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Commit 4161b450 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: ak411x: Fix stall in work callback 



When ak4114 work calls its callback and the callback invokes
ak4114_reinit(), it stalls due to flush_delayed_work().  For avoiding
this, control the reentrance by introducing a refcount.  Also
flush_delayed_work() is replaced with cancel_delayed_work_sync().

The exactly same bug is present in ak4113.c and fixed as well.

Reported-by: default avatarPavel Hofman <pavel.hofman@ivitera.com>
Acked-by: default avatarJaroslav Kysela <perex@perex.cz>
Tested-by: default avatarPavel Hofman <pavel.hofman@ivitera.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 0767e95b

include/sound/ak4113.h

+1 −1
Original line number Diff line number Diff line
@@ -286,7 +286,7 @@ struct ak4113 { 
	ak4113_write_t *write;

	ak4113_read_t *read;

	void *private_data;

	unsigned int init:1;

	atomic_t wq_processing;

	spinlock_t lock;

	unsigned char regmap[AK4113_WRITABLE_REGS];

	struct snd_kcontrol *kctls[AK4113_CONTROLS];

include/sound/ak4114.h

+1 −1
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ struct ak4114 { 
	ak4114_write_t * write;

	ak4114_read_t * read;

	void * private_data;

	unsigned int init: 1;

	atomic_t wq_processing;

	spinlock_t lock;

	unsigned char regmap[6];

	unsigned char txcsb[5];

sound/i2c/other/ak4113.c

+8 −9
Original line number Diff line number Diff line
@@ -56,8 +56,7 @@ static inline unsigned char reg_read(struct ak4113 *ak4113, unsigned char reg) 


static void snd_ak4113_free(struct ak4113 *chip)

{

	chip->init = 1;	/* don't schedule new work */

	mb();

	atomic_inc(&chip->wq_processing);	/* don't schedule new work */

	cancel_delayed_work_sync(&chip->work);

	kfree(chip);

}
@@ -89,6 +88,7 @@ int snd_ak4113_create(struct snd_card *card, ak4113_read_t *read, 
	chip->write = write;

	chip->private_data = private_data;

	INIT_DELAYED_WORK(&chip->work, ak4113_stats);

	atomic_set(&chip->wq_processing, 0);



	for (reg = 0; reg < AK4113_WRITABLE_REGS ; reg++)

		chip->regmap[reg] = pgm[reg];
@@ -139,13 +139,11 @@ static void ak4113_init_regs(struct ak4113 *chip) 


void snd_ak4113_reinit(struct ak4113 *chip)

{

	chip->init = 1;

	mb();

	flush_delayed_work(&chip->work);

	if (atomic_inc_return(&chip->wq_processing) == 1)

		cancel_delayed_work_sync(&chip->work);

	ak4113_init_regs(chip);

	/* bring up statistics / event queing */

	chip->init = 0;

	if (chip->kctls[0])

	if (atomic_dec_and_test(&chip->wq_processing))

		schedule_delayed_work(&chip->work, HZ / 10);

}

EXPORT_SYMBOL_GPL(snd_ak4113_reinit);
@@ -632,8 +630,9 @@ static void ak4113_stats(struct work_struct *work) 
{

	struct ak4113 *chip = container_of(work, struct ak4113, work.work);



	if (!chip->init)

	if (atomic_inc_return(&chip->wq_processing) == 1)

		snd_ak4113_check_rate_and_errors(chip, chip->check_flags);



	if (atomic_dec_and_test(&chip->wq_processing))

		schedule_delayed_work(&chip->work, HZ / 10);

}

sound/i2c/other/ak4114.c

+8 −10
Original line number Diff line number Diff line
@@ -66,8 +66,7 @@ static void reg_dump(struct ak4114 *ak4114) 


static void snd_ak4114_free(struct ak4114 *chip)

{

	chip->init = 1;	/* don't schedule new work */

	mb();

	atomic_inc(&chip->wq_processing);	/* don't schedule new work */

	cancel_delayed_work_sync(&chip->work);

	kfree(chip);

}
@@ -100,6 +99,7 @@ int snd_ak4114_create(struct snd_card *card, 
	chip->write = write;

	chip->private_data = private_data;

	INIT_DELAYED_WORK(&chip->work, ak4114_stats);

	atomic_set(&chip->wq_processing, 0);



	for (reg = 0; reg < 6; reg++)

		chip->regmap[reg] = pgm[reg];
@@ -152,13 +152,11 @@ static void ak4114_init_regs(struct ak4114 *chip) 


void snd_ak4114_reinit(struct ak4114 *chip)

{

	chip->init = 1;

	mb();

	flush_delayed_work(&chip->work);

	if (atomic_inc_return(&chip->wq_processing) == 1)

		cancel_delayed_work_sync(&chip->work);

	ak4114_init_regs(chip);

	/* bring up statistics / event queing */

	chip->init = 0;

	if (chip->kctls[0])

	if (atomic_dec_and_test(&chip->wq_processing))

		schedule_delayed_work(&chip->work, HZ / 10);

}
@@ -612,9 +610,9 @@ static void ak4114_stats(struct work_struct *work) 
{

	struct ak4114 *chip = container_of(work, struct ak4114, work.work);



	if (!chip->init)

	if (atomic_inc_return(&chip->wq_processing) == 1)

		snd_ak4114_check_rate_and_errors(chip, chip->check_flags);



	if (atomic_dec_and_test(&chip->wq_processing))

		schedule_delayed_work(&chip->work, HZ / 10);

}