1 files changed, 34 insertions, 24 deletions

diff --git a/kernel/sound/core/pcm_native.c b/kernel/sound/core/pcm_native.c
index ec8486c45..34e501868 100644
--- a/kernel/sound/core/pcm_native.c
+++ b/kernel/sound/core/pcm_native.c
@@ -74,6 +74,18 @@ static int snd_pcm_open(struct file *file, struct snd_pcm *pcm, int stream);
 static DEFINE_RWLOCK(snd_pcm_link_rwlock);
 static DECLARE_RWSEM(snd_pcm_link_rwsem);
 
+/* Writer in rwsem may block readers even during its waiting in queue,
+ * and this may lead to a deadlock when the code path takes read sem
+ * twice (e.g. one in snd_pcm_action_nonatomic() and another in
+ * snd_pcm_stream_lock()).  As a (suboptimal) workaround, let writer to
+ * spin until it gets the lock.
+ */
+static inline void down_write_nonblock(struct rw_semaphore *lock)
+{
+	while (!down_write_trylock(lock))
+		cond_resched();
+}
+
 /**
  * snd_pcm_stream_lock - Lock the PCM stream
  * @substream: PCM substream
@@ -486,6 +498,16 @@ static void snd_pcm_set_state(struct snd_pcm_substream *substream, int state)
 	snd_pcm_stream_unlock_irq(substream);
 }
 
+static inline void snd_pcm_timer_notify(struct snd_pcm_substream *substream,
+					int event)
+{
+#ifdef CONFIG_SND_PCM_TIMER
+	if (substream->timer)
+		snd_timer_notify(substream->timer, event,
+					&substream->runtime->trigger_tstamp);
+#endif
+}
+
 static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
 			     struct snd_pcm_hw_params *params)
 {
@@ -650,7 +672,8 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
 	}
 	snd_pcm_stream_unlock_irq(substream);
 
-	if (params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
+	if (params->tstamp_mode < 0 ||
+	    params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
 		return -EINVAL;
 	if (params->proto >= SNDRV_PROTOCOL_VERSION(2, 0, 12) &&
 	    params->tstamp_type > SNDRV_PCM_TSTAMP_TYPE_LAST)
@@ -1042,9 +1065,7 @@ static void snd_pcm_post_start(struct snd_pcm_substream *substream, int state)
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 	    runtime->silence_size > 0)
 		snd_pcm_playback_silence(substream, ULONG_MAX);
-	if (substream->timer)
-		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSTART,
-				 &runtime->trigger_tstamp);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTART);
 }
 
 static struct action_ops snd_pcm_action_start = {
@@ -1092,9 +1113,7 @@ static void snd_pcm_post_stop(struct snd_pcm_substream *substream, int state)
 	if (runtime->status->state != state) {
 		snd_pcm_trigger_tstamp(substream);
 		runtime->status->state = state;
-		if (substream->timer)
-			snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSTOP,
-					 &runtime->trigger_tstamp);
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTOP);
 	}
 	wake_up(&runtime->sleep);
 	wake_up(&runtime->tsleep);
@@ -1208,18 +1227,12 @@ static void snd_pcm_post_pause(struct snd_pcm_substream *substream, int push)
 	snd_pcm_trigger_tstamp(substream);
 	if (push) {
 		runtime->status->state = SNDRV_PCM_STATE_PAUSED;
-		if (substream->timer)
-			snd_timer_notify(substream->timer,
-					 SNDRV_TIMER_EVENT_MPAUSE,
-					 &runtime->trigger_tstamp);
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MPAUSE);
 		wake_up(&runtime->sleep);
 		wake_up(&runtime->tsleep);
 	} else {
 		runtime->status->state = SNDRV_PCM_STATE_RUNNING;
-		if (substream->timer)
-			snd_timer_notify(substream->timer,
-					 SNDRV_TIMER_EVENT_MCONTINUE,
-					 &runtime->trigger_tstamp);
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MCONTINUE);
 	}
 }
 
@@ -1267,9 +1280,7 @@ static void snd_pcm_post_suspend(struct snd_pcm_substream *substream, int state)
 	snd_pcm_trigger_tstamp(substream);
 	runtime->status->suspended_state = runtime->status->state;
 	runtime->status->state = SNDRV_PCM_STATE_SUSPENDED;
-	if (substream->timer)
-		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MSUSPEND,
-				 &runtime->trigger_tstamp);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSUSPEND);
 	wake_up(&runtime->sleep);
 	wake_up(&runtime->tsleep);
 }
@@ -1373,9 +1384,7 @@ static void snd_pcm_post_resume(struct snd_pcm_substream *substream, int state)
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	snd_pcm_trigger_tstamp(substream);
 	runtime->status->state = runtime->status->suspended_state;
-	if (substream->timer)
-		snd_timer_notify(substream->timer, SNDRV_TIMER_EVENT_MRESUME,
-				 &runtime->trigger_tstamp);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MRESUME);
 }
 
 static struct action_ops snd_pcm_action_resume = {
@@ -1816,7 +1825,7 @@ static int snd_pcm_link(struct snd_pcm_substream *substream, int fd)
 		res = -ENOMEM;
 		goto _nolock;
 	}
-	down_write(&snd_pcm_link_rwsem);
+	down_write_nonblock(&snd_pcm_link_rwsem);
 	write_lock_irq(&snd_pcm_link_rwlock);
 	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN ||
 	    substream->runtime->status->state != substream1->runtime->status->state ||
@@ -1863,7 +1872,7 @@ static int snd_pcm_unlink(struct snd_pcm_substream *substream)
 	struct snd_pcm_substream *s;
 	int res = 0;
 
-	down_write(&snd_pcm_link_rwsem);
+	down_write_nonblock(&snd_pcm_link_rwsem);
 	write_lock_irq(&snd_pcm_link_rwlock);
 	if (!snd_pcm_stream_linked(substream)) {
 		res = -EALREADY;
@@ -2226,7 +2235,8 @@ void snd_pcm_release_substream(struct snd_pcm_substream *substream)
 
 	snd_pcm_drop(substream);
 	if (substream->hw_opened) {
-		if (substream->ops->hw_free != NULL)
+		if (substream->ops->hw_free &&
+		    substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
 			substream->ops->hw_free(substream);
 		substream->ops->close(substream);
 		substream->hw_opened = 0;