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authorTakashi Iwai <tiwai@suse.de>2018-01-08 14:03:53 +0100
committerTakashi Iwai <tiwai@suse.de>2018-01-08 16:40:26 +0100
commit900498a34a3ac9c611e9b425094c8106bdd7dc1c (patch)
tree844ccba051c0491b8e7d74879e6a8d20f11c6e53 /sound/core
parent29159a4ed7044c52e3e2cf1a9fb55cec4745c60b (diff)
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>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/oss/pcm_oss.c36
1 files changed, 21 insertions, 15 deletions
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index e317964bd2ea..c2db7e905f7d 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -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;
}