ALSA: firewire: bebob: Use guard() for mutex locks

Replace the manual mutex lock/unlock pairs with guard() for code
simplification.

Only code refactoring, and no behavior change.

Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250828132802.9032-2-tiwai@suse.de

sound/firewire/bebob/bebob.c

@@ -122,9 +122,9 @@ bebob_card_free(struct snd_card *card)
 {
 	struct snd_bebob *bebob = card->private_data;
 
-	mutex_lock(&devices_mutex);
-	clear_bit(bebob->card_index, devices_used);
-	mutex_unlock(&devices_mutex);
+	scoped_guard(mutex, &devices_mutex) {
+		clear_bit(bebob->card_index, devices_used);
+	}
 
 	snd_bebob_stream_destroy_duplex(bebob);
 
@@ -207,25 +207,21 @@ static int bebob_probe(struct fw_unit *unit, const struct ieee1394_device_id *en
 			return -ENODEV;
 	}
 
-	mutex_lock(&devices_mutex);
-	for (card_index = 0; card_index < SNDRV_CARDS; card_index++) {
-		if (!test_bit(card_index, devices_used) && enable[card_index])
-			break;
-	}
-	if (card_index >= SNDRV_CARDS) {
-		mutex_unlock(&devices_mutex);
-		return -ENOENT;
-	}
+	scoped_guard(mutex, &devices_mutex) {
+		for (card_index = 0; card_index < SNDRV_CARDS; card_index++) {
+			if (!test_bit(card_index, devices_used) && enable[card_index])
+				break;
+		}
+		if (card_index >= SNDRV_CARDS)
+			return -ENOENT;
 
-	err = snd_card_new(&unit->device, index[card_index], id[card_index], THIS_MODULE,
-			   sizeof(*bebob), &card);
-	if (err < 0) {
-		mutex_unlock(&devices_mutex);
-		return err;
+		err = snd_card_new(&unit->device, index[card_index], id[card_index], THIS_MODULE,
+				   sizeof(*bebob), &card);
+		if (err < 0)
+			return err;
+		card->private_free = bebob_card_free;
+		set_bit(card_index, devices_used);
 	}
-	card->private_free = bebob_card_free;
-	set_bit(card_index, devices_used);
-	mutex_unlock(&devices_mutex);
 
 	bebob = card->private_data;
 	bebob->unit = fw_unit_get(unit);

sound/firewire/bebob/bebob_maudio.c

@@ -265,7 +265,7 @@ snd_bebob_maudio_special_discover(struct snd_bebob *bebob, bool is1814)
 	if (!params)
 		return -ENOMEM;
 
-	mutex_lock(&bebob->mutex);
+	guard(mutex)(&bebob->mutex);
 
 	bebob->maudio_special_quirk = (void *)params;
 	params->is1814 = is1814;
@@ -277,12 +277,12 @@ snd_bebob_maudio_special_discover(struct snd_bebob *bebob, bool is1814)
 	if (err < 0) {
 		dev_err(&bebob->unit->device,
 			"fail to initialize clock params: %d\n", err);
-		goto end;
+		return err;
 	}
 
 	err = add_special_controls(bebob);
 	if (err < 0)
-		goto end;
+		return err;
 
 	special_stream_formation_set(bebob);
 
@@ -293,8 +293,6 @@ snd_bebob_maudio_special_discover(struct snd_bebob *bebob, bool is1814)
 		bebob->midi_input_ports = 2;
 		bebob->midi_output_ports = 2;
 	}
-end:
-	mutex_unlock(&bebob->mutex);
 	return err;
 }
 
@@ -383,14 +381,12 @@ static int special_clk_ctl_put(struct snd_kcontrol *kctl,
 	if (id >= ARRAY_SIZE(special_clk_types))
 		return -EINVAL;
 
-	mutex_lock(&bebob->mutex);
+	guard(mutex)(&bebob->mutex);
 
 	err = avc_maudio_set_special_clk(bebob, id,
 					 params->dig_in_fmt,
 					 params->dig_out_fmt,
 					 params->clk_lock);
-	mutex_unlock(&bebob->mutex);
-
 	if (err >= 0)
 		err = 1;
 
@@ -456,14 +452,14 @@ static int special_dig_in_iface_ctl_get(struct snd_kcontrol *kctl,
 	unsigned int dig_in_iface;
 	int err, val;
 
-	mutex_lock(&bebob->mutex);
+	guard(mutex)(&bebob->mutex);
 
 	err = avc_audio_get_selector(bebob->unit, 0x00, 0x04,
 				     &dig_in_iface);
 	if (err < 0) {
 		dev_err(&bebob->unit->device,
 			"fail to get digital input interface: %d\n", err);
-		goto end;
+		return err;
 	}
 
 	/* encoded id for user value */
@@ -474,9 +470,7 @@ static int special_dig_in_iface_ctl_get(struct snd_kcontrol *kctl,
 		val = 2;
 
 	uval->value.enumerated.item[0] = val;
-end:
-	mutex_unlock(&bebob->mutex);
-	return err;
+	return 0;
 }
 static int special_dig_in_iface_ctl_set(struct snd_kcontrol *kctl,
 					struct snd_ctl_elem_value *uval)
@@ -494,7 +488,7 @@ static int special_dig_in_iface_ctl_set(struct snd_kcontrol *kctl,
 	dig_in_fmt = (id >> 1) & 0x01;
 	dig_in_iface = id & 0x01;
 
-	mutex_lock(&bebob->mutex);
+	guard(mutex)(&bebob->mutex);
 
 	err = avc_maudio_set_special_clk(bebob,
 					 params->clk_src,
@@ -502,24 +496,19 @@ static int special_dig_in_iface_ctl_set(struct snd_kcontrol *kctl,
 					 params->dig_out_fmt,
 					 params->clk_lock);
 	if (err < 0)
-		goto end;
+		return err;
 
 	/* For ADAT, optical interface is only available. */
-	if (params->dig_in_fmt > 0) {
-		err = 1;
-		goto end;
-	}
+	if (params->dig_in_fmt > 0)
+		return 1;
 
 	/* For S/PDIF, optical/coaxial interfaces are selectable. */
 	err = avc_audio_set_selector(bebob->unit, 0x00, 0x04, dig_in_iface);
 	if (err < 0)
 		dev_err(&bebob->unit->device,
 			"fail to set digital input interface: %d\n", err);
-	err = 1;
-end:
 	special_stream_formation_set(bebob);
-	mutex_unlock(&bebob->mutex);
-	return err;
+	return 1;
 }
 static const struct snd_kcontrol_new special_dig_in_iface_ctl = {
 	.name	= "Digital Input Interface",
@@ -546,9 +535,9 @@ static int special_dig_out_iface_ctl_get(struct snd_kcontrol *kctl,
 {
 	struct snd_bebob *bebob = snd_kcontrol_chip(kctl);
 	struct special_params *params = bebob->maudio_special_quirk;
-	mutex_lock(&bebob->mutex);
+
+	guard(mutex)(&bebob->mutex);
 	uval->value.enumerated.item[0] = params->dig_out_fmt;
-	mutex_unlock(&bebob->mutex);
 	return 0;
 }
 static int special_dig_out_iface_ctl_set(struct snd_kcontrol *kctl,
@@ -563,7 +552,7 @@ static int special_dig_out_iface_ctl_set(struct snd_kcontrol *kctl,
 	if (id >= ARRAY_SIZE(special_dig_out_iface_labels))
 		return -EINVAL;
 
-	mutex_lock(&bebob->mutex);
+	guard(mutex)(&bebob->mutex);
 
 	err = avc_maudio_set_special_clk(bebob,
 					 params->clk_src,
@@ -574,7 +563,6 @@ static int special_dig_out_iface_ctl_set(struct snd_kcontrol *kctl,
 		err = 1;
 	}
 
-	mutex_unlock(&bebob->mutex);
 	return err;
 }
 static const struct snd_kcontrol_new special_dig_out_iface_ctl = {

sound/firewire/bebob/bebob_midi.c

@@ -16,15 +16,15 @@ static int midi_open(struct snd_rawmidi_substream *substream)
 	if (err < 0)
 		return err;
 
-	mutex_lock(&bebob->mutex);
-	err = snd_bebob_stream_reserve_duplex(bebob, 0, 0, 0);
-	if (err >= 0) {
-		++bebob->substreams_counter;
-		err = snd_bebob_stream_start_duplex(bebob);
-		if (err < 0)
-			--bebob->substreams_counter;
+	scoped_guard(mutex, &bebob->mutex) {
+		err = snd_bebob_stream_reserve_duplex(bebob, 0, 0, 0);
+		if (err >= 0) {
+			++bebob->substreams_counter;
+			err = snd_bebob_stream_start_duplex(bebob);
+			if (err < 0)
+				--bebob->substreams_counter;
+		}
 	}
-	mutex_unlock(&bebob->mutex);
 	if (err < 0)
 		snd_bebob_stream_lock_release(bebob);
 
@@ -35,10 +35,10 @@ static int midi_close(struct snd_rawmidi_substream *substream)
 {
 	struct snd_bebob *bebob = substream->rmidi->private_data;
 
-	mutex_lock(&bebob->mutex);
-	bebob->substreams_counter--;
-	snd_bebob_stream_stop_duplex(bebob);
-	mutex_unlock(&bebob->mutex);
+	scoped_guard(mutex, &bebob->mutex) {
+		bebob->substreams_counter--;
+		snd_bebob_stream_stop_duplex(bebob);
+	}
 
 	snd_bebob_stream_lock_release(bebob);
 	return 0;

sound/firewire/bebob/bebob_pcm.c

@@ -149,49 +149,42 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	if (err < 0)
 		goto err_locked;
 
-	mutex_lock(&bebob->mutex);
+	scoped_guard(mutex, &bebob->mutex) {
+		// When source of clock is not internal or any stream is reserved for
+		// transmission of PCM frames, the available sampling rate is limited
+		// at current one.
+		if (src == SND_BEBOB_CLOCK_TYPE_EXTERNAL ||
+		    (bebob->substreams_counter > 0 && d->events_per_period > 0)) {
+			unsigned int frames_per_period = d->events_per_period;
+			unsigned int frames_per_buffer = d->events_per_buffer;
+			unsigned int sampling_rate;
 
-	// When source of clock is not internal or any stream is reserved for
-	// transmission of PCM frames, the available sampling rate is limited
-	// at current one.
-	if (src == SND_BEBOB_CLOCK_TYPE_EXTERNAL ||
-	    (bebob->substreams_counter > 0 && d->events_per_period > 0)) {
-		unsigned int frames_per_period = d->events_per_period;
-		unsigned int frames_per_buffer = d->events_per_buffer;
-		unsigned int sampling_rate;
-
-		err = spec->get(bebob, &sampling_rate);
-		if (err < 0) {
-			mutex_unlock(&bebob->mutex);
-			dev_err(&bebob->unit->device,
-				"fail to get sampling rate: %d\n", err);
-			goto err_locked;
-		}
-
-		substream->runtime->hw.rate_min = sampling_rate;
-		substream->runtime->hw.rate_max = sampling_rate;
-
-		if (frames_per_period > 0) {
-			err = snd_pcm_hw_constraint_minmax(substream->runtime,
-					SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
-					frames_per_period, frames_per_period);
+			err = spec->get(bebob, &sampling_rate);
 			if (err < 0) {
-				mutex_unlock(&bebob->mutex);
+				dev_err(&bebob->unit->device,
+					"fail to get sampling rate: %d\n", err);
 				goto err_locked;
 			}
 
-			err = snd_pcm_hw_constraint_minmax(substream->runtime,
-					SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
-					frames_per_buffer, frames_per_buffer);
-			if (err < 0) {
-				mutex_unlock(&bebob->mutex);
-				goto err_locked;
+			substream->runtime->hw.rate_min = sampling_rate;
+			substream->runtime->hw.rate_max = sampling_rate;
+
+			if (frames_per_period > 0) {
+				err = snd_pcm_hw_constraint_minmax(substream->runtime,
+								   SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
+								   frames_per_period, frames_per_period);
+				if (err < 0)
+					goto err_locked;
+
+				err = snd_pcm_hw_constraint_minmax(substream->runtime,
+								   SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
+								   frames_per_buffer, frames_per_buffer);
+				if (err < 0)
+					goto err_locked;
 			}
 		}
 	}
 
-	mutex_unlock(&bebob->mutex);
-
 	snd_pcm_set_sync(substream);
 
 	return 0;
@@ -219,12 +212,11 @@ static int pcm_hw_params(struct snd_pcm_substream *substream,
 		unsigned int frames_per_period = params_period_size(hw_params);
 		unsigned int frames_per_buffer = params_buffer_size(hw_params);
 
-		mutex_lock(&bebob->mutex);
+		guard(mutex)(&bebob->mutex);
 		err = snd_bebob_stream_reserve_duplex(bebob, rate,
 					frames_per_period, frames_per_buffer);
 		if (err >= 0)
 			++bebob->substreams_counter;
-		mutex_unlock(&bebob->mutex);
 	}
 
 	return err;
@@ -234,15 +226,13 @@ static int pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	struct snd_bebob *bebob = substream->private_data;
 
-	mutex_lock(&bebob->mutex);
+	guard(mutex)(&bebob->mutex);
 
 	if (substream->runtime->state != SNDRV_PCM_STATE_OPEN)
 		bebob->substreams_counter--;
 
 	snd_bebob_stream_stop_duplex(bebob);
 
-	mutex_unlock(&bebob->mutex);
-
 	return 0;
 }