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| author | Takashi Iwai <tiwai@suse.de> | 2023-07-18 16:13:02 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2023-07-20 10:03:00 +0200 |
| commit | b1e055f67611daf098e27e8731386eeb5257bde3 (patch) | |
| tree | b7a4d8ddcbbf6f83a276aada4cc25f919b873f29 /include/sound/control.h | |
| parent | ALSA: control: Make snd_ctl_find_id() argument const (diff) | |
| download | linux-b1e055f67611daf098e27e8731386eeb5257bde3.tar.xz linux-b1e055f67611daf098e27e8731386eeb5257bde3.zip | |
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 'include/sound/control.h')
| -rw-r--r-- | include/sound/control.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/sound/control.h b/include/sound/control.h index e61b749bf204..42e8dbb22d8e 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -140,7 +140,9 @@ int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id); int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id); void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl, const char *name); int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id, int active); -struct snd_kcontrol *snd_ctl_find_numid(struct snd_card * card, unsigned int numid); +struct snd_kcontrol *snd_ctl_find_numid_locked(struct snd_card *card, unsigned int numid); +struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid); +struct snd_kcontrol *snd_ctl_find_id_locked(struct snd_card *card, const struct snd_ctl_elem_id *id); struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card, const struct snd_ctl_elem_id *id); int snd_ctl_create(struct snd_card *card); |