media: usbtv: Fix deadlock on suspend

usbtv doesn't support power management, so on system suspend the
.disconnect callback of the driver is called. The teardown sequence
includes a call to snd_card_free. Its implementation waits until the
refcount of the sound card device drops to zero, however, if its file is
open, snd_card_file_add takes a reference, which can't be dropped during
the suspend, because the userspace processes are already frozen at this
point. snd_card_free waits for completion forever, leading to a hang on
suspend.

This commit fixes this deadlock condition by replacing snd_card_free
with snd_card_free_when_closed, that doesn't wait until all references
are released, allowing suspend to progress.

Fixes: 63ddf68de52e ("[media] usbtv: add audio support")
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: Drop superfluous ioctl PCM ops

PCM core deals the empty ioctl field now as default.
Let's kill the redundant lines.

Cc: Bluecherry Maintainers <maintainers@bluecherrydvr.com>
Cc: Anton Sviridenko <anton@corp.bluecherry.net>
Cc: Andrey Utkin <andrey.utkin@corp.bluecherry.net>
Cc: Ismael Luceno <ismael@iodev.co.uk>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: usbtv: Use managed buffer allocation

Clean up the driver with the new managed buffer allocation API.
The hw_params and hw_free callbacks became superfluous and dropped.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: solo6x10: Remove superfluous snd_dma_continuous_data()

The recent change (commit 08422d2c559d: "ALSA: memalloc: Allow NULL
device for SNDRV_DMA_TYPE_CONTINOUS type") made the PCM preallocation
helper accepting NULL as the device pointer for the default usage.
Drop the snd_dma_continuous_data() usage that became superfluous from
the callers.

Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

media: use strscpy() instead of strlcpy()

The implementation of strscpy() is more robust and safer.

That's now the recommended way to copy NUL terminated strings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: usbtv: use irqsave() in USB's complete callback

The USB completion callback does not disable interrupts while acquiring
the lock. We want to remove the local_irq_disable() invocation from
__usb_hcd_giveback_urb() and therefore it is required for the callback
handler to disable the interrupts while acquiring the lock.
The callback may be invoked either in IRQ or BH context depending on the
USB host controller.
Use the _irqsave() variant of the locking primitives.

Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: usb: make snd_pcm_hardware const

Make these const as they are only used during a copy operation.
Done using Coccinelle.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] usb: constify snd_pcm_ops structures

Check for snd_pcm_ops structures that are only stored in the ops field of a
snd_soc_platform_driver structure or passed as the third argument to
snd_pcm_set_ops. The corresponding field or parameter is declared const,
so snd_pcm_ops structures that have this property can be declared as const
also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct snd_pcm_ops i@p = { ... };

@ok1@
identifier r.i;
struct snd_soc_platform_driver e;
position p;
@@
e.ops = &i@p;

@ok2@
identifier r.i;
expression e1, e2;
position p;
@@
snd_pcm_set_ops(e1, e2, &i@p)

@bad@
position p != {r.p,ok1.p,ok2.p};
identifier r.i;
struct snd_pcm_ops e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct snd_pcm_ops i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] media: usbtv: prevent access to free'd resources

When disconnecting the usbtv device, the sound card is unregistered
from ALSA and the snd member of the usbtv struct is set to NULL. If
the usbtv snd_trigger work is running, this can cause a race condition
where the kernel will attempt to access free'd resources, shown in
[1].

This patch fixes the disconnection code by cancelling any snd_trigger
work before unregistering the sound card from ALSA and checking that
the snd member still exists in the work function.

[1]:
usb 3-1.2: USB disconnect, device number 6
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: [<ffffffff81093850>] process_one_work+0x30/0x480
PGD 405bbf067 PUD 405bbe067 PMD 0
Call Trace:
[<ffffffff81093ce8>] worker_thread+0x48/0x4e0
[<ffffffff81093ca0>] ? process_one_work+0x480/0x480
[<ffffffff81093ca0>] ? process_one_work+0x480/0x480
[<ffffffff81099998>] kthread+0xd8/0xf0
[<ffffffff815c73c2>] ret_from_fork+0x22/0x40
[<ffffffff810998c0>] ? kthread_worker_fn+0x170/0x170
---[ end trace 0f3dac5c1a38e610 ]---

Signed-off-by: Matthew Leach <matthew@mattleach.net>
Tested-by: Peter Sutton <foxxy@foxdogstudios.com>
Cc: stable@vger.kernel.org
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] usbtv: clarify the licensing

OpenBSD would like to reuse some code but consider the licensing not
clear enough. Let's clarify it a bit so that it suits their conventions:

1.) Keep the "extra text" away from the copyright statement and the
rights grant.

2.) Add the warranty disclaimer -- it should not be legally required,
nevertheless the clause 1. of the rights grant refest to it.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Federico Simoncelli <fsimonce@redhat.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] Media: USB: usbtv: Fixed all coding style issues in usbtv source files

Fixed various coding styles, ignoring coding style error on line 5 for all files containing a link that is longer than 80 characters long.

Signed-off-by: Amber Thrall <amber.rose.thrall@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

[media] usbtv: add audio support

Add an ALSA handler inside usbtv module, in order to make
audio to work with those devices.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Tested-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>