Merge tag 'tags/ctl-lock-fixes-6.6' into for-next

ALSA: Make control API taking controls_rwsem consistently

A few ALSA control API helpers like snd_ctl_rename(), snd_ctl_remove()
and snd_ctl_find_*() suppose the callers taking card->controls_rwsem.
But it's error-prone and fragile.  This patch set tries to change
those API functions to take the card->controls>rwsem internally by
themselves, so that the drivers don't need to take care of lockings.

After applying this patch set, only a couple of places still touch
card->controls_rwsem (which are OK-ish as they need for traversing the
control linked list).

Link: https://lore.kernel.org/r/20230718141304.1032-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

drivers/staging/greybus/audio_codec.c

@@ -807,7 +807,6 @@ int gbaudio_register_module(struct gbaudio_module_info *module)
 {
 	int ret;
 	struct snd_soc_component *comp;
-	struct snd_card *card;
 	struct gbaudio_jack *jack = NULL;
 
 	if (!gbcodec) {
@@ -816,21 +815,20 @@ int gbaudio_register_module(struct gbaudio_module_info *module)
 	}
 
 	comp = gbcodec->component;
-	card = comp->card->snd_card;
 
-	down_write(&card->controls_rwsem);
+	mutex_lock(&gbcodec->register_mutex);
 
 	if (module->num_dais) {
 		dev_err(gbcodec->dev,
 			"%d:DAIs not supported via gbcodec driver\n",
 			module->num_dais);
-		up_write(&card->controls_rwsem);
+		mutex_unlock(&gbcodec->register_mutex);
 		return -EINVAL;
 	}
 
 	ret = gbaudio_init_jack(module, comp->card);
 	if (ret) {
-		up_write(&card->controls_rwsem);
+		mutex_unlock(&gbcodec->register_mutex);
 		return ret;
 	}
 
@@ -867,7 +865,7 @@ int gbaudio_register_module(struct gbaudio_module_info *module)
 		ret = snd_soc_dapm_new_widgets(comp->card);
 	dev_dbg(comp->dev, "Registered %s module\n", module->name);
 
-	up_write(&card->controls_rwsem);
+	mutex_unlock(&gbcodec->register_mutex);
 	return ret;
 }
 EXPORT_SYMBOL(gbaudio_register_module);
@@ -935,13 +933,12 @@ static void gbaudio_codec_cleanup(struct gbaudio_module_info *module)
 void gbaudio_unregister_module(struct gbaudio_module_info *module)
 {
 	struct snd_soc_component *comp = gbcodec->component;
-	struct snd_card *card = comp->card->snd_card;
 	struct gbaudio_jack *jack, *n;
 	int mask;
 
 	dev_dbg(comp->dev, "Unregister %s module\n", module->name);
 
-	down_write(&card->controls_rwsem);
+	mutex_lock(&gbcodec->register_mutex);
 	mutex_lock(&gbcodec->lock);
 	gbaudio_codec_cleanup(module);
 	list_del(&module->list);
@@ -978,10 +975,8 @@ void gbaudio_unregister_module(struct gbaudio_module_info *module)
 		dev_dbg(comp->dev, "Removing %d controls\n",
 			module->num_controls);
 		/* release control semaphore */
-		up_write(&card->controls_rwsem);
 		gbaudio_remove_component_controls(comp, module->controls,
 						  module->num_controls);
-		down_write(&card->controls_rwsem);
 	}
 	if (module->dapm_widgets) {
 		dev_dbg(comp->dev, "Removing %d widgets\n",
@@ -992,7 +987,7 @@ void gbaudio_unregister_module(struct gbaudio_module_info *module)
 
 	dev_dbg(comp->dev, "Unregistered %s module\n", module->name);
 
-	up_write(&card->controls_rwsem);
+	mutex_unlock(&gbcodec->register_mutex);
 }
 EXPORT_SYMBOL(gbaudio_unregister_module);
 
@@ -1012,6 +1007,7 @@ static int gbcodec_probe(struct snd_soc_component *comp)
 	info->dev = comp->dev;
 	INIT_LIST_HEAD(&info->module_list);
 	mutex_init(&info->lock);
+	mutex_init(&info->register_mutex);
 	INIT_LIST_HEAD(&info->dai_list);
 
 	/* init dai_list used to maintain runtime stream info */

drivers/staging/greybus/audio_codec.h

@@ -71,6 +71,7 @@ struct gbaudio_codec_info {
 	/* to maintain runtime stream params for each DAI */
 	struct list_head dai_list;
 	struct mutex lock;
+	struct mutex register_mutex;
 };
 
 struct gbaudio_widget {

drivers/staging/greybus/audio_helper.c

@@ -149,7 +149,6 @@ static int gbaudio_remove_controls(struct snd_card *card, struct device *dev,
 	for (i = 0; i < num_controls; i++) {
 		const struct snd_kcontrol_new *control = &controls[i];
 		struct snd_ctl_elem_id id;
-		struct snd_kcontrol *kctl;
 
 		if (prefix)
 			snprintf(id.name, sizeof(id.name), "%s %s", prefix,
@@ -161,17 +160,10 @@ static int gbaudio_remove_controls(struct snd_card *card, struct device *dev,
 		id.device = control->device;
 		id.subdevice = control->subdevice;
 		id.index = control->index;
-		kctl = snd_ctl_find_id(card, &id);
-		if (!kctl) {
-			dev_err(dev, "Failed to find %s\n", control->name);
-			continue;
-		}
-		err = snd_ctl_remove(card, kctl);
-		if (err < 0) {
+		err = snd_ctl_remove_id(card, &id);
+		if (err < 0)
 			dev_err(dev, "%d: Failed to remove %s\n", err,
 				control->name);
-			continue;
-		}
 	}
 	return 0;
 }
@@ -181,11 +173,7 @@ int gbaudio_remove_component_controls(struct snd_soc_component *component,
 				      unsigned int num_controls)
 {
 	struct snd_card *card = component->card->snd_card;
-	int err;
 
-	down_write(&card->controls_rwsem);
-	err = gbaudio_remove_controls(card, component->dev, controls,
+	return gbaudio_remove_controls(card, component->dev, controls,
 				       num_controls, component->name_prefix);
-	up_write(&card->controls_rwsem);
-	return err;
 }

include/sound/control.h

@@ -140,8 +140,10 @@ 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_id(struct snd_card * card, struct snd_ctl_elem_id *id);
+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);
 

sound/core/control.c

@@ -39,6 +39,9 @@ static LIST_HEAD(snd_control_compat_ioctls);
 #endif
 static struct snd_ctl_layer_ops *snd_ctl_layer;
 
+static int snd_ctl_remove_locked(struct snd_card *card,
+				 struct snd_kcontrol *kcontrol);
+
 static int snd_ctl_open(struct inode *inode, struct file *file)
 {
 	unsigned long flags;
@@ -466,11 +469,13 @@ static int __snd_ctl_add_replace(struct snd_card *card,
 	struct snd_kcontrol *old;
 	int err;
 
+	lockdep_assert_held_write(&card->controls_rwsem);
+
 	id = kcontrol->id;
 	if (id.index > UINT_MAX - kcontrol->count)
 		return -EINVAL;
 
-	old = snd_ctl_find_id(card, &id);
+	old = snd_ctl_find_id_locked(card, &id);
 	if (!old) {
 		if (mode == CTL_REPLACE)
 			return -EINVAL;
@@ -483,7 +488,7 @@ static int __snd_ctl_add_replace(struct snd_card *card,
 			return -EBUSY;
 		}
 
-		err = snd_ctl_remove(card, old);
+		err = snd_ctl_remove_locked(card, old);
 		if (err < 0)
 			return err;
 	}
@@ -575,6 +580,8 @@ static int __snd_ctl_remove(struct snd_card *card,
 {
 	unsigned int idx;
 
+	lockdep_assert_held_write(&card->controls_rwsem);
+
 	if (snd_BUG_ON(!card || !kcontrol))
 		return -EINVAL;
 	list_del(&kcontrol->list);
@@ -589,20 +596,32 @@ static int __snd_ctl_remove(struct snd_card *card,
 	return 0;
 }
 
+static inline int snd_ctl_remove_locked(struct snd_card *card,
+					struct snd_kcontrol *kcontrol)
+{
+	return __snd_ctl_remove(card, kcontrol, true);
+}
+
 /**
  * snd_ctl_remove - remove the control from the card and release it
  * @card: the card instance
  * @kcontrol: the control instance to remove
  *
  * Removes the control from the card and then releases the instance.
- * You don't need to call snd_ctl_free_one(). You must be in
- * the write lock - down_write(&card->controls_rwsem).
+ * You don't need to call snd_ctl_free_one().
  *
  * Return: 0 if successful, or a negative error code on failure.
+ *
+ * Note that this function takes card->controls_rwsem lock internally.
  */
 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 {
-	return __snd_ctl_remove(card, kcontrol, true);
+	int ret;
+
+	down_write(&card->controls_rwsem);
+	ret = snd_ctl_remove_locked(card, kcontrol);
+	up_write(&card->controls_rwsem);
+	return ret;
 }
 EXPORT_SYMBOL(snd_ctl_remove);
 
@@ -622,12 +641,12 @@ int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 	int ret;
 
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, id);
+	kctl = snd_ctl_find_id_locked(card, id);
 	if (kctl == NULL) {
 		up_write(&card->controls_rwsem);
 		return -ENOENT;
 	}
-	ret = snd_ctl_remove(card, kctl);
+	ret = snd_ctl_remove_locked(card, kctl);
 	up_write(&card->controls_rwsem);
 	return ret;
 }
@@ -651,7 +670,7 @@ static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 	int idx, ret;
 
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, id);
+	kctl = snd_ctl_find_id_locked(card, id);
 	if (kctl == NULL) {
 		ret = -ENOENT;
 		goto error;
@@ -665,7 +684,7 @@ static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 			ret = -EBUSY;
 			goto error;
 		}
-	ret = snd_ctl_remove(card, kctl);
+	ret = snd_ctl_remove_locked(card, kctl);
 error:
 	up_write(&card->controls_rwsem);
 	return ret;
@@ -692,7 +711,7 @@ int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 	int ret;
 
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, id);
+	kctl = snd_ctl_find_id_locked(card, id);
 	if (kctl == NULL) {
 		ret = -ENOENT;
 		goto unlock;
@@ -746,7 +765,7 @@ int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 	int saved_numid;
 
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, src_id);
+	kctl = snd_ctl_find_id_locked(card, src_id);
 	if (kctl == NULL) {
 		up_write(&card->controls_rwsem);
 		return -ENOENT;
@@ -769,11 +788,12 @@ EXPORT_SYMBOL(snd_ctl_rename_id);
  *
  * Renames the specified control on the card to the new name.
  *
- * Make sure to take the control write lock - down_write(&card->controls_rwsem).
+ * Note that this function takes card->controls_rwsem lock internally.
  */
 void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,
 		    const char *name)
 {
+	down_write(&card->controls_rwsem);
 	remove_hash_entries(card, kctl);
 
 	if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0)
@@ -781,6 +801,7 @@ void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,
 			name, kctl->id.name);
 
 	add_hash_entries(card, kctl);
+	up_write(&card->controls_rwsem);
 }
 EXPORT_SYMBOL(snd_ctl_rename);
 
@@ -799,7 +820,7 @@ snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
 #endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
 
 /**
- * snd_ctl_find_numid - find the control instance with the given number-id
+ * snd_ctl_find_numid_locked - find the control instance with the given number-id
  * @card: the card instance
  * @numid: the number-id to search
  *
@@ -809,22 +830,46 @@ snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
  * (if the race condition can happen).
  *
  * Return: The pointer of the instance if found, or %NULL if not.
- *
  */
-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)
 {
 	if (snd_BUG_ON(!card || !numid))
 		return NULL;
+	lockdep_assert_held(&card->controls_rwsem);
 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 	return xa_load(&card->ctl_numids, numid);
 #else
 	return snd_ctl_find_numid_slow(card, numid);
 #endif
 }
+EXPORT_SYMBOL(snd_ctl_find_numid_locked);
+
+/**
+ * snd_ctl_find_numid - find the control instance with the given number-id
+ * @card: the card instance
+ * @numid: the number-id to search
+ *
+ * Finds the control instance with the given number-id from the card.
+ *
+ * Return: The pointer of the instance if found, or %NULL if not.
+ *
+ * Note that this function takes card->controls_rwsem lock internally.
+ */
+struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card,
+					unsigned int numid)
+{
+	struct snd_kcontrol *kctl;
+
+	down_read(&card->controls_rwsem);
+	kctl = snd_ctl_find_numid_locked(card, numid);
+	up_read(&card->controls_rwsem);
+	return kctl;
+}
 EXPORT_SYMBOL(snd_ctl_find_numid);
 
 /**
- * snd_ctl_find_id - find the control instance with the given id
+ * snd_ctl_find_id_locked - find the control instance with the given id
  * @card: the card instance
  * @id: the id to search
  *
@@ -834,17 +879,17 @@ EXPORT_SYMBOL(snd_ctl_find_numid);
  * (if the race condition can happen).
  *
  * Return: The pointer of the instance if found, or %NULL if not.
- *
  */
-struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
-				     struct snd_ctl_elem_id *id)
+struct snd_kcontrol *snd_ctl_find_id_locked(struct snd_card *card,
+					    const struct snd_ctl_elem_id *id)
 {
 	struct snd_kcontrol *kctl;
 
 	if (snd_BUG_ON(!card || !id))
 		return NULL;
+	lockdep_assert_held(&card->controls_rwsem);
 	if (id->numid != 0)
-		return snd_ctl_find_numid(card, id->numid);
+		return snd_ctl_find_numid_locked(card, id->numid);
 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
 	kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
 	if (kctl && elem_id_matches(kctl, id))
@@ -859,6 +904,29 @@ struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 
 	return NULL;
 }
+EXPORT_SYMBOL(snd_ctl_find_id_locked);
+
+/**
+ * snd_ctl_find_id - find the control instance with the given id
+ * @card: the card instance
+ * @id: the id to search
+ *
+ * Finds the control instance with the given id from the card.
+ *
+ * Return: The pointer of the instance if found, or %NULL if not.
+ *
+ * Note that this function takes card->controls_rwsem lock internally.
+ */
+struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
+				     const struct snd_ctl_elem_id *id)
+{
+	struct snd_kcontrol *kctl;
+
+	down_read(&card->controls_rwsem);
+	kctl = snd_ctl_find_id_locked(card, id);
+	up_read(&card->controls_rwsem);
+	return kctl;
+}
 EXPORT_SYMBOL(snd_ctl_find_id);
 
 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
@@ -1173,7 +1241,7 @@ static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 	int result;
 
 	down_read(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, &info->id);
+	kctl = snd_ctl_find_id_locked(card, &info->id);
 	if (kctl == NULL)
 		result = -ENOENT;
 	else
@@ -1212,7 +1280,7 @@ static int snd_ctl_elem_read(struct snd_card *card,
 	int ret;
 
 	down_read(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, &control->id);
+	kctl = snd_ctl_find_id_locked(card, &control->id);
 	if (kctl == NULL) {
 		ret = -ENOENT;
 		goto unlock;
@@ -1289,7 +1357,7 @@ static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 	int result;
 
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, &control->id);
+	kctl = snd_ctl_find_id_locked(card, &control->id);
 	if (kctl == NULL) {
 		up_write(&card->controls_rwsem);
 		return -ENOENT;
@@ -1370,7 +1438,7 @@ static int snd_ctl_elem_lock(struct snd_ctl_file *file,
 	if (copy_from_user(&id, _id, sizeof(id)))
 		return -EFAULT;
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, &id);
+	kctl = snd_ctl_find_id_locked(card, &id);
 	if (kctl == NULL) {
 		result = -ENOENT;
 	} else {
@@ -1398,7 +1466,7 @@ static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
 	if (copy_from_user(&id, _id, sizeof(id)))
 		return -EFAULT;
 	down_write(&card->controls_rwsem);
-	kctl = snd_ctl_find_id(card, &id);
+	kctl = snd_ctl_find_id_locked(card, &id);
 	if (kctl == NULL) {
 		result = -ENOENT;
 	} else {
@@ -1507,6 +1575,8 @@ static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
 	int i;
 	int change;
 
+	lockdep_assert_held_write(&ue->card->controls_rwsem);
+
 	if (size > 1024 * 128)	/* sane value */
 		return -EINVAL;
 
@@ -1583,6 +1653,8 @@ static int snd_ctl_elem_init_enum_names(struct user_element *ue)
 	unsigned int i;
 	const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
 
+	lockdep_assert_held_write(&ue->card->controls_rwsem);
+
 	buf_len = ue->info.value.enumerated.names_length;
 	if (buf_len > 64 * 1024)
 		return -EINVAL;
@@ -1887,6 +1959,8 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
 	struct snd_ctl_elem_id id;
 	struct snd_kcontrol_volatile *vd;
 
+	lockdep_assert_held(&file->card->controls_rwsem);
+
 	if (copy_from_user(&header, buf, sizeof(header)))
 		return -EFAULT;
 
@@ -1900,7 +1974,7 @@ static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
 	container_size = header.length;
 	container = buf->tlv;
 
-	kctl = snd_ctl_find_numid(file->card, header.numid);
+	kctl = snd_ctl_find_numid_locked(file->card, header.numid);
 	if (kctl == NULL)
 		return -ENOENT;
 

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;

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];

sound/core/jack.c

@@ -66,12 +66,10 @@ static int snd_jack_dev_free(struct snd_device *device)
 	struct snd_card *card = device->card;
 	struct snd_jack_kctl *jack_kctl, *tmp_jack_kctl;
 
-	down_write(&card->controls_rwsem);
 	list_for_each_entry_safe(jack_kctl, tmp_jack_kctl, &jack->kctl_list, list) {
 		list_del_init(&jack_kctl->list);
 		snd_ctl_remove(card, jack_kctl->kctl);
 	}
-	up_write(&card->controls_rwsem);
 
 	if (jack->private_free)
 		jack->private_free(jack);

sound/core/oss/mixer_oss.c

@@ -524,7 +524,7 @@ static struct snd_kcontrol *snd_mixer_oss_test_id(struct snd_mixer_oss *mixer, c
 	id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 	strscpy(id.name, name, sizeof(id.name));
 	id.index = index;
-	return snd_ctl_find_id(card, &id);
+	return snd_ctl_find_id_locked(card, &id);
 }
 
 static void snd_mixer_oss_get_volume1_vol(struct snd_mixer_oss_file *fmixer,
@@ -540,7 +540,7 @@ static void snd_mixer_oss_get_volume1_vol(struct snd_mixer_oss_file *fmixer,
 	if (numid == ID_UNKNOWN)
 		return;
 	down_read(&card->controls_rwsem);
-	kctl = snd_ctl_find_numid(card, numid);
+	kctl = snd_ctl_find_numid_locked(card, numid);
 	if (!kctl) {
 		up_read(&card->controls_rwsem);
 		return;
@@ -579,7 +579,7 @@ static void snd_mixer_oss_get_volume1_sw(struct snd_mixer_oss_file *fmixer,
 	if (numid == ID_UNKNOWN)
 		return;
 	down_read(&card->controls_rwsem);
-	kctl = snd_ctl_find_numid(card, numid);
+	kctl = snd_ctl_find_numid_locked(card, numid);
 	if (!kctl) {
 		up_read(&card->controls_rwsem);
 		return;
@@ -645,7 +645,7 @@ static void snd_mixer_oss_put_volume1_vol(struct snd_mixer_oss_file *fmixer,
 	if (numid == ID_UNKNOWN)
 		return;
 	down_read(&card->controls_rwsem);
-	kctl = snd_ctl_find_numid(card, numid);
+	kctl = snd_ctl_find_numid_locked(card, numid);
 	if (!kctl) {
 		up_read(&card->controls_rwsem);
 		return;
@@ -688,7 +688,7 @@ static void snd_mixer_oss_put_volume1_sw(struct snd_mixer_oss_file *fmixer,
 	if (numid == ID_UNKNOWN)
 		return;
 	down_read(&card->controls_rwsem);
-	kctl = snd_ctl_find_numid(card, numid);
+	kctl = snd_ctl_find_numid_locked(card, numid);
 	if (!kctl) {
 		up_read(&card->controls_rwsem);
 		return;

sound/core/pcm.c

@@ -814,9 +814,7 @@ static void free_chmap(struct snd_pcm_str *pstr)
 	if (pstr->chmap_kctl) {
 		struct snd_card *card = pstr->pcm->card;
 
-		down_write(&card->controls_rwsem);
 		snd_ctl_remove(card, pstr->chmap_kctl);
-		up_write(&card->controls_rwsem);
 		pstr->chmap_kctl = NULL;
 	}
 }

sound/isa/sb/emu8000.c

@@ -1040,10 +1040,8 @@ snd_emu8000_create_mixer(struct snd_card *card, struct snd_emu8000 *emu)
 
 __error:
 	for (i = 0; i < EMU8000_NUM_CONTROLS; i++) {
-		down_write(&card->controls_rwsem);
 		if (emu->controls[i])
 			snd_ctl_remove(card, emu->controls[i]);
-		up_write(&card->controls_rwsem);
 	}
 	return err;
 }

sound/isa/sb/sb16_csp.c

@@ -1080,7 +1080,6 @@ static void snd_sb_qsound_destroy(struct snd_sb_csp * p)
 
 	card = p->chip->card;	
 	
-	down_write(&card->controls_rwsem);
 	if (p->qsound_switch) {
 		snd_ctl_remove(card, p->qsound_switch);
 		p->qsound_switch = NULL;
@@ -1089,7 +1088,6 @@ static void snd_sb_qsound_destroy(struct snd_sb_csp * p)
 		snd_ctl_remove(card, p->qsound_space);
 		p->qsound_space = NULL;
 	}
-	up_write(&card->controls_rwsem);
 
 	/* cancel pending transfer of QSound parameters */
 	spin_lock_irqsave (&p->q_lock, flags);

sound/pci/emu10k1/emufx.c

@@ -793,13 +793,10 @@ static int snd_emu10k1_verify_controls(struct snd_emu10k1 *emu,
 		if (snd_emu10k1_look_for_ctl(emu, &gctl->id))
 			continue;
 		gctl_id = (struct snd_ctl_elem_id *)&gctl->id;
-		down_read(&emu->card->controls_rwsem);
 		if (snd_ctl_find_id(emu->card, gctl_id)) {
-			up_read(&emu->card->controls_rwsem);
 			err = -EEXIST;
 			goto __error;
 		}
-		up_read(&emu->card->controls_rwsem);
 		if (gctl_id->iface != SNDRV_CTL_ELEM_IFACE_MIXER &&
 		    gctl_id->iface != SNDRV_CTL_ELEM_IFACE_PCM) {
 			err = -EINVAL;
@@ -971,11 +968,9 @@ static int snd_emu10k1_del_controls(struct snd_emu10k1 *emu,
 				       in_kernel);
 		if (err < 0)
 			return err;
-		down_write(&card->controls_rwsem);
 		ctl = snd_emu10k1_look_for_ctl(emu, &id);
 		if (ctl)
 			snd_ctl_remove(card, ctl->kcontrol);
-		up_write(&card->controls_rwsem);
 	}
 	return 0;
 }

sound/pci/hda/hda_codec.c

@@ -1769,10 +1769,8 @@ void snd_hda_ctls_clear(struct hda_codec *codec)
 	int i;
 	struct hda_nid_item *items = codec->mixers.list;
 
-	down_write(&codec->card->controls_rwsem);
 	for (i = 0; i < codec->mixers.used; i++)
 		snd_ctl_remove(codec->card, items[i].kctl);
-	up_write(&codec->card->controls_rwsem);
 	snd_array_free(&codec->mixers);
 	snd_array_free(&codec->nids);
 }

sound/soc/atmel/mchp-pdmc.c

@@ -386,7 +386,6 @@ static int mchp_pdmc_open(struct snd_soc_component *component,
 	for (i = 0; i < ARRAY_SIZE(mchp_pdmc_snd_controls); i++) {
 		const struct snd_kcontrol_new *control = &mchp_pdmc_snd_controls[i];
 		struct snd_ctl_elem_id id;
-		struct snd_kcontrol *kctl;
 		int err;
 
 		if (component->name_prefix)
@@ -400,17 +399,10 @@ static int mchp_pdmc_open(struct snd_soc_component *component,
 		id.device = control->device;
 		id.subdevice = control->subdevice;
 		id.index = control->index;
-		kctl = snd_ctl_find_id(component->card->snd_card, &id);
-		if (!kctl) {
-			dev_err(component->dev, "Failed to find %s\n", control->name);
-			continue;
-		}
-		err = snd_ctl_remove(component->card->snd_card, kctl);
-		if (err < 0) {
+		err = snd_ctl_remove_id(component->card->snd_card, &id);
+		if (err < 0)
 			dev_err(component->dev, "%d: Failed to remove %s\n", err,
 				control->name);
-			continue;
-		}
 	}
 
 	return 0;

sound/soc/codecs/sigmadsp.c

@@ -669,36 +669,19 @@ static void sigmadsp_activate_ctrl(struct sigmadsp *sigmadsp,
 	struct sigmadsp_control *ctrl, unsigned int samplerate_mask)
 {
 	struct snd_card *card = sigmadsp->component->card->snd_card;
-	struct snd_kcontrol_volatile *vd;
-	struct snd_ctl_elem_id id;
 	bool active;
-	bool changed = false;
+	int changed;
 
 	active = sigmadsp_samplerate_valid(ctrl->samplerates, samplerate_mask);
-
-	down_write(&card->controls_rwsem);
-	if (!ctrl->kcontrol) {
-		up_write(&card->controls_rwsem);
+	if (!ctrl->kcontrol)
 		return;
-	}
-
-	id = ctrl->kcontrol->id;
-	vd = &ctrl->kcontrol->vd[0];
-	if (active == (bool)(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)) {
-		vd->access ^= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
-		changed = true;
-	}
-	up_write(&card->controls_rwsem);
-
-	if (active && changed) {
+	changed = snd_ctl_activate_id(card, &ctrl->kcontrol->id, active);
+	if (active && changed > 0) {
 		mutex_lock(&sigmadsp->lock);
 		if (ctrl->cached)
 			sigmadsp_ctrl_write(sigmadsp, ctrl, ctrl->cache);
 		mutex_unlock(&sigmadsp->lock);
 	}
-
-	if (changed)
-		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, &id);
 }
 
 /**

sound/soc/soc-topology.c

@@ -2564,7 +2564,6 @@ EXPORT_SYMBOL_GPL(snd_soc_tplg_component_load);
 /* remove dynamic controls from the component driver */
 int snd_soc_tplg_component_remove(struct snd_soc_component *comp)
 {
-	struct snd_card *card = comp->card->snd_card;
 	struct snd_soc_dobj *dobj, *next_dobj;
 	int pass;
 
@@ -2572,7 +2571,6 @@ int snd_soc_tplg_component_remove(struct snd_soc_component *comp)
 	for (pass = SOC_TPLG_PASS_END; pass >= SOC_TPLG_PASS_START; pass--) {
 
 		/* remove mixer controls */
-		down_write(&card->controls_rwsem);
 		list_for_each_entry_safe(dobj, next_dobj, &comp->dobj_list,
 			list) {
 
@@ -2607,7 +2605,6 @@ int snd_soc_tplg_component_remove(struct snd_soc_component *comp)
 				break;
 			}
 		}
-		up_write(&card->controls_rwsem);
 	}
 
 	/* let caller know if FW can be freed when no objects are left */