ALSA: firewire: lib: 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 <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

sound/firewire/amdtp-stream.c

···
 	struct pkt_desc *descs;
 	int i, type, tag, err;
 
-	mutex_lock(&s->mutex);
+	guard(mutex)(&s->mutex);
 
 	if (WARN_ON(amdtp_stream_running(s) ||
-		    (s->data_block_quadlets < 1))) {
-		err = -EBADFD;
-		goto err_unlock;
-	}
+		    (s->data_block_quadlets < 1)))
+		return -EBADFD;
 
 	if (s->direction == AMDTP_IN_STREAM) {
 		// NOTE: IT context should be used for constant IRQ.
-		if (is_irq_target) {
-			err = -EINVAL;
-			goto err_unlock;
-		}
+		if (is_irq_target)
+			return -EINVAL;
 
 		s->data_block_counter = UINT_MAX;
 	} else {
···
 
 	err = iso_packets_buffer_init(&s->buffer, s->unit, queue_size, max_ctx_payload_size, dir);
 	if (err < 0)
-		goto err_unlock;
+		return err;
 	s->queue_size = queue_size;
 
 	s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
···
 	if (err < 0)
 		goto err_pkt_descs;
 
-	mutex_unlock(&s->mutex);
-
 	return 0;
 err_pkt_descs:
 	kfree(s->packet_descs);
···
 	s->context = ERR_PTR(-1);
 err_buffer:
 	iso_packets_buffer_destroy(&s->buffer, s->unit);
-err_unlock:
-	mutex_unlock(&s->mutex);
 
 	return err;
 }
···
  */
 static void amdtp_stream_stop(struct amdtp_stream *s)
 {
-	mutex_lock(&s->mutex);
+	guard(mutex)(&s->mutex);
 
-	if (!amdtp_stream_running(s)) {
-		mutex_unlock(&s->mutex);
+	if (!amdtp_stream_running(s))
 		return;
-	}
 
 	cancel_work_sync(&s->period_work);
 	fw_iso_context_stop(s->context);
···
 		if (s->domain->replay.enable)
 			kfree(s->ctx_data.tx.cache.descs);
 	}
-
-	mutex_unlock(&s->mutex);
 }
 
 /**

sound/firewire/cmp.c

···
 int cmp_connection_reserve(struct cmp_connection *c,
 			   unsigned int max_payload_bytes)
 {
-	int err;
+	guard(mutex)(&c->mutex);
 
-	mutex_lock(&c->mutex);
-
-	if (WARN_ON(c->resources.allocated)) {
-		err = -EBUSY;
-		goto end;
-	}
+	if (WARN_ON(c->resources.allocated))
+		return -EBUSY;
 
 	c->speed = min(c->max_speed,
 		       fw_parent_device(c->resources.unit)->max_speed);
 
-	err = fw_iso_resources_allocate(&c->resources, max_payload_bytes,
-					c->speed);
-end:
-	mutex_unlock(&c->mutex);
-
-	return err;
+	return fw_iso_resources_allocate(&c->resources, max_payload_bytes,
+					 c->speed);
 }
 EXPORT_SYMBOL(cmp_connection_reserve);
 
 void cmp_connection_release(struct cmp_connection *c)
 {
-	mutex_lock(&c->mutex);
+	guard(mutex)(&c->mutex);
 	fw_iso_resources_free(&c->resources);
-	mutex_unlock(&c->mutex);
 }
 EXPORT_SYMBOL(cmp_connection_release);
 
···
 {
 	int err;
 
-	mutex_lock(&c->mutex);
+	guard(mutex)(&c->mutex);
 
-	if (WARN_ON(c->connected)) {
-		mutex_unlock(&c->mutex);
+	if (WARN_ON(c->connected))
 		return -EISCONN;
-	}
 
 retry_after_bus_reset:
 	if (c->direction == CMP_OUTPUT)
···
 	}
 	if (err >= 0)
 		c->connected = true;
-
-	mutex_unlock(&c->mutex);
 
 	return err;
 }
···
 {
 	int err;
 
-	mutex_lock(&c->mutex);
+	guard(mutex)(&c->mutex);
 
-	if (!c->connected) {
-		mutex_unlock(&c->mutex);
+	if (!c->connected)
 		return;
-	}
 
 	err = pcr_modify(c, pcr_break_modify, NULL, SUCCEED_ON_BUS_RESET);
 	if (err < 0)
 		cmp_error(c, "plug is still connected\n");
 
 	c->connected = false;
-
-	mutex_unlock(&c->mutex);
 }
 EXPORT_SYMBOL(cmp_connection_break);

sound/firewire/iso-resources.c

···
 	if (err < 0)
 		return err;
 
-	mutex_lock(&r->mutex);
-
-	bandwidth = r->bandwidth + r->bandwidth_overhead;
-	fw_iso_resource_manage(card, r->generation, r->channels_mask,
-			       &channel, &bandwidth, true);
-	if (channel == -EAGAIN) {
-		mutex_unlock(&r->mutex);
-		goto retry_after_bus_reset;
+	scoped_guard(mutex, &r->mutex) {
+		bandwidth = r->bandwidth + r->bandwidth_overhead;
+		fw_iso_resource_manage(card, r->generation, r->channels_mask,
+				       &channel, &bandwidth, true);
+		if (channel == -EAGAIN)
+			goto retry_after_bus_reset;
+		if (channel >= 0) {
+			r->channel = channel;
+			r->allocated = true;
+		} else {
+			if (channel == -EBUSY)
+				dev_err(&r->unit->device,
+					"isochronous resources exhausted\n");
+			else
+				dev_err(&r->unit->device,
+					"isochronous resource allocation failed\n");
+		}
 	}
-	if (channel >= 0) {
-		r->channel = channel;
-		r->allocated = true;
-	} else {
-		if (channel == -EBUSY)
-			dev_err(&r->unit->device,
-				"isochronous resources exhausted\n");
-		else
-			dev_err(&r->unit->device,
-				"isochronous resource allocation failed\n");
-	}
-
-	mutex_unlock(&r->mutex);
 
 	return channel;
 }
···
 	struct fw_card *card = fw_parent_device(r->unit)->card;
 	int bandwidth, channel;
 
-	mutex_lock(&r->mutex);
+	guard(mutex)(&r->mutex);
 
-	if (!r->allocated) {
-		mutex_unlock(&r->mutex);
+	if (!r->allocated)
 		return 0;
-	}
 
 	spin_lock_irq(&card->lock);
 	r->generation = card->generation;
···
 				"isochronous resource allocation failed\n");
 	}
 
-	mutex_unlock(&r->mutex);
-
 	return channel;
 }
 EXPORT_SYMBOL(fw_iso_resources_update);
···
 		return;
 	card = fw_parent_device(r->unit)->card;
 
-	mutex_lock(&r->mutex);
+	guard(mutex)(&r->mutex);
 
 	if (r->allocated) {
 		bandwidth = r->bandwidth + r->bandwidth_overhead;
···
 
 		r->allocated = false;
 	}
-
-	mutex_unlock(&r->mutex);
 }
 EXPORT_SYMBOL(fw_iso_resources_free);