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| author | Takashi Iwai <tiwai@suse.de> | 2023-07-18 17:13:02 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2023-07-20 11:03:00 +0300 |
| commit | b1e055f67611daf098e27e8731386eeb5257bde3 (patch) | |
| tree | b7a4d8ddcbbf6f83a276aada4cc25f919b873f29 /sound/core/control_led.c | |
| parent | 6723670a483501497dc339ae37676525245a913a (diff) | |
| download | linux-b1e055f67611daf098e27e8731386eeb5257bde3.tar.xz | |
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 <tiwai@suse.de>
Diffstat (limited to 'sound/core/control_led.c')
| -rw-r--r-- | sound/core/control_led.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/core/control_led.c b/sound/core/control_led.c index ee77547bf8dc..67fc2a1dcf7a 100644 --- a/sound/core/control_led.c +++ b/sound/core/control_led.c @@ -251,7 +251,7 @@ static int snd_ctl_led_set_id(int card_number, struct snd_ctl_elem_id *id, card = snd_card_ref(card_number); if (card) { down_write(&card->controls_rwsem); - kctl = snd_ctl_find_id(card, id); + kctl = snd_ctl_find_id_locked(card, id); if (kctl) { ioff = snd_ctl_get_ioff(kctl, id); vd = &kctl->vd[ioff]; |