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authorTakashi Iwai <tiwai@suse.de>2014-10-21 15:32:13 +0200
committerTakashi Iwai <tiwai@suse.de>2014-10-21 18:17:02 +0200
commitdde1c652d7b1e69a3f1959697f039ad6dfaeb5dd (patch)
treebf0d5cd0cdc609592862947b2872f4114bf669d5
parentb1974f965a506c131b60cd3e483340884e831920 (diff)
downloadlinux-dde1c652d7b1e69a3f1959697f039ad6dfaeb5dd.tar.bz2
ALSA: pcm: Fix false lockdep warnings
As PCM core handles the multiple linked streams in parallel, lockdep gets confused (partly because of weak annotations) and spews the false-positive warnings. This hasn't been a problem for long time but the latest PCM lock path update seems to have woken up a sleeping dog. Here is an attempt to paper over this issue: pass the lock subclass just calculated from the depth in snd_pcm_action_group(). Also, a (possibly) wrong lock subclass set in snd_pcm_action_lock_mutex() is dropped, too. Reported-and-tested-by: Arthur Marsh <arthur.marsh@internode.on.net> Signed-off-by: Takashi Iwai <tiwai@suse.de>
-rw-r--r--sound/core/pcm_native.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 815396d8427f..166d59cdc86b 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -781,16 +781,15 @@ static int snd_pcm_action_group(struct action_ops *ops,
{
struct snd_pcm_substream *s = NULL;
struct snd_pcm_substream *s1;
- int res = 0;
+ int res = 0, depth = 1;
snd_pcm_group_for_each_entry(s, substream) {
if (do_lock && s != substream) {
if (s->pcm->nonatomic)
- mutex_lock_nested(&s->self_group.mutex,
- SINGLE_DEPTH_NESTING);
+ mutex_lock_nested(&s->self_group.mutex, depth);
else
- spin_lock_nested(&s->self_group.lock,
- SINGLE_DEPTH_NESTING);
+ spin_lock_nested(&s->self_group.lock, depth);
+ depth++;
}
res = ops->pre_action(s, state);
if (res < 0)
@@ -906,8 +905,7 @@ static int snd_pcm_action_lock_mutex(struct action_ops *ops,
down_read(&snd_pcm_link_rwsem);
if (snd_pcm_stream_linked(substream)) {
mutex_lock(&substream->group->mutex);
- mutex_lock_nested(&substream->self_group.mutex,
- SINGLE_DEPTH_NESTING);
+ mutex_lock(&substream->self_group.mutex);
res = snd_pcm_action_group(ops, substream, state, 1);
mutex_unlock(&substream->self_group.mutex);
mutex_unlock(&substream->group->mutex);