sound: snd_ctl_remove_unlocked_id: simplify user control counting
Move the decrementing of the user controls counter from
snd_ctl_elem_remove to snd_ctl_remove_unlocked_id; this saves the
separate locking of the controls semaphore, and therefore removes
a harmless race.
Since the purpose of the function is to operate on user controls (the
control being unlocked is just a prerequisite), rename it to
snd_ctl_remove_user_ctl.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/control.c b/sound/core/control.c
index 9d91f77..bc64b72 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -414,7 +414,7 @@
EXPORT_SYMBOL(snd_ctl_remove_id);
/**
- * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
+ * snd_ctl_remove_user_ctl - remove and release the unlocked user control
* @file: active control handle
* @id: the control id to remove
*
@@ -423,8 +423,8 @@
*
* Returns 0 if successful, or a negative error code on failure.
*/
-static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,
- struct snd_ctl_elem_id *id)
+static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
+ struct snd_ctl_elem_id *id)
{
struct snd_card *card = file->card;
struct snd_kcontrol *kctl;
@@ -442,6 +442,9 @@
goto error;
}
ret = snd_ctl_remove(card, kctl);
+ if (ret < 0)
+ goto error;
+ card->user_ctl_count--;
error:
up_write(&card->controls_rwsem);
return ret;
@@ -1053,18 +1056,10 @@
struct snd_ctl_elem_id __user *_id)
{
struct snd_ctl_elem_id id;
- int err;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
- err = snd_ctl_remove_unlocked_id(file, &id);
- if (! err) {
- struct snd_card *card = file->card;
- down_write(&card->controls_rwsem);
- card->user_ctl_count--;
- up_write(&card->controls_rwsem);
- }
- return err;
+ return snd_ctl_remove_user_ctl(file, &id);
}
static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)