BMC/Intel-BMC/linux.git/sound/core/seq/oss, branch v4.4

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

ALSA: seq_oss: Drop debug prints

2014-02-14T07:14:13+00:00

The debug prints in snd-seq-oss module are rather useless. Let's clean up before further modifications. Signed-off-by: Takashi Iwai

ALSA: Drop unused name argument in snd_register_oss_device()

2014-02-12T09:58:19+00:00

The last argument, name, of snd_oss_register_device() is nowhere referred in the function in the current code. Let's drop it. Signed-off-by: Takashi Iwai