s390/dasd: use new address translation helpers

Use virt_to_dma32() and friends to properly convert virtual to physical and
physical to virtual addresses so that "make C=1" does not generate any
warnings anymore.

Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

dasd: use the atomic queue limits API

Pass the constant limits directly to blk_mq_alloc_disk, set the nonrot
flag there as well, and then use the commit API to change the transfer
size and logical block size dependent values.

This relies on the assumption that no I/O can be pending before the
devices moves into the ready state and doesn't need extra freezing
for changes to the queue limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240228133742.806274-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dasd: move queue setup to common code

Most of the code in setup_blk_queue is shared between all disciplines.
Move it to common code and leave a method to query the maximum number
of transferable blocks, and a flag to indicate discard support.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240228133742.806274-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dasd: cleamup dasd_state_basic_to_ready

Reflow dasd_state_basic_to_ready a bit to make it easier to modify.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240228133742.806274-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390: port block device access to file

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-16-adbd023e19cc@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

s390/dasd: fix double module refcount decrement

Once the discipline is associated with the device, deleting the device
takes care of decrementing the module's refcount. Doing it manually on
this error path causes refcount to artificially decrease on each error
while it should just stay the same.

Fixes: c020d722b110 ("s390/dasd: fix panic during offline processing")
Signed-off-by: Miroslav Franc <mfranc@suse.cz>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240209124522.3697827-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Use dev_*() for device log messages

All log messages in dasd.c use the printk variants of pr_*(). They all
add the name of the affected device manually to the log message.
This can be simplified by using the dev_*() variants of printk, which
include the device information and make a separate call to dev_name()
unnecessary.

The KMSG_COMPONENT and the pr_fmt() definition can be dropped. Note that
this removes the "dasd: " prefix from the one pr_info() call in
dasd_init(). However, the log message already provides all relevant
information.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240208164248.540985-10-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Remove PRINTK_HEADER and KMSG_COMPONENT definitions

PRINTK_HEADER was mainly used to prefix log messages with the module
name. Most components don't use this definition anymore. Either because
there are no log messages being generated anymore, or pr_*() were
replaced by dev_*(), which contains device and component information
already.

PRINTK_HEADER is also dropped in the function
dasd_3990_erp_handle_match_erp() in dasd_3990_erp.c from a panic() call
as panic() already provides all relevant information.

KMSG_COMPONENT was mainly used to identify a component in a long gone
kernel message catalog feature.

Remove both definition since they're either not used or alternatives
make the code slightly shorter and more readable.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240208164248.540985-9-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Remove %p format specifier from error messages

Printing pointer in error messages doesn't add any value since the
addresses are hashed. Remove the %p format specifier and adapt the error
messages slightly.

Replace %p with %px in ERP to get the actual addresses since ERP is used
for debugging purposes only anyway.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240208164248.540985-8-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Move allocation error message to DBF

All error messages for a failling dasd_smalloc_request() call are logged
via DBF, except one. There is no value in logging this particular
allocation failure via dev_err(). Move the message to DBF, too, to be
in line with the rest.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240208164248.540985-5-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Remove unnecessary errorstring generation

In quite a few cases an errorstring is generated using snprintf() before
it's passed to dev_err(). This indirection is unnecessary and all
information can simply be passed directly to dev_err() instead.
The errrorstring and ERRORLENGTH definitions are removed entirely.

While at it, rephrase the error messages to provide more context where
possible. Also, fix a few incorrectly used format specifier (e.g. %x02
-> %02x) in those messages.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240208164248.540985-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: remove dasd_stats_generic_show()

Patch series "s390: A couple of fixes for -Wmissing-prototypes".

This series resolves a couple of -Wmissing-prototypes that I see in my
builds of -next, even though the issues appear to be latent. This
addresses issues which will be exposed by the later patch
"Makefile.extrawarn: turn on missing-prototypes globally".


This patch (of 2):

With CONFIG_DASD_PROFILE=n, there is a warning that
dasd_stats_generic_show() is missing a prototype:

drivers/s390/block/dasd.c:1109:5: warning: no previous prototype for 'dasd_stats_generic_show' [-Wmissing-prototypes]
1109 | int dasd_stats_generic_show(struct seq_file *m, void *v)
| ^~~~~~~~~~~~~~~~~~~~~~~

This function has been unused since its introduction in commit
4fa52aa7a82f ("[S390] dasd: add enhanced DASD statistics interface"),
remove it to clear up the warning.

Link: https://lkml.kernel.org/r/20231130-s390-missing-prototypes-v1-0-799d3cf07fb7@kernel.org
Link: https://lkml.kernel.org/r/20231130-s390-missing-prototypes-v1-1-799d3cf07fb7@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jan Höppner <hoeppner@linux.ibm.com>
Cc: Stefan Haberland <sth@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

s390/dasd: protect device queue against concurrent access

In dasd_profile_start() the amount of requests on the device queue are
counted. The access to the device queue is unprotected against
concurrent access. With a lot of parallel I/O, especially with alias
devices enabled, the device queue can change while dasd_profile_start()
is accessing the queue. In the worst case this leads to a kernel panic
due to incorrect pointer accesses.

Fix this by taking the device lock before accessing the queue and
counting the requests. Additionally the check for a valid profile data
pointer can be done earlier to avoid unnecessary locking in a hot path.

Cc: <stable@vger.kernel.org>
Fixes: 4fa52aa7a82f ("[S390] dasd: add enhanced DASD statistics interface")
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20231025132437.1223363-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Convert to bdev_open_by_path()

Convert dasd to use bdev_open_by_path() and pass the handle around.

CC: linux-s390@vger.kernel.org
CC: Christian Borntraeger <borntraeger@linux.ibm.com>
CC: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-14-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>

block: consolidate __invalidate_device and fsync_bdev

We currently have two interfaces that take a block_devices and the find
a mounted file systems to flush or invaldidate data on it. Both are a
bit problematic because they only work for the "main" block devices
that is used as s_dev for the super_block, and because they don't call
into the file system at all.

Merge the two into a new bdev_mark_dead helper that does both the
syncing and invalidation and which is properly documented. This is
in preparation of merging the functionality into the ->mark_dead
holder operation so that it will work on additional block devices
used by a file systems and give us a single entry point for invalidation
of dead devices or media.

Note that a single standalone fsync_bdev call for an obscure ioctl
remains for now, but that one will also be deal with in a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-14-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

dasd: also call __invalidate_device when setting the device offline

Don't just write out the data, but also invalidate all caches when setting
the device offline. Stop canceling the offlining when writeback fails
as there is no way to recover from that anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-12-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

s390/dasd: fix hanging device after request requeue

The DASD device driver has a function to requeue requests to the
blocklayer.
This function is used in various cases when basic settings for the device
have to be changed like High Performance Ficon related parameters or copy
pair settings.

The functions iterates over the device->ccw_queue and also removes the
requests from the block->ccw_queue.
In case the device is started on an alias device instead of the base
device it might be removed from the block->ccw_queue without having it
canceled properly before. This might lead to a hanging device since the
request is no longer on a queue and can not be handled properly.

Fix by iterating over the block->ccw_queue instead of the
device->ccw_queue. This will take care of all blocklayer related requests
and handle them on all associated DASD devices.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20230721193647.3889634-4-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Rename BLK_STS_NEXUS to BLK_STS_RESV_CONFLICT

BLK_STS_NEXUS is used for NVMe/SCSI reservation conflicts and DASD's
locking feature which works similar to NVMe/SCSI reservations where a
host can get a lock on a device and when the lock is taken it will get
failures.

This patch renames BLK_STS_NEXUS so it better reflects this type of
use.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20230407200551.12660-3-michael.christie@oracle.com
Acked-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

block: replace fmode_t with a block-specific type for block open flags

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the unused mode argument to ->release

The mode argument to the ->release block_device_operation is never used,
so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a gendisk to ->open

->open is only called on the whole device. Make that explicit by
passing a gendisk instead of the block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: fix hanging blockdevice after request requeue

The DASD driver does not kick the requeue list when requeuing IO requests
to the blocklayer. This might lead to hanging blockdevice when there is
no other trigger for this.

Fix by automatically kick the requeue list when requeuing DASD requests
to the blocklayer.

Fixes: e443343e509a ("s390/dasd: blk-mq conversion")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20230405142017.2446986-8-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: add autoquiesce event for start IO error

Add a check for errors in the start_io function that signal a not
working device. Trigger an autoquiesce event in that case.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20230405142017.2446986-7-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: add aq_timeouts autoquiesce trigger

Add a sysfs attribute aq_timeouts that controls after how many
timeouts a autoquiesce event might be triggered.

The default value is 32768 which is the maximum number of retries
for the DASD device driver DASD_RETRIES_MAX. This means that the
timeout trigger will never happen.

The default value for DASD retries is 255.
Setting the value to below 255 will trigger the timeout autoquiesce
event before an IO error is generated.

Also add the check for the configured amount of timeouts and trigger
an autoquiesce event if exceeded.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20230405142017.2446986-6-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: add autoquiesce feature

Add the internal logic to check for autoquiesce triggers and handle
them.

Quiesce and resume are functions that tell Linux to stop/resume
issuing I/Os to a specific DASD.
The DASD driver allows a manual quiesce/resume via ioctl.

Autoquiesce will define an amount of triggers that will lead to
an automatic quiesce if a certain event occurs.
There is no automatic resume.

All events will be reported via DASD Extended Error Reporting (EER)
if configured.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20230405142017.2446986-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: sort out physical vs virtual pointers usage

This does not fix a real bug, since virtual addresses
are currently indentical to physical ones.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20230210000253.1644903-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: use blk_mq_alloc_disk

As far as I can tell there is no need for the staged setup in
dasd, so allocate the tagset and the disk with the queue in
dasd_gendisk_alloc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220928143945.1687114-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: add copy pair swap capability

In case of errors or misbehaviour of the primary device a controlled
failover to one of the configured secondary devices needs to be
performed.

The swap processing stops I/O on the primary device, all requests are
re-queued to the blocklayer queue, the entries in the copy relation are
swapped and finally the link to the blockdevice is moved from primary to
secondary dasd device.
After this, the secondary becomes the new primary device and I/O is
restarted on that device.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-5-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: drop unexpected word 'for' in comments

there is an unexpected word 'for' in the comments that need to be dropped

file - drivers/s390/block/dasd.c
line - 1728

/* check for for attention message */

changed to:

/* check for attention message */

Signed-off-by: Jiang Jian <jiangjian@cdjrlc.com>
Link: https://lore.kernel.org/r/20220623102114.33249-1-jiangjian@cdjrlc.com
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220804213926.3361574-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: Drop blk_mq_ops.timeout 'reserved' arg

With new API blk_mq_is_reserved_rq() we can tell if a request is from
the reserved pool, so stop passing 'reserved' arg. There is actually
only a single user of that arg for all the callback implementations, which
can use blk_mq_is_reserved_rq() instead.

This will also allow us to stop passing the same 'reserved' around the
blk-mq iter functions next.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/1657109034-206040-4-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: simplify disk shutdown

Set the queue dying flag and call blk_mq_exit_queue from del_gendisk for
all disks that do not have separately allocated queues, and thus remove
the need to call blk_cleanup_queue for them.

Rename blk_cleanup_disk to blk_mq_destroy_queue to make it clear that
this function is intended only for separately allocated blk-mq queues.

This saves an extra queue freeze for devices without a separately
allocated queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20220619060552.1850436-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Fix read inconsistency for ESE DASD devices

Read requests that return with NRF error are partially completed in
dasd_eckd_ese_read(). The function keeps track of the amount of
processed bytes and the driver will eventually return this information
back to the block layer for further processing via __dasd_cleanup_cqr()
when the request is in the final stage of processing (from the driver's
perspective).

For this, blk_update_request() is used which requires the number of
bytes to complete the request. As per documentation the nr_bytes
parameter is described as follows:
"number of bytes to complete for @req".

This was mistakenly interpreted as "number of bytes _left_ for @req"
leading to new requests with incorrect data length. The consequence are
inconsistent and completely wrong read requests as data from random
memory areas are read back.

Fix this by correctly specifying the amount of bytes that should be used
to complete the request.

Fixes: 5e6bdd37c552 ("s390/dasd: fix data corruption for thin provisioned devices")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-5-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: prevent double format of tracks for ESE devices

For ESE devices we get an error for write operations on an unformatted
track. Afterwards the track will be formatted and the IO operation
restarted.
When using alias devices a track might be accessed by multiple requests
simultaneously and there is a race window that a track gets formatted
twice resulting in data loss.

Prevent this by remembering the amount of formatted tracks when starting
a request and comparing this number before actually formatting a track
on the fly. If the number has changed there is a chance that the current
track was finally formatted in between. As a result do not format the
track and restart the current IO to check.

The number of formatted tracks does not match the overall number of
formatted tracks on the device and it might wrap around but this is no
problem. It is only needed to recognize that a track has been formatted at
all in between.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: fix data corruption for ESE devices

For ESE devices we get an error when accessing an unformatted track.
The handling of this error will return zero data for read requests and
format the track on demand before writing to it. To do this the code needs
to distinguish between read and write requests. This is done with data from
the blocklayer request. A pointer to the blocklayer request is stored in
the CQR.

If there is an error on the device an ERP request is built to do error
recovery. While the ERP request is mostly a copy of the original CQR the
pointer to the blocklayer request is not copied to not accidentally pass
it back to the blocklayer without cleanup.

This leads to the error that during ESE handling after an ERP request was
built it is not possible to determine the IO direction. This leads to the
formatting of a track for read requests which might in turn lead to data
corruption.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220505141733.1989450-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: fix possibly missed path verification

__dasd_device_check_path_events() calls the discipline path event handler.
This handler can leave the 'to be verified pathmask' populated for an
additional verification.

There is a race window where the worker has finished before
dasd_path_clear_all_verify() is called which resets the tbvpm.

Due to this there could be outstanding path verifications missed.

Fix by clearing the pathmasks before calling the handler and add them
again in case of an error.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20211020115124.1735254-8-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dasd: unexport dasd_set_target_state

dasd_set_target_state is only used inside of dasd_mod.ko, so don't
export it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20210701142221.3408680-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: let driver core manage the sysfs attributes

Wire up device_driver->dev_groups, so that really_probe() creates the
sysfs attributes for us automatically.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20210316094513.2601218-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

module: remove never implemented MODULE_SUPPORTED_DEVICE

MODULE_SUPPORTED_DEVICE was added in pre-git era and never was
implemented. We can safely remove it, because the kernel has grown
to have many more reliable mechanisms to determine if device is
supported or not.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

s390/dasd: fix hanging IO request during DASD driver unbind

Prevent that an IO request is build during device shutdown initiated by
a driver unbind. This request will never be able to be processed or
canceled and will hang forever. This will lead also to a hanging unbind.

Fix by checking not only if the device is in READY state but also check
that there is no device offline initiated before building a new IO request.

Fixes: e443343e509a ("s390/dasd: blk-mq conversion")

Cc: <stable@vger.kernel.org> # v4.14+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Tested-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: fix hanging DASD driver unbind

In case of an unbind of the DASD device driver the function
dasd_generic_remove() is called which shuts down the device.
Among others this functions removes the int_handler from the cdev.
During shutdown the device cancels all outstanding IO requests and waits
for completion of the clear request.
Unfortunately the clear interrupt will never be received when there is no
interrupt handler connected.

Fix by moving the int_handler removal after the call to the state machine
where no request or interrupt is outstanding.

Cc: stable@vger.kernel.org
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Tested-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add a disk_uevent helper

Add a helper to call kobject_uevent for the disk and all partitions, and
unexport the disk_part_iter_* helpers that are now only used in the core
block code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: remove unused pm related functions

The power-management related functions are unused since the
'commit 394216275c7d ("s390: remove broken hibernate / power management
support")'. Remove them from dasd drivers.

Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

block: switch disk_part_iter_* to use a struct block_device

Switch the partition iter infrastructure to iterate over block_device
references instead of hd_struct ones mostly used to get at the
block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: fix null pointer dereference for ERP requests

When requeueing all requests on the device request queue to the blocklayer
we might get to an ERP (error recovery) request that is a copy of an
original CQR.

Those requests do not have blocklayer request information or a pointer to
the dasd_queue set. When trying to access those data it will lead to a
null pointer dereference in dasd_requeue_all_requests().

Fix by checking if the request is an ERP request that can simply be
ignored. The blocklayer request will be requeued by the original CQR that
is on the device queue right behind the ERP request.

Fixes: 9487cfd3430d ("s390/dasd: fix handling of internal requests")
Cc: <stable@vger.kernel.org> #4.16
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Process FCES path event notification

If the Fibre Channel Endpoint-Security status of a path changes, a
corresponding path event is received from the CIO layer.

Process this event by re-reading the FCES information.

As the information is retrieved for all paths on a single CU in one
call, the internal status can also be updated for all paths and no
processing per path is necessary.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Prepare for additional path event handling

As more path events need to be handled for ECKD the current path
verification infrastructure can be reused. Rename all path verifcation
code to fit the more broadly based task of path event handling and put
the path verification in a new separate function.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Remove unused parameter from dasd_generic_probe()

The discipline argument in dasd_generic_probe() isn't used and there is
no history how it was used in the past. Remove it.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

dasd: implement ->set_read_only to hook into BLKROSET processing

Implement the ->set_read_only method instead of parsing the actual
ioctl command.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-mq: move failure injection out of blk_mq_complete_request

Move the call to blk_should_fake_timeout out of blk_mq_complete_request
and into the drivers, skipping call sites that are obvious error
handlers, and remove the now superflous blk_mq_force_complete_rq helper.
This ensures we don't keep injecting errors into completions that just
terminate the Linux request after the hardware has been reset or the
command has been aborted.

Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: fix data corruption for thin provisioned devices

Devices are formatted in multiple of tracks.
For an Extent Space Efficient (ESE) volume we get errors when accessing
unformatted tracks. In this case the driver either formats the track on
the flight for write requests or returns zero data for read requests.

In case a request spans multiple tracks, the indication of an unformatted
track presented for the first track is incorrectly applied to all tracks
covered by the request. As a result, tracks containing data will be handled
as empty, resulting in zero data being returned on read, or overwriting
existing data with zero on write.

Fix by determining the track that gets the NRF error.
For write requests only format the track that is surely not formatted.
For Read requests all tracks before have returned valid data and should not
be touched.
All tracks after the unformatted track might be formatted or not. Those are
returned to the blocklayer to build a new request.

When using alias devices there is a chance that multiple write requests
trigger a format of the same track which might lead to data loss. Ensure
that a track is formatted only once by maintaining a list of currently
processed tracks.

Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes")
Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Handle out-of-space constraint

The storage server issues three different types of out-of-space messages
whenever the Extent Pool or Extent Repository space runs short. When a
configured warning watermark is reached, the physical space is
completeley exhausted, or the capacity constraints have been relieved, a
message is received.

A log entry for the sysadmin to react to is generated in any case. In
case the physical space is completely exhausted, sense data that reads
"no space left on device" is received. In this case, currently running
I/O will be blocked until space has either been released or added to the
extent pool, and a relieve message was received via an attention
interrupt.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/dasd: Make dasd_setup_queue() a discipline function

ECKD, FBA, and the DIAG discipline use slightly different block layer
settings. In preparation of even more diverse queue settings, make
dasd_setup_queue() a discipline function.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/dasd: Add dasd_sleep_on_queue_interruptible()

There is dasd_sleep_on() and dasd_sleep_on_interruptible() to start CCW
requests uninterruptible and interruptible. However, there is only
dasd_sleep_on_queue() to start requests from CCW queues uninterruptible.

Add dasd_sleep_on_queue_interruptible() to provide a way to start
requests from CCW queues interruptible. _dasd_sleep_on_queue() already
provides this functionality.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/dasd: Add dynamic formatting support for ESE volumes

A dynamic formatting is issued whenever a write request returns with
either a No Record Found error (Command Mode), Incorrect Length error
(Transport Mode), or File Protected error (Transport Mode). All three
cases mean that the tracks in question haven't been initialized in a
desired format yet.

The part of the volume that was tried to be written on is then formatted
and the original request is re-queued.

As the formatting will happen during normal I/O operations, it is quite
likely that there won't be any memory available to build the respective
request. Another two pages of memory are allocated per volume
specifically for the dynamic formatting.

The dasd_eckd_build_format() function is extended to make sure that the
original startdev is reused. Also, all formatting and format check
functions use the new memory pool exclusively now to reduce complexity.

Read operations will always return zero data when unformatted areas are
read.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

s390/dasd: fix read device characteristic with CONFIG_VMAP_STACK=y

The dasd_eckd_restore_device() function calls dasd_generic_read_dev_chars
with a temporary buffer on the stack. With CONFIG_VMAP_STACK=y this is
a vmalloc address but dasd_generic_restore_device() uses the address of
the buffer as I/O address. Circumvent this by using the already allocated
cqr->data buffer for the RDC data.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: convert to DEFINE_SHOW_ATTRIBUTE

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: remove unnecessary condition check

kmem_cache_destroy() can handle NULL pointer correctly, so there is
no need to check NULL pointer before calling kmem_cache_destroy().

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix cast-function-type warnings

Change the tasklets parameter type to fix W=1 warnings when building
with gcc 8 like below:

drivers/s390/block/dasd.c: In function 'dasd_alloc_device':
drivers/s390/block/dasd.c:129:8: warning: cast between incompatible function types
from 'void (*)(struct dasd_device *)' to 'void (*)(long unsigned int)' [-Wcast-function-type]
(void (*)(unsigned long)) dasd_device_tasklet,
^

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Acked-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: correct numa_node in dasd_alloc_queue

The numa_node field of the tag_set struct has to be explicitly
initialized, otherwise it stays as 0, which is a valid numa node id and
cause memory allocation failure if node 0 is offline.

Acked-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: reduce the default queue depth and nr of hardware queues

Reduce the default values for the number of hardware queues and queue depth
to significantly reduce the memory footprint of a DASD device.
The memory consumption per DASD device reduces from approximately 40MB to
approximately 1.5MB.

This is necessary to build systems with a large number of DASD devices and
a reasonable amount of memory.
Performance measurements showed that good performance results are possible
with the new default values even on systems with lots of CPUs and lots of
alias devices.

Fixes: e443343e509a ("s390/dasd: blk-mq conversion")
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: only use preallocated requests

Change the remaining users of dasd_kmalloc_request to use
preallocated memory and remove this function.

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: move dasd_ccw_req to per request data

Let the block layer allocate per request data to store
struct dasd_ccw_req. We still need extra preallocated
memory for usage by ccw programs (which vary in length)
and for requests which don't originate from the block
layer.

Link: https://lkml.kernel.org/r/20180530074130.GA6927@infradead.org
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: simplify locking in process_final_queue

Simplify locking in __dasd_device_process_final_queue to fix
the following sparse warning:

drivers/s390/block/dasd.c:1902:9: warning:
context imbalance in '__dasd_device_process_final_queue' - different lock contexts for basic block

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: rename BLK_EH_NOT_HANDLED to BLK_EH_DONE

The BLK_EH_NOT_HANDLED implies nothing happen, but very often that
is not what is happening - instead the driver already completed the
command. Fix the symbolic name to reflect that a little better.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: simplify locking in dasd_times_out

Provide __dasd_cancel_req that is called with the ccw device lock
held to simplify the locking in dasd_times_out. Also this removes
the following sparse warning:
context imbalance in 'dasd_times_out' - different lock contexts for basic block

Note: with this change dasd_schedule_device_bh is now called (via
dasd_cancel_req) with the ccw device lock held. But is is already
the case for other codepaths.

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: use blk_mq_rq_from_pdu for per request data

Dasd uses completion_data from struct request to store per request
private data - this is problematic since this member is part of a
union which is also used by IO schedulers.
Let the block layer maintain space for per request data behind each
struct request.

Fixes crashes on block layer timeouts like this one:

Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 0000000000000000 TEID: 0000000000000483
Fault in home space mode while using kernel ASCE.
AS:0000000001308007 R3:00000000fffc8007 S:00000000fffcc000 P:000000000000013d
Oops: 0004 ilc:2 [#1] PREEMPT SMP
Modules linked in: [...]
CPU: 0 PID: 1480 Comm: kworker/0:2H Not tainted 4.17.0-rc4-00046-gaa3bcd43b5af #203
Hardware name: IBM 3906 M02 702 (LPAR)
Workqueue: kblockd blk_mq_timeout_work
Krnl PSW : 0000000067ac406b 00000000b6960308 (do_raw_spin_trylock+0x30/0x78)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 0000000000000c00 0000000000000000 0000000000000000 0000000000000001
0000000000b9d3c8 0000000000000000 0000000000000001 00000000cf9639d8
0000000000000000 0700000000000000 0000000000000000 000000000099f09e
0000000000000000 000000000076e9d0 000000006247bb08 000000006247bae0
Krnl Code: 00000000001c159c: b90400c2 lgr %r12,%r2
00000000001c15a0: a7180000 lhi %r1,0
#00000000001c15a4: 583003a4 l %r3,932
>00000000001c15a8: ba132000 cs %r1,%r3,0(%r2)
00000000001c15ac: a7180001 lhi %r1,1
00000000001c15b0: a784000b brc 8,1c15c6
00000000001c15b4: c0e5004e72aa brasl %r14,b8fb08
00000000001c15ba: 1812 lr %r1,%r2
Call Trace:
([<0700000000000000>] 0x700000000000000)
[<0000000000b9d3d2>] _raw_spin_lock_irqsave+0x7a/0xb8
[<000000000099f09e>] dasd_times_out+0x46/0x278
[<000000000076ea6e>] blk_mq_terminate_expired+0x9e/0x108
[<000000000077497a>] bt_for_each+0x102/0x130
[<0000000000774e54>] blk_mq_queue_tag_busy_iter+0x74/0xd8
[<000000000076fea0>] blk_mq_timeout_work+0x260/0x320
[<0000000000169dd4>] process_one_work+0x3bc/0x708
[<000000000016a382>] worker_thread+0x262/0x408
[<00000000001723a8>] kthread+0x160/0x178
[<0000000000b9e73a>] kernel_thread_starter+0x6/0xc
[<0000000000b9e734>] kernel_thread_starter+0x0/0xc
INFO: lockdep is turned off.
Last Breaking-Event-Address:
[<0000000000b9d3cc>] _raw_spin_lock_irqsave+0x74/0xb8

Kernel panic - not syncing: Fatal exception: panic_on_oops

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: Use blk_queue_flag_*() in drivers instead of queue_flag_*()

This patch has been generated as follows:

for verb in set_unlocked clear_unlocked set clear; do
replace-in-files queue_flag_${verb} blk_queue_flag_${verb%_unlocked} \
$(git grep -lw queue_flag_${verb} drivers block/bsg*)
done

Except for protecting all queue flag changes with the queue lock
this patch does not change any functionality.

Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: remove unneeded sanity check

Reported by smatch that the usage of cqr->block is inconsistent.
The sanity check is not needed because _dasd_requeue_request already
checks for a valid cqr->block pointer and all referenced ERP requests
have a valid cqr->block pointer as well since it is copied during ERP
process.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix handling of internal requests

Internal DASD device driver I/O such as query host access count or
path verification is started using the _sleep_on() function.
To mark a request as started or ended the callback_data is set to either
DASD_SLEEPON_START_TAG or DASD_SLEEPON_END_TAG.

In cases where the request has to be stopped unconditionally the status is
set to DASD_SLEEPON_END_TAG as well which leads to immediate clearing of
the request.
But the request might still be on a device request queue for normal
operation which might lead to a panic because of a BUG() statement in
__dasd_device_process_final_queue() or a list corruption of the device
request queue.

Fix by removing the setting of DASD_SLEEPON_END_TAG in the
dasd_cancel_req() and dasd_generic_requeue_all_requests() functions and
ensure that the request is not deleted in the requeue function.
Trigger the device tasklet in the requeue function and let the normal
processing cleanup the request.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Remove dead return code checks

In dasd_term_IO() ccw_device_clear() is called and the return code is
checked afterwards. Though, the return codes -EIO and -EBUSY will never
be returned and can therefore be removed from the check.

In dasd_start_IO() the return code of either ccw_device_tm_start() or
ccw_device_start() is checked. However, neither of them returns
-ETIMEDOUT. Remove that check as well.

Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Acked-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: remove 'struct timespec' usage

getnstimeofday() and timespec are deprecated since they can
overflow on 32-bit architectures. This simply changes to the
explicitly typed timespec64 version that doesn't have that
problem.

It would be nice to also convert to monotonic timestamps
and call ktime_get_ts64() rather than ktime_get_real_ts64(),
but that would be a user-visible change.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: block: add SPDX identifiers to the remaining files

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/s390/block/ files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Stefan Haberland <sth@linux.vnet.ibm.com>
Cc: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

treewide: setup_timer() -> timer_setup()

This converts all remaining cases of the old setup_timer() API into using
timer_setup(), where the callback argument is the structure already
holding the struct timer_list. These should have no behavioral changes,
since they just change which pointer is passed into the callback with
the same available pointers after conversion. It handles the following
examples, in addition to some other variations.

Casting from unsigned long:

void my_callback(unsigned long data)
{
struct something *ptr = (struct something *)data;
...
}
...
setup_timer(&ptr->my_timer, my_callback, ptr);

and forced object casts:

void my_callback(struct something *ptr)
{
...
}
...
setup_timer(&ptr->my_timer, my_callback, (unsigned long)ptr);

become:

void my_callback(struct timer_list *t)
{
struct something *ptr = from_timer(ptr, t, my_timer);
...
}
...
timer_setup(&ptr->my_timer, my_callback, 0);

Direct function assignments:

void my_callback(unsigned long data)
{
struct something *ptr = (struct something *)data;
...
}
...
ptr->my_timer.function = my_callback;

have a temporary cast added, along with converting the args:

void my_callback(struct timer_list *t)
{
struct something *ptr = from_timer(ptr, t, my_timer);
...
}
...
ptr->my_timer.function = (TIMER_FUNC_TYPE)my_callback;

And finally, callbacks without a data assignment:

void my_callback(unsigned long data)
{
...
}
...
setup_timer(&ptr->my_timer, my_callback, 0);

have their argument renamed to verify they're unused during conversion:

void my_callback(struct timer_list *unused)
{
...
}
...
timer_setup(&ptr->my_timer, my_callback, 0);

The conversion is done with the following Coccinelle script:

spatch --very-quiet --all-includes --include-headers \
-I ./arch/x86/include -I ./arch/x86/include/generated \
-I ./include -I ./arch/x86/include/uapi \
-I ./arch/x86/include/generated/uapi -I ./include/uapi \
-I ./include/generated/uapi --include ./include/linux/kconfig.h \
--dir . \
--cocci-file ~/src/data/timer_setup.cocci

@fix_address_of@
expression e;
@@

setup_timer(
-&(e)
+&e
, ...)

// Update any raw setup_timer() usages that have a NULL callback, but
// would otherwise match change_timer_function_usage, since the latter
// will update all function assignments done in the face of a NULL
// function initialization in setup_timer().
@change_timer_function_usage_NULL@
expression _E;
identifier _timer;
type _cast_data;
@@

(
-setup_timer(&_E->_timer, NULL, _E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E->_timer, NULL, (_cast_data)_E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, &_E);
+timer_setup(&_E._timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, (_cast_data)&_E);
+timer_setup(&_E._timer, NULL, 0);
)

@change_timer_function_usage@
expression _E;
identifier _timer;
struct timer_list _stl;
identifier _callback;
type _cast_func, _cast_data;
@@

(
-setup_timer(&_E->_timer, _callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
_E->_timer@_stl.function = _callback;
|
_E->_timer@_stl.function = &_callback;
|
_E->_timer@_stl.function = (_cast_func)_callback;
|
_E->_timer@_stl.function = (_cast_func)&_callback;
|
_E._timer@_stl.function = _callback;
|
_E._timer@_stl.function = &_callback;
|
_E._timer@_stl.function = (_cast_func)_callback;
|
_E._timer@_stl.function = (_cast_func)&_callback;
)

// callback(unsigned long arg)
@change_callback_handle_cast
depends on change_timer_function_usage@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
identifier _handle;
@@

void _callback(
-_origtype _origarg
+struct timer_list *t
)
{
(
... when != _origarg
_handletype *_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle;
... when != _handle
_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle;
... when != _handle
_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
)
}

// callback(unsigned long arg) without existing variable
@change_callback_handle_cast_no_arg
depends on change_timer_function_usage &&
!change_callback_handle_cast@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
@@

void _callback(
-_origtype _origarg
+struct timer_list *t
)
{
+ _handletype *_origarg = from_timer(_origarg, t, _timer);
+
... when != _origarg
- (_handletype *)_origarg
+ _origarg
... when != _origarg
}

// Avoid already converted callbacks.
@match_callback_converted
depends on change_timer_function_usage &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier t;
@@

void _callback(struct timer_list *t)
{ ... }

// callback(struct something *handle)
@change_callback_handle_arg
depends on change_timer_function_usage &&
!match_callback_converted &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
@@

void _callback(
-_handletype *_handle
+struct timer_list *t
)
{
+ _handletype *_handle = from_timer(_handle, t, _timer);
...
}

// If change_callback_handle_arg ran on an empty function, remove
// the added handler.
@unchange_callback_handle_arg
depends on change_timer_function_usage &&
change_callback_handle_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
identifier t;
@@

void _callback(struct timer_list *t)
{
- _handletype *_handle = from_timer(_handle, t, _timer);
}

// We only want to refactor the setup_timer() data argument if we've found
// the matching callback. This undoes changes in change_timer_function_usage.
@unchange_timer_function_usage
depends on change_timer_function_usage &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg &&
!change_callback_handle_arg@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type change_timer_function_usage._cast_data;
@@

(
-timer_setup(&_E->_timer, _callback, 0);
+setup_timer(&_E->_timer, _callback, (_cast_data)_E);
|
-timer_setup(&_E._timer, _callback, 0);
+setup_timer(&_E._timer, _callback, (_cast_data)&_E);
)

// If we fixed a callback from a .function assignment, fix the
// assignment cast now.
@change_timer_function_assignment
depends on change_timer_function_usage &&
(change_callback_handle_cast ||
change_callback_handle_cast_no_arg ||
change_callback_handle_arg)@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_func;
typedef TIMER_FUNC_TYPE;
@@

(
_E->_timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-&_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-(_cast_func)_callback;
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-&_callback;
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-(_cast_func)_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
;
)

// Sometimes timer functions are called directly. Replace matched args.
@change_timer_function_calls
depends on change_timer_function_usage &&
(change_callback_handle_cast ||
change_callback_handle_cast_no_arg ||
change_callback_handle_arg)@
expression _E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_data;
@@

_callback(
(
-(_cast_data)_E
+&_E->_timer
|
-(_cast_data)&_E
+&_E._timer
|
-_E
+&_E->_timer
)
)

// If a timer has been configured without a data argument, it can be
// converted without regard to the callback argument, since it is unused.
@match_timer_function_unused_data@
expression _E;
identifier _timer;
identifier _callback;
@@

(
-setup_timer(&_E->_timer, _callback, 0);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0L);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0UL);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0L);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0UL);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0L);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0UL);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0L);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0UL);
+timer_setup(_timer, _callback, 0);
)

@change_callback_unused_data
depends on match_timer_function_unused_data@
identifier match_timer_function_unused_data._callback;
type _origtype;
identifier _origarg;
@@

void _callback(
-_origtype _origarg
+struct timer_list *unused
)
{
... when != _origarg
}

Signed-off-by: Kees Cook <keescook@chromium.org>

treewide: init_timer() -> setup_timer()

This mechanically converts all remaining cases of ancient open-coded timer
setup with the old setup_timer() API, which is the first step in timer
conversions. This has no behavioral changes, since it ultimately just
changes the order of assignment to fields of struct timer_list when
finding variations of:

init_timer(&t);
f.function = timer_callback;
t.data = timer_callback_arg;

to be converted into:

setup_timer(&t, timer_callback, timer_callback_arg);

The conversion is done with the following Coccinelle script, which
is an improved version of scripts/cocci/api/setup_timer.cocci, in the
following ways:
- assignments-before-init_timer() cases
- limit the .data case removal to the specific struct timer_list instance
- handling calls by dereference (timer->field vs timer.field)

spatch --very-quiet --all-includes --include-headers \
-I ./arch/x86/include -I ./arch/x86/include/generated \
-I ./include -I ./arch/x86/include/uapi \
-I ./arch/x86/include/generated/uapi -I ./include/uapi \
-I ./include/generated/uapi --include ./include/linux/kconfig.h \
--dir . \
--cocci-file ~/src/data/setup_timer.cocci

@fix_address_of@
expression e;
@@

init_timer(
-&(e)
+&e
, ...)

// Match the common cases first to avoid Coccinelle parsing loops with
// "... when" clauses.

@match_immediate_function_data_after_init_timer@
expression e, func, da;
@@

-init_timer
+setup_timer
( \(&e\|e\)
+, func, da
);
(
-\(e.function\|e->function\) = func;
-\(e.data\|e->data\) = da;
|
-\(e.data\|e->data\) = da;
-\(e.function\|e->function\) = func;
)

@match_immediate_function_data_before_init_timer@
expression e, func, da;
@@

(
-\(e.function\|e->function\) = func;
-\(e.data\|e->data\) = da;
|
-\(e.data\|e->data\) = da;
-\(e.function\|e->function\) = func;
)
-init_timer
+setup_timer
( \(&e\|e\)
+, func, da
);

@match_function_and_data_after_init_timer@
expression e, e2, e3, e4, e5, func, da;
@@

-init_timer
+setup_timer
( \(&e\|e\)
+, func, da
);
... when != func = e2
when != da = e3
(
-e.function = func;
... when != da = e4
-e.data = da;
|
-e->function = func;
... when != da = e4
-e->data = da;
|
-e.data = da;
... when != func = e5
-e.function = func;
|
-e->data = da;
... when != func = e5
-e->function = func;
)

@match_function_and_data_before_init_timer@
expression e, e2, e3, e4, e5, func, da;
@@
(
-e.function = func;
... when != da = e4
-e.data = da;
|
-e->function = func;
... when != da = e4
-e->data = da;
|
-e.data = da;
... when != func = e5
-e.function = func;
|
-e->data = da;
... when != func = e5
-e->function = func;
)
... when != func = e2
when != da = e3
-init_timer
+setup_timer
( \(&e\|e\)
+, func, da
);

@r1 exists@
expression t;
identifier f;
position p;
@@

f(...) { ... when any
init_timer@p(\(&t\|t\))
... when any
}

@r2 exists@
expression r1.t;
identifier g != r1.f;
expression e8;
@@

g(...) { ... when any
\(t.data\|t->data\) = e8
... when any
}

// It is dangerous to use setup_timer if data field is initialized
// in another function.
@script:python depends on r2@
p << r1.p;
@@

cocci.include_match(False)

@r3@
expression r1.t, func, e7;
position r1.p;
@@

(
-init_timer@p(&t);
+setup_timer(&t, func, 0UL);
... when != func = e7
-t.function = func;
|
-t.function = func;
... when != func = e7
-init_timer@p(&t);
+setup_timer(&t, func, 0UL);
|
-init_timer@p(t);
+setup_timer(t, func, 0UL);
... when != func = e7
-t->function = func;
|
-t->function = func;
... when != func = e7
-init_timer@p(t);
+setup_timer(t, func, 0UL);
)

Signed-off-by: Kees Cook <keescook@chromium.org>

s390/dasd: fix race during dasd initialization

Fix a panic in blk_mq_hctx_has_pending() that is caused by a racy call to
blk_mq_run_hw_queues in a dasd function that might get called with the
request queue not yet initialized during initialization.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: blk-mq conversion

Use new blk-mq interfaces. Use multiple queues and also use the block
layer complete helper that finish the IO on the CPU that initiated it.

Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Add discard support for FBA devices

The z/VM hypervisor provides virtual disks (VDISK) which are backed by
main memory of the hypervisor. Those devices are seen as DASD FBA disks
within the Linux guest.

Whenever data is written to such a device, memory is allocated
on-the-fly by z/VM accordingly. This memory, however, is not being freed
if data on the device is deleted by the guest OS.

In order to make memory usable after deletion again, add discard support
to the FBA discipline.

While at it, update comments regarding the DASD_FEATURE_* flags.

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Change unsigned long long to unsigned long

Unsigned long long and unsigned long were different in size for 31-bit.
For 64-bit the size for both datatypes is 8 Bytes and since the support
for 31-bit is long gone we can clean up a little and change everything
to unsigned long.
Change get_phys_clock() along the way to accept unsigned long as well so
that the DASD code can be consistent.

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: add average request times to dasd statistics

Add average times to the DASD statistics interface.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: remove unneeded code

Fix these set but not used warnings:

drivers/s390/block/dasd.c:3933:6: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
drivers/s390/block/dasd_alias.c:757:6: warning: variable 'rc' set but not used [-Wunused-but-set-variable]

In addition to that remove the test if an unsigned is < 0:

drivers/s390/block/dasd_devmap.c:153:11: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix hanging safe offline

The safe offline processing may hang forever because it waits for I/O
which can not be started because of the offline flag that prevents new
I/O from being started.

Allow I/O to be started during safe offline processing because in this
special case we take care that the queues are empty before throwing away
the device.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix unusable device after safe offline processing

The safe offline processing needs, as well as the normal offline
processing, to be locked against multiple parallel executions. But it
should be able to be overtaken by a normal offline processing to make sure
that the device does not wait forever for outstanding I/O if the user
wants to.

Unfortunately the parallel processing of safe offline and normal offline
might lead to a race situation where both threads report successful
execution to the CIO layer which in turn tries to deregister the kobject
of the device twice. This leads to a

refcount_t: underflow; use-after-free.

error and the device is not able to be set online again afterwards without
a reboot.

Correct the locking of the safe offline processing by doing the following:
- Use the cdev lock to secure all set and test operations to the
device flags.
- Two safe offline processes are locked against each other using
the DASD_FLAG_SAFE_OFFLINE and DASD_FLAG_SAFE_OFFLINE_RUNNING
device flags.
The differentiation between offline triggered and offline running
is needed since the normal offline attribute is owned by CIO and
we have to pass over control in between.
- The dasd_generic_set_offline process handles the offline
processing. It is locked against parallel execution using the
DASD_FLAG_OFFLINE.
- Only a running safe offline should be able to be overtaken by a
single normal offline. This is ensured by clearing the
DASD_FLAG_SAFE_OFFLINE_RUNNING flag when a normal offline
overtakes. So this can only happen ones.
- The safe offline just aborts in this case doing nothing and
the normal offline processing finishes as usual.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: introduce new block status code type

Currently we use nornal Linux errno values in the block layer, and while
we accept any error a few have overloaded magic meanings. This patch
instead introduces a new blk_status_t value that holds block layer specific
status codes and explicitly explains their meaning. Helpers to convert from
and to the previous special meanings are provided for now, but I suspect
we want to get rid of them in the long run - those drivers that have a
errno input (e.g. networking) usually get errnos that don't know about
the special block layer overloads, and similarly returning them to userspace
will usually return somethings that strictly speaking isn't correct
for file system operations, but that's left as an exercise for later.

For now the set of errors is a very limited set that closely corresponds
to the previous overloaded errno values, but there is some low hanging
fruite to improve it.

blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse
typechecking, so that we can easily catch places passing the wrong values.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

s390/dasd: check blockdevice pointer before trying to sync blockdevice

If safe offline is called for a DASD alias device a null pointer is passed
to fsync_bdev. So check for existence of the blockdevice before calling
fsync_bdev.
Should not be a real world problem since safe offline for an alias device
does not make sense and fsync_bdev can deal with a NULL pointer which it
gets after successful NULL pointer dereferencing on s390.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: check for device error pointer within state change interrupts

Check if the device pointer is valid. Just a sanity check since we already
are in the int handler of the device.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: channel path aware error recovery

With this feature, the DASD device driver more robustly handles DASDs
that are attached via multiple channel paths and are subject to
constant Interface-Control-Checks (IFCCs) and Channel-Control-Checks
(CCCs) or loss of High-Performance-FICON (HPF) functionality on one or
more of these paths.

If a channel path does not work correctly, it is removed from normal
operation as long as other channel paths are available. All extended
error recovery states can be queried and reset via user space
interfaces.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: extend dasd path handling

Store flags and path_data per channel path.
Implement get/set functions for various path masks.
The patch does not add functional changes.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Eliminate race condition in dasd_generic_set_offline()

Before we set a device offline, the open_count for the block device is
checked and certain flags are checked and set as well.
However, this is all done without holding any lock. Potentially, if the
open_count was checked but the DASD_FLAG_OFFLINE wasn't set yet, a
different process might want to increase the open_count depending on
whether DASD_FLAG_OFFLINE is set or not in the meanwhile.

This is quite racy and can lead to the loss of the device for that
process and subsequently lead to a panic.

Fix this by checking the open_count and setting the offline flags while
holding the ccwdev lock.

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Define often used variable

block->request_queue is used many times in dasd_setup_queue. Define a
separate variable to increase readability a bit and to make it better
reusable.

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Make setting queue_max_segments more explicit

Currently the block queue value max_segments is set to -1L, which
is then implicitly casted to unsigned short in blk_queue_max_segments.
This results in 65535 (64k) max_segments.

Even though the resulting value is correct, setting it implicitly using
-1L is rather confusing. Set the value explicitly using the USHRT_MAX
macro instead.

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix panic during offline processing

A DASD device consists of the device itself and a discipline with a
corresponding private structure. These fields are set up during online
processing right after the device is created and before it is processed by
the state machine and made available for I/O.
During offline processing the discipline pointer and the private data gets
freed within the state machine and without protection of the existing
reference count. This might lead to a kernel panic because a function might
have taken a device reference and accesses the discipline pointer and/or
private data of the device while this is already freed.

Fix by freeing the discipline pointer and the private data after ensuring
that there is no reference to the device left.

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix hanging offline processing

Internal I/O is processed by the _sleep_on_function which might wait for a
device to get operational. During offline processing this will never happen
and therefore the refcount of the device will not drop to zero and the
offline processing blocks as well.

Fix by letting requests fail in the _sleep_on function during offline
processing. No further handling of the requests is necessary since this is
internal I/O and the device is thrown away afterwards.

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: add missing KOBJ_CHANGE event for unformatted devices

The DASD device driver throws change events for the DASD blockdevice
after the online processing is done so that udev rules can take
actions after it.
The change event was missing for unformatted devices.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix hanging device after clear subchannel

When a device is in a status where CIO has killed all I/O by itself the
interrupt for a clear request may not contain an irb to determine the
clear function. Instead it contains an error pointer -EIO.
This was ignored by the DASD int_handler leading to a hanging device
waiting for a clear interrupt.

Handle -EIO error pointer correctly for requests that are clear pending and
treat the clear as successful.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Add new ioctl BIODASDCHECKFMT

Implement new DASD IOCTL BIODASDCHECKFMT to check a range of tracks on a
DASD volume for correct formatting. The following characteristics are
checked:
- Block size
- ECKD key length
- ECKD record ID
- Number of records per track

Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: add query host access to volume support

With this feature, applications can query if a DASD volume is online
to another operating system instances by checking the online status of
all attached hosts from the storage server.

Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix performance drop

Commit ca369d51b ("sd: Fix device-imposed transfer length limits")
introduced a new queue limit max_dev_sectors which limits the maximum
sectors for requests. The default value leads to small dasd requests
and therefor to a performance drop.
Set the max_dev_sectors value to the same value as the max_hw_sectors
to use the maximum available request size for DASD devices.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix failfast for disconnected devices

Enabling failfast should let request fail immediately if either an
error occurred or the device gets disconnected.
For disconnected devices new requests are not fetches from the block
queue and therefore failfast is not triggered.

Fix by letting the DASD driver fetch requests for disconnected devices
with failfast active.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: mark DASD devices as non rotational

We were able to reduce the CPU overhead of big paging scenarios
when announcing our paging disks as non-rotational.
Almost all dasd devices are implemented in storage servers with
cache, raid, striping and lots of magic. There is no point in
optimizing the disk schedulers and swap code for a single platter
moving arm rotational disks. Given the complexity of the setup
and the fact that this change is mostly to disable the additional
overhead in swap code, lets keep the other functionality unchanged
and do not disable the this device as entropy source - unlike other
non-rotational devices.

Suggested-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix kernel panic when alias is set offline

The dasd device driver selects which (alias or base) device is used
for a given requests when the request is build. If the chosen alias
device is set offline before the request gets queued to the device
queue the starting function may use device structures that are
already freed. This might lead to a hanging offline process or a
kernel panic.

Add a check to the starting function that returns the request to the
upper layer if the device is already in offline processing.

In addition to that prevent that an alias device that's already in
offline processing gets chosen as start device.

Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <peter.oberparleiter@linux.vnet.ibm.com>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Enable automatic loading of dasd_diag_mod

Enabling a DASD that was configured to use the DIAG250 access method
while the corresponding kernel module dasd_diag_mod has not been loaded
fails with an error message. To fix this, users need to manually load
the dasd_diag_mod module.

This procedure can be simplified by automatically loading the
dasd_diag_mod from within the kernel when a DASD configured for DIAG250
is set online.

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Fix unresumed device after suspend/resume having no paths

The DASD device driver prevents I/O from being started on stopped
devices. This also prevented channel paths to be verified and so
the device was unable to be resumed.
Fix by allowing path verification requests on stopped devices.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix unresumed device after suspend/resume

The DASD device driver only has a limited amount of memory to build
I/O requests.
This memory was used by blocklayer requests leading to an inability
to build needed internal requests to resume the device.
Fix by preventing the DASD driver to fetch requests for a stopped
device.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Reference-ID: RQM 2520
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix inability to set a DASD device offline

Fix ref counting for DASD devices leading to an inability to set a
DASD device offline.
Before a worker is scheduled the DASD device driver takes a reference
to the device. If the worker was already scheduled this reference was
never freed.
Fix by giving the reference to the DASD device free when
schedule_work() returns false.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: remove setting of scheduler from driver

Remove the hard coded scheduler for the DASD device driver to enable
change of the scheduler during runtime. Set recommended deadline
scheduler via additional udev rule.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: remove 31 bit support

Remove the 31 bit support in order to reduce maintenance cost and
effectively remove dead code. Since a couple of years there is no
distribution left that comes with a 31 bit kernel.

The 31 bit kernel also has been broken since more than a year before
anybody noticed. In addition I added a removal warning to the kernel
shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning
message") which let everybody know about the plan to remove 31 bit
code. We didn't get any response.

Given that the last 31 bit only machine was introduced in 1999 let's
remove the code.
Anybody with 31 bit user space code can still use the compat mode.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: cleanup profiling

The dasd driver has a lot of duplicated code to handle
dasd_global_profile. With this patch we use the same code for the
global and the per device profiling data. Note that dasd_stats_write
had to change slightly to maintain some odd differences between
A) per device and global profile and B) proc and sysfs interface
usage.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: add locking for global_profile access

Access to DASDs global statistics is done without locking which
can lead to inconsistent data. Add locking to fix this. Also move
the relevant structs in a global dasd_profile struct.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix list corruption for sleep_on requests

Fix race for sleep_on requests leading to list corruption.
The SLEEP_ON_END_TAG is set during CQR clean up. Remove it from
interrupt handler to avoid the CQR from being cleared when it is
still in the device_queue.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix infinite term I/O loop

During device activation all paths could be lost and since the device
is not active it has no indication of this fact - hence the CQR will
time-out. The following cancelation might fail with -EINVAL because
CIO took over control and started path verification. In this case mark
the CQR as being CLEARED since it could not be running any more.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: remove unused code

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: add support for control unit initiated reconfiguration

Add support for Control Unit Initiated Reconfiguration (CUIR) to
Linux, a storage server interface to reconcile concurrent hardware
changes between storage and host.

Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix infinite loop during format

Error recovery requests may not be cleaned up correctly so that other
needed erp requests can not be build because of insufficient memory.
This would lead to an infinite loop trying to build erp requests.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

dasd: fix error recovery for alias devices during format

Kernel panic or a hanging device during format if an alias device is
set offline or I/O errors occur.

Omit the error recovery procedure for alias devices and do retries on
the base device with full erp.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

dasd: fix list_del corruption during format

If I/O errors occur during format a kernel panic with a list_del
corruption may occur.

Stop error recovery procedure after an erp action was taken.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

dasd: fix unresponsive device during format

If path events occur the formatting process stucks because path
events may flush format requests from the queue.

Kick the format process after path events are handled.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

dasd: use aliases for formatted devices during format

Formatting of a previously formatted device is slower than newly
format a device when alias devices are available.
For already formatted devices the alias devices are not used for
formatting.

Fix the alias handling for already formatted devices.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: replace seq_printf by seq_puts

Fix checkpatch warnings:
"WARNING: Prefer seq_puts to seq_printf"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: replace pr_warning by pr_warn

Fix checkpatch warning:
"WARNING: Prefer pr_warn(... to pr_warning(..."
+ coalesce formats.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Move EXPORT_SYMBOL after function/variable

Fix checkpatch warnings:
"WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: remove unnecessary null test before debugfs_remove

This fixes checkpatch warning:
"WARNING: debugfs_remove(NULL) is safe this check is probably not required"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390: Fix misspellings using 'codespell' tool

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: hold request queue sysfs lock when calling elevator_init()

"elevator: Fix a race in elevator switching and md device initialization"
changed the semantics of elevator_init() in a way that now enforces to hold
the corresponding request queue's sysfs_lock when calling elevator_init()
to fix a race.
The patch did not convert the s390 dasd device driver which is the only
device driver which also calls elevator_init(). So add the missing locking.

Cc: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

s390/dasd: Write to profile data area only if it is available

We check for the existence of block->profile.data before we write to
it, but the dependent code block misses braces.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix hanging devices after path events

The processing of the dasd_block tasklet may have been interrupted
by a path event.
Restart the dasd tasklets in sleep_on_immediately function.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Fail all requests when DASD_FLAG_ABORTIO is set

Whenever a DASD request encounters a timeout we might
need to abort all outstanding requests on this or
even other devices.

This is especially useful if one wants to fail all
devices on one side of a RAID10 configuration, even
though only one device exhibited an error.

To handle this I've introduced a new device flag
DASD_FLAG_ABORTIO.
This flag is evaluated in __dasd_process_request_queue()
and will invoke blk_abort_request() for all
outstanding requests with DASD_CQR_FLAGS_FAILFAST set.
This will cause any of these requests to be aborted
immediately if the blk_timeout function is activated.

The DASD_FLAG_ABORTIO is also evaluated in
__dasd_process_request_queue to abort all
new request which would have the
DASD_CQR_FLAGS_FAILFAST bit set.

The flag can be set with the new ioctls 'BIODASDABORTIO'
and removed with 'BIODASDALLOWIO'.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Add 'timeout' attribute

This patch adds a 'timeout' attibute to the DASD driver.
When set to non-zero, the blk_timeout function will
be enabled with the timeout specified in the attribute.
Setting 'timeout' to '0' will disable block timeouts.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block/dasd: detailed I/O errors

The DASD driver is using FASTFAIL as an equivalent to the
transport errors in SCSI. And the 'steal lock' function maps
roughly to a reservation error. So we should be returning the
appropriate error codes when completing a request.

Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Implement block timeout handling

This patch implements generic block layer timeout handling
callbacks for DASDs. When the timeout expires the respective
cqr is aborted.

With this timeout handler time-critical request abort
is guaranteed as the abort does not depend on the internal
state of the various DASD driver queues.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: process all requests in the device tasklet

Originally the DASD device tasklet would process the entries on
the ccw_queue until the first non-final request was found.
Which was okay as long as all requests have the same retries and
expires parameter.
However, as we're now allowing to modify both it is possible to
have requests _after_ the first request which already have expired.
So we need to check all requests in the device tasklet.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: Clarify comment

dasd_cancel_req will never return 1, only 0.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix handling of gone paths

When a path is gone and dasd_generic_path_event is called with a
PE_PATH_GONE event, we must assume that any I/O request on that
subchannel is still running. This is unlike the dasd_generic_notify
handler and the CIO_NO_PATH event, which implies that the subchannel
has been cleared.
If dasd_generic_path_event finds that the path has been the last
usable path, it must not call dasd_generic_last_path_gone (which would
reset the state of running requests), but just set the
DASD_STOPPED_DC_WAIT bit.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block_device_operations->release() should return void

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

s390/dasd: fix hanging device after resume with internal error 13

If too many ccw requests are pre-build before a suspend/resume cycle
the device might not get enough memory to do path verification
during resume.
Requeue requests to the block device request queue on suspend and free
pre-build ccw requests.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: improve speed of dasdfmt

Reorganize format IO requests and enable usage of PAV.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

dasd: fix sysfs cleanup in dasd_generic_remove

When the DASD devices are detached from the driver, then the
dasd_generic_remove function is called. One of the things this
function should do is to remove the DASD specific sysfs attributes,
but this is not done in all cases. This is likely to cause an oops
when at a later point sysfs stumbles over the stale pointers. In
particular this happens when when the modules are unloaded and loaded
again.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/time: rename tod clock access functions

Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: add safe offline interface

The regular behavior of the DASD device driver when setting a device
offline is to return all outstanding I/O as failed. This behavior is
different from that of other System z operating systems and may lead
to unexpected data loss. Adding an explicit 'safe' offline function
will allow customers to use DASDs in the way they expect them to work.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: fix pathgroup race

If a new path is available we need to verify the path data. If it is the
first path for a device the stop bits are removed after path verification.
If a pathgroup is established we need to set system characteristics for
the lcu. Therefore I/O has to be started.
If the device is stopped the set system characteristics worker may block
the path verification worker and the device is blocked.

Turn on failfast for set system characteristics CQR to prevent a deadlock
with the path verification worker.

If a pathgroup is established on a device that is not in use trigger path
verification. Maybe we were not informed about a working path.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/dasd: move wake_up call

Ensure that all work is done when the process waiting for a
dasd state change is woken up. With this change it is save
to assume that after a userspace triggered state change and
a udev settle invocation there are no unexpected users of a
dasd device.

Acked-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/comments: unify copyright messages and remove file names

Remove the file name from the comment at top of many files. In most
cases the file name was wrong anyway, so it's rather pointless.

Also unify the IBM copyright statement. We did have a lot of sightly
different statements and wanted to change them one after another
whenever a file gets touched. However that never happened. Instead
people start to take the old/"wrong" statements to use as a template
for new files.
So unify all of them in one go.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

s390/dasd: add shutdown action

Add a mechanism to wait for outstanding IO during shutdown.
Schedule the block_bh and device_bh and wait until our request queues
are empty.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] dasd: prevent validate server for offline devices

Calling validate server on devices in offline processing may cause
an OOPS in the dasd_sleep_on function.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: revalidate server for new pathgroup

If a pathgroup is established we get an event and have to revalidate
the server to propagate supported features like PAV and enable them.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

switch debugfs to umode_t

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: move code out of buffer.c

Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[S390] dasd: prevent path verification before resume

Mark the device as suspended and delay execution of the path
verification worker to prevent mix-up.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: re-initialize read_conf buffer for retries

The buffer for read configuration data has to be initialized with an
EBCDIC string to show support for extended UIDs to z/VM.
If this read configuration data CQR needs to be retried, the buffer
may have changed in between. So re-initialize the buffer to get a
correct extended UID under z/VM.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: wait for terminated request

After terminating a request in the dasd_sleep_on_immediatly function,
wait for the clear interrupt to be received before starting the
new request. This prevents the requests from getting mixed up.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] fix mismatch in summation of I/O IRQ statistics

Current IRQ statistics support does not show detail counts for I/O
interrupts which are processed internally only. The result is a
summation count which is way off such as this one:

CPU0 CPU1 CPU2
I/O: 1331 710 442
[...]
QAI: 15 16 16 [I/O] QDIO Adapter Interrupt
QDI: 1 0 0 [I/O] QDIO Interrupt
DAS: 706 645 381 [I/O] DASD
C15: 26 10 0 [I/O] 3215
C70: 0 0 0 [I/O] 3270
TAP: 0 0 0 [I/O] Tape
VMR: 0 0 0 [I/O] Unit Record Devices
LCS: 0 0 0 [I/O] LCS
CLW: 0 0 0 [I/O] CLAW
CTC: 0 0 0 [I/O] CTC
APB: 0 0 0 [I/O] AP Bus

Fix this by moving I/O interrupt accounting into the common I/O layer.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: use vmalloc for statistics input buffer

The size of the buffer that is used to store DASD statistics input
strings depends on the user input. If the input string is to large,
the write operation could fail with -ENOMEM. To avoid this, use
vmalloc instead of kmalloc.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] dasd: add enhanced DASD statistics interface

This patch extends the DASD statistics to allow for a more detailed
analysis of DASD I/O operations. In particular we want the statistics
to provide answers to the following questions:
- How many requests used a PAV alias?
- How many requests used High Performance FICON?
- How do read request perform versus write requests?

The existing DASD statistics interface has several shortcomings
- The interface for global data is a formatted text table in procfs
(/proc/dasd/statistics). The layout is meant for human readers and
is not to easy to parse. If values get to large for the table
layout, they get scaled down.
- The statistics which are collected per block device can be
accessed via an ioctl interface, which can only be extended by
defining a new ioctl.
- There is no statistics interface for individual PAV base and alias
devices.

To overcome theses shortcomings we create a new DASD statistics
interface in debugfs. This interface will contain one entry for global
data, one per DASD block device, and one per DASD base and alias
device. Each file contains the statistic data in easy to parse
name/value and name/array pairs. The existing interfaces will remain
functional, but they will not be extended.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: prevent IO error during reserve/release loop

The termination of running CQR caused by reserve/release operations
may lead to an IO error if reserve/release is done in a tight loop.
Prevent this by increasing the retry counter after termination.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix race between open and offline

The dasd_open function uses the private_data pointer of the gendisk to
find the dasd_block structure that matches the gendisk. When a DASD
device is set offline, we set the private_data pointer of the gendisk
to NULL and later remove the dasd_block structure, but there is still
a small race window, in which dasd_open could first read a pointer
from the private_data field and then try to use it, after the structure
has already been freed.
To close this race window, we will store a pointer to the dasd_devmap
structure of the base device in the private_data field. The devmap
entries are not deleted, and we already have proper locking and
reference counting in place, so that we can safely get from a devmap
pointer to the dasd_device and dasd_block structures of the device.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: remove per-queue plugging

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

[S390] dasd: Correct retry counter for terminated I/O.

In case the DASD driver needs to term a running I/O the retry counter
is decreased twice.
Remove the unnecessary retry counter decrease in das_term_IO.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: Add support for raw ECKD access.

Normal I/O operations through the DASD device driver give only access
to the data fields of an ECKD device even for track based I/O.
This patch extends the DASD device driver to give access to whole
ECKD tracks including count, key and data fields.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: Prevent deadlock during suspend/resume.

The freeze callback may set a stop bit so that a worker thread could
not start I/O. The discipline specific freeze function waits for the
worker to be completed.
Set the stop_bit after the discipline specific freeze function has
returned and no worker is running.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: Improve handling of stolen DASD reservation

If a DASD device has been reserved by a Linux system, and later
this reservation is ‘stolen’ by a second system by means of an
unconditional reserve, then the first system receives a
notification about this fact. With this patch such an event can
be either ignored, as before, or it can be used to let the device
fail all I/O request, so that the device will not block anymore.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: do path verification for paths added at runtime

When a new path is added at runtime, the CIO layer will call the drivers
path_event callback. The DASD device driver uses this callback to trigger
a path verification for the new path. The driver will use only those
paths for I/O, which have been successfully verified.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: add High Performance FICON multitrack support

Some storage systems support multitrack High Performance FICON
requests, which read or write data to more than one track.
This patch enables the DASD device driver to generate multitrack
High Performance FICON requests.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: add support for irq statistics

Add support for DASD I/O interrupt statistics in /proc/interrupts.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: ignore unsolicited interrupts for DIAG

For the DASD DIAG discipline IO is started through special diagnose
calls. Unsolicited interrupts may contain information about the device
itself. But this information is not needed because the device is not
used directly.
Fix the case that an unimplemented dicipline function may be called
by ignoring unsolicited interrupts for the DIAG disciplin.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix unsolicited interrupt recognition

The dasd interrupt handler needs to distinguish solicited from
unsolicited interrupts, as unsolicited interrupts may require special
handling (e.g. summary unit checks) and solicited interrupts require
proper error recovery for the failed I/O request.
The interrupt handler needs to check several bit fields in the
interrupt response block (irb) to make this distinction.
So far our check of the status control bits has not been specific
enough, which may lead to a failed request getting just retried
instead of the necessary error recovery.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390/block: kill the big kernel lock

The dasd and dcssblk drivers gained the big
kernel lock in the recent pushdown from the
block layer, but they don't really need it,
so remove the calls without a replacement.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org

block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush()

Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA
requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with
-EOPNOTSUPP and blk_queue_ordered() is replaced with simpler
blk_queue_flush().

blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a
device has write cache and can flush it, it should set REQ_FLUSH. If
the device can handle FUA writes, it should also set REQ_FUA.

All blk_queue_ordered() users are converted.

* ORDERED_DRAIN is mapped to 0 which is the default value.
* ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH.
* ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

[S390] dasd: fix format string types

Get rid of these warnings:

drivers/s390/block/dasd.c: In function '__dasd_device_check_expire':
drivers/s390/block/dasd.c:1330: warning: format '%i' expects type 'int', but argument 4 has type 'long unsigned int'
drivers/s390/block/dasd.c:1337: warning: format '%i' expects type 'int', but argument 4 has type 'long unsigned int'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: push down BKL into .open and .release

The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.

This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.

The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.

Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: remove q->prepare_flush_fn completely

This removes q->prepare_flush_fn completely (changes the
blk_queue_ordered API).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

[S390] dasd: unit check handling during internal cio I/O

React on unit checks during cio internal I/O.
Handle as unsolicited interrupt and advice cio to retry.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: add dynamic pav toleration

For base Parallel Access Volume (PAV) there is a fixed mapping of
base and alias devices. With dynamic PAV this mapping can be changed
so that an alias device is used with another base device.
This patch enables the DASD device driver to tolerate dynamic PAV
changes.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix race between tasklet and dasd_sleep_on

The various dasd_sleep_on functions use a global wait queue when
waiting for a cqr. The wait condition checks the status and devlist
fields of the cqr to determine if it is safe to continue. This
evaluation may return true, although the tasklet has not finished
processing of the cqr and the callback function has not been called
yet. When the callback is finally called, the data in the cqr may
already be invalid. The sleep_on wait condition needs a safe way to
determine if the tasklet has finished processing. Use the
callback_data field of the cqr to store a token, which is set by
the callback function itself.

Cc: <stable@kernel.org>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix endless loop in erp

If not enough memory is available to build a new erp request it ended
up in an endless loop trying to build erp requests. Fixed the loop to
proceed the next request instead.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: automatic recognition of read-only devices

In z/VM it is possible to attach a device as read-only. To prevent
unintentional write requests and subsequent I/O errors, we can detect
this configuration using the z/VM DIAG 210 interface and set the
respective linux block device to read-only as well.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: correct offline processing

Flushing the dasd ccw request queue may stop the processing of the
block device request queue. Destroy partitions may wait for
outstanding requests and thus hang.
Swapping dasd_destroy_partitions and dasd_flush_request_queue so that
the request queue is empty before dasd_destroy_partitions is called.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix refcounting.

The function dasd_device_from_cdev returns a reference to the dasd
device and increases the refcount by one. If an exception occurs,
the refcount was not decreased in all cases
e.g. in dasd_discipline_show.
Prevent the offline processing from hang by correcting two functions
to decrease the refcount even if an error occured.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix online/offline race

Setting a DASD online and offline in quick succession may cause
a kernel panic or let the chhccwdev command wait forever.
The Online process is split into two parts. After the first part
is finished the offline process may be called. This may result
in a situation where the second online processing part tries to
set the DASD offline as well.
Use a mutex to protect online and offline against each other.
Also correct some checking.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: Consolidate phys_segment and hw_segment limits

Except for SCSI no device drivers distinguish between physical and
hardware segment limits. Consolidate the two into a single segment
limit.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: Rename blk_queue_max_sectors to blk_queue_max_hw_sectors

The block layer calling convention is blk_queue_<limit name>.
blk_queue_max_sectors predates this practice, leading to some confusion.
Rename the function to appropriately reflect that its intended use is to
set max_hw_sectors.

Also introduce a temporary wrapper for backwards compability. This can
be removed after the merge window is closed.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

[S390] dasd: fix possible NULL pointer errors

Fix possible NULL pointer in DASD messages and correct discipline
checking.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: remove strings from s390dbf

Remove strings from s390 debugfeature entries that could lead to a
crash when the data is read from dbf because the strings do not exist
any more.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: improve error recovery for internal I/O

Most of the error conditions reported by a FICON storage server
indicate situations which can be recovered. Sometimes the host just
needs to retry an I/O request, but sometimes the recovery
is more complex and requires the device driver to wait, choose
a different path, etc.

The DASD device driver has a fully featured error recovery
for normal block layer I/O, but not for internal I/O request which
are for example used during the device bring up.
This can lead to situations where the IPL of a system fails because
DASD devices are not properly recognized.
This patch will extend the internal I/O handling to use the existing
error recovery procedures.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: remove dead code

the todclk.h header file is dead code. Remove it.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] cio: split PGID settings and status

Split setting (driver wants feature enabled) and status (feature
setup was successful) for PGID related ccw device features so that
setup errors can be detected. Previously, incorrectly handled setup
errors could in rare cases lead to erratic I/O behavior and
permanently unusuable devices.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: use idal for device characteristics

If the rdc_buffer is above 2G we need indirect addresssing so we have
to use an idaw to give the rdc_buffer to the ccw.
If the rdc_buffer is under 2G nothing changes.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix race condition in resume code

There is a race while re-reading the device characteristics. After
cleaning the memory area a cqr is build which reads the device
characteristics. This may take a rather long time and the device
characteristics structure is zero during this. Now it could be
possible that the block tasklet starts working and a new cqr will be
build. The build_cp command refers to the device characteristics
structure and this may lead into a divide by zero exception.
Fix this by re-reading the device characteristics into a temporary
structur and copy the data to the original structure. Also take the
ccwdev_lock.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

const: make block_device_operations const

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[S390] dasd: optimize cpu usage in goodcase

remove unnecessary dbf call, remove string operations for magic

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fail requests when device state is less then ready

A DASD device that is not ready or online has no defined disk layout,
so all requests that arrive in such a state need to be returned as
failed.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] drivers/s390: put NULL test before dereference

If the NULL test on block is needed, it should be before the dereference of
the base field.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression E1,E2;
identifier fld;
statement S1,S2;
@@

E1 = E2->fld;
(
if (E1 == NULL) S1 else S2
|
*if (E2 == NULL) S1 else S2
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix refcounting in dasd_change_state

To set a dasd online dasd_change_state is called twice. The first
cycle will schedule initial analysis of the device, set the rc to
-EAGAIN and will not touch the device state any more.
The initial analysis will in turn call dasd_change_state to increase
the state to the final DASD_STATE_ONLINE.

If the dasd_change_state on the second thread outruns the other one
both finish with the state set to DASD_STATE_ONLINE and the device
refcount will be decreased by 2.

Fix this by leaving dasd_change_state on rc == -EAGAIN so that the
refcount will always be decreased by 1.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd_pm: fix stop flag handling

The stop flags are handled in the generic restore function so the
stop flag is removed also for FBA and DIAG devices.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] pm: dasd power management callbacks.

Introduce the power management callbacks to the dasd driver. On suspend
the dasd devices are stopped and removed from the focus of alias
management.
On resume they are reinitialized by rereading the device characteristics
and adding the device to the alias management.
In case the device has gone away during suspend it will caught in the
suspend state with stopped flag set to UNRESUMED. After it appears again
the restore function is called again.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: forward internal errors to dasd_sleep_on caller

If a DASD requests is started with dasd_sleep_on and fails, then the
calling function may need to know the reason for the failure.
In cases of hardware errors it can inspect the sense data in the irb,
but when the reason is internal (e.g. start_IO failed) then it needs
a meaningfull return code.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: check_characteristics cleanup

Fix a broken memset (sizeof pointer vs sizeof the underlying
structure) by cleaning up the involved functions.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

block: Do away with the notion of hardsect_size

Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case. The
sector size will be 4KB but the logical block size will remain
512-bytes. Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: implement and enforce request peek/start/fetch

Till now block layer allowed two separate modes of request execution.
A request is always acquired from the request queue via
elv_next_request(). After that, drivers are free to either dequeue it
or process it without dequeueing. Dequeue allows elv_next_request()
to return the next request so that multiple requests can be in flight.

Executing requests without dequeueing has its merits mostly in
allowing drivers for simpler devices which can't do sg to deal with
segments only without considering request boundary. However, the
benefit this brings is dubious and declining while the cost of the API
ambiguity is increasing. Segment based drivers are usually for very
old or limited devices and as converting to dequeueing model isn't
difficult, it doesn't justify the API overhead it puts on block layer
and its more modern users.

Previous patches converted all block low level drivers to dequeueing
model. This patch completes the API transition by...

* renaming elv_next_request() to blk_peek_request()

* renaming blkdev_dequeue_request() to blk_start_request()

* adding blk_fetch_request() which is combination of peek and start

* disallowing completion of queued (not started) requests

* applying new API to all LLDs

Renamings are for consistency and to break out of tree code so that
it's apparent that out of tree drivers need updating.

[ Impact: block request issue API cleanup, no functional change ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: unsik Kim <donari75@gmail.com>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Laurent Vivier <Laurent@lvivier.info>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: convert to pos and nr_sectors accessors

With recent cleanups, there is no place where low level driver
directly manipulates request fields. This means that the 'hard'
request fields always equal the !hard fields. Convert all
rq->sectors, nr_sectors and current_nr_sectors references to
accessors.

While at it, drop superflous blk_rq_pos() < 0 test in swim.c.

[ Impact: use pos and nr_sectors accessors ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Mike Miller <mike.miller@hp.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: unsik Kim <donari75@gmail.com>
Cc: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

block: implement and use [__]blk_end_request_all()

There are many [__]blk_end_request() call sites which call it with
full request length and expect full completion. Many of them ensure
that the request actually completes by doing BUG_ON() the return
value, which is awkward and error-prone.

This patch adds [__]blk_end_request_all() which takes @rq and @error
and fully completes the request. BUG_ON() is added to to ensure that
this actually happens.

Most conversions are simple but there are a few noteworthy ones.

* cdrom/viocd: viocd_end_request() replaced with direct calls to
__blk_end_request_all().

* s390/block/dasd: dasd_end_request() replaced with direct calls to
__blk_end_request_all().

* s390/char/tape_block: tapeblock_end_request() replaced with direct
calls to blk_end_request_all().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>

[S390] dasd: Use the new async framework for autoonlining.

The dasd driver can automatically online detected dasds, which
especially important for finding the root device. Currently,
it will wait for each online operation to finish individually,
which may take long if many dasds need to be onlined. When using
the new async framework, these onlining operations can run in
parallel and presence of the root device is ensured by the fact
that prepare_namespace() waits for all async threads to finish.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] cio: introduce notifier for boxed state

If a ccw device did not respond in time during internal io, we set it
into boxed state. With this patch we have the following behaviour:
* the ccw driver will get a notification if the device was online and
goes into the boxed state
* if the device was disconnected and got boxed nothing special is to be
done (it will be handled in reprobing later)
* if the device got boxed while initial sensing it will be unregistered

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: message cleanup

Moved some Messages into s390 debug feature and changed remaining
messages to use the dev_xxx and pr_xxx macros.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: add High Performance FICON support

To support High Performance FICON, the DASD device driver has to
translate I/O requests into the new transport mode control words (TCW)
instead of the traditional (command mode) CCW requests.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: enable compat ioctls

All of the ioctls are compatible. Just enable them.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix race in dasd timer handling

In dasd_device_set_timer and dasd_block_set_timer we interpret the
return value of mod_timer in a wrong way. If the timer expires in
the small window between our check of timer_pending and the call to
mod_timer, then the timer will be set, mod_timer returns zero and
we will call add_timer for a timer that is already pending.
As del_timer and mod_timer do all the necessary checking themselves,
we can simplify our code and remove the race a the same time.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: send change uevents for dasd block devices

When a DASD device enters or leaves the 'online' state we need to
trigger change events for the respective disk and partitions.
These extra events are needed because when disk and partitions are
first added, udev rules that try to read disk labels or other data
may fail as the disk may not yet be ready.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: call cleanup_cqr with request_queue_lock

__dasd_cleanup_cqr should be called with request_queue_lock held and
__dasd_block_process_erp with queue_lock

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: log sense for fatal errors

The logging of sense data for fatal errors was accidentally removed
during Hyper PAV implementation.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[PATCH] switch dasd

->compat_ioctl() actually had been useless here; generic
logics works fine.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[PATCH] beginning of methods conversion

To keep the size of changesets sane we split the switch by drivers;
to keep the damn thing bisectable we do the following:
1) rename the affected methods, add ones with correct
prototypes, make (few) callers handle both. That's this changeset.
2) for each driver convert to new methods. *ALL* drivers
are converted in this series.
3) kill the old (renamed) methods.

Note that it _is_ a flagday; all in-tree drivers are converted and by the
end of this series no trace of old methods remain. The only reason why
we do that this way is to keep the damn thing bisectable and allow per-driver
debugging if anything goes wrong.

New methods:
open(bdev, mode)
release(disk, mode)
ioctl(bdev, mode, cmd, arg) /* Called without BKL */
compat_ioctl(bdev, mode, cmd, arg)
locked_ioctl(bdev, mode, cmd, arg) /* Called with BKL, legacy */

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[S390] bus_id -> dev_name conversions

bus_id -> dev_name() conversions in s390 code.

[cornelia.huck@de.ibm.com: minor adaptions]
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] cio: call ccw driver notify function with lock held

Calling a ccw driver's notify function without the ccw device lock
held opens up a race window between discovery and handling of a change
in the device operational state. As a result, the device driver may
encounter unexpected device malfunction, leading to out-of-retry
situations or similar.

Remove race by extending the ccw device lock from state change
discovery to the calling of the notify function.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] cio: introduce fcx enabled scsw format

Extend the scsw data structure to the format required by fcx. Also
provide helper functions for easier access to fields which are present
in both the traditional as well as the modified format.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] dasd: use a generic wait_queue for sleep_on

Use a generic wait_queue to prevent the wait_queue in dasd_sleep_on_
functions from being referenced by callback_data while it does not
exist any more.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix timeout handling in interrupt handler

When the dasd_int_handler is called with an error code instead of
an irb, the associated request should be restarted. This handling
was missing from the -ETIMEDOUT case. In fact it should be done in
any case.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] Fix a lot of sparse warnings.

Most noteable part of this commit is the new local header file entry.h
which contains all the function declarations of functions that get only
called from asm code or are arch internal. That way we can avoid extern
declarations in C files.
This is more or less the same that was done for sparc64.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] replace remaining __FUNCTION__ occurrences

__FUNCTION__ is gcc-specific, use __func__

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] dasd: fix double elevator_exit call when deadline iosched fails to load

I compiled the kernel without deadline, and the dasd code exits the old
scheduler (CFQ), fails to load the new one (deadline), and then things just
hang - with one of these (sorry about the weird chars - I copy & pasted it
from a 3270 console):

dasd(eckd): 0.0.0151: 3390/0A(CU:3990/01) Cyl:3338 Head:15 Sec:224
------------ cut here ------------
Badness at kernel/mutex.c:134
Modules linked in: dasd_eckd_mod dasd_mod
CPU: 0 Not tainted 2.6.25-rc3 #9
Process exe (pid: 538, task: 000000000d172000, ksp: 000000000d21ef88)
Krnl PSW : 0404000180000000 000000000022fb5c (mutex_lock_nested+0x2a4/0x2cc)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000024218 000000000076fc78 0000000000000000 000000000000000f
000000000022f92e 0000000000449898 000000000f921c00 000003e000162590
00000000001539c4 000000000d172000 070000007fffffff 000000000d21f400
000000000f8f2560 00000000002413f8 000000000022fb44 000000000d21f400
Krnl Code: 000000000022fb50: bf2f1000 icm %r2,15,0(%r1)
000000000022fb54: a774fef6 brc 7,22f940
000000000022fb58: a7f40001 brc 15,22fb5a
>000000000022fb5c: a7f4fef2 brc 15,22f940
000000000022fb60: c0e5fffa112a brasl %r14,171db4
000000000022fb66: 1222 ltr %r2,%r2
000000000022fb68: a784fedb brc 8,22f91e
000000000022fb6c: c010002a0086 larl %r1,76fc78
Call Trace:
(<000000000022f92e> mutex_lock_nested+0x76/0x2cc)
<00000000001539c4> elevator_exit+0x38/0x80
<0000000000156ffe> blk_cleanup_queue+0x62/0x7c
<000003e0001d5414> dasd_change_state+0xe0/0x8ec
<000003e0001d5cae> dasd_set_target_state+0x8e/0x9c
<000003e0001d5f74> dasd_generic_set_online+0x160/0x284
<000003e00011e83a> dasd_eckd_set_online+0x2e/0x40
<0000000000199bf4> ccw_device_set_online+0x170/0x2c0
<0000000000199d9e> online_store_recog_and_online+0x5a/0x14c
<000000000019a08a> online_store+0xbe/0x2ec
<000000000018456c> dev_attr_store+0x38/0x58
<000000000010efbc> sysfs_write_file+0x130/0x190
<00000000000af582> vfs_write+0xb2/0x160
<00000000000afc7c> sys_write+0x54/0x9c
<0000000000025e16> sys32_write+0x2e/0x50
<0000000000024218> sysc_noemu+0x10/0x16
<0000000077e82bd2> 0x77e82bd2

Set elevator pointer to NULL in order to avoid double elevator_exit
calls when elevator_init call for deadline iosched fails.
Also make sure the dasd device driver depends on IOSCHED_DEADLINE so
the default IO scheduler of the dasd driver is present.

Signed-off-by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] dasd: fix locking in __dasd_device_process_final_queue

After setting the status of the cqr and releasing the lock for the
block cqr queue, we call the cqr callback function, which will usually
just trigger the dasd_block_tasklet. But when the tasklet is already
running the cqr might be processed before we invoke the callback
function. In rare cases the callback pointer may already be invalid
by the time we want to call it, which will result in a panic.
Solution: Call the callback function first and then release the lock.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix panic caused by alias device offline

When an alias device is set offline while it is in use this may
result in a panic in the cleanup part of the dasd_block_tasklet.
The problem here is that there may exist some ccw requests that were
originally created for the alias device and transferred to the base
device when the alias was set offline. When these request are
cleaned up later, the discipline pointer in the alias device may not
be valid anymore. To fix this use the base device discipline to find
the cleanup function.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: add ifcc handling

Adding interface control check (ifcc) handling in error recovery.
First retry up to 255 times and if all retries fail try an alternate
path if possible.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

blk_end_request: changing s390 (take 4)

This patch converts s390 to use blk_end_request interfaces.
Related 'uptodate' arguments are converted to 'error'.

As a result, the interfaces of internal functions below are changed:
o dasd_end_request
o tapeblock_end_request

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

[S390] usage of s390dbf: shrink number of debug areas to use.

Signed-off-by: Peter Tiedemann <ptiedem@de.ibm.com>

[S390] dasd: fix loop in request expiration handling

Add time to the 'expires' value to avoid a loop caused by the cqr
termination function

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: add hyper PAV support to DASD device driver, part 1

Parallel access volumes (PAV) is a storage server feature, that allows
to start multiple channel programs on the same DASD in parallel. It
defines alias devices which can be used as alternative paths to the
same disk. With the old base PAV support we only needed rudimentary
functionality in the DASD device driver. As the mapping between base
and alias devices was static, we just had to export an identifier
(uid) and could leave the combining of devices to external layers
like a device mapper multipath.
Now hyper PAV removes the requirement to dedicate alias devices to
specific base devices. Instead each alias devices can be combined with
multiple base device on a per request basis. This requires full
support by the DASD device driver as now each channel program itself
has to identify the target base device.
The changes to the dasd device driver and the ECKD discipline are:
- Separate subchannel device representation (dasd_device) from block
device representation (dasd_block). Only base devices are block
devices.
- Gather information about base and alias devices and possible
combinations.
- For each request decide which dasd_device should be used (base or
alias) and build specific channel program.
- Support summary unit checks, which allow the storage server to
upgrade / downgrade between base and hyper PAV at runtime (support
is mandatory).

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix return value of dasd_generic_probe()

Using the return value of ccw_device_set_online as return value for
dasd_generic_probe() causes the DASD to fail setting online

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[BLOCK] Get rid of request_queue_t typedef

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

[S390] Avoid sparse warnings.

Monthly sparse warning avoidance patch. Sigh.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[S390] dasd: Fix modular build.

Add missing export of dasd_generic_read_dev_chars().

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: New read device characteristics and read configuration data.

Instead of the deprecated read_dev_chars() and read_conf_data_lpm(),
implement dasd_generic_read_dev_chars() and dasd_eckd_read_conf_lpm().
These should even recover better from error than the original cio
functions.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: Add sysfs attribute status and generate uevents.

This patch adds a sysfs-attribute 'status' to make the DASD device-status
accessible from user-space. In addition, the DASD driver generates an
uevent(CHANGE) for the ccw-device on each device-status change.
This enables user-space applications (e.g. udev) to do related processing.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] Avoid excessive inlining.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] ETR support.

This patch adds support for clock synchronization to an external time
reference (ETR). The external time reference sends an oscillator
signal and a synchronization signal every 2^20 microseconds to keep
the TOD clocks of all connected servers in sync. For availability
two ETR units can be connected to a machine. If the clock deviates
for more than the sync-check tolerance all cpus get a machine check
that indicates that the clock is out of sync. For the lovely details
how to get the clock back in sync see the code below.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix unconditional reserve handling.

The reserve/release IOCTLs sometimes do not work. If second system
does a 'steal lock' the pending unit check (Format 3 Msg F) is
delivered. Since ERP is disabled for reserve/release, the IOCTL call
fails. We have to allow basic ERP (retries) for reserve/release IOCTLs.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] Get rid of a lot of sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] New DASD feature for ERP related logging

It is now possible to enable/disable ERP related logging without re-compile
and re-ipl. A additional sysfs-attribute 'erplog' allows to switch the
logging non-interruptive.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[PATCH] More work_struct induced breakage (s390)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[S390] Enhanced handling of failed termination requests.

In case a request timed out and termination did not work, the console was
flooded with retry messages (every 1/10s). Now we use a 5s delay per retry and
generate a more precise message.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: clean up timer.

Clean up dasd timer when when a dasd device is set offline.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd default debug level.

Enhanced default DBF level to get most important messages
in debug feature files.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd deadlock after state change pending interrupt.

The dasd_device_from_cdev function is called from interrupt context
to get the struct dasd_device associated with a ccw device. The
driver_data of the ccw device points to the dasd_devmap structure
which contains the pointer to the dasd_device structure. The lock
that protects the dasd_devmap structure is acquire with out irqsave.
To prevent the deadlock in dasd_device_from_cdev if it is called
from interrupt context the dependency to the dasd_devmap structure
needs to be removed. Let the driver_data of the ccw device point
to the dasd_device structure directly and use the ccw device lock
to protect the access.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd: fix device shutdown process.

Fix clear_IO handling (need to wait for interrupt) and
introduced error-handling in shutdown processing.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd set offline kernel bug.

The request queue flush function of the dasd driver has to dequeue
the requests first and then call the end request function. Otherwise
a kernel bug in ll_rw_block.c might get triggered.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Remove obsolete #include <linux/config.h>

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

[S390] add PAV support to the dasd driver.

Add support for parallel-access-volumes to the dasd driver. This
allows concurrent access to dasd devices with multiple channel
programs.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[S390] dasd whitespace and other cosmetics.

Dasd code cleanup: 1) remove white space, 2) remove the emacs override
sections, and 3) use kzalloc instead of kmalloc.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

[PATCH] devfs: Remove devfs_remove() function from the kernel tree

Removes the devfs_remove() function and all callers of it.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] devfs: Remove devfs_mk_dir() function from the kernel tree

Removes the devfs_mk_dir() function and all callers of it.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] s390: dasd ioctl never returns

The dasd state machine is not designed to enable an unformatted device, since
'unformatted' is a final state. The BIODASDENABLE ioctl calls
dasd_enable_device() which never returns if the device is in this special
state. Return -EPERM in dasd_increase_state for unformatted devices to make
dasd_enable_device terminate. Note: To get such an unformatted device online
it has to be re-analyzed. This means that the device needs to be disabled
prior to re-enablement.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: fail-fast requests on quiesced devices

Using the fail-fast flag in i/o requests on a dasd disk which has been
quiesced leads to kernel panics. Modify the request start function to only
work on requests in a valid state.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd device offline messages

The dasd driver sometimes print the misleading message "Can't offline dasd
device with open count = 0". The reason why it can't offline the device in
this case is that the device is still in the startup phase. Print a more
meaningful message.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Remove MODULE_PARM

MODULE_PARM was actually breaking: recent gcc version optimize them out as
unused. It's time to replace the last users, which are generally in the
most unloved drivers anyway.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

BUG_ON() Conversion in drivers/s390/block/dasd.c

this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

[PATCH] s390: kzalloc() conversion in drivers/s390

Convert all kmalloc + memset sequences in drivers/s390 to kzalloc usage.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd extended error reporting

The DASD extended error reporting is a facility that allows to get detailed
information about certain problems in the DASD I/O. This information can be
used to implement fail-over applications that can recover these problems.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: use normal switch statement for ioctls in dasd_ioctlc

Handle ioctls implemented in dasd_ioctl through the normal switch statement
that most drivers use instead of the awkward dasd_ioctl_no_register routine.
This avoids searching a linear list on every call to dasd_ioctl(), and allows
to give the various ioctl implementation functions sane prototypes, aswell as
moving the check for bdev->bd_disk->private_data from the individual functions
to dasd_ioctl. (I think it can't actually every be NULL, but let's keep that
for later)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd partition detection

DASD allows to open a device as soon as gendisk is registered, which means the
device is a fake device (capacity=0) and we do know nothing about blocksize
and partitions at that point of time. In case the device is opened by
someone, the bdev and inode creation is done with the fake device info and the
following partition detection code is just using the wrong data.

To avoid this modify the DASD state machine to make sure that the open is
rejected until the device analysis is either finished or an unformatted device
was detected.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: revert dasd eer module

Revert dasd eer module until we have a common understanding of how the
interface should be.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd reference counting

When using the dasd diag discipline, the base discipline module (eckd or fba)
can be unloaded, even though the dasd driver requires both discipline modules
(base and diag) to work correctly.

Implement reference counting for both base and diag discipline modules in
order to fix this.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd extended error reporting module

The DASD extended error reporting is a facility that allows to get detailed
information about certain problems in the DASD I/O. This information can be
used to implement fail-over applications that can recover these problems.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd wait for clear i/o interrupt

The sleep_on function clears a running cqr without waiting for the related
interrupt. This can lead to a panic at the time the interrupt is processed
because the related memory might already be freed. Wait for clear-interrupt
and de-queue cqr prior to return.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: Remove CVS generated information

- Remove all CVS generated information like e.g. revision IDs from
drivers/s390 and include/asm-s390 (none present in arch/s390).

- Add newline at end of arch/s390/lib/Makefile to avoid diff message.

Acked-by: Andreas Herrmann <aherrman@de.ibm.com>
Acked-by: Frank Pavlic <pavlic@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: fix blk_queue_ordered call in dasd.c fixup

The QUEUE_ORDERED_* numbers got renumbered and by accident the dasd driver
was changed to use QUEUE_ORDERED_DRAIN instead of QUEUE_ORDERED_TAG.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: fix blk_queue_ordered call in dasdc

Add the missing third argument to the blk_queue_ordered call and use the
constant QUEUE_ORDERED_DRAIN instead of "1".

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] add ->compat_ioctl to dasd

Add a compat_ioctl method to the dasd driver so the last entries in
arch/s390/kernel/compat_ioctl.c can go away. Unlike the previous attempt this
one does not replace the ioctl method with an unlocked_ioctl method so that
the ioctl_by_bdev calls in s390 partition code continue to work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Add block_device_operations.getgeo block device method

HDIO_GETGEO is implemented in most block drivers, and all of them have to
duplicate the code to copy the structure to userspace, as well as getting
the start sector. This patch moves that to common code [1] and adds a
->getgeo method to fill out the raw kernel hd_geometry structure. For many
drivers this means ->ioctl can go away now.

[1] the s390 block drivers are odd in this respect. xpram sets ->start
to 4 always which seems more than odd, and the dasd driver shifts
the start offset around, probably because of it's non-standard
sector size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@suse.de>
Cc: <mike.miller@hp.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: cleanup Kconfig

Sanitize some s390 Kconfig options. We have ARCH_S390, ARCH_S390X,
ARCH_S390_31, 64BIT, S390_SUPPORT and COMPAT. Replace these 6 options by
S390, 64BIT and COMPAT.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: dasd failfast support

To properly support multipath-failover handling, the linux block layer has
introduced a special request flag, 'REQ_FAILFAST'. This flag is now used to
return requests immediately in case the device is not operational.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: atomic primitives

Hugh Dickins <hugh@veritas.com>

Fix the broken atomic_cmpxchg primitive. Add atomic_sub_and_test,
atomic64_sub_return, atomic64_sub_and_test, atomic64_cmpxchg,
atomic64_add_unless and atomic64_inc_not_zero. Replace old style
atomic_compare_and_swap by atomic_cmpxchg. Shorten the whole header by
defining most primitives with the two inline functions atomic_add_return and
atomic_sub_return.

In addition this patch contains the s390 related fixes of Hugh's "mm: fill
arch atomic64 gaps" patch.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[BLOCK] add @uptodate to end_that_request_last() and @error to rq_end_io_fn()

add @uptodate argument to end_that_request_last() and @error
to rq_end_io_fn(). there's no generic way to pass error code
to request completion function, making generic error handling
of non-fs request difficult (rq->errors is driver-specific and
each driver uses it differently). this patch adds @uptodate
to end_that_request_last() and @error to rq_end_io_fn().

for fs requests, this doesn't really matter, so just using the
same uptodate argument used in the last call to
end_that_request_first() should suffice. imho, this can also
help the generic command-carrying request jens is working on.

Signed-off-by: tejun heo <htejun@gmail.com>
Signed-Off-By: Jens Axboe <axboe@suse.de>

[PATCH] kfree cleanup: drivers/s390

This is the drivers/s390/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in drivers/s390/.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Cornelia Huck <cohuck@de.ibm.com>
Acked-by: Stefan Bader <Stefan.Bader@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: deadlock in dasd_devmap

Reintroduce a read-only copy of the devmap features in the device struct.
This is necessary to solve a deadlock on the dasd_devmap_lock which is
acquired by dasd_get_features called from the dasd tasklet. The current
implementation of devmap doesn't allow to call any devmap function from
interrupt or softirq context.

Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] s390: free dasd slab cache

Free dasd slab cache on module unload.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>