From b1e055f67611daf098e27e8731386eeb5257bde3 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 18 Jul 2023 16:13:02 +0200 Subject: ALSA: control: Introduce unlocked version for snd_ctl_find_*() helpers For reducing the unnecessary use of controls_rwsem in the drivers, this patch adds a new variant for snd_ctl_find_*() helpers: snd_ctl_find_id_locked() and snd_ctl_find_numid_locked() look for a kctl element inside the card->controls_rwsem -- that is, doing the very same as what snd_ctl_find_id() and snd_ctl_find_numid() did until now. snd_ctl_find_id() and snd_ctl_find_numid() remain same, i.e. still unlocked version, but they will be switched to locked version once after all callers are replaced. The patch also replaces the calls of snd_ctl_find_id() and snd_ctl_find_numid() in a few places; all of those are places where we know that the functions are called properly with controls_rwsem held. All others are without rwsem (although they should have been). After this patch, we'll turn on the locking in snd_ctl_find_id() and snd_ctl_find_numid() to be more race-free. Link: https://lore.kernel.org/r/20230718141304.1032-10-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/core/control_compat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'sound/core/control_compat.c') diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c index 9cae5d74335c..0e8b1bfb040e 100644 --- a/sound/core/control_compat.c +++ b/sound/core/control_compat.c @@ -173,7 +173,7 @@ static int get_ctl_type(struct snd_card *card, struct snd_ctl_elem_id *id, int err; down_read(&card->controls_rwsem); - kctl = snd_ctl_find_id(card, id); + kctl = snd_ctl_find_id_locked(card, id); if (! kctl) { up_read(&card->controls_rwsem); return -ENOENT; -- cgit v1.2.3-73-gaa49b