| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 122/128] ASoC: Use nested lock for snd_soc_dapm_mutex_lock | Date | Sun, 24 Jan 2016 22:01:17 +0000 |
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3.16.7-ckt23 -stable review patch. If anyone has any objections, please let me know.
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From: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
commit 783513eec3209542fcd6ac0cbcb030b3c17a4827 upstream.
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: f6d5e586b416 ("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> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- include/sound/soc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/sound/soc.h b/include/sound/soc.h index a34d34649195..4dc6904ebbf9 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -1390,7 +1390,7 @@ 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)
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