walk.

Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support")
Reported-by: Stephan Gerhold <stephan@gerhold.net>
Tested-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/17705994.d592GUb2YH@kreacher
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

device property: add description of fwnode cases

There are only four valid fwnode cases which are
- primary --> secondary --> -ENODEV
- primary --> NULL
- secondary --> -ENODEV
- NULL

dev->fwnode should be converted between the 4 cases above no matter
how/when set_primary_fwnode() and set_secondary_fwnode() are called.
Describe it in the code so people will keep it in mind.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
[ rjw: Comment edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "device property: Keep secondary firmware node secondary by type"

While commit d5dcce0c414f ("device property: Keep secondary firmware
node secondary by type") describes everything correct in its commit
message, the change it made does the opposite and original commit
c15e1bdda436 ("device property: Fix the secondary firmware node handling
in set_primary_fwnode()") was fully correct.

Revert the former one here and improve documentation in the next patch.

Fixes: d5dcce0c414f ("device property: Keep secondary firmware node secondary by type")
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

driver core: Fix a couple of typos

These were just some minor typos that have crept in recently and are
easily fixed.

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20201127104630.1839171-1-thierry.reding@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Delete pointless parameter in fwnode_operations.add_links

The struct device input to add_links() is not used for anything. So
delete it.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-18-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Refactor fw_devlink feature

The current implementation of fw_devlink is very inefficient because it
tries to get away without creating fwnode links in the name of saving
memory usage. Past attempts to optimize runtime at the cost of memory
usage were blocked with request for data showing that the optimization
made significant improvement for real world scenarios.

We have those scenarios now. There have been several reports of boot
time increase in the order of seconds in this thread [1]. Several OEMs
and SoC manufacturers have also privately reported significant
(350-400ms) increase in boot time due to all the parsing done by
fw_devlink.

So this patch uses all the setup done by the previous patches in this
series to refactor fw_devlink to be more efficient. Most of the code has
been moved out of firmware specific (DT mostly) code into driver core.

This brings the following benefits:
- Instead of parsing the device tree multiple times during bootup,
fw_devlink parses each fwnode node/property only once and creates
fwnode links. The rest of the fw_devlink code then just looks at these
fwnode links to do rest of the work.

- Makes it much easier to debug probe issue due to fw_devlink in the
future. fw_devlink=on blocks the probing of devices if they depend on
a device that hasn't been added yet. With this refactor, it'll be very
easy to tell what that device is because we now have a reference to
the fwnode of the device.

- Much easier to add fw_devlink support to ACPI and other firmware
types. A refactor to move the common bits from DT specific code to
driver core was in my TODO list as a prerequisite to adding ACPI
support to fw_devlink. This series gets that done.

[1] - https://lore.kernel.org/linux-omap/ea02f57e-871d-cd16-4418-c1da4bbc4696@ti.com/

Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-17-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Use device's fwnode to check if it is waiting for suppliers

To check if a device is still waiting for its supplier devices to be
added, we used to check if the devices is in a global
waiting_for_suppliers list. Since the global list will be deleted in
subsequent patches, this patch stops using this check.

Instead, this patch uses a more device specific check. It checks if the
device's fwnode has any fwnode links that haven't been converted to
device links yet.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-14-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add fw_devlink_parse_fwtree()

This function is a wrapper around fwnode_operations.add_links().

This function parses each node in a fwnode tree and create fwnode links
for each of those nodes. The information for creating the fwnode links
(the supplier and consumer fwnode) is obtained by parsing the properties
in each of the fwnodes.

This function also ensures that no fwnode is parsed more than once by
marking the fwnodes as parsed.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-13-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Allow only unprobed consumers for SYNC_STATE_ONLY device links

SYNC_STATE_ONLY device links only affect the behavior of sync_state()
callbacks. Specifically, they prevent sync_state() only callbacks from
being called on a device if one or more of its consumers haven't probed.

So, creating a SYNC_STATE_ONLY device link from an already probed
consumer is useless. So, don't allow creating such device links.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-10-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add fwnode link support

Add support for creating supplier-consumer links between fwnodes. It is
intended for internal use the driver core and generic firmware support
code (eg. Device Tree, ACPI), so it is simple by design and the API
provided is limited.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-9-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: fw_devlink: Add support for batching fwnode parsing"

This reverts commit 716a7a25969003d82ab738179c3f1068a120ed11.

The fw_devlink_pause/resume() APIs added by the commit being reverted
were a first cut attempt at optimizing boot time. But these APIs don't
fully solve the problem and are very fragile (can only be used for the
top level devices being added). This series replaces them with a much
better optimization that works for all device additions and also has the
benefit of reducing the complexity of the firmware (DT, EFI) specific
code and abstracting out common code to driver core.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-7-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Don't do deferred probe in parallel with kernel_init thread"

This reverts commit cec72f3efc6272420c2c2c699607f03d09b93e41.

Commit cec72f3efc62 ("driver core: Don't do deferred probe in parallel
with kernel_init thread") was fixing a commit 716a7a259690 ("driver
core: fw_devlink: Add support for batching fwnode parsing"). Since the
commit being fixed itself is going to be reverted, the fix can also be
reverted.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Rename dev_links_info.defer_sync to defer_hook"

This reverts commit ec7bd78498f29680f536451fbdf9464e851273ed.

This field rename was done to reuse defer_syc list head for multiple
lists. That's not needed anymore and this list head will only be used
for defer sync. So revert this patch to avoid conflicts with the other
reverts coming after this.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Avoid deferred probe due to fw_devlink_pause/resume()"

This reverts commit 2451e746478a6a6e981cfa66b62b791ca93b90c8.

fw_devlink_pause/resume() was an incomplete attempt at boot time
optimization. That's going to get replaced by a much better optimization
at the end of the series. Since fw_devlink_pause/resume() is going away,
changes made for that can also go away.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver: core: Fix list corruption after device_del()

The device_links_purge() function (called from device_del()) tries to
remove the links.needs_suppliers list entry, but it's using
list_del(), hence it doesn't initialize after the removal. This is OK
for normal cases where device_del() is called via device_destroy().
However, it's not guaranteed that the device object will be really
deleted soon after device_del(). In a minor case like HD-audio codec
reconfiguration that re-initializes the device after device_del(), it
may lead to a crash by the corrupted list entry.

As a simple fix, replace list_del() with list_del_init() in order to
make the list intact after the device_del() call.

Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
Cc: <stable@vger.kernel.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20201208190326.27531-1-tiwai@suse.de
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix lockdep warning on wfs_lock

There's a potential deadlock with the following cycle:
wfs_lock --> device_links_lock --> kn->count

Fix this by simply dropping the lock around a list_empty() check that's
just exported to a sysfs file. The sysfs file output is an instantaneous
check anyway and the lock doesn't really add any protection.

Lockdep log:

[ 48.808132]
[ 48.808132] the existing dependency chain (in reverse order) is:
[ 48.809069]
[ 48.809069] -> #2 (kn->count){++++}:
[ 48.809707] __kernfs_remove.llvm.7860393000964815146+0x2d4/0x460
[ 48.810537] kernfs_remove_by_name_ns+0x54/0x9c
[ 48.811171] sysfs_remove_file_ns+0x18/0x24
[ 48.811762] device_del+0x2b8/0x5a8
[ 48.812269] __device_link_del+0x98/0xb8
[ 48.812829] device_links_driver_bound+0x210/0x2d8
[ 48.813496] driver_bound+0x44/0xf8
[ 48.814000] really_probe+0x340/0x6e0
[ 48.814526] driver_probe_device+0xb8/0x100
[ 48.815117] device_driver_attach+0x78/0xb8
[ 48.815708] __driver_attach+0xe0/0x194
[ 48.816255] bus_for_each_dev+0xa8/0x11c
[ 48.816816] driver_attach+0x24/0x30
[ 48.817331] bus_add_driver+0x100/0x1e0
[ 48.817880] driver_register+0x78/0x114
[ 48.818427] __platform_driver_register+0x44/0x50
[ 48.819089] 0xffffffdbb3227038
[ 48.819551] do_one_initcall+0xd8/0x1e0
[ 48.820099] do_init_module+0xd8/0x298
[ 48.820636] load_module+0x3afc/0x44c8
[ 48.821173] __arm64_sys_finit_module+0xbc/0xf0
[ 48.821807] el0_svc_common+0xbc/0x1d0
[ 48.822344] el0_svc_handler+0x74/0x98
[ 48.822882] el0_svc+0x8/0xc
[ 48.823310]
[ 48.823310] -> #1 (device_links_lock){+.+.}:
[ 48.824036] __mutex_lock_common+0xe0/0xe44
[ 48.824626] mutex_lock_nested+0x28/0x34
[ 48.825185] device_link_add+0xd4/0x4ec
[ 48.825734] of_link_to_suppliers+0x158/0x204
[ 48.826347] of_fwnode_add_links+0x50/0x64
[ 48.826928] device_link_add_missing_supplier_links+0x90/0x11c
[ 48.827725] fw_devlink_resume+0x58/0x130
[ 48.828296] of_platform_default_populate_init+0xb4/0xd0
[ 48.829030] do_one_initcall+0xd8/0x1e0
[ 48.829578] do_initcall_level+0xb8/0xcc
[ 48.830137] do_basic_setup+0x60/0x7c
[ 48.830662] kernel_init_freeable+0x128/0x1ac
[ 48.831275] kernel_init+0x18/0x29c
[ 48.831781] ret_from_fork+0x10/0x18
[ 48.832297]
[ 48.832297] -> #0 (wfs_lock){+.+.}:
[ 48.832922] __lock_acquire+0xe04/0x2e20
[ 48.833480] lock_acquire+0xbc/0xec
[ 48.833984] __mutex_lock_common+0xe0/0xe44
[ 48.834577] mutex_lock_nested+0x28/0x34
[ 48.835136] waiting_for_supplier_show+0x3c/0x98
[ 48.835781] dev_attr_show+0x48/0xb4
[ 48.836295] sysfs_kf_seq_show+0xe8/0x184
[ 48.836864] kernfs_seq_show+0x48/0x8c
[ 48.837401] seq_read+0x1c8/0x600
[ 48.837884] kernfs_fop_read+0x68/0x204
[ 48.838431] __vfs_read+0x60/0x214
[ 48.838925] vfs_read+0xbc/0x15c
[ 48.839397] ksys_read+0x78/0xe4
[ 48.839869] __arm64_sys_read+0x1c/0x28
[ 48.840416] el0_svc_common+0xbc/0x1d0
[ 48.840953] el0_svc_handler+0x74/0x98
[ 48.841490] el0_svc+0x8/0xc
[ 48.841917]
[ 48.841917] other info that might help us debug this:
[ 48.841917]
[ 48.842920] Chain exists of:
[ 48.842920] wfs_lock --> device_links_lock --> kn->count
[ 48.842920]
[ 48.844152] Possible unsafe locking scenario:
[ 48.844152]
[ 48.844895] CPU0 CPU1
[ 48.845463] ---- ----
[ 48.846032] lock(kn->count);
[ 48.846417] lock(device_links_lock);
[ 48.847203] lock(kn->count);
[ 48.847902] lock(wfs_lock);
[ 48.848276]
[ 48.848276] *** DEADLOCK ***

Reported-by: Cheng-Jui.Wang@mediatek.com
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201104205431.3795207-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: runtime: Drop runtime PM references to supplier on link removal

While removing a device link, drop the supplier device's runtime PM
usage counter as many times as needed to drop all of the runtime PM
references to it from the consumer in addition to dropping the
consumer's link count.

Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

device property: Don't clear secondary pointer for shared primary firmware node

It appears that firmware nodes can be shared between devices. In such case
when a (child) device is about to be deleted, its firmware node may be shared
and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link
of the shared primary firmware node.

In order to prevent that, check, if the device has a parent and parent's
firmware node is shared with its child, and avoid crashing the link.

Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
Reported-by: Ferry Toth <fntoth@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

device property: Keep secondary firmware node secondary by type

Behind primary and secondary we understand the type of the nodes
which might define their ordering. However, if primary node gone,
we can't maintain the ordering by definition of the linked list.
Thus, by ordering secondary node becomes first in the list.
But in this case the meaning of it is still secondary (or auxiliary).
The type of the node is maintained by the secondary pointer in it:

secondary pointer Meaning
NULL or valid primary node
ERR_PTR(-ENODEV) secondary node

So, if by some reason we do the following sequence of calls

set_primary_fwnode(dev, NULL);
set_primary_fwnode(dev, primary);

we should preserve secondary node.

This concept is supported by the description of set_primary_fwnode()
along with implementation of set_secondary_fwnode(). Hence, fix
the commit c15e1bdda436 to follow this as well.

Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
Cc: Ferry Toth <fntoth@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers: core: fix kernel-doc markup for dev_err_probe()

There are two literal blocks there. Fix the markups, in order
to produce the right html output and solve those warnings:

./drivers/base/core.c:4218: WARNING: Unexpected indentation.
./drivers/base/core.c:4222: WARNING: Definition list ends without a blank line; unexpected unindent.
./drivers/base/core.c:4223: WARNING: Block quote ends without a blank line; unexpected unindent.

Fixes: a787e5400a1c ("driver core: add device probe log helper")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/base: make device_find_child_by_name() compatible with sysfs inputs

Use sysfs_streq() in device_find_child_by_name() to allow it to use a
sysfs input string that might contain a trailing newline.

The other "device by name" interfaces,
{bus,driver,class}_find_device_by_name(), already account for sysfs
strings.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: David Hildenbrand <david@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hulk Robot <hulkci@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Yan <yanaijie@huawei.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Jia He <justin.he@arm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/159643102106.4062302.12229802117645312104.stgit@dwillia2-desk3.amr.corp.intel.com
Link: https://lkml.kernel.org/r/160106114576.30709.2960091665444712180.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers core: Miscellaneous changes for sysfs_emit

Change additional instances that could use sysfs_emit and sysfs_emit_at
that the coccinelle script could not convert.

o macros creating show functions with ## concatenation
o unbound sprintf uses with buf+len for start of output to sysfs_emit_at
o returns with ?: tests and sprintf to sysfs_emit
o sysfs output with struct class * not struct device * arguments

Miscellanea:

o remove unnecessary initializations around these changes
o consistently use int len for return length of show functions
o use octal permissions and not S_<FOO>
o rename a few show function names so DEVICE_ATTR_<FOO> can be used
o use DEVICE_ATTR_ADMIN_RO where appropriate
o consistently use const char *output for strings
o checkpatch/style neatening

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/8bc24444fe2049a9b2de6127389b57edfdfe324d.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers core: Remove strcat uses around sysfs_emit and neaten

strcat is no longer necessary for sysfs_emit and sysfs_emit_at uses.

Convert the strcat uses to sysfs_emit calls and neaten other block
uses of direct returns to use an intermediate const char *.

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/5d606519698ce4c8f1203a2b35797d8254c6050a.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers core: Use sysfs_emit and sysfs_emit_at for show(device *...) functions

Convert the various sprintf fmaily calls in sysfs device show functions
to sysfs_emit and sysfs_emit_at for PAGE_SIZE buffer safety.

Done with:

$ spatch -sp-file sysfs_emit_dev.cocci --in-place --max-width=80 .

And cocci script:

$ cat sysfs_emit_dev.cocci
@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- sprintf(buf,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- snprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- scnprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier d_show;
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- strcpy(buf, chr);
+ sysfs_emit(buf, chr);
...>
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
len =
- sprintf(buf,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
len =
- snprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
len =
- scnprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
- len += scnprintf(buf + len, PAGE_SIZE - len,
+ len += sysfs_emit_at(buf, len,
...);
...>
return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
...
- strcpy(buf, chr);
- return strlen(buf);
+ return sysfs_emit(buf, chr);
}

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/3d033c33056d88bbe34d4ddb62afd05ee166ab9a.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

printk: move dictionary keys to dev_printk_info

Dictionaries are only used for SUBSYSTEM and DEVICE properties. The
current implementation stores the property names each time they are
used. This requires more space than otherwise necessary. Also,
because the dictionary entries are currently considered optional,
it cannot be relied upon that they are always available, even if the
writer wanted to store them. These issues will increase should new
dictionary properties be introduced.

Rather than storing the subsystem and device properties in the
dict ring, introduce a struct dev_printk_info with separate fields
to store only the property values. Embed this struct within the
struct printk_info to provide guaranteed availability.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/87mu1jl6ne.fsf@jogness.linutronix.de

dma-mapping: introduce DMA range map, supplanting dma_pfn_offset

The new field 'dma_range_map' in struct device is used to facilitate the
use of single or multiple offsets between mapping regions of cpu addrs and
dma addrs. It subsumes the role of "dev->dma_pfn_offset" which was only
capable of holding a single uniform offset and had no region bounds
checking.

The function of_dma_get_range() has been modified so that it takes a single
argument -- the device node -- and returns a map, NULL, or an error code.
The map is an array that holds the information regarding the DMA regions.
Each range entry contains the address offset, the cpu_start address, the
dma_start address, and the size of the region.

of_dma_configure() is the typical manner to set range offsets but there are
a number of ad hoc assignments to "dev->dma_pfn_offset" in the kernel
driver code. These cases now invoke the function
dma_direct_set_offset(dev, cpu_addr, dma_addr, size).

Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
[hch: various interface cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>

driver core: force NOIO allocations during unplug

There is one overlooked situation under which a driver must not do IO to
allocate memory. You cannot do that while disconnecting a device. A
device being disconnected is no longer functional in most cases, yet IO
may fail only when the handler runs.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20200916191544.5104-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix device_pm_lock() locking for device links

This commit fixes two issues:

1. The lockdep warning reported by Dong Aisheng <dongas86@gmail.com> [1].

It is a warning about a cycle (dpm_list_mtx --> kn->active#3 --> fw_lock)
that was introduced when device-link devices were added to expose device
link information in sysfs.

The patch that "introduced" this cycle can't be reverted because it's fixes
a real SRCU issue and also ensures that the device-link device is deleted
as soon as the device-link is deleted. This is important to avoid sysfs
name collisions if the device-link is create again immediately (this can
happen a lot with deferred probing).

2. Inconsistency in grabbing device_pm_lock() during device link deletion

Some device link deletion code paths grab device_pm_lock(), while others
don't. The device_pm_lock() is grabbed during device_link_add() because it
checks if the supplier is in the dpm_list and also reorders the dpm_list.
However, when a device link is deleted, it does not do either of those and
therefore device_pm_lock() is not necessary. Dropping the device_pm_lock()
in all the device link deletion paths removes the inconsistency in locking.

Thanks to Stephen Boyd for helping me understand the lockdep splat.

Fixes: 843e600b8a2b ("driver core: Fix sleeping in invalid context during device link deletion")
[1] - https://lore.kernel.org/lkml/CAA+hA=S4eAreb7vo69LAXSk2t5=DEKNxHaiY1wSpk4xTp9urLg@mail.gmail.com/
Reported-by: Dong Aisheng <dongas86@gmail.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20200901184445.1736658-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver code: print symbolic error code

dev_err_probe() prepends the message with an error code. Let's make it
more readable by translating the code to a more recognisable symbol.

Fixes: a787e5400a1c ("driver core: add device probe log helper")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/ea3f973e4708919573026fdce52c264db147626d.1598630856.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

device property: Fix the secondary firmware node handling in set_primary_fwnode()

When the primary firmware node pointer is removed from a
device (set to NULL) the secondary firmware node pointer,
when it exists, is made the primary node for the device.
However, the secondary firmware node pointer of the original
primary firmware node is never cleared (set to NULL).

To avoid situation where the secondary firmware node pointer
is pointing to a non-existing object, clearing it properly
when the primary node is removed from a device in
set_primary_fwnode().

Fixes: 97badf873ab6 ("device property: Make it possible to use secondary firmware nodes")
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

driver core: add deferring probe reason to devices_deferred property

/sys/kernel/debug/devices_deferred property contains list of deferred devices.
This list does not contain reason why the driver deferred probe, the patch
improves it.
The natural place to set the reason is dev_err_probe function introduced
recently, ie. if dev_err_probe will be called with -EPROBE_DEFER instead of
printk the message will be attached to a deferred device and printed when user
reads devices_deferred property.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20200713144324.23654-3-a.hajda@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: add device probe log helper

During probe every time driver gets resource it should usually check for
error printk some message if it is not -EPROBE_DEFER and return the error.
This pattern is simple but requires adding few lines after any resource
acquisition code, as a result it is often omitted or implemented only
partially.
dev_err_probe helps to replace such code sequences with simple call,
so code:
if (err != -EPROBE_DEFER)
dev_err(dev, ...);
return err;
becomes:
return dev_err_probe(dev, err, ...);

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200713144324.23654-2-a.hajda@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Change delimiter in devlink device's name to "--"

The devlink device name is of the form "supplier:consumer". But ":" is
fairly common in device names and makes it visually hard to distinguish
supplier and consumer. So, replace it with "--" to make it easier.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200724180523.1393383-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix sleeping in invalid context during device link deletion

Marek and Guenter reported that commit 287905e68dd2 ("driver core:
Expose device link details in sysfs") caused sleeping/scheduling while
atomic warnings.

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1
2 locks held by kworker/0:1/12:
#0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
#1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc
Preemption disabled at:
[<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154
----- 8< ----- SNIP
[<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64)
[<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154)
[<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc)
[<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c)
[<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0)
[<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20)
Exception stack(0xee921fb0 to 0xee921ff8)

This was caused by the device link device being released in the context
of srcu_invoke_callbacks(). There is no need to wait till the RCU
callback to release the device link device. So release the device
earlier and move the call_srcu() into the device release code. That way,
the memory will get freed only after the device is released AND the RCU
callback is called.

Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200716214523.2924704-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add waiting_for_supplier sysfs file for devices

This would be useful to check if a device is not probing because it's
waiting for a supplier to be added and then linked to before it can
probe.

To reduce sysfs clutter, this file is added only if it can ever be 1.
So, if fw_devlink is disabled or set to permissive, this file is not
added. Also, this file is removed once the device probes as it's no
longer relevant.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200521191800.136035-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Expose device link details in sysfs

It's helpful to be able to look at device link details from sysfs. So,
expose it in sysfs.

Say device-A is supplier of device-B. These are the additional files
this patch would create:

/sys/class/devlink/device-A:device-B/
auto_remove_on
consumer/ -> .../device-B/
runtime_pm
status
supplier/ -> .../device-A/
sync_state_only

/sys/devices/.../device-A/
consumer:device-B/ -> /sys/class/devlink/device-A:device-B/

/sys/devices/.../device-B/
supplier:device-A/ -> /sys/class/devlink/device-A:device-B/

That way:
To get a list of all the device link in the system:
ls /sys/class/devlink/

To get the consumer names and links of a device:
ls -d /sys/devices/.../device-X/consumer:*

To get the supplier names and links of a device:
ls -d /sys/devices/.../device-X/supplier:*

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200521191800.136035-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Avoid deferred probe due to fw_devlink_pause/resume()

With the earlier patch in this series, all devices that deferred probe
due to fw_devlink_pause() will have their probes delayed till the
deferred probe thread is kicked off during late_initcall. This will also
affect all their consumers.

This delayed probing in unnecessary. So this patch just keeps track of
the devices that had their probe deferred due to fw_devlink_pause() and
attempts to probe them once during fw_devlink_resume().

Fixes: 716a7a259690 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Rename dev_links_info.defer_sync to defer_hook

The defer_sync field is used as a hook to add the device to the
deferred_sync list. Rename it so that it's more meaningful for the next
patch that'll also use this field as a hook to a deferred_fw_devlink
list.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Don't do deferred probe in parallel with kernel_init thread

The current deferred probe implementation can mess up suspend/resume
ordering if deferred probe thread is kicked off in parallel with the
main initcall thread (kernel_init thread) [1].

For example:

Say device-B is a consumer of device-A.

Initcall thread Deferred probe thread
=============== =====================
1. device-A is added.
2. device-B is added.
3. dpm_list is now [device-A, device-B].
4. driver-A defers probe of device-A.
5. device-A is moved to
end of dpm_list
6. dpm_list is now
[device-B, device-A]
7. driver-B is registereed and probes device-B.
8. dpm_list stays as [device-B, device-A].

The reverse order of dpm_list is used for suspend. So in this case
device-A would incorrectly get suspended before device-B.

Commit 716a7a259690 ("driver core: fw_devlink: Add support for batching
fwnode parsing") kicked off the deferred probe thread early during boot
to run in parallel with the initcall thread and caused suspend/resume
regressions. This patch removes the parallel run of the deferred probe
thread to avoid the suspend/resume regressions.

[1] - https://lore.kernel.org/lkml/CAGETcx8W96KAw-d_siTX4qHB_-7ddk0miYRDQeHE6E0_8qx-6Q@mail.gmail.com/

Fixes: 716a7a259690 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add device_is_dependent() to linux/device.h

DT implementation of fw_devlink needs this function to detect cycles. So
make it available.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>

driver core: Update device link status correctly for SYNC_STATE_ONLY links

When SYNC_STATE_ONLY support was added in commit 05ef983e0d65 ("driver
core: Add device link support for SYNC_STATE_ONLY flag"),
SYNC_STATE_ONLY links were treated similar to STATELESS links in terms
of not blocking consumer probe if the supplier hasn't probed yet.

That caused a SYNC_STATE_ONLY device link's status to not get updated.
Since SYNC_STATE_ONLY device link is no longer useful once the
consumer probes, commit 21c27f06587d ("driver core: Fix
SYNC_STATE_ONLY device link implementation") addresses the status
update issue by deleting the SYNC_STATE_ONLY device link instead of
complicating the status update code.

However, there are still some cases where we need to update the status
of a SYNC_STATE_ONLY device link. This is because a SYNC_STATE_ONLY
device link can later get converted into a normal MANAGED device link
when a normal MANAGED device link is created between a supplier and
consumer that already have a SYNC_STATE_ONLY device link between them.

If a SYNC_STATE_ONLY device link's status isn't maintained correctly
till it's converted to a normal MANAGED device link, then the normal
MANAGED device link will end up with a wrong link status. This can cause
a warning stack trace[1] when the consumer device probes successfully.

This commit fixes the SYNC_STATE_ONLY device link status update issue
where it wouldn't transition correctly from DL_STATE_DORMANT or
DL_STATE_AVAILABLE to DL_STATE_CONSUMER_PROBE. It also resets the status
back to DL_STATE_DORMANT or DL_STATE_AVAILABLE if the consumer probe
fails.

[1] - https://lore.kernel.org/lkml/20200522204120.3b3c9ed6@apollo/
Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Fixes: 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation")
Reported-by: Michael Walle <michael@walle.cc>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rafael J. Wysocki <rrafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200526220928.49939-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Remove unnecessary is_fwnode_dev variable in device_add()

That variable is no longer necessary. Remove it and also fix a minor
typo in comments.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200520034824.79049-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix handling of SYNC_STATE_ONLY + STATELESS device links

Commit 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link
implementation") didn't completely fix STATELESS + SYNC_STATE_ONLY
handling.

What looks like an optimization in that commit is actually a bug that
causes an if condition to always take the else path. This prevents
reordering of devices in the dpm_list when a DL_FLAG_STATELESS device
link is create on top of an existing DL_FLAG_SYNC_STATE_ONLY device
link.

Fixes: 21c27f06587d ("driver core: Fix SYNC_STATE_ONLY device link implementation")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200520043626.181820-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix SYNC_STATE_ONLY device link implementation

When SYNC_STATE_ONLY support was added in commit 05ef983e0d65 ("driver
core: Add device link support for SYNC_STATE_ONLY flag"),
device_link_add() incorrectly skipped adding the new SYNC_STATE_ONLY
device link to the supplier's and consumer's "device link" list.

This causes multiple issues:
- The device link is lost forever from driver core if the caller
didn't keep track of it (caller typically isn't expected to). This is
a memory leak.
- The device link is also never visible to any other code path after
device_link_add() returns.

If we fix the "device link" list handling, that exposes a bunch of
issues.

1. The device link "status" state management code rightfully doesn't
handle the case where a DL_FLAG_MANAGED device link exists between a
supplier and consumer, but the consumer manages to probe successfully
before the supplier. The addition of DL_FLAG_SYNC_STATE_ONLY links break
this assumption. This causes device_links_driver_bound() to throw a
warning when this happens.

Since DL_FLAG_SYNC_STATE_ONLY device links are mainly used for creating
proxy device links for child device dependencies and aren't useful once
the consumer device probes successfully, this patch just deletes
DL_FLAG_SYNC_STATE_ONLY device links once its consumer device probes.
This way, we avoid the warning, free up some memory and avoid
complicating the device links "status" state management code.

2. Creating a DL_FLAG_STATELESS device link between two devices that
already have a DL_FLAG_SYNC_STATE_ONLY device link will result in the
DL_FLAG_STATELESS flag not getting set correctly. This patch also fixes
this.

Lastly, this patch also fixes minor whitespace issues.

Cc: stable@vger.kernel.org
Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200519063000.128819-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink: Add support for batching fwnode parsing

The amount of time spent parsing fwnodes of devices can become really
high if the devices are added in an non-ideal order. Worst case can be
O(N^2) when N devices are added. But this can be optimized to O(N) by
adding all the devices and then parsing all their fwnodes in one batch.

This commit adds fw_devlink_pause() and fw_devlink_resume() to allow
doing this.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200515053500.215929-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Look for waiting consumers only for a fwnode's primary device

Commit 4dbe191c046e ("driver core: Add device links from fwnode only for
the primary device") skipped linking a fwnode's secondary device to
the suppliers listed in its fwnode.

However, a fwnode's secondary device can't be found using
get_dev_from_fwnode(). So, there's no point in trying to see if devices
waiting for suppliers might want to link to a fwnode's secondary device.

This commit removes that unnecessary step for devices that aren't a
fwnode's primary device and also moves the code to a more appropriate
part of the file.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200515053500.215929-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Move code to the right part of the file

This commit just moves around code to match the general organization of
the file.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200515053500.215929-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: remove device_create_vargs

All external users of device_create_vargs are gone, so remove it and
open code it in the only caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Revert "Revert "driver core: Set fw_devlink to "permissive" behavior by default""

This reverts commit 18555cb6db2373b9a5ec1f7572773fd58c77f9ba.

The reason[1] for the original revert has now been fixed by
commit 00b247557858 ("driver core: Fix handling of
fw_devlink=permissive"). So, this patch reverts the revert. Marek has
also tested this patch with the fix mentioned above and confirmed that
the issue has been fixed.

[1] - https://lore.kernel.org/lkml/CAGETcx8nbz-J1gLvoEKE_HgCcVGyV2o8rZeq_USFKM6=s7WmNg@mail.gmail.com/T/#m12dfb5dfd23805b84c49f4bb2238a8cce436c2f7
[2] - https://lore.kernel.org/lkml/CAGETcx8nbz-J1gLvoEKE_HgCcVGyV2o8rZeq_USFKM6=s7WmNg@mail.gmail.com/T/#m2408a6ce098b2ebf583ca8534329695923ae57fe
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200428192006.109006-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix handling of fw_devlink=permissive

When commit 8375e74f2bca ("driver core: Add fw_devlink kernel
commandline option") added fw_devlink, it didn't implement "permissive"
mode correctly.

That commit got the device links flags correct to make sure unprobed
suppliers don't block the probing of a consumer. However, if a consumer
is waiting for mandatory suppliers to register, that could still block a
consumer from probing.

This commit fixes that by making sure in permissive mode, all suppliers
to a consumer are treated as a optional suppliers. So, even if a
consumer is waiting for suppliers to register and link itself (using the
DL_FLAG_SYNC_STATE_ONLY flag) to the supplier, the consumer is never
blocked from probing.

Fixes: 8375e74f2bca ("driver core: Add fw_devlink kernel commandline option")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200331022832.209618-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

docs: filesystems: fix renamed references

Some filesystem references got broken by a previous patch
series I submitted. Address those.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> # fs/affs/Kconfig
Link: https://lore.kernel.org/r/57318c53008dbda7f6f4a5a9e5787f4d37e8565a.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

device property: export set_secondary_fwnode() to modules

Some drivers when compiled as modules may need to set secondary firmware node.
Export set_secondary_fwnode() to make it possible without code duplication.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

Revert "driver core: Set fw_devlink to "permissive" behavior by default"

This reverts commit c442a0d18744d4a5857d513f171d68ed6a54df5b as it
breaks some of the Raspberry Pi devices. Marek writes:
This patch has just landed in linux-next 20200326. Sadly it
breaks booting of the Raspberry Pi3b and Pi4 boards, either in
32bit or 64bit mode. There is no warning nor panic message, just
a silent freeze. The last message shown on the earlycon is:

[    0.893217] Serial: 8250/16550 driver, 1 ports, IRQ sharing enabled

so revert it for now and let's try again and add it to linux-next after
5.7-rc1 is out so that we can try to get more debugging/testing
happening.

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Set fw_devlink to "permissive" behavior by default

Set fw_devlink to "permissive" behavior by default so that device links
are automatically created (with DL_FLAG_SYNC_STATE_ONLY) by scanning the
firmware.

This ensures suppliers get their sync_state() calls only after all their
consumers have probed successfully. Without this, suppliers will get
their sync_state() calls at late_initcall_sync() even if their consuer

Ideally, we'd want to set fw_devlink to "on" or "rpm" by default. But
that needs more testing as it's known to break some corner case
drivers/platforms.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200321210305.28937-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add device links from fwnode only for the primary device

Sometimes, more than one (generally two) device can point to the same
fwnode. However, only one device is set as the fwnode's device
(fwnode->dev) and can be looked up from the fwnode.

Typically, only one of these devices actually have a driver and actually
probe. If we create device links for all these devices, then the
suppliers' of these devices (with the same fwnode) will never get a
sync_state() call because one of their consumer devices will never probe
(because they don't have a driver).

So, create device links only for the device that is considered as the
fwnode's device.

One such example of this is the PCI bridge platform_device and the
corresponding pci_bus device. Both these devices will have the same
fwnode. It's the platform_device that is registered first and is set as
the fwnode's device. Also the platform_device is the one that actually
probes. Without this patch none of the suppliers of a PCI bridge
platform_device would get a sync_state() callback.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200321045448.15192-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: fw_devlink_flags can be static

Fixes: 8375e74f2bca ("driver core: Add fw_devlink kernel commandline option")
Signed-off-by: kbuild test robot <lkp@intel.com>
Acked-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200305020916.GA14234@3143ef58ba07
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add missing annotation for device_links_write_lock()

Sparse reports a warning at device_links_write_lock()

warning: context imbalance in evice_links_write_lock()
- wrong count at exit

The root cause is the missing annotation at device_links_write_lock()
Add the missing __acquires(&device_links_srcu) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Link: https://lore.kernel.org/r/20200214204741.94112-19-jbi.octave@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add missing annotation for device_links_read_lock()

Sparse reports a warning at device_links_read_unlock()

warning: warning: context imbalance in device_links_read_unlock()
- unexpected unlock

The root cause is the missing annotation at device_links_read_unlock()
Add the missing __releases(&device_links_srcu) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Link: https://lore.kernel.org/r/20200214204741.94112-20-jbi.octave@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add fw_devlink kernel commandline option

fwnode_operations.add_links allows creating device links from
information provided by firmware.

fwnode_operations.add_links is currently implemented only by
OF/devicetree code and a specific case of efi. However, there's nothing
preventing ACPI or other firmware types from implementing it.

The OF implementation is currently controlled by a kernel commandline
parameter called of_devlink.

Since this feature is generic isn't limited to OF, add a generic
fw_devlink kernel commandline parameter to control this feature across
firmware types.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200222014038.180923-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Reevaluate dev->links.need_for_probe as suppliers are added

A previous patch 03324507e66c ("driver core: Allow
fwnode_operations.add_links to differentiate errors") forgot to update
all call sites to fwnode_operations.add_links. This patch fixes that.

Legend:
-> Denotes RHS is an optional/potential supplier for LHS
=> Denotes RHS is a mandatory supplier for LHS

Example:

Device A => Device X
Device A -> Device Y

Before this patch:
1. Device A is added.
2. Device A is marked as waiting for mandatory suppliers
3. Device X is added
4. Device A is left marked as waiting for mandatory suppliers

Step 4 is wrong since all mandatory suppliers of Device A have been
added.

After this patch:
1. Device A is added.
2. Device A is marked as waiting for mandatory suppliers
3. Device X is added
4. Device A is no longer considered as waiting for mandatory suppliers

This is the correct behavior.

Fixes: 03324507e66c ("driver core: Allow fwnode_operations.add_links to differentiate errors")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200222014038.180923-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Skip unnecessary work when device doesn't have sync_state()

A bunch of busy work is done for devices that don't have sync_state()
support. Stop doing the busy work.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200221080510.197337-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Call sync_state() even if supplier has no consumers

The initial patch that added sync_state() support didn't handle the case
where a supplier has no consumers. This was because when a device is
successfully bound with a driver, only its suppliers were checked to see
if they are eligible to get a sync_state(). This is not sufficient for
devices that have no consumers but still need to do device state clean
up. So fix this.

Fixes: fc5a251d0fd7ca90 (driver core: Add sync_state driver/bus callback)
Signed-off-by: Saravana Kannan <saravanak@google.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200221080510.197337-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/power: add dpm_sysfs_change_owner()

Add a helper to change the owner of a device's power entries. This
needs to happen when the ownership of a device is changed, e.g. when
moving network devices between network namespaces.
This function will be used to correctly account for ownership changes,
e.g. when moving network devices between network namespaces.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

device: add device_change_owner()

Add a helper to change the owner of a device's sysfs entries. This
needs to happen when the ownership of a device is changed, e.g. when
moving network devices between network namespaces.
This function will be used to correctly account for ownership changes,
e.g. when moving network devices between network namespaces.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

driver core: Allow device link operations inside sync_state()

Some sync_state() implementations might need to call APIs that in turn
make calls to device link APIs. So, do the sync_state() callbacks
without holding the device link lock.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20191114225646.251277-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Allow fwnode_operations.add_links to differentiate errors

When add_links() still has suppliers that it needs to link to in the
future, this patch allows it to differentiate between suppliers that are
needed for probing vs suppliers that are needed for sync_state()
correctness.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Allow a device to wait on optional suppliers

Before this change, if a device is waiting on suppliers, it's assumed
that all those suppliers are needed for the device to probe
successfully. This change allows marking a devices as waiting only on
optional suppliers. This allows a device to wait on suppliers (and link
to them as soon as they are available) without preventing the device
from being probed.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add device link support for SYNC_STATE_ONLY flag

Parent devices might need to create "proxy" device links from themselves
to supplier devices to make sure the supplier devices don't get a
sync_state() before the child consumer devices get a chance to add
device links to the supplier devices.

However, the parent device has no real dependency on the supplier device
and probing, suspend/resume or runtime PM don't need to be affected by
the supplier device. To capture these cases, create a SYNC_STATE_ONLY
device link flag that only affects sync_state() behavior and doesn't
affect probing, suspend/resume or runtime PM.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

cpufreq: Avoid cpufreq_suspend() deadlock on system shutdown

It is incorrect to set the cpufreq syscore shutdown callback pointer
to cpufreq_suspend(), because that function cannot be run in the
syscore stage of system shutdown for two reasons: (a) it may attempt
to carry out actions depending on devices that have already been shut
down at that point and (b) the RCU synchronization carried out by it
may not be able to make progress then.

The latter issue has been present since commit 45975c7d21a1 ("rcu:
Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds"),
but the former one has been there since commit 90de2a4aa9f3 ("cpufreq:
suspend cpufreq governors on shutdown") regardless.

Fix that by dropping cpufreq_syscore_ops altogether and making
device_shutdown() call cpufreq_suspend() directly before shutting
down devices, which is along the lines of what system-wide power
management does.

Fixes: 45975c7d21a1 ("rcu: Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds")
Fixes: 90de2a4aa9f3 ("cpufreq: suspend cpufreq governors on shutdown")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+

driver core: Add sync_state driver/bus callback

This sync_state driver/bus callback is called once all the consumers
of a supplier have probed successfully.

This allows the supplier device's driver/bus to sync the supplier
device's state to the software state with the guarantee that all the
consumers are actively managing the resources provided by the supplier
device.

To maintain backwards compatibility and ease transition from existing
frameworks and resource cleanup schemes, late_initcall_sync is the
earliest when the sync_state callback might be called.

There is no upper bound on the time by which the sync_state callback
has to be called. This is because if a consumer device never probes,
the supplier has to maintain its resources in the state left by the
bootloader. For example, if the bootloader leaves the display
backlight at a fixed voltage and the backlight driver is never probed,
you don't want the backlight to ever be turned off after boot up.

Also, when multiple devices are added after kernel init, some
suppliers could be added before their consumer devices get added. In
these instances, the supplier devices could get their sync_state
callback called right after they probe because the consumers devices
haven't had a chance to create device links to the suppliers.

To handle this correctly, this change also provides APIs to
pause/resume sync state callbacks so that when multiple devices are
added, their sync_state callback evaluation can be postponed to happen
after all of them are added.

kbuild test robot reported missing documentation for device.state_synced
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add support for linking devices during device addition

The firmware corresponding to a device (dev.fwnode) might be able to
provide functional dependency information between a device and its
supplier and consumer devices. Tracking this functional dependency
allows optimizing device probe order and informing a supplier when all
its consumers have probed (and thereby actively managing their
resources).

The existing device links feature allows tracking and using
supplier-consumer relationships. So, this patch adds the add_links()
fwnode callback to allow firmware to create device links for each
device as the device is added.

However, when consumer devices are added, they might not have a supplier
device to link to despite needing mandatory resources/functionality from
one or more suppliers. A waiting_for_suppliers list is created to track
such consumers and retry linking them when new devices get added.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add fwnode_to_dev() to look up device from fwnode

It's often useful to look up a device that corresponds to a fwnode. So
add an API to do that irrespective of the bus on which the device has
been added to.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Add support for linking devices during device addition"

This reverts commit 5302dd7dd0b6d04c63cdce51d1e9fda9ef0be886.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged. It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Add edit_links() callback for drivers"

This reverts commit 134b23eec9e3a3c795a6ceb0efe2fa63e87983b2.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged. It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "driver core: Add sync_state driver/bus callback"

This reverts commit 8f8184d6bf676a8680d6f441e40317d166b46f73.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged. It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver/core: Convert to use built-in RCU list checking

This commit applies the consolidated hlist_for_each_entry_rcu() support
for lockdep conditions.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

driver core: Add sync_state driver/bus callback

This sync_state driver/bus callback is called once all the consumers
of a supplier have probed successfully.

This allows the supplier device's driver/bus to sync the supplier
device's state to the software state with the guarantee that all the
consumers are actively managing the resources provided by the supplier
device.

To maintain backwards compatibility and ease transition from existing
frameworks and resource cleanup schemes, late_initcall_sync is the
earliest when the sync_state callback might be called.

There is no upper bound on the time by which the sync_state callback
has to be called. This is because if a consumer device never probes,
the supplier has to maintain its resources in the state left by the
bootloader. For example, if the bootloader leaves the display
backlight at a fixed voltage and the backlight driver is never probed,
you don't want the backlight to ever be turned off after boot up.

Also, when multiple devices are added after kernel init, some
suppliers could be added before their consumer devices get added. In
these instances, the supplier devices could get their sync_state
callback called right after they probe because the consumers devices
haven't had a chance to create device links to the suppliers.

To handle this correctly, this change also provides APIs to
pause/resume sync state callbacks so that when multiple devices are
added, their sync_state callback evaluation can be postponed to happen
after all of them are added.

kbuild test robot reported missing documentation for device.state_synced
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add edit_links() callback for drivers

The driver core/bus adding supplier-consumer dependencies by default
enables functional dependencies to be tracked correctly even when the
consumer devices haven't had their drivers registered or loaded (if they
are modules).

However, when the bus incorrectly adds dependencies that it shouldn't
have added, the devices might never probe.

For example, if device-C is a consumer of device-S and they have
phandles to each other in DT, the following could happen:

1. Device-S get added first.
2. The bus add_links() callback will (incorrectly) try to link it as
a consumer of device-C.
3. Since device-C isn't present, device-S will be put in
"waiting-for-supplier" list.
4. Device-C gets added next.
5. All devices in "waiting-for-supplier" list are retried for linking.
6. Device-S gets linked as consumer to Device-C.
7. The bus add_links() callback will (correctly) try to link it as
a consumer of device-S.
8. This isn't allowed because it would create a cyclic device links.

Neither devices will get probed since the supplier is marked as
dependent on the consumer. And the consumer will never probe because the
consumer can't get resources from the supplier.

Without this patch, things stay in this broken state. However, with this
patch, the execution will continue like this:

9. Device-C's driver is loaded.
10. Device-C's driver removes Device-S as a consumer of Device-C.
11. Device-C's driver adds Device-C as a consumer of Device-S.
12. Device-S probes.
14. Device-C probes.

kbuild test robot reported missing documentation for device.has_edit_links
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add support for linking devices during device addition

When devices are added, the bus might want to create device links to track
functional dependencies between supplier and consumer devices. This
tracking of supplier-consumer relationship allows optimizing device probe
order and tracking whether all consumers of a supplier are active. The
add_links bus callback is added to support this.

However, when consumer devices are added, they might not have a supplier
device to link to despite needing mandatory resources/functionality from
one or more suppliers. A waiting_for_suppliers list is created to track
such consumers and retry linking them when new devices get added.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix use-after-free and double free on glue directory

There is a race condition between removing glue directory and adding a new
device under the glue dir. It can be reproduced in following test:

CPU1: CPU2:

device_add()
get_device_parent()
class_dir_create_and_add()
kobject_add_internal()
create_dir() // create glue_dir

device_add()
get_device_parent()
kobject_get() // get glue_dir

device_del()
cleanup_glue_dir()
kobject_del(glue_dir)

kobject_add()
kobject_add_internal()
create_dir() // in glue_dir
sysfs_create_dir_ns()
kernfs_create_dir_ns(sd)

sysfs_remove_dir() // glue_dir->sd=NULL
sysfs_put() // free glue_dir->sd

// sd is freed
kernfs_new_node(sd)
kernfs_get(glue_dir)
kernfs_add_one()
kernfs_put()

Before CPU1 remove last child device under glue dir, if CPU2 add a new
device under glue dir, the glue_dir kobject reference count will be
increase to 2 via kobject_get() in get_device_parent(). And CPU2 has
been called kernfs_create_dir_ns(), but not call kernfs_new_node().
Meanwhile, CPU1 call sysfs_remove_dir() and sysfs_put(). This result in
glue_dir->sd is freed and it's reference count will be 0. Then CPU2 call
kernfs_get(glue_dir) will trigger a warning in kernfs_get() and increase
it's reference count to 1. Because glue_dir->sd is freed by CPU1, the next
call kernfs_add_one() by CPU2 will fail(This is also use-after-free)
and call kernfs_put() to decrease reference count. Because the reference
count is decremented to 0, it will also call kmem_cache_free() to free
the glue_dir->sd again. This will result in double free.

In order to avoid this happening, we also should make sure that kernfs_node
for glue_dir is released in CPU1 only when refcount for glue_dir kobj is
1 to fix this race.

The following calltrace is captured in kernel 4.14 with the following patch
applied:

commit 726e41097920 ("drivers: core: Remove glue dirs from sysfs earlier")

--------------------------------------------------------------------------
[ 3.633703] WARNING: CPU: 4 PID: 513 at .../fs/kernfs/dir.c:494
Here is WARN_ON(!atomic_read(&kn->count) in kernfs_get().
....
[ 3.633986] Call trace:
[ 3.633991] kernfs_create_dir_ns+0xa8/0xb0
[ 3.633994] sysfs_create_dir_ns+0x54/0xe8
[ 3.634001] kobject_add_internal+0x22c/0x3f0
[ 3.634005] kobject_add+0xe4/0x118
[ 3.634011] device_add+0x200/0x870
[ 3.634017] _request_firmware+0x958/0xc38
[ 3.634020] request_firmware_into_buf+0x4c/0x70
....
[ 3.634064] kernel BUG at .../mm/slub.c:294!
Here is BUG_ON(object == fp) in set_freepointer().
....
[ 3.634346] Call trace:
[ 3.634351] kmem_cache_free+0x504/0x6b8
[ 3.634355] kernfs_put+0x14c/0x1d8
[ 3.634359] kernfs_create_dir_ns+0x88/0xb0
[ 3.634362] sysfs_create_dir_ns+0x54/0xe8
[ 3.634366] kobject_add_internal+0x22c/0x3f0
[ 3.634370] kobject_add+0xe4/0x118
[ 3.634374] device_add+0x200/0x870
[ 3.634378] _request_firmware+0x958/0xc38
[ 3.634381] request_firmware_into_buf+0x4c/0x70
--------------------------------------------------------------------------

Fixes: 726e41097920 ("drivers: core: Remove glue dirs from sysfs earlier")
Signed-off-by: Muchun Song <smuchun@gmail.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Link: https://lore.kernel.org/r/20190727032122.24639-1-smuchun@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: Add generic helper to match any device

Add a generic helper to match any/all devices. Using this
introduce new wrappers {bus/driver/class}_find_next_device().

Cc: Elie Morisse <syniurge@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Nehal Shah <nehal-bakulchandra.shah@amd.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Shyam Sundar S K <shyam-sundar.s-k@amd.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # PCI
Link: https://lore.kernel.org/r/20190723221838.12024-7-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: Introduce device lookup variants by ACPI_COMPANION device

Add a generic helper to match a device by the ACPI_COMPANION device
and provide wrappers for the device lookup APIs.

Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: linux-i2c@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C parts
Link: https://lore.kernel.org/r/20190723221838.12024-6-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: Introduce device lookup variants by device type

Add a helper to match a device by its type and provide wrappers
for {bus/class/driver}_find_device() APIs.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-5-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: Introduce device lookup variants by fwnode

Add a helper to match the firmware node handle of a device and provide
wrappers for {bus/class/driver}_find_device() APIs to avoid proliferation
of duplicate custom match functions.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-usb@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20190723221838.12024-4-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: Introduce device lookup variants by name

Add a helper to match the device name for device lookup. Also
reuse this generic exported helper for the existing bus_find_device_by_name().
and add similar variants for driver/class.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-leds@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20190723221838.12024-2-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix creation of device links with PM-runtime flags

After commit 515db266a9da ("driver core: Remove device link creation
limitation"), if PM-runtime flags are passed to device_link_add(), it
will fail (returning NULL) due to an overly restrictive flags check
introduced by that commit.

Fix this issue by extending the check in question to cover the
PM-runtime flags too.

Fixes: 515db266a9da ("driver core: Remove device link creation limitation")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/7674989.cD04D8YV3U@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Remove device link creation limitation

If device_link_add() is called for a consumer/supplier pair with an
existing device link between them and the existing link's type is
not in agreement with the flags passed to that function by its
caller, NULL will be returned. That is seriously inconvenient,
because it forces the callers of device_link_add() to worry about
what others may or may not do even if that is not relevant to them
for any other reasons.

It turns out, however, that this limitation can be made go away
relatively easily.

The underlying observation is that if DL_FLAG_STATELESS has been
passed to device_link_add() in flags for the given consumer/supplier
pair at least once, calling either device_link_del() or
device_link_remove() to release the link returned by it should work,
but there are no other requirements associated with that flag. In
turn, if at least one of the callers of device_link_add() for the
given consumer/supplier pair has not passed DL_FLAG_STATELESS to it
in flags, the driver core should track the status of the link and act
on it as appropriate (ie. the link should be treated as "managed").
This means that DL_FLAG_STATELESS needs to be set for managed device
links and it should be valid to call device_link_del() or
device_link_remove() to drop references to them in certain
sutiations.

To allow that to happen, introduce a new (internal) device link flag
called DL_FLAG_MANAGED and make device_link_add() set it automatically
whenever DL_FLAG_STATELESS is not passed to it. Also make it take
additional references to existing device links that were previously
stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED
unset) and will need to be managed going forward and initialize
their status (which has been DL_STATE_NONE so far).

Accordingly, when a managed device link is dropped automatically
by the driver core, make it clear DL_FLAG_MANAGED, reset the link's
status back to DL_STATE_NONE and drop the reference to it associated
with DL_FLAG_MANAGED instead of just deleting it right away (to
allow it to stay around in case it still needs to be released
explicitly by someone).

With that, since setting DL_FLAG_STATELESS doesn't mean that the
device link in question is not managed any more, replace all of the
status-tracking checks against DL_FLAG_STATELESS with analogous
checks against DL_FLAG_MANAGED and update the documentation to
reflect these changes.

While at it, make device_link_add() reject flags that it does not
recognize, including DL_FLAG_MANAGED.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Review-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver-core, libnvdimm: Let device subsystems add local lockdep coverage

For good reason, the standard device_lock() is marked
lockdep_set_novalidate_class() because there is simply no sane way to
describe the myriad ways the device_lock() ordered with other locks.
However, that leaves subsystems that know their own local device_lock()
ordering rules to find lock ordering mistakes manually. Instead,
introduce an optional / additional lockdep-enabled lock that a subsystem
can acquire in all the same paths that the device_lock() is acquired.

A conversion of the NFIT driver and NVDIMM subsystem to a
lockdep-validate device_lock() scheme is included. The
debug_nvdimm_lock() implementation implements the correct lock-class and
stacking order for the libnvdimm device topology hierarchy.

Yes, this is a hack, but hopefully it is a useful hack for other
subsystems device_lock() debug sessions. Quoting Greg:

"Yeah, it feels a bit hacky but it's really up to a subsystem to mess up
using it as much as anything else, so user beware :)

I don't object to it if it makes things easier for you to debug."

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com

drivers/base: Introduce kill_device()

The libnvdimm subsystem arranges for devices to be destroyed as a result
of a sysfs operation. Since device_unregister() cannot be called from
an actively running sysfs attribute of the same device libnvdimm
arranges for device_unregister() to be performed in an out-of-line async
context.

The driver core maintains a 'dead' state for coordinating its own racing
async registration / de-registration requests. Rather than add local
'dead' state tracking infrastructure to libnvdimm device objects, export
the existing state tracking via a new kill_device() helper.

The kill_device() helper simply marks the device as dead, i.e. that it
is on its way to device_del(), or returns that the device was already
dead. This can be used in advance of calling device_unregister() for
subsystems like libnvdimm that might need to handle multiple user
threads racing to delete a device.

This refactoring does not change any behavior, but it is a pre-requisite
for follow-on fixes and therefore marked for -stable.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver...")
Cc: <stable@vger.kernel.org>
Tested-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/156341207332.292348.14959761496009347574.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers: Add generic helper to match by of_node

Add a helper to match device by the of_node. This will be later used
to provide wrappers to the device iterators for {bus/class/driver}_find_device().
Convert other users to reuse this new helper.

Cc: Alan Tull <atull@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: devicetree@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-fpga@vger.kernel.org
Cc: linux-i2c@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Moritz Fischer <mdf@kernel.org>
Cc: Peter Rosin <peda@axentia.se>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add helper device_find_child_by_name()

It looks like the child device is often matched with a name.
This introduces a helper that does it automatically.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

driver core: Clarify which counterparts to use to device_add()

It is not absolutely clear from the docs how the cleanup path after
device_add() should look like so spell it out explicitly.

No functional changes, just documentation.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix PM-runtime for links added during consumer probe

Commit 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage
counter imbalance") introduced a regression that causes suppliers
to be suspended prematurely for device links added during consumer
driver probe if the initial PM-runtime status of the consumer is
"suspended" and the consumer is resumed after adding the link and
before pm_runtime_put_suppliers() is called. In that case,
pm_runtime_put_suppliers() will drop the rpm_active refcount for
the link by one and (since rpm_active is equal to two after the
preceding consumer resume) the supplier's PM-runtime usage counter
will be decremented, which may cause the supplier to suspend even
though the consumer's PM-runtime status is "active".

For this reason, partially revert commit 4c06c4e6cf63 as the problem
it tried to fix needs to be addressed somewhat differently, and
change pm_runtime_get_suppliers() and pm_runtime_put_suppliers() so
that the latter only drops rpm_active references acquired by the
former. [This requires adding a new field to struct device_link,
but I coulnd't find a cleaner way to address the issue that would
work in all cases.]

This causes pm_runtime_put_suppliers() to effectively ignore device
links added during consumer probe, so device_link_add() doesn't need
to worry about ensuring that suppliers will remain active after
pm_runtime_put_suppliers() for links created with DL_FLAG_RPM_ACTIVE
set and it only needs to bump up rpm_active by one for those links,
so pm_runtime_active_link() is not necessary any more.

Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix possible supplier PM-usage counter imbalance

If a stateless device link to a certain supplier with
DL_FLAG_PM_RUNTIME set in the flags is added and then removed by the
consumer driver's probe callback, the supplier's PM-runtime usage
counter will be nonzero after that which effectively causes the
supplier to remain "always on" going forward.

Namely, device_link_add() called to add the link invokes
device_link_rpm_prepare() which notices that the consumer driver is
probing, so it increments the supplier's PM-runtime usage counter
with the assumption that the link will stay around until
pm_runtime_put_suppliers() is called by driver_probe_device(),
but if the link goes away before that point, the supplier's
PM-runtime usage counter will remain nonzero.

To prevent that from happening, first rework pm_runtime_get_suppliers()
and pm_runtime_put_suppliers() to use the rpm_active refounts of device
links and make the latter only drop rpm_active and the supplier's
PM-runtime usage counter for each link by one, unless rpm_active is
one already for it. Next, modify device_link_add() to bump up the
new link's rpm_active refcount and the suppliers PM-runtime usage
counter by two, to prevent pm_runtime_put_suppliers(), if it is
called subsequently, from suspending the supplier prematurely (in
case its PM-runtime usage counter goes down to 0 in there).

Due to the way rpm_put_suppliers() works, this change does not
affect runtime suspend of the consumer ends of new device links (or,
generally, device links for which DL_FLAG_PM_RUNTIME has just been
set).

Fixes: e2f3cd831a28 ("driver core: Fix handling of runtime PM flags in device_link_add()")
Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER

Add a new device link flag, DL_FLAG_AUTOPROBE_CONSUMER, to request the
driver core to probe for a consumer driver automatically after binding
a driver to the supplier device on a persistent managed device link.

As unbinding the supplier driver on a managed device link causes the
consumer driver to be detached from its device automatically, this
flag provides a complementary mechanism which is needed to address
some "composite device" use cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Make driver core own stateful device links

Even though stateful device links are managed by the driver core in
principle, their creators are allowed and sometimes even expected
to drop references to them via device_link_del() or
device_link_remove(), but that doesn't really play well with the
"persistent" link concept.

If "persistent" managed device links are created from driver
probe callbacks, device_link_add() called to do that will take a
new reference on the link each time the callback runs and those
references will never be dropped, which kind of isn't nice.

This issues arises because of the link reference counting carried
out by device_link_add() for existing links, but that is only done to
avoid deleting device links that may still be necessary, which
shouldn't be a concern for managed (stateful) links. These device
links are managed by the driver core and whoever creates one of them
will need it at least as long as until the consumer driver is detached
from its device and deleting it may be left to the driver core just
fine.

For this reason, rework device_link_add() to apply the reference
counting to stateless links only and make device_link_del() and
device_link_remove() drop references to stateless links only too.
After this change, if called to add a stateful device link for
a consumer-supplier pair for which a stateful device link is
present already, device_link_add() will return the existing link
without incrementing its reference counter. Accordingly,
device_link_del() and device_link_remove() will WARN() and do
nothing when called to drop a reference to a stateful link. Thus,
effectively, all stateful device links will be owned by the driver
core.

In addition, clean up the handling of the link management flags,
DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER, so that
(a) they are never set at the same time and (b) if device_link_add()
is called for a consumer-supplier pair with an existing stateful link
between them, the flags of that link will be combined with the flags
passed to device_link_add() to ensure that the life time of the link
is sufficient for all of the callers of device_link_add() for the
same consumer-supplier pair.

Update the device_link_add() kerneldoc comment to reflect the
above changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Do not call rpm_put_suppliers() in pm_runtime_drop_link()

Calling rpm_put_suppliers() from pm_runtime_drop_link() is excessive
as it affects all suppliers of the consumer device and not just the
one pointed to by the device link being dropped. Worst case it may
cause the consumer device to stop working unexpectedly. Moreover, in
principle it is racy with respect to runtime PM of the consumer
device.

To avoid these problems drop runtime PM references on the particular
supplier pointed to by the link in question only and do that after
the link has been dropped from the consumer device's list of links to
suppliers, which is in device_link_free().

Fixes: a0504aecba76 ("PM / runtime: Drop usage count for suppliers at device link removal")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix adding device links to probing suppliers

Currently, it is not valid to add a device link from a consumer
driver ->probe callback to a supplier that is still probing too, but
generally this is a valid use case. For example, if the consumer has
just acquired a resource that can only be available if the supplier
is functional, adding a device link to that supplier right away
should be safe (and even desirable arguably), but device_link_add()
doesn't handle that case correctly and the initial state of the link
created by it is wrong then.

To address this problem, change the initial state of device links
added between a probing supplier and a probing consumer to
DL_STATE_CONSUMER_PROBE and update device_links_driver_bound() to
skip such links on the supplier side.

With this change, if the supplier probe completes first,
device_links_driver_bound() called for it will skip the link state
update and when it is called for the consumer, the link state will
be updated to "active". In turn, if the consumer probe completes
first, device_links_driver_bound() called for it will change the
state of the link to "active" and when it is called for the
supplier, the link status update will be skipped.

However, in principle the supplier or consumer probe may still fail
after the link has been added, so modify device_links_no_driver() to
change device links in the "active" or "consumer probe" state to
"dormant" on the supplier side and update __device_links_no_driver()
to change the link state to "available" only if it is "consumer
probe" or "active".

Then, if the supplier probe fails first, the leftover link to the
probing consumer will become "dormant" and device_links_no_driver()
called for the consumer (when its probe fails) will clean it up.
In turn, if the consumer probe fails first, it will either drop the
link, or change its state to "available" and, in the latter case,
when device_links_no_driver() is called for the supplier, it will
update the link state to "dormant". [If the supplier probe fails,
but the consumer probe succeeds, which should not happen as long as
the consumer driver is correct, the link still will be around, but
it will be "dormant" until the supplier is probed again.]

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix handling of runtime PM flags in device_link_add()

After commit ead18c23c263 ("driver core: Introduce device links
reference counting"), if there is a link between the given supplier
and the given consumer already, device_link_add() will refcount it
and return it unconditionally without updating its flags. It is
possible, however, that the second (or any subsequent) caller of
device_link_add() for the same consumer-supplier pair will pass
DL_FLAG_PM_RUNTIME, possibly along with DL_FLAG_RPM_ACTIVE, in flags
to it and the existing link may not behave as expected then.

First, if DL_FLAG_PM_RUNTIME is not set in the existing link's flags
at all, it needs to be set like during the original initialization of
the link.

Second, if DL_FLAG_RPM_ACTIVE is passed to device_link_add() in flags
(in addition to DL_FLAG_PM_RUNTIME), the existing link should to be
updated to reflect the "active" runtime PM configuration of the
consumer-supplier pair and extra care must be taken here to avoid
possible destructive races with runtime PM of the consumer.

To that end, redefine the rpm_active field in struct device_link
as a refcount, initialize it to 1 and make rpm_resume() (for the
consumer) and device_link_add() increment it whenever they acquire
a runtime PM reference on the supplier device. Accordingly, make
rpm_suspend() (for the consumer) and pm_runtime_clean_up_links()
decrement it and drop runtime PM references to the supplier
device in a loop until rpm_active becones 1 again.

Fixes: ead18c23c263 ("driver core: Introduce device links reference counting")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Do not resume suppliers under device_links_write_lock()

It is incorrect to call pm_runtime_get_sync() under
device_links_write_lock(), because it may end up trying to take
device_links_read_lock() while resuming the target device and that
will deadlock in the non-SRCU case, so avoid that by resuming the
supplier device in device_link_add() before calling
device_links_write_lock().

Fixes: 21d5c57b3726 ("PM / runtime: Use device links")
Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Avoid careless re-use of existing device links

After commit ead18c23c263 ("driver core: Introduce device links
reference counting"), if there is a link between the given supplier
and the given consumer already, device_link_add() will refcount it
and return it unconditionally. However, if the flags passed to
it on the second (or any subsequent) attempt to create a device
link between the same consumer-supplier pair are not compatible with
the existing link's flags, that is incorrect.

First off, if the existing link is stateless and the next caller of
device_link_add() for the same consumer-supplier pair wants a
stateful one, or the other way around, the existing link cannot be
returned, because it will not match the expected behavior, so make
device_link_add() dump the stack and return NULL in that case.

Moreover, if the DL_FLAG_AUTOREMOVE_CONSUMER flag is passed to
device_link_add(), its caller will expect its reference to the link
to be dropped automatically on consumer driver removal, which will
not happen if that flag is not set in the link's flags (and
analogously for DL_FLAG_AUTOREMOVE_SUPPLIER). For this reason, make
device_link_add() update the existing link's flags accordingly
before returning it to the caller.

Fixes: ead18c23c263 ("driver core: Introduce device links reference counting")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Fix DL_FLAG_AUTOREMOVE_SUPPLIER device link flag handling

Change the list walk in device_links_driver_cleanup() to a safe one
to avoid use-after-free when dropping a link from the list during the
walk.

Also, while at it, fix device_link_add() to refuse to create
stateless device links with DL_FLAG_AUTOREMOVE_SUPPLIER set, which is
an invalid combination (setting that flag means that the driver core
should manage the link, so it cannot be stateless), and extend the
kerneldoc comment of device_link_add() to cover the
DL_FLAG_AUTOREMOVE_SUPPLIER flag properly too.

Fixes: 1689cac5b32a ("driver core: Add flag to autoremove device link on supplier unbind")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Establish order of operations for device_add and device_del via bitflag

Add an additional bit flag to the device_private struct named "dead".

This additional flag provides a guarantee that when a device_del is
executed on a given interface an async worker will not attempt to attach
the driver following the earlier device_del call. Previously this
guarantee was not present and could result in the device_del call
attempting to remove a driver from an interface only to have the async
worker attempt to probe the driver later when it finally completes the
asynchronous probe call.

One additional change added was that I pulled the check for dev->driver
out of the __device_attach_driver call and instead placed it in the
__device_attach_async_helper call. This was motivated by the fact that the
only other caller of this, __device_attach, had already taken the
device_lock() and checked for dev->driver. Instead of testing for this
twice in this path it makes more sense to just consolidate the dev->dead
and dev->driver checks together into one set of checks.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Remove the link if there is no driver with AUTO flag

DL_FLAG_AUTOREMOVE_CONSUMER/SUPPLIER means "Remove the link
automatically on consumer/supplier driver unbind", that means we should
remove whole the device_link when there is no this driver no matter what
the ref_count of the link is.

CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: silence device link messages unless debugging

On platforms making a fair use of regulators, the dev_info() messages
coming from the device link function are a bit too verbose. The amount
of message will increase further with the clock framework joining the
device link party.

These messages looks valuable for people debugging device link related
issues, so dev_dbg() looks more appropriate than dev_info().

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: move device->knode_class to device_private

As the description of struct device_private says, it stores data which
is private to driver core. And it already has similar fields like:
knode_parent, knode_driver, knode_driver and knode_bus. This look it is
more proper to put knode_class together with those fields to make it
private to driver core.

This patch move device->knode_class to device_private to make it comply
with code convention.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kobject: return error code if writing /sys/.../uevent fails

Propagate error code back to userspace if writing the /sys/.../uevent
file fails. Before, the write operation always returned with success,
even if we failed to recognize the input string or if we failed to
generate the uevent itself.

With the error codes properly propagated back to userspace, we are
able to react in userspace accordingly by not assuming and awaiting
a uevent that is not delivered.

Signed-off-by: Peter Rajnoha <prajnoha@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kref/kobject: Improve documentation

The current kref and kobject documentation may be
insufficient to understand these common pitfalls regarding
object lifetime and object releasing.

Add a bit more documentation and improve the warnings
seen by the user, pointing to the right piece of documentation.

Also, it's important to understand that making fun of people
publicly is not at all helpful, doesn't provide any value,
and it's not a healthy way of encouraging developers to do better.

"Mocking mercilessly" will, if anything, make developers feel bad
and go away. This kind of behavior should not be encouraged or justified.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Replace simple_strto{l,ul} by kstrtou{l,ul}

The simple_strto{l,ul} are deprecated, use kstrtou{l,ul} instead.

Signed-off-by: Kaitao cheng <pilgrimtao@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: base: Introducing software nodes to the firmware node framework

Software node is a new struct fwnode_handle type that can be
used to describe devices in kernel (software). It is meant
to complement fwnodes representing real firmware nodes when
they are incomplete (for example missing device properties)
and to supply the primary fwnode when the firmware lacks
hardware description for a device completely.

The software node type is really meant to replace the
currently used "property_set" struct fwnode_handle type. The
handling of struct property_set is glued to the generic
device property handling code, and it is not possible to
create a struct property_set independently from the device
that it is bind to. struct property_set is only created when
device properties are added to already initialized struct
device, and control of it is only possible from the generic
property handling code.

Software nodes are instead designed to be created
independently from the device entries (struct device). It
makes them much more flexible, as then the device meant to
be bind to the node can be created at a later time, and from
another location. It is also possible to bind multiple
devices to a single software node if needed.

The software node implementation also includes support for
node hierarchy, which was the main motivation for this
commit. The node hierarchy was something that was requested
for the struct property_set, but it did not seem reasonable
to try to extend the property_set support for that purpose.
struct property_set was really meant only for device
property handling like the name suggests.

Support for struct property_set is not yet removed in this
commit, but it will be in the following one.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>