From 900498a34a3ac9c611e9b425094c8106bdd7dc1c Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 8 Jan 2018 14:03:53 +0100 Subject: [PATCH] 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: Signed-off-by: Takashi Iwai --- sound/core/oss/pcm_oss.c | 36 +++++++++++++++++++++--------------- 1 file 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; } -- 2.30.2