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 | |
| 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')
| -rw-r--r-- | include/sound/control.h | 22 | ||||
| -rw-r--r-- | include/sound/core.h | 2 |
2 files changed, 3 insertions, 21 deletions
diff --git a/include/sound/control.h b/include/sound/control.h index c1659036c4a7..4851a86c72ef 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -140,9 +140,7 @@ 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_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); /** @@ -167,27 +165,11 @@ snd_ctl_find_id_mixer(struct snd_card *card, const char *name) return snd_ctl_find_id(card, &id); } -/** - * snd_ctl_find_id_mixer_locked - find the control instance with the given name string - * @card: the card instance - * @name: the name string - * - * Finds the control instance with the given name and - * @SNDRV_CTL_ELEM_IFACE_MIXER. Other fields are set to zero. - * - * This is merely a wrapper to snd_ctl_find_id_locked(). - * The caller must down card->controls_rwsem before calling this function. - * - * Return: The pointer of the instance if found, or %NULL if not. - */ +/* to be removed */ static inline struct snd_kcontrol * snd_ctl_find_id_mixer_locked(struct snd_card *card, const char *name) { - struct snd_ctl_elem_id id = {}; - - id.iface = SNDRV_CTL_ELEM_IFACE_MIXER; - strscpy(id.name, name, sizeof(id.name)); - return snd_ctl_find_id_locked(card, &id); + return snd_ctl_find_id_mixer(card, name); } int snd_ctl_create(struct snd_card *card); 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 */ |