USB: atm: Use the correct style for SPDX License Identifier

This patch corrects the SPDX License Identifier style in
header file related to USB DSL modem support drivers.
For C header files Documentation/process/license-rules.rst
mandates C-like comments (opposed to C source files where
C++ style should be used).

Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Link: https://lore.kernel.org/r/20200315102844.GA3460@nishad
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200220132017.GA29262@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: atm: Remove redundant license text

Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Duncan Sands <duncan.sands@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: add SPDX identifiers to all remaining files in drivers/usb/

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/usb/ and include/linux/usb* 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: 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>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usbatm: Fix dynamic_debug / ratelimited atm_dbg and atm_rldbg macros

Fix atm_dbg to use normal pr_debug not dynamic_pr_debug
because dynamic_pr_debug may not be compiled in at all.

Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbatm: move the atm_dbg() call to use dynamic debug

Move the atm_dbg() call to use the dynamic debug subsystem, and not rely
on CONFIG_USB_DEBUG for if things should be printed out or not.

This also means the drivers do not have to be rebuilt to get debugging
messages, important for getting information from users who can not
rebuild their kernels.

Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbatm: don't rely on CONFIG_USB_DEBUG

Enable the USB atm drivers to use the dynamic debugging subsystem, and
not rely on if CONFIG_USB_DEBUG is enabled or not for debugging
messages. This also provides a saner debug message, pointing out the
exact device the message is coming from.

This also means the drivers do not have to be rebuilt to get debugging
messages, important for getting information from users who can not
rebuild their kernels.

Cc: Duncan Sands <duncan.sands@free.fr>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

USB: usbatm: remove unused UDSL_ASSERT macro

If this code isn't triggering this assert by now, it never will, so just
remove it, it's pointless.

Cc: Duncan Sands <duncan.sands@free.fr>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: atm: fixed spacing and indentation coding style issues

Fixed spacing and indentation coding style issues.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

USB: cxacru: check device isn't being removed during sysfs calls

It is possible for usb_get_intfdata() to return NULL if
sysfs is accessed while the module is being unloaded or
the device is being removed.

Move the access code to an inline function in usbatm.h,
and return -ENODEV if any of the pointers are NULL.

It should not be possible for the instance data or atm
device to be invalid until after unbind() completes and
the sysfs attributes have been removed.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

USB: remove warn() macro from usb drivers

USB should not be having it's own printk macros, so remove warn() and
use the system-wide standard of dev_warn() wherever possible. In the
few places that will not work out, use a basic printk().

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

USB: usbatm: convert heavy init dances to kthread API

This is an attempt to kill two birds with one stone.

First, we kill one more user of kernel_thread, which is scheduled
for removal. Second - we kill one of the last users of kill_proc -
the function which is also to be removed, because it uses a pid_t
which is not safe now.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers: Remove unnecessary inclusions of asm/semaphore.h

None of these files use any of the functionality promised by
asm/semaphore.h. It's possible that they rely on it dragging in some
unrelated header file, but I can't build all these files, so we'll have
fix any build failures as they come up.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

[PATCH] USBATM: semaphore to mutex conversion

This is the usbatm part of the Arjan, Jes and Ingo
mass semaphore to mutex conversion, reworked to apply on top
of the patches I just sent to you. This time, with correct
attribution and signed-off lines.

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: -EILSEQ workaround

Don't throttle on -EILSEQ urb status if requested by a minidriver.
It seems the ueagle modems are buggy, giving -EILSEQ when they
have no data to send. The ueagle change will be sent separately
by the ueagle guys. Patch by Matthieu Castet.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: handle urbs containing partial cells

The receive logic has always assumed that urbs contain an integral
number of ATM cells, which is a bit naughty, though it never caused
any problems with bulk transfers. Isochronous urbs spank us soundly
for this. Fixed thanks to this patch, mostly by Stanislaw Gruszka.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: allow isochronous transfer

While the usbatm core has had some support for using isoc urbs
for some time, there was no way for users to turn it on. While
use of isoc transfer should still be considered experimental, it
now works well enough to let users turn it on. Minidrivers signal
to the core that they want to use isoc transfer by setting the new
UDSL_USE_ISOC flag. The speedtch minidriver gets a new module
parameter enable_isoc (defaults to false), plus some logic that
checks for the existence of an isoc receive endpoint (not all
speedtouch modems have one).

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: shutdown open connections when disconnected

This patch causes vcc_release_async to be applied to any open
vcc's when the modem is disconnected. This signals a socket
shutdown, letting the socket user know that the game is up.
I wrote this patch because of reports that pppd would keep
connections open forever when the modem is disconnected.
This patch does not fix that problem, but it's a step in the
right direction. It doesn't help because the pppoatm module
doesn't yet monitor state changes on the ATM socket, so simply
never realises that the ATM connection has gone down (meaning
it doesn't tell the ppp layer). But at least there is a socket
state change now. Unfortunately this patch may create problems
for those rare users like me who use routed IP or some other
non-ppp connection method that goes via the ATM ARP daemon: the
daemon is buggy, and with this patch will crash when the modem
is disconnected. Users with a buggy atmarpd can simply restart
it after disconnecting the modem.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: remove .owner

Remove the unused .owner field in struct usbatm_driver.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: add flags field

Have minidrivers and the core signal special requirements
using a flags field in struct usbatm_data. For the moment
this is only used to replace the need_heavy_init bind
parameter, but there'll be new flags in later patches.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USBATM: trivial modifications

Formatting, changes to variable names, comments, log level changes,
printk rate limiting.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USB: move CONFIG_USB_DEBUG checks into the Makefile

This lets us remove a lot of code in the drivers that were all checking
the same thing. It also found some bugs in a few of the drivers, which
has been fixed up.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] USB: fix usbatm gcc-2.95.x bug

Work around the gcc-2.95.x macro expansion bug.

Cc: Duncan Sands <baldrick@free.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] USB ATM: new usbatm core

Rework the core usbatm code: minidrivers (i.e. drivers for particular
modems) now register themselves with the usbatm core, supplying methods
for binding/unbinding etc. The design was inspired by usb-serial and
usbnet. At the same time, more common code from the speedtch and
cxacru (patch 3/5) drivers was generalized and moved into the core. The
transmission and reception parts have been unified and simplified. Since
this is a major change and I don't like underscores in file names,
usb_atm.[ch] has been renamed usbatm.[ch].

Many thanks to Roman Kagan, who did a lot of the coding.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>