linux-kernel - [GIT PULL] ALSA fixes

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Date:	Fri, 26 Sep 2008 18:13:00 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: [GIT PULL] ALSA fixes

Hi Linus,

please pull another ALSA updates for 2.6.27-rc7 from:

  git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git for-linus

These are fixes for possible mutex/semaphore deadlocks found via
recent lockdep.  The deadlock possibility is quite low and I guess
it never happened in the real use yet, though.

Thanks!

Takashi

==

Takashi Iwai (2):
      ALSA: fix locking in snd_pcm_open*() and snd_rawmidi_open*()
      ALSA: remove unneeded power_mutex lock in snd_pcm_drop

 sound/core/pcm.c        |    4 ++--
 sound/core/pcm_native.c |   13 +++----------
 sound/core/rawmidi.c    |    4 ++--
 3 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 9dd9bc7..ece25c7 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -781,7 +781,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
 		return -ENODEV;
 
 	card = pcm->card;
-	down_read(&card->controls_rwsem);
+	read_lock(&card->ctl_files_rwlock);
 	list_for_each_entry(kctl, &card->ctl_files, list) {
 		if (kctl->pid == current->pid) {
 			prefer_subdevice = kctl->prefer_pcm_subdevice;
@@ -789,7 +789,7 @@ int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
 				break;
 		}
 	}
-	up_read(&card->controls_rwsem);
+	read_unlock(&card->ctl_files_rwlock);
 
 	switch (stream) {
 	case SNDRV_PCM_STREAM_PLAYBACK:
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index c49b9d9..c487025 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1546,16 +1546,10 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream)
 	card = substream->pcm->card;
 
 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
-	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED ||
+	    runtime->status->state == SNDRV_PCM_STATE_SUSPENDED)
 		return -EBADFD;
 
-	snd_power_lock(card);
-	if (runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
-		result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
-		if (result < 0)
-			goto _unlock;
-	}
-
 	snd_pcm_stream_lock_irq(substream);
 	/* resume pause */
 	if (runtime->status->state == SNDRV_PCM_STATE_PAUSED)
@@ -1564,8 +1558,7 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream)
 	snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
 	/* runtime->control->appl_ptr = runtime->status->hw_ptr; */
 	snd_pcm_stream_unlock_irq(substream);
- _unlock:
-	snd_power_unlock(card);
+
 	return result;
 }
 
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index f7ea728..b917a9f 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -418,7 +418,7 @@ static int snd_rawmidi_open(struct inode *inode, struct file *file)
 	mutex_lock(&rmidi->open_mutex);
 	while (1) {
 		subdevice = -1;
-		down_read(&card->controls_rwsem);
+		read_lock(&card->ctl_files_rwlock);
 		list_for_each_entry(kctl, &card->ctl_files, list) {
 			if (kctl->pid == current->pid) {
 				subdevice = kctl->prefer_rawmidi_subdevice;
@@ -426,7 +426,7 @@ static int snd_rawmidi_open(struct inode *inode, struct file *file)
 					break;
 			}
 		}
-		up_read(&card->controls_rwsem);
+		read_unlock(&card->ctl_files_rwlock);
 		err = snd_rawmidi_kernel_open(rmidi->card, rmidi->device,
 					      subdevice, fflags, rawmidi_file);
 		if (err >= 0)
--
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