ALSA: pcm - Simplify snd_pcm_drain() implementation
Simplify snd_pcm_drain() implementation and avoid unneeded array-
allocation for waitqueues. Instead, one waitqueue is used for the
first draining stream, and wait until all streams finished.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 59e5fbe..561d6d9 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1387,11 +1387,6 @@
.post_action = snd_pcm_post_drain_init
};
-struct drain_rec {
- struct snd_pcm_substream *substream;
- wait_queue_t wait;
-};
-
static int snd_pcm_drop(struct snd_pcm_substream *substream);
/*
@@ -1407,10 +1402,9 @@
struct snd_card *card;
struct snd_pcm_runtime *runtime;
struct snd_pcm_substream *s;
+ wait_queue_t wait;
int result = 0;
- int i, num_drecs;
int nonblock = 0;
- struct drain_rec *drec, drec_tmp, *d;
card = substream->pcm->card;
runtime = substream->runtime;
@@ -1433,38 +1427,10 @@
} else if (substream->f_flags & O_NONBLOCK)
nonblock = 1;
- if (nonblock)
- goto lock; /* no need to allocate waitqueues */
-
- /* allocate temporary record for drain sync */
down_read(&snd_pcm_link_rwsem);
- if (snd_pcm_stream_linked(substream)) {
- drec = kmalloc(substream->group->count * sizeof(*drec), GFP_KERNEL);
- if (! drec) {
- up_read(&snd_pcm_link_rwsem);
- snd_power_unlock(card);
- return -ENOMEM;
- }
- } else
- drec = &drec_tmp;
-
- /* count only playback streams */
- num_drecs = 0;
- snd_pcm_group_for_each_entry(s, substream) {
- runtime = s->runtime;
- if (s->stream == SNDRV_PCM_STREAM_PLAYBACK) {
- d = &drec[num_drecs++];
- d->substream = s;
- init_waitqueue_entry(&d->wait, current);
- add_wait_queue(&runtime->sleep, &d->wait);
- }
- }
- up_read(&snd_pcm_link_rwsem);
-
- lock:
snd_pcm_stream_lock_irq(substream);
/* resume pause */
- if (substream->runtime->status->state == SNDRV_PCM_STATE_PAUSED)
+ if (runtime->status->state == SNDRV_PCM_STATE_PAUSED)
snd_pcm_pause(substream, 0);
/* pre-start/stop - all running streams are changed to DRAINING state */
@@ -1479,25 +1445,35 @@
for (;;) {
long tout;
+ struct snd_pcm_runtime *to_check;
if (signal_pending(current)) {
result = -ERESTARTSYS;
break;
}
- /* all finished? */
- for (i = 0; i < num_drecs; i++) {
- runtime = drec[i].substream->runtime;
- if (runtime->status->state == SNDRV_PCM_STATE_DRAINING)
+ /* find a substream to drain */
+ to_check = NULL;
+ snd_pcm_group_for_each_entry(s, substream) {
+ if (s->stream != SNDRV_PCM_STREAM_PLAYBACK)
+ continue;
+ runtime = s->runtime;
+ if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
+ to_check = runtime;
break;
+ }
}
- if (i == num_drecs)
- break; /* yes, all drained */
-
+ if (!to_check)
+ break; /* all drained */
+ init_waitqueue_entry(&wait, current);
+ add_wait_queue(&to_check->sleep, &wait);
set_current_state(TASK_INTERRUPTIBLE);
snd_pcm_stream_unlock_irq(substream);
+ up_read(&snd_pcm_link_rwsem);
snd_power_unlock(card);
tout = schedule_timeout(10 * HZ);
snd_power_lock(card);
+ down_read(&snd_pcm_link_rwsem);
snd_pcm_stream_lock_irq(substream);
+ remove_wait_queue(&to_check->sleep, &wait);
if (tout == 0) {
if (substream->runtime->status->state == SNDRV_PCM_STATE_SUSPENDED)
result = -ESTRPIPE;
@@ -1512,16 +1488,7 @@
unlock:
snd_pcm_stream_unlock_irq(substream);
-
- if (!nonblock) {
- for (i = 0; i < num_drecs; i++) {
- d = &drec[i];
- runtime = d->substream->runtime;
- remove_wait_queue(&runtime->sleep, &d->wait);
- }
- if (drec != &drec_tmp)
- kfree(drec);
- }
+ up_read(&snd_pcm_link_rwsem);
snd_power_unlock(card);
return result;