From 746df94898554b3d8e91d855e934852e626c701c Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 15 May 2006 19:49:05 +0200 Subject: [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: Takashi Iwai --- sound/core/init.c | 51 +++++++++++++++++++++++++++++++-------------------- sound/core/sound.c | 7 +------ 2 files changed, 32 insertions(+), 26 deletions(-) (limited to 'sound/core') diff --git a/sound/core/init.c b/sound/core/init.c index 2ff0e5e90865..38b2d4a9d672 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -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 diff --git a/sound/core/sound.c b/sound/core/sound.c index 8313f97907d8..02c8cc4ebffe 100644 --- a/sound/core/sound.c +++ b/sound/core/sound.c @@ -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; -- cgit v1.2.3-59-g8ed1b