diff options
| author | Takashi Iwai <tiwai@suse.de> | 2024-08-09 12:42:30 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2024-08-09 14:24:55 +0200 |
| commit | 38ea4c3dc306edf6f4e483e8ad9cb8d33943afde (patch) | |
| tree | 241b50a1da29ca1bafcd5115ca43d3567aec3f38 /include/sound/core.h | |
| parent | f428cc9eac6e29d57579be4978ba210c344322ea (diff) | |
ALSA: control: Optimize locking for look-up
For a fast look-up of a control element via either numid or name
matching (enabled via CONFIG_SND_CTL_FAST_LOOKUP), a locking isn't
needed at all thanks to Xarray. OTOH, the locking is still needed for
a slow linked-list traversal, and that's rather a rare case.
In this patch, we reduce the use of locking at snd_ctl_find_*() API
functions, and switch from controls_rwsem to controls_rwlock for
avoiding unnecessary lock inversions. This also resulted in a nice
cleanup, as *_unlocked() version of snd_ctl_find_*() APIs can be
dropped.
snd_ctl_find_id_mixer_unlocked() is still left just as an alias of
snd_ctl_find_id_mixer(), since soc-card.c has a wrapper and there are
several users. Once after converting there, we can remove it later.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20240809104234.8488-3-tiwai@suse.de
Diffstat (limited to 'include/sound/core.h')
| -rw-r--r-- | include/sound/core.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/sound/core.h b/include/sound/core.h index 55607e91d5fd..5c418ab24aa4 100644 --- a/include/sound/core.h +++ b/include/sound/core.h @@ -99,7 +99,7 @@ struct snd_card { struct device *ctl_dev; /* control device */ unsigned int last_numid; /* last used numeric ID */ struct rw_semaphore controls_rwsem; /* controls lock (list and values) */ - rwlock_t controls_rwlock; /* lock for ctl_files list */ + rwlock_t controls_rwlock; /* lock for lookup and ctl_files list */ int controls_count; /* count of all controls */ size_t user_ctl_alloc_size; // current memory allocation by user controls. struct list_head controls; /* all controls for this card */ |