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ALSA: control: Take lock in snd_ctl_find_id() and snd_ctl_find_numid() 

Now all needed callers have been replaced with *_locked() versions,
let's turn on the locking in snd_ctl_find_id() and
snd_ctl_find_numid().

This patch also adds the lockdep assertions for debugging, too.

Link: https://lore.kernel.org/r/20230718141304.1032-11-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2023-07-18 16:13:03 +02:00
parent b1e055f676
commit 9c2cc5652e
1 changed files with 18 additions and 2 deletions
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20
sound/core/control.c
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@ -836,6 +836,7 @@ snd_ctl_find_numid_locked(struct snd_card *card, unsigned int numid)
{
if (snd_BUG_ON(!card || !numid))
return NULL;
lockdep_assert_held(&card->controls_rwsem);
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
return xa_load(&card->ctl_numids, numid);
#else
@ -852,11 +853,18 @@ EXPORT_SYMBOL(snd_ctl_find_numid_locked);
* Finds the control instance with the given number-id from the card.
*
* Return: The pointer of the instance if found, or %NULL if not.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card,
unsigned int numid)
{
return snd_ctl_find_numid_locked(card, numid);
struct snd_kcontrol *kctl;
down_read(&card->controls_rwsem);
kctl = snd_ctl_find_numid_locked(card, numid);
up_read(&card->controls_rwsem);
return kctl;
}
EXPORT_SYMBOL(snd_ctl_find_numid);
@ -879,6 +887,7 @@ struct snd_kcontrol *snd_ctl_find_id_locked(struct snd_card *card,
if (snd_BUG_ON(!card || !id))
return NULL;
lockdep_assert_held(&card->controls_rwsem);
if (id->numid != 0)
return snd_ctl_find_numid_locked(card, id->numid);
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
@ -905,11 +914,18 @@ EXPORT_SYMBOL(snd_ctl_find_id_locked);
* Finds the control instance with the given id from the card.
*
* Return: The pointer of the instance if found, or %NULL if not.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
const struct snd_ctl_elem_id *id)
{
return snd_ctl_find_id_locked(card, id);
struct snd_kcontrol *kctl;
down_read(&card->controls_rwsem);
kctl = snd_ctl_find_id_locked(card, id);
up_read(&card->controls_rwsem);
return kctl;
}
EXPORT_SYMBOL(snd_ctl_find_id);