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,
-				      num_controls, component->name_prefix);
-	up_write(&card->controls_rwsem);
-	return err;
+	return gbaudio_remove_controls(card, component->dev, controls,
+				       num_controls, component->name_prefix);
 }

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_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 */