ALSA: ak411x: Fix race of reinit() calls

Protect the call with a mutex, as this may be called in parallel
(either from the PCM rate change and the clock change).

Acked-by: Jaroslav Kysela <perex@perex.cz>
Tested-by: Pavel Hofman <pavel.hofman@ivitera.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/ak4113.h

@@ -287,6 +287,7 @@ struct ak4113 {
 	ak4113_read_t *read;
 	void *private_data;
 	atomic_t wq_processing;
+	struct mutex reinit_mutex;
 	spinlock_t lock;
 	unsigned char regmap[AK4113_WRITABLE_REGS];
 	struct snd_kcontrol *kctls[AK4113_CONTROLS];

include/sound/ak4114.h

@@ -169,6 +169,7 @@ struct ak4114 {
 	ak4114_read_t * read;
 	void * private_data;
 	atomic_t wq_processing;
+	struct mutex reinit_mutex;
 	spinlock_t lock;
 	unsigned char regmap[6];
 	unsigned char txcsb[5];

sound/i2c/other/ak4113.c

@@ -89,6 +89,7 @@ int snd_ak4113_create(struct snd_card *card, ak4113_read_t *read,
 	chip->private_data = private_data;
 	INIT_DELAYED_WORK(&chip->work, ak4113_stats);
 	atomic_set(&chip->wq_processing, 0);
+	mutex_init(&chip->reinit_mutex);
 
 	for (reg = 0; reg < AK4113_WRITABLE_REGS ; reg++)
 		chip->regmap[reg] = pgm[reg];
@@ -141,7 +142,9 @@ void snd_ak4113_reinit(struct ak4113 *chip)
 {
 	if (atomic_inc_return(&chip->wq_processing) == 1)
 		cancel_delayed_work_sync(&chip->work);
+	mutex_lock(&chip->reinit_mutex);
 	ak4113_init_regs(chip);
+	mutex_unlock(&chip->reinit_mutex);
 	/* bring up statistics / event queing */
 	if (atomic_dec_and_test(&chip->wq_processing))
 		schedule_delayed_work(&chip->work, HZ / 10);

sound/i2c/other/ak4114.c

@@ -100,6 +100,7 @@ int snd_ak4114_create(struct snd_card *card,
 	chip->private_data = private_data;
 	INIT_DELAYED_WORK(&chip->work, ak4114_stats);
 	atomic_set(&chip->wq_processing, 0);
+	mutex_init(&chip->reinit_mutex);
 
 	for (reg = 0; reg < 6; reg++)
 		chip->regmap[reg] = pgm[reg];
@@ -156,7 +157,9 @@ void snd_ak4114_reinit(struct ak4114 *chip)
 {
 	if (atomic_inc_return(&chip->wq_processing) == 1)
 		cancel_delayed_work_sync(&chip->work);
+	mutex_lock(&chip->reinit_mutex);
 	ak4114_init_regs(chip);
+	mutex_unlock(&chip->reinit_mutex);
 	/* bring up statistics / event queing */
 	if (atomic_dec_and_test(&chip->wq_processing))
 		schedule_delayed_work(&chip->work, HZ / 10);