From 9c2cc5652e4390bd4492433d96ad4caa785b09de Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 18 Jul 2023 16:13:03 +0200 Subject: 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 --- sound/core/control.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'sound/core/control.c') diff --git a/sound/core/control.c b/sound/core/control.c index 30741293708d..e13e9d6b3b89 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -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); -- cgit v1.2.3-59-g8ed1b