From: Takashi Iwai Date: Tue, 21 Oct 2014 13:32:13 +0000 (+0200) Subject: ALSA: pcm: Fix false lockdep warnings X-Git-Tag: v4.9.8~5095^2~72 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dde1c652d7b1e69a3f1959697f039ad6dfaeb5dd;p=platform%2Fkernel%2Flinux-rpi3.git 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 Signed-off-by: Takashi Iwai --- diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index 815396d..166d59c 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);