diff options
Diffstat (limited to 'sound/core/timer.c')
-rw-r--r-- | sound/core/timer.c | 77 |
1 files changed, 49 insertions, 28 deletions
diff --git a/sound/core/timer.c b/sound/core/timer.c index 2c0f292226d7..22589a073423 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -88,6 +88,9 @@ static LIST_HEAD(snd_timer_slave_list); /* lock for slave active lists */ static DEFINE_SPINLOCK(slave_active_lock); +#define MAX_SLAVE_INSTANCES 1000 +static int num_slaves; + static DEFINE_MUTEX(register_mutex); static int snd_timer_free(struct snd_timer *timer); @@ -240,7 +243,8 @@ static int snd_timer_check_master(struct snd_timer_instance *master) return 0; } -static int snd_timer_close_locked(struct snd_timer_instance *timeri); +static int snd_timer_close_locked(struct snd_timer_instance *timeri, + struct device **card_devp_to_put); /* * open a timer instance @@ -252,38 +256,42 @@ int snd_timer_open(struct snd_timer_instance **ti, { struct snd_timer *timer; struct snd_timer_instance *timeri = NULL; + struct device *card_dev_to_put = NULL; int err; + mutex_lock(®ister_mutex); if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) { /* open a slave instance */ if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE || tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) { pr_debug("ALSA: timer: invalid slave class %i\n", tid->dev_sclass); - return -EINVAL; + err = -EINVAL; + goto unlock; + } + if (num_slaves >= MAX_SLAVE_INSTANCES) { + err = -EBUSY; + goto unlock; } - mutex_lock(®ister_mutex); timeri = snd_timer_instance_new(owner, NULL); if (!timeri) { - mutex_unlock(®ister_mutex); - return -ENOMEM; + err = -ENOMEM; + goto unlock; } timeri->slave_class = tid->dev_sclass; timeri->slave_id = tid->device; timeri->flags |= SNDRV_TIMER_IFLG_SLAVE; list_add_tail(&timeri->open_list, &snd_timer_slave_list); + num_slaves++; err = snd_timer_check_slave(timeri); if (err < 0) { - snd_timer_close_locked(timeri); + snd_timer_close_locked(timeri, &card_dev_to_put); timeri = NULL; } - mutex_unlock(®ister_mutex); - *ti = timeri; - return err; + goto unlock; } /* open a master instance */ - mutex_lock(®ister_mutex); timer = snd_timer_find(tid); #ifdef CONFIG_MODULES if (!timer) { @@ -294,25 +302,26 @@ int snd_timer_open(struct snd_timer_instance **ti, } #endif if (!timer) { - mutex_unlock(®ister_mutex); - return -ENODEV; + err = -ENODEV; + goto unlock; } if (!list_empty(&timer->open_list_head)) { - timeri = list_entry(timer->open_list_head.next, + struct snd_timer_instance *t = + list_entry(timer->open_list_head.next, struct snd_timer_instance, open_list); - if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) { - mutex_unlock(®ister_mutex); - return -EBUSY; + if (t->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) { + err = -EBUSY; + goto unlock; } } if (timer->num_instances >= timer->max_instances) { - mutex_unlock(®ister_mutex); - return -EBUSY; + err = -EBUSY; + goto unlock; } timeri = snd_timer_instance_new(owner, timer); if (!timeri) { - mutex_unlock(®ister_mutex); - return -ENOMEM; + err = -ENOMEM; + goto unlock; } /* take a card refcount for safe disconnection */ if (timer->card) @@ -321,16 +330,16 @@ int snd_timer_open(struct snd_timer_instance **ti, timeri->slave_id = slave_id; if (list_empty(&timer->open_list_head) && timer->hw.open) { - int err = timer->hw.open(timer); + err = timer->hw.open(timer); if (err) { kfree(timeri->owner); kfree(timeri); + timeri = NULL; if (timer->card) - put_device(&timer->card->card_dev); + card_dev_to_put = &timer->card->card_dev; module_put(timer->module); - mutex_unlock(®ister_mutex); - return err; + goto unlock; } } @@ -338,10 +347,15 @@ int snd_timer_open(struct snd_timer_instance **ti, timer->num_instances++; err = snd_timer_check_master(timeri); if (err < 0) { - snd_timer_close_locked(timeri); + snd_timer_close_locked(timeri, &card_dev_to_put); timeri = NULL; } + + unlock: mutex_unlock(®ister_mutex); + /* put_device() is called after unlock for avoiding deadlock */ + if (card_dev_to_put) + put_device(card_dev_to_put); *ti = timeri; return err; } @@ -351,12 +365,15 @@ EXPORT_SYMBOL(snd_timer_open); * close a timer instance * call this with register_mutex down. */ -static int snd_timer_close_locked(struct snd_timer_instance *timeri) +static int snd_timer_close_locked(struct snd_timer_instance *timeri, + struct device **card_devp_to_put) { struct snd_timer *timer = NULL; struct snd_timer_instance *slave, *tmp; list_del(&timeri->open_list); + if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) + num_slaves--; /* force to stop the timer */ snd_timer_stop(timeri); @@ -403,7 +420,7 @@ static int snd_timer_close_locked(struct snd_timer_instance *timeri) timer->hw.close(timer); /* release a card refcount for safe disconnection */ if (timer->card) - put_device(&timer->card->card_dev); + *card_devp_to_put = &timer->card->card_dev; module_put(timer->module); } @@ -415,14 +432,18 @@ static int snd_timer_close_locked(struct snd_timer_instance *timeri) */ int snd_timer_close(struct snd_timer_instance *timeri) { + struct device *card_dev_to_put = NULL; int err; if (snd_BUG_ON(!timeri)) return -ENXIO; mutex_lock(®ister_mutex); - err = snd_timer_close_locked(timeri); + err = snd_timer_close_locked(timeri, &card_dev_to_put); mutex_unlock(®ister_mutex); + /* put_device() is called after unlock for avoiding deadlock */ + if (card_dev_to_put) + put_device(card_dev_to_put); return err; } EXPORT_SYMBOL(snd_timer_close); 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