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Commit f217ac59 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Takashi Iwai
Browse files

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: default avatarClemens Ladisch <clemens@ladisch.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 317b8081

sound/core/control.c

+7 −12
Original line number Diff line number Diff line
@@ -414,7 +414,7 @@ int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id) 
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

 *
@@ -423,7 +423,7 @@ EXPORT_SYMBOL(snd_ctl_remove_id); 
 * 

 * Returns 0 if successful, or a negative error code on failure.

 */

static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file,

static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,

				   struct snd_ctl_elem_id *id)

{

	struct snd_card *card = file->card;
@@ -442,6 +442,9 @@ static int snd_ctl_remove_unlocked_id(struct snd_ctl_file * file, 
			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 @@ static int snd_ctl_elem_remove(struct snd_ctl_file *file, 
			       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)