[GIT PULL] ALSA fixes

From: Takashi Iwai
Date: Fri Sep 26 2008 - 12:13:18 EST


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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