Commit 4cdc115f authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: pcm - Fix drain behavior in non-blocking mode



The current PCM core has the following problems regarding PCM draining
in non-blocking mode:

- the current f_flags isn't checked in snd_pcm_drain(), thus changing
  the mode dynamically via snd_pcm_nonblock() after open doesn't work.
- calling drain in non-blocking mode just return -EAGAIN error, but
  doesn't provide any way to sync with draining.

This patch fixes these issues.
- check file->f_flags in snd_pcm_drain() properly
- when O_NONBLOCK is set, PCM core sets the stream(s) to DRAIN state
  but quits ioctl immediately without waiting the whole drain; the
  caller can sync the drain manually via poll()

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 64f1607f
......@@ -197,13 +197,17 @@ static int snd_pcm_update_hw_ptr_post(struct snd_pcm_substream *substream,
avail = snd_pcm_capture_avail(runtime);
if (avail > runtime->avail_max)
runtime->avail_max = avail;
if (avail >= runtime->stop_threshold) {
if (substream->runtime->status->state == SNDRV_PCM_STATE_DRAINING)
if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
if (avail >= runtime->buffer_size) {
snd_pcm_drain_done(substream);
else
return -EPIPE;
}
} else {
if (avail >= runtime->stop_threshold) {
xrun(substream);
return -EPIPE;
}
}
if (avail >= runtime->control->avail_min)
wake_up(&runtime->sleep);
return 0;
......
......@@ -1343,8 +1343,6 @@ static int snd_pcm_prepare(struct snd_pcm_substream *substream,
static int snd_pcm_pre_drain_init(struct snd_pcm_substream *substream, int state)
{
if (substream->f_flags & O_NONBLOCK)
return -EAGAIN;
substream->runtime->trigger_master = substream;
return 0;
}
......@@ -1392,7 +1390,6 @@ static struct action_ops snd_pcm_action_drain_init = {
struct drain_rec {
struct snd_pcm_substream *substream;
wait_queue_t wait;
snd_pcm_uframes_t stop_threshold;
};
static int snd_pcm_drop(struct snd_pcm_substream *substream);
......@@ -1404,13 +1401,15 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream);
* After this call, all streams are supposed to be either SETUP or DRAINING
* (capture only) state.
*/
static int snd_pcm_drain(struct snd_pcm_substream *substream)
static int snd_pcm_drain(struct snd_pcm_substream *substream,
struct file *file)
{
struct snd_card *card;
struct snd_pcm_runtime *runtime;
struct snd_pcm_substream *s;
int result = 0;
int i, num_drecs;
int nonblock = 0;
struct drain_rec *drec, drec_tmp, *d;
card = substream->pcm->card;
......@@ -1428,6 +1427,15 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream)
}
}
if (file) {
if (file->f_flags & O_NONBLOCK)
nonblock = 1;
} 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)) {
......@@ -1449,16 +1457,11 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream)
d->substream = s;
init_waitqueue_entry(&d->wait, current);
add_wait_queue(&runtime->sleep, &d->wait);
/* stop_threshold fixup to avoid endless loop when
* stop_threshold > buffer_size
*/
d->stop_threshold = runtime->stop_threshold;
if (runtime->stop_threshold > runtime->buffer_size)
runtime->stop_threshold = runtime->buffer_size;
}
}
up_read(&snd_pcm_link_rwsem);
lock:
snd_pcm_stream_lock_irq(substream);
/* resume pause */
if (substream->runtime->status->state == SNDRV_PCM_STATE_PAUSED)
......@@ -1466,9 +1469,12 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream)
/* pre-start/stop - all running streams are changed to DRAINING state */
result = snd_pcm_action(&snd_pcm_action_drain_init, substream, 0);
if (result < 0) {
snd_pcm_stream_unlock_irq(substream);
goto _error;
if (result < 0)
goto unlock;
/* in non-blocking, we don't wait in ioctl but let caller poll */
if (nonblock) {
result = -EAGAIN;
goto unlock;
}
for (;;) {
......@@ -1504,18 +1510,18 @@ static int snd_pcm_drain(struct snd_pcm_substream *substream)
}
}
unlock:
snd_pcm_stream_unlock_irq(substream);
_error:
if (!nonblock) {
for (i = 0; i < num_drecs; i++) {
d = &drec[i];
runtime = d->substream->runtime;
remove_wait_queue(&runtime->sleep, &d->wait);
runtime->stop_threshold = d->stop_threshold;
}
if (drec != &drec_tmp)
kfree(drec);
}
snd_power_unlock(card);
return result;
......@@ -2544,7 +2550,7 @@ static int snd_pcm_common_ioctl1(struct file *file,
return snd_pcm_hw_params_old_user(substream, arg);
#endif
case SNDRV_PCM_IOCTL_DRAIN:
return snd_pcm_drain(substream);
return snd_pcm_drain(substream, file);
case SNDRV_PCM_IOCTL_DROP:
return snd_pcm_drop(substream);
case SNDRV_PCM_IOCTL_PAUSE:
......
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