Commit 746df948 authored by Takashi Iwai's avatar Takashi Iwai Committed by Jaroslav Kysela
Browse files

[ALSA] Fix rwlock around snd_iprintf() in sound core 



Fixed rwlock around snd_iprintf() in sound core part.
Replaced with mutex.
Also, make mutex and flags static variables with addition of
snd_card_locked() function (just for sound.c).

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 0defb267

include/sound/core.h

+1 −2
Original line number Diff line number Diff line
@@ -233,9 +233,8 @@ int copy_from_user_toio(volatile void __iomem *dst, const void __user *src, size 


/* init.c */



extern unsigned int snd_cards_lock;

extern struct snd_card *snd_cards[SNDRV_CARDS];

extern rwlock_t snd_card_rwlock;

int snd_card_locked(int card);

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)

#define SND_MIXER_OSS_NOTIFY_REGISTER	0

#define SND_MIXER_OSS_NOTIFY_DISCONNECT	1

sound/core/init.c

+31 −20
Original line number Diff line number Diff line
@@ -38,11 +38,11 @@ struct snd_shutdown_f_ops { 
	struct snd_shutdown_f_ops *next;

};



unsigned int snd_cards_lock = 0;	/* locked for registering/using */

static unsigned int snd_cards_lock = 0;	/* locked for registering/using */

struct snd_card *snd_cards[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = NULL};

EXPORT_SYMBOL(snd_cards);



DEFINE_RWLOCK(snd_card_rwlock);

static DEFINE_MUTEX(snd_card_mutex);



#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)

int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
@@ -112,7 +112,7 @@ struct snd_card *snd_card_new(int idx, const char *xid, 
		strlcpy(card->id, xid, sizeof(card->id));

	}

	err = 0;

	write_lock(&snd_card_rwlock);

	mutex_lock(&snd_card_mutex);

	if (idx < 0) {

		int idx2;

		for (idx2 = 0; idx2 < SNDRV_CARDS; idx2++)
@@ -130,12 +130,12 @@ struct snd_card *snd_card_new(int idx, const char *xid, 
	else

		err = -ENODEV;

	if (idx < 0 || err < 0) {

		write_unlock(&snd_card_rwlock);

		mutex_unlock(&snd_card_mutex);

		snd_printk(KERN_ERR "cannot find the slot for index %d (range 0-%i)\n", idx, snd_ecards_limit - 1);

		goto __error;

	}

	snd_cards_lock |= 1 << idx;		/* lock it */

	write_unlock(&snd_card_rwlock);

	mutex_unlock(&snd_card_mutex);

	card->number = idx;

	card->module = module;

	INIT_LIST_HEAD(&card->devices);
@@ -173,6 +173,17 @@ struct snd_card *snd_card_new(int idx, const char *xid, 


EXPORT_SYMBOL(snd_card_new);



/* return non-zero if a card is already locked */

int snd_card_locked(int card)

{

	int locked;



	mutex_lock(&snd_card_mutex);

	locked = snd_cards_lock & (1 << card);

	mutex_unlock(&snd_card_mutex);

	return locked;

}



static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)

{

	return -ENODEV;
@@ -240,9 +251,9 @@ int snd_card_disconnect(struct snd_card *card) 
	spin_unlock(&card->files_lock);



	/* phase 1: disable fops (user space) operations for ALSA API */

	write_lock(&snd_card_rwlock);

	mutex_lock(&snd_card_mutex);

	snd_cards[card->number] = NULL;

	write_unlock(&snd_card_rwlock);

	mutex_unlock(&snd_card_mutex);

	

	/* phase 2: replace file->f_op with special dummy operations */
@@ -321,9 +332,9 @@ int snd_card_free(struct snd_card *card) 


	if (card == NULL)

		return -EINVAL;

	write_lock(&snd_card_rwlock);

	mutex_lock(&snd_card_mutex);

	snd_cards[card->number] = NULL;

	write_unlock(&snd_card_rwlock);

	mutex_unlock(&snd_card_mutex);



#ifdef CONFIG_PM

	wake_up(&card->power_sleep);
@@ -359,9 +370,9 @@ int snd_card_free(struct snd_card *card) 
		card->s_f_ops = s_f_ops->next;

		kfree(s_f_ops);

	}

	write_lock(&snd_card_rwlock);

	mutex_lock(&snd_card_mutex);

	snd_cards_lock &= ~(1 << card->number);

	write_unlock(&snd_card_rwlock);

	mutex_unlock(&snd_card_mutex);

	kfree(card);

	return 0;

}
@@ -497,16 +508,16 @@ int snd_card_register(struct snd_card *card) 
	snd_assert(card != NULL, return -EINVAL);

	if ((err = snd_device_register_all(card)) < 0)

		return err;

	write_lock(&snd_card_rwlock);

	mutex_lock(&snd_card_mutex);

	if (snd_cards[card->number]) {

		/* already registered */

		write_unlock(&snd_card_rwlock);

		mutex_unlock(&snd_card_mutex);

		return 0;

	}

	if (card->id[0] == '\0')

		choose_default_id(card);

	snd_cards[card->number] = card;

	write_unlock(&snd_card_rwlock);

	mutex_unlock(&snd_card_mutex);

	init_info_for_card(card);

#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)

	if (snd_mixer_oss_notify_callback)
@@ -527,7 +538,7 @@ static void snd_card_info_read(struct snd_info_entry *entry, 
	struct snd_card *card;



	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {

		read_lock(&snd_card_rwlock);

		mutex_lock(&snd_card_mutex);

		if ((card = snd_cards[idx]) != NULL) {

			count++;

			snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
@@ -538,7 +549,7 @@ static void snd_card_info_read(struct snd_info_entry *entry, 
			snd_iprintf(buffer, "                      %s\n",

					card->longname);

		}

		read_unlock(&snd_card_rwlock);

		mutex_unlock(&snd_card_mutex);

	}

	if (!count)

		snd_iprintf(buffer, "--- no soundcards ---\n");
@@ -552,12 +563,12 @@ void snd_card_info_read_oss(struct snd_info_buffer *buffer) 
	struct snd_card *card;



	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {

		read_lock(&snd_card_rwlock);

		mutex_lock(&snd_card_mutex);

		if ((card = snd_cards[idx]) != NULL) {

			count++;

			snd_iprintf(buffer, "%s\n", card->longname);

		}

		read_unlock(&snd_card_rwlock);

		mutex_unlock(&snd_card_mutex);

	}

	if (!count) {

		snd_iprintf(buffer, "--- no soundcards ---\n");
@@ -575,11 +586,11 @@ static void snd_card_module_info_read(struct snd_info_entry *entry, 
	struct snd_card *card;



	for (idx = 0; idx < SNDRV_CARDS; idx++) {

		read_lock(&snd_card_rwlock);

		mutex_lock(&snd_card_mutex);

		if ((card = snd_cards[idx]) != NULL)

			snd_iprintf(buffer, "%2i %s\n",

				    idx, card->module->name);

		read_unlock(&snd_card_rwlock);

		mutex_unlock(&snd_card_mutex);

	}

}

#endif

sound/core/sound.c

+1 −6
Original line number Diff line number Diff line
@@ -81,14 +81,9 @@ extern struct class *sound_class; 
 */

void snd_request_card(int card)

{

	int locked;



	if (! current->fs->root)

		return;

	read_lock(&snd_card_rwlock);

	locked = snd_cards_lock & (1 << card);

	read_unlock(&snd_card_rwlock);

	if (locked)

	if (snd_card_locked(card))

		return;

	if (card < 0 || card >= cards_limit)

		return;