linux-toradex.git/sound/core/seq/oss, branch v4.4.2

ALSA: seq: Degrade the error message for too many opens

2016-02-17T20:30:58+00:00

commit da10816e3d923565b470fec78a674baba794ed33 upstream.

ALSA OSS sequencer spews a kernel error message ("ALSA: seq_oss: too
many applications") when user-space tries to open more than the
limit.  This means that it can easily fill the log buffer.

Since it's merely a normal error, it's safe to suppress it via
pr_debug() instead.

Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Fix incorrect sanity check at snd_seq_oss_synth_cleanup()

2016-02-17T20:30:58+00:00

commit 599151336638d57b98d92338aa59c048e3a3e97d upstream.

ALSA sequencer OSS emulation code has a sanity check for currently
opened devices, but there is a thinko there, eventually it spews
warnings and skips the operation wrongly like:
  WARNING: CPU: 1 PID: 7573 at sound/core/seq/oss/seq_oss_synth.c:311

Fix this off-by-one error.

Reported-by: Dmitry Vyukov 
Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

ALSA: seq_oss: fix waitqueue_active without memory barrier in snd-seq-oss

2015-10-09T07:45:52+00:00

snd_seq_oss_readq_put_event() seems to be missing a memory barrier which
might cause the waker to not notice the waiter and miss sending a
wake_up as in the following figure.

    snd_seq_oss_readq_put_event		    snd_seq_oss_readq_wait
------------------------------------------------------------------------
					/* wait_event_interruptible_timeout */
					 /* __wait_event_interruptible_timeout */
					  /* ___wait_event */
					  for (;;) {									 prepare_to_wait_event(&wq, &__wait,
					    state);
spin_lock_irqsave(&q->lock, flags);
if (waitqueue_active(&q->midi_sleep))
/* The CPU might reorder the test for
   the waitqueue up here, before
   prior writes complete */
					  if ((q->qlen>0 || q->head==q->tail)
					  ...
					  __ret = schedule_timeout(__ret)
if (q->qlen >= q->maxlen - 1) {
memcpy(&q->q[q->tail], ev, sizeof(*ev));
q->tail = (q->tail + 1) % q->maxlen;
q->qlen++;
------------------------------------------------------------------------

There are two other place in sound/core/seq/oss/ which have similar
code.  The attached patch removes the call to waitqueue_active() leaving
just wake_up() behind.  This fixes the problem because the call to
spin_lock_irqsave() in wake_up() will be an ACQUIRE operation.

I found this issue when I was looking through the linux source code
for places calling waitqueue_active() before wake_up*(), but without
preceding memory barriers, after sending a patch to fix a similar
issue in drivers/tty/n_tty.c  (Details about the original issue can be
found here: https://lkml.org/lkml/2015/9/28/849).

Signed-off-by: Kosuke Tatsukawa 
Signed-off-by: Takashi Iwai

ALSA: replace CONFIG_PROC_FS with CONFIG_SND_PROC_FS

2015-05-27T19:25:19+00:00

We may disable proc fs only for sound part, to reduce ALSA
memory footprint. So add CONFIG_SND_PROC_FS and replace the
old CONFIG_PROC_FSs in alsa code.

With sound proc fs disabled, we can save about 9KB memory
size on X86_64 platform.

Signed-off-by: Jie Yang 
Reviewed-by: Mark Brown 
Signed-off-by: Takashi Iwai

ALSA: seq_oss: Drop superfluous error/debug messages after malloc failures

2015-03-10T14:39:55+00:00

The kernel memory allocators already report the errors when the
requested allocation fails, thus we don't need to warn it again in
each caller side.

Signed-off-by: Takashi Iwai

ALSA: seq: Drop snd_seq_autoload_lock() and _unlock()

2015-02-12T13:42:31+00:00

The autoload lock became already superfluous due to the recent rework
of autoload code.  Let's drop them now.  This allows us to simplify a
few codes nicely.

Signed-off-by: Takashi Iwai

ALSA: seq: Define driver object in each driver

2015-02-12T13:15:54+00:00

This patch moves the driver object initialization and allocation to
each driver's module init/exit code like other normal drivers.  The
snd_seq_driver struct is now published in seq_device.h, and each
driver is responsible to define it with proper driver attributes
(name, probe and remove) with snd_seq_driver specific attributes as id
and argsize fields.  The helper functions snd_seq_driver_register(),
snd_seq_driver_unregister() and module_snd_seq_driver() are used for
simplifying codes.

Signed-off-by: Takashi Iwai

ALSA: seq: Deletion of unnecessary checks before the function call "snd_midi_event_free"

2015-01-04T14:11:05+00:00

The snd_midi_event_free() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Takashi Iwai

ALSA: core: Deletion of unnecessary checks before two function calls

2014-11-21T19:06:57+00:00

The functions snd_seq_oss_timer_delete() and vunmap() perform also input
parameter validation. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
Signed-off-by: Takashi Iwai

ALSA: seq_oss: Use standard printk helpers

2014-02-14T07:14:18+00:00

Use the standard pr_xxx() helpers instead of home-baked snd_print*().

Signed-off-by: Takashi Iwai