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Subject[PATCH 3.16 108/136] ALSA: timer: Simplify error path in snd_timer_open()
3.16.80-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@suse.de>

commit 41672c0c24a62699d20aab53b98d843b16483053 upstream.

Just a minor refactoring to use the standard goto for error paths in
snd_timer_open() instead of open code. The first mutex_lock() is
moved to the beginning of the function to make the code clearer.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.16 as dependency of commit a39331867335
"ALSA: timer: Fix mutex deadlock at releasing card"]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
sound/core/timer.c | 39 ++++++++++++++++++++-------------------
1 file changed, 20 insertions(+), 19 deletions(-)

--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -255,19 +255,20 @@ int snd_timer_open(struct snd_timer_inst
struct snd_timer_instance *timeri = NULL;
int err;

+ mutex_lock(&register_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;
}
- mutex_lock(&register_mutex);
timeri = snd_timer_instance_new(owner, NULL);
if (!timeri) {
- mutex_unlock(&register_mutex);
- return -ENOMEM;
+ err = -ENOMEM;
+ goto unlock;
}
timeri->slave_class = tid->dev_sclass;
timeri->slave_id = tid->device;
@@ -278,13 +279,10 @@ int snd_timer_open(struct snd_timer_inst
snd_timer_close_locked(timeri);
timeri = NULL;
}
- mutex_unlock(&register_mutex);
- *ti = timeri;
- return err;
+ goto unlock;
}

/* open a master instance */
- mutex_lock(&register_mutex);
timer = snd_timer_find(tid);
#ifdef CONFIG_MODULES
if (!timer) {
@@ -295,25 +293,26 @@ int snd_timer_open(struct snd_timer_inst
}
#endif
if (!timer) {
- mutex_unlock(&register_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, open_list);
if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
- mutex_unlock(&register_mutex);
- return -EBUSY;
+ err = -EBUSY;
+ timeri = NULL;
+ goto unlock;
}
}
if (timer->num_instances >= timer->max_instances) {
- mutex_unlock(&register_mutex);
- return -EBUSY;
+ err = -EBUSY;
+ goto unlock;
}
timeri = snd_timer_instance_new(owner, timer);
if (!timeri) {
- mutex_unlock(&register_mutex);
- return -ENOMEM;
+ err = -ENOMEM;
+ goto unlock;
}
/* take a card refcount for safe disconnection */
if (timer->card)
@@ -322,16 +321,16 @@ int snd_timer_open(struct snd_timer_inst
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);
module_put(timer->module);
- mutex_unlock(&register_mutex);
- return err;
+ goto unlock;
}
}

@@ -342,6 +341,8 @@ int snd_timer_open(struct snd_timer_inst
snd_timer_close_locked(timeri);
timeri = NULL;
}
+
+ unlock:
mutex_unlock(&register_mutex);
*ti = timeri;
return err;
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