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ALSA: pcm: Allow aborting mutex lock at OSS read/write loops 

PCM OSS read/write loops keep taking the mutex lock for the whole
read/write, and this might take very long when the exceptionally high
amount of data is given.  Also, since it invokes with mutex_lock(),
the concurrent read/write becomes unbreakable.

This patch tries to address these issues by replacing mutex_lock()
with mutex_lock_interruptible(), and also splits / re-takes the lock
at each read/write period chunk, so that it can switch the context
more finely if requested.

Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2018-01-08 14:03:53 +01:00
parent 29159a4ed7
commit 900498a34a
1 changed files with 21 additions and 15 deletions
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36
sound/core/oss/pcm_oss.c
View File

@ -1334,8 +1334,11 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
return tmp;
mutex_lock(&runtime->oss.params_lock);
while (bytes > 0) {
if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
tmp = -ERESTARTSYS;
break;
}
if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
tmp = bytes;
if (tmp + runtime->oss.buffer_used > runtime->oss.period_bytes)
@ -1379,18 +1382,18 @@ static ssize_t snd_pcm_oss_write1(struct snd_pcm_substream *substream, const cha
xfer += tmp;
if ((substream->f_flags & O_NONBLOCK) != 0 &&
tmp != runtime->oss.period_bytes)
break;
tmp = -EAGAIN;
}
err:
mutex_unlock(&runtime->oss.params_lock);
if (tmp < 0)
break;
if (signal_pending(current)) {
tmp = -ERESTARTSYS;
goto err;
break;
}
tmp = 0;
}
mutex_unlock(&runtime->oss.params_lock);
return xfer;
err:
mutex_unlock(&runtime->oss.params_lock);
return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
}
@ -1438,8 +1441,11 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
return tmp;
mutex_lock(&runtime->oss.params_lock);
while (bytes > 0) {
if (mutex_lock_interruptible(&runtime->oss.params_lock)) {
tmp = -ERESTARTSYS;
break;
}
if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
if (runtime->oss.buffer_used == 0) {
tmp = snd_pcm_oss_read2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
@ -1470,16 +1476,16 @@ static ssize_t snd_pcm_oss_read1(struct snd_pcm_substream *substream, char __use
bytes -= tmp;
xfer += tmp;
}
err:
mutex_unlock(&runtime->oss.params_lock);
if (tmp < 0)
break;
if (signal_pending(current)) {
tmp = -ERESTARTSYS;
goto err;
break;
}
tmp = 0;
}
mutex_unlock(&runtime->oss.params_lock);
return xfer;
err:
mutex_unlock(&runtime->oss.params_lock);
return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp;
}