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ASoC: Use nested lock for snd_soc_dapm_mutex_lock 

snd_soc_dapm_mutex_lock currently uses the un-nested call which can
cause lockdep warnings when called from control handlers (a relatively
common usage) and using modules. As creating the control causes a
potential mutex inversion with the handler, creating the control will
take the controls_rwsem under the dapm_mutex and accessing the control
will take the dapm_mutex under controls_rwsem.

All the users look like they want to be using the runtime class of the
lock anyway, so this patch just changes snd_soc_dapm_mutex_lock to use
the nested call, with the SND_SOC_DAPM_CLASS_RUNTIME class.

Fixes: f6d5e586b4 ("ASoC: dapm: Add helpers to lock/unlock DAPM mutex")
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Charles Keepax 2015-12-29 16:25:13 +00:00 committed by Mark Brown
parent 8005c49d9a
commit 783513eec3
1 changed files with 1 additions and 1 deletions
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2
include/sound/soc.h
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@ -1655,7 +1655,7 @@ extern const struct dev_pm_ops snd_soc_pm_ops;
/* Helper functions */
static inline void snd_soc_dapm_mutex_lock(struct snd_soc_dapm_context *dapm)
{
mutex_lock(&dapm->card->dapm_mutex);
mutex_lock_nested(&dapm->card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
}
static inline void snd_soc_dapm_mutex_unlock(struct snd_soc_dapm_context *dapm)