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.

---
 include/sound/soc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index a2deeb9..aae55d0 100644
@@ -1687,7 +1687,7 @@ 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)

2.1.4

A couple of call sites were missed when the snd_soc_dapm_mutex_lock function was added this patch fixes those up.

---
 sound/soc/codecs/wm5110.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

index c364096..eb1e665 100644
@@ -439,18 +439,17 @@ static int wm5110_in_pga_get(struct snd_kcontrol *kcontrol,
 {
 	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
 	struct snd_soc_dapm_context *dapm = snd_soc_codec_get_dapm(codec);
-	struct snd_soc_card *card = dapm->card;
 	int ret;
 
 	/*
 	 * PGA Volume is also used as part of the enable sequence, so
 	 * usage of it should be avoided whilst that is running.
 	 */
-	mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
+	snd_soc_dapm_mutex_lock(dapm);
 
 	ret = snd_soc_get_volsw_range(kcontrol, ucontrol);
 
-	mutex_unlock(&card->dapm_mutex);
+	snd_soc_dapm_mutex_unlock(dapm);
 
 	return ret;
 }

@@ -460,18 +459,17 @@ static int wm5110_in_pga_put(struct snd_kcontrol *kcontrol,
 {
 	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
 	struct snd_soc_dapm_context *dapm = snd_soc_codec_get_dapm(codec);
-	struct snd_soc_card *card = dapm->card;
 	int ret;
 
 	/*
 	 * PGA Volume is also used as part of the enable sequence, so
 	 * usage of it should be avoided whilst that is running.
 	 */
-	mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
+	snd_soc_dapm_mutex_lock(dapm);
 
 	ret = snd_soc_put_volsw_range(kcontrol, ucontrol);
 
-	mutex_unlock(&card->dapm_mutex);
+	snd_soc_dapm_mutex_unlock(dapm);
 
 	return ret;
 }

2.1.4

The patch

ASoC: wm5110: Use helper function to lock the DAPM mutex

has been applied to the asoc tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

From: Charles Keepax <[email protected]>
Date: Tue, 29 Dec 2015 16:25:14 +0000
Subject: [PATCH] ASoC: wm5110: Use helper function to lock the DAPM mutex

A couple of call sites were missed when the snd_soc_dapm_mutex_lock function was added this patch fixes those up.

---
 sound/soc/codecs/wm5110.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

index e93e5420943e..605daffebc9c 100644
@@ -439,18 +439,17 @@ static int wm5110_in_pga_get(struct snd_kcontrol *kcontrol,
 {
 	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
 	struct snd_soc_dapm_context *dapm = snd_soc_codec_get_dapm(codec);
-	struct snd_soc_card *card = dapm->card;
 	int ret;
 
 	/*
 	 * PGA Volume is also used as part of the enable sequence, so
 	 * usage of it should be avoided whilst that is running.
 	 */
-	mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
+	snd_soc_dapm_mutex_lock(dapm);
 
 	ret = snd_soc_get_volsw_range(kcontrol, ucontrol);
 
-	mutex_unlock(&card->dapm_mutex);
+	snd_soc_dapm_mutex_unlock(dapm);
 
 	return ret;
 }

@@ -460,18 +459,17 @@ static int wm5110_in_pga_put(struct snd_kcontrol *kcontrol,
 {
 	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
 	struct snd_soc_dapm_context *dapm = snd_soc_codec_get_dapm(codec);
-	struct snd_soc_card *card = dapm->card;
 	int ret;
 
 	/*
 	 * PGA Volume is also used as part of the enable sequence, so
 	 * usage of it should be avoided whilst that is running.
 	 */
-	mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
+	snd_soc_dapm_mutex_lock(dapm);
 
 	ret = snd_soc_put_volsw_range(kcontrol, ucontrol);
 
-	mutex_unlock(&card->dapm_mutex);
+	snd_soc_dapm_mutex_unlock(dapm);
 
 	return ret;
 }

2.6.2

The patch

ASoC: Use nested lock for snd_soc_dapm_mutex_lock

has been applied to the asoc tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

From: Charles Keepax <[email protected]>
Date: Tue, 29 Dec 2015 16:25:13 +0000
Subject: [PATCH] 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.

---
 include/sound/soc.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index a8b4b9c8b1d2..fb955e69a78e 100644
@@ -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)

2.6.2