ALSA: timer: Use guard() for locking

We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

For making changes easier, some functions widen the application of
register_mutex, but those shouldn't influence on any actual
performance.

Also, one code block was factored out as a function so that guard()
can be applied cleanly without much indentation.

There are still a few remaining explicit spin_lock/unlock calls, and
those are for the places where we do temporary unlock/relock, which
doesn't fit well with the guard(), so far.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

sound/core/timer.c

···
 		return -EBUSY;
 	list_move_tail(&slave->open_list, &master->slave_list_head);
 	master->timer->num_instances++;
-	spin_lock_irq(&slave_active_lock);
-	spin_lock(&master->timer->lock);
+	guard(spinlock_irq)(&slave_active_lock);
+	guard(spinlock)(&master->timer->lock);
 	slave->master = master;
 	slave->timer = master->timer;
 	if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
 		list_add_tail(&slave->active_list, &master->slave_active_head);
-	spin_unlock(&master->timer->lock);
-	spin_unlock_irq(&slave_active_lock);
 	return 1;
 }
 
···
 }
 EXPORT_SYMBOL(snd_timer_open);
 
+/* remove slave links, called from snd_timer_close_locked() below */
+static void remove_slave_links(struct snd_timer_instance *timeri,
+			       struct snd_timer *timer)
+{
+	struct snd_timer_instance *slave, *tmp;
+
+	guard(spinlock_irq)(&slave_active_lock);
+	guard(spinlock)(&timer->lock);
+	timeri->timer = NULL;
+	list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head, open_list) {
+		list_move_tail(&slave->open_list, &snd_timer_slave_list);
+		timer->num_instances--;
+		slave->master = NULL;
+		slave->timer = NULL;
+		list_del_init(&slave->ack_list);
+		list_del_init(&slave->active_list);
+	}
+}
+
 /*
  * close a timer instance
  * call this with register_mutex down.
···
 				   struct device **card_devp_to_put)
 {
 	struct snd_timer *timer = timeri->timer;
-	struct snd_timer_instance *slave, *tmp;
 
 	if (timer) {
-		spin_lock_irq(&timer->lock);
+		guard(spinlock)(&timer->lock);
 		timeri->flags |= SNDRV_TIMER_IFLG_DEAD;
-		spin_unlock_irq(&timer->lock);
 	}
 
 	if (!list_empty(&timeri->open_list)) {
···
 		}
 		spin_unlock_irq(&timer->lock);
 
-		/* remove slave links */
-		spin_lock_irq(&slave_active_lock);
-		spin_lock(&timer->lock);
-		timeri->timer = NULL;
-		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
-					 open_list) {
-			list_move_tail(&slave->open_list, &snd_timer_slave_list);
-			timer->num_instances--;
-			slave->master = NULL;
-			slave->timer = NULL;
-			list_del_init(&slave->ack_list);
-			list_del_init(&slave->active_list);
-		}
-		spin_unlock(&timer->lock);
-		spin_unlock_irq(&slave_active_lock);
+		remove_slave_links(timeri, timer);
 
 		/* slave doesn't need to release timer resources below */
 		if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
···
 	if (snd_BUG_ON(!timeri))
 		return;
 
-	mutex_lock(&register_mutex);
-	snd_timer_close_locked(timeri, &card_dev_to_put);
-	mutex_unlock(&register_mutex);
+	scoped_guard(mutex, &register_mutex)
+		snd_timer_close_locked(timeri, &card_dev_to_put);
 	/* put_device() is called after unlock for avoiding deadlock */
 	if (card_dev_to_put)
 		put_device(card_dev_to_put);
···
 {
 	struct snd_timer * timer;
 	unsigned long ret = 0;
-	unsigned long flags;
 
 	if (timeri == NULL)
 		return 0;
 	timer = timeri->timer;
 	if (timer) {
-		spin_lock_irqsave(&timer->lock, flags);
+		guard(spinlock_irqsave)(&timer->lock);
 		ret = snd_timer_hw_resolution(timer);
-		spin_unlock_irqrestore(&timer->lock, flags);
 	}
 	return ret;
 }
···
 {
 	struct snd_timer *timer;
 	int result;
-	unsigned long flags;
 
 	timer = timeri->timer;
 	if (!timer)
 		return -EINVAL;
 
-	spin_lock_irqsave(&timer->lock, flags);
-	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
-		result = -EINVAL;
-		goto unlock;
-	}
-	if (timer->card && timer->card->shutdown) {
-		result = -ENODEV;
-		goto unlock;
-	}
+	guard(spinlock_irqsave)(&timer->lock);
+	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD)
+		return -EINVAL;
+	if (timer->card && timer->card->shutdown)
+		return -ENODEV;
 	if (timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
-			     SNDRV_TIMER_IFLG_START)) {
-		result = -EBUSY;
-		goto unlock;
-	}
+			     SNDRV_TIMER_IFLG_START))
+		return -EBUSY;
 
 	if (start)
 		timeri->ticks = timeri->cticks = ticks;
···
 	}
 	snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
 			  SNDRV_TIMER_EVENT_CONTINUE);
- unlock:
-	spin_unlock_irqrestore(&timer->lock, flags);
 	return result;
 }
 
···
 static int snd_timer_start_slave(struct snd_timer_instance *timeri,
 				 bool start)
 {
-	unsigned long flags;
-	int err;
-
-	spin_lock_irqsave(&slave_active_lock, flags);
-	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
-		err = -EINVAL;
-		goto unlock;
-	}
-	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
-		err = -EBUSY;
-		goto unlock;
-	}
+	guard(spinlock_irqsave)(&slave_active_lock);
+	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD)
+		return -EINVAL;
+	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING)
+		return -EBUSY;
 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
 	if (timeri->master && timeri->timer) {
-		spin_lock(&timeri->timer->lock);
+		guard(spinlock)(&timeri->timer->lock);
 		list_add_tail(&timeri->active_list,
 			      &timeri->master->slave_active_head);
 		snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
 				  SNDRV_TIMER_EVENT_CONTINUE);
-		spin_unlock(&timeri->timer->lock);
 	}
-	err = 1; /* delayed start */
- unlock:
-	spin_unlock_irqrestore(&slave_active_lock, flags);
-	return err;
+	return 1; /* delayed start */
 }
 
 /* stop/pause a master timer */
 static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
 {
 	struct snd_timer *timer;
-	int result = 0;
-	unsigned long flags;
 
 	timer = timeri->timer;
 	if (!timer)
 		return -EINVAL;
-	spin_lock_irqsave(&timer->lock, flags);
+	guard(spinlock_irqsave)(&timer->lock);
 	list_del_init(&timeri->ack_list);
 	list_del_init(&timeri->active_list);
 	if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
-			       SNDRV_TIMER_IFLG_START))) {
-		result = -EBUSY;
-		goto unlock;
-	}
+			       SNDRV_TIMER_IFLG_START)))
+		return -EBUSY;
 	if (timer->card && timer->card->shutdown)
-		goto unlock;
+		return 0;
 	if (stop) {
 		timeri->cticks = timeri->ticks;
 		timeri->pticks = 0;
···
 		timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;
 	snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
 			  SNDRV_TIMER_EVENT_PAUSE);
- unlock:
-	spin_unlock_irqrestore(&timer->lock, flags);
-	return result;
+	return 0;
 }
 
 /* stop/pause a slave timer */
 static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
 {
-	unsigned long flags;
 	bool running;
 
-	spin_lock_irqsave(&slave_active_lock, flags);
+	guard(spinlock_irqsave)(&slave_active_lock);
 	running = timeri->flags & SNDRV_TIMER_IFLG_RUNNING;
 	timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
 	if (timeri->timer) {
-		spin_lock(&timeri->timer->lock);
+		guard(spinlock)(&timeri->timer->lock);
 		list_del_init(&timeri->ack_list);
 		list_del_init(&timeri->active_list);
 		if (running)
 			snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
 					  SNDRV_TIMER_EVENT_PAUSE);
-		spin_unlock(&timeri->timer->lock);
 	}
-	spin_unlock_irqrestore(&slave_active_lock, flags);
 	return running ? 0 : -EBUSY;
 }
 
···
 static void snd_timer_clear_callbacks(struct snd_timer *timer,
 				      struct list_head *head)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&timer->lock, flags);
+	guard(spinlock_irqsave)(&timer->lock);
 	while (!list_empty(head))
 		list_del_init(head->next);
-	spin_unlock_irqrestore(&timer->lock, flags);
 }
 
 /*
···
 static void snd_timer_work(struct work_struct *work)
 {
 	struct snd_timer *timer = container_of(work, struct snd_timer, task_work);
-	unsigned long flags;
 
 	if (timer->card && timer->card->shutdown) {
 		snd_timer_clear_callbacks(timer, &timer->sack_list_head);
 		return;
 	}
 
-	spin_lock_irqsave(&timer->lock, flags);
+	guard(spinlock_irqsave)(&timer->lock);
 	snd_timer_process_callbacks(timer, &timer->sack_list_head);
-	spin_unlock_irqrestore(&timer->lock, flags);
 }
 
 /*
···
 	struct snd_timer_instance *ti, *ts, *tmp;
 	unsigned long resolution;
 	struct list_head *ack_list_head;
-	unsigned long flags;
-	bool use_work = false;
 
 	if (timer == NULL)
 		return;
···
 		return;
 	}
 
-	spin_lock_irqsave(&timer->lock, flags);
+	guard(spinlock_irqsave)(&timer->lock);
 
 	/* remember the current resolution */
 	resolution = snd_timer_hw_resolution(timer);
···
 	snd_timer_process_callbacks(timer, &timer->ack_list_head);
 
 	/* do we have any slow callbacks? */
-	use_work = !list_empty(&timer->sack_list_head);
-	spin_unlock_irqrestore(&timer->lock, flags);
-
-	if (use_work)
+	if (!list_empty(&timer->sack_list_head))
 		queue_work(system_highpri_wq, &timer->task_work);
 }
 EXPORT_SYMBOL(snd_timer_interrupt);
···
 	if (!timer)
 		return 0;
 
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	if (! list_empty(&timer->open_list_head)) {
 		struct list_head *p, *n;
 		struct snd_timer_instance *ti;
···
 		}
 	}
 	list_del(&timer->device_list);
-	mutex_unlock(&register_mutex);
 
 	if (timer->private_free)
 		timer->private_free(timer);
···
 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
 	    	return -EINVAL;
 
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
 		if (timer1->tmr_class > timer->tmr_class)
 			break;
···
 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
 			continue;
 		/* conflicts.. */
-		mutex_unlock(&register_mutex);
 		return -EBUSY;
 	}
 	list_add_tail(&timer->device_list, &timer1->device_list);
-	mutex_unlock(&register_mutex);
 	return 0;
 }
 
···
 	struct snd_timer *timer = device->device_data;
 	struct snd_timer_instance *ti;
 
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	list_del_init(&timer->device_list);
 	/* wake up pending sleepers */
 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
 		if (ti->disconnect)
 			ti->disconnect(ti);
 	}
-	mutex_unlock(&register_mutex);
 	return 0;
 }
 
 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec64 *tstamp)
 {
-	unsigned long flags;
 	unsigned long resolution = 0;
 	struct snd_timer_instance *ti, *ts;
 
···
 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
 		       event > SNDRV_TIMER_EVENT_MRESUME))
 		return;
-	spin_lock_irqsave(&timer->lock, flags);
+	guard(spinlock_irqsave)(&timer->lock);
 	if (event == SNDRV_TIMER_EVENT_MSTART ||
 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
 	    event == SNDRV_TIMER_EVENT_MRESUME)
···
 			if (ts->ccallback)
 				ts->ccallback(ts, event, tstamp, resolution);
 	}
-	spin_unlock_irqrestore(&timer->lock, flags);
 }
 EXPORT_SYMBOL(snd_timer_notify);
 
···
 	struct snd_timer_instance *ti;
 	unsigned long resolution;
 
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	list_for_each_entry(timer, &snd_timer_list, device_list) {
 		if (timer->card && timer->card->shutdown)
 			continue;
···
 				    timer->tmr_device, timer->tmr_subdevice);
 		}
 		snd_iprintf(buffer, "%s :", timer->name);
-		spin_lock_irq(&timer->lock);
-		resolution = snd_timer_hw_resolution(timer);
-		spin_unlock_irq(&timer->lock);
+		scoped_guard(spinlock_irq, &timer->lock)
+			resolution = snd_timer_hw_resolution(timer);
 		if (resolution)
 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
 				    resolution / 1000,
···
 						  SNDRV_TIMER_IFLG_RUNNING))
 				    ? "running" : "stopped");
 	}
-	mutex_unlock(&register_mutex);
 }
 
 static struct snd_info_entry *snd_timer_proc_entry;
···
 	struct snd_timer_read *r;
 	int prev;
 
-	spin_lock(&tu->qlock);
+	guard(spinlock)(&tu->qlock);
 	if (tu->qused > 0) {
 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
 		r = &tu->queue[prev];
···
 		tu->qused++;
 	}
       __wake:
-	spin_unlock(&tu->qlock);
 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
 	wake_up(&tu->qchange_sleep);
 }
···
 {
 	struct snd_timer_user *tu = timeri->callback_data;
 	struct snd_timer_tread64 r1;
-	unsigned long flags;
 
 	if (event >= SNDRV_TIMER_EVENT_START &&
 	    event <= SNDRV_TIMER_EVENT_PAUSE)
···
 	r1.tstamp_sec = tstamp->tv_sec;
 	r1.tstamp_nsec = tstamp->tv_nsec;
 	r1.val = resolution;
-	spin_lock_irqsave(&tu->qlock, flags);
-	snd_timer_user_append_to_tqueue(tu, &r1);
-	spin_unlock_irqrestore(&tu->qlock, flags);
+	scoped_guard(spinlock_irqsave, &tu->qlock)
+		snd_timer_user_append_to_tqueue(tu, &r1);
 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
 	wake_up(&tu->qchange_sleep);
 }
···
 
 	memset(&r1, 0, sizeof(r1));
 	memset(&tstamp, 0, sizeof(tstamp));
-	spin_lock(&tu->qlock);
-	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
-			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
-		spin_unlock(&tu->qlock);
-		return;
-	}
-	if (tu->last_resolution != resolution || ticks > 0) {
-		if (timer_tstamp_monotonic)
-			ktime_get_ts64(&tstamp);
-		else
-			ktime_get_real_ts64(&tstamp);
-	}
-	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
-	    tu->last_resolution != resolution) {
-		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
+	scoped_guard(spinlock, &tu->qlock) {
+		if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
+				   (1 << SNDRV_TIMER_EVENT_TICK))) == 0)
+			return;
+		if (tu->last_resolution != resolution || ticks > 0) {
+			if (timer_tstamp_monotonic)
+				ktime_get_ts64(&tstamp);
+			else
+				ktime_get_real_ts64(&tstamp);
+		}
+		if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
+		    tu->last_resolution != resolution) {
+			r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
+			r1.tstamp_sec = tstamp.tv_sec;
+			r1.tstamp_nsec = tstamp.tv_nsec;
+			r1.val = resolution;
+			snd_timer_user_append_to_tqueue(tu, &r1);
+			tu->last_resolution = resolution;
+			append++;
+		}
+		if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
+			break;
+		if (ticks == 0)
+			break;
+		if (tu->qused > 0) {
+			prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
+			r = &tu->tqueue[prev];
+			if (r->event == SNDRV_TIMER_EVENT_TICK) {
+				r->tstamp_sec = tstamp.tv_sec;
+				r->tstamp_nsec = tstamp.tv_nsec;
+				r->val += ticks;
+				append++;
+				break;
+			}
+		}
+		r1.event = SNDRV_TIMER_EVENT_TICK;
 		r1.tstamp_sec = tstamp.tv_sec;
 		r1.tstamp_nsec = tstamp.tv_nsec;
-		r1.val = resolution;
+		r1.val = ticks;
 		snd_timer_user_append_to_tqueue(tu, &r1);
-		tu->last_resolution = resolution;
 		append++;
 	}
-	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
-		goto __wake;
-	if (ticks == 0)
-		goto __wake;
-	if (tu->qused > 0) {
-		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
-		r = &tu->tqueue[prev];
-		if (r->event == SNDRV_TIMER_EVENT_TICK) {
-			r->tstamp_sec = tstamp.tv_sec;
-			r->tstamp_nsec = tstamp.tv_nsec;
-			r->val += ticks;
-			append++;
-			goto __wake;
-		}
-	}
-	r1.event = SNDRV_TIMER_EVENT_TICK;
-	r1.tstamp_sec = tstamp.tv_sec;
-	r1.tstamp_nsec = tstamp.tv_nsec;
-	r1.val = ticks;
-	snd_timer_user_append_to_tqueue(tu, &r1);
-	append++;
-      __wake:
-	spin_unlock(&tu->qlock);
 	if (append == 0)
 		return;
 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
···
 			return -ENOMEM;
 	}
 
-	spin_lock_irq(&tu->qlock);
+	guard(spinlock_irq)(&tu->qlock);
 	kfree(tu->queue);
 	kfree(tu->tqueue);
 	tu->queue_size = size;
 	tu->queue = queue;
 	tu->tqueue = tqueue;
 	tu->qhead = tu->qtail = tu->qused = 0;
-	spin_unlock_irq(&tu->qlock);
 
 	return 0;
 }
···
 	if (file->private_data) {
 		tu = file->private_data;
 		file->private_data = NULL;
-		mutex_lock(&tu->ioctl_lock);
-		if (tu->timeri) {
-			snd_timer_close(tu->timeri);
-			snd_timer_instance_free(tu->timeri);
+		scoped_guard(mutex, &tu->ioctl_lock) {
+			if (tu->timeri) {
+				snd_timer_close(tu->timeri);
+				snd_timer_instance_free(tu->timeri);
+			}
 		}
-		mutex_unlock(&tu->ioctl_lock);
 		snd_fasync_free(tu->fasync);
 		kfree(tu->queue);
 		kfree(tu->tqueue);
···
 
 	if (copy_from_user(&id, _tid, sizeof(id)))
 		return -EFAULT;
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	if (id.dev_class < 0) {		/* first item */
 		if (list_empty(&snd_timer_list))
 			snd_timer_user_zero_id(&id);
···
 			snd_timer_user_zero_id(&id);
 		}
 	}
-	mutex_unlock(&register_mutex);
 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
 		return -EFAULT;
 	return 0;
···
 	struct snd_timer_id tid;
 	struct snd_timer *t;
 	struct list_head *p;
-	int err = 0;
 
 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
 	if (IS_ERR(ginfo))
···
 	tid = ginfo->tid;
 	memset(ginfo, 0, sizeof(*ginfo));
 	ginfo->tid = tid;
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	t = snd_timer_find(&tid);
-	if (t != NULL) {
-		ginfo->card = t->card ? t->card->number : -1;
-		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
-			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
-		strscpy(ginfo->id, t->id, sizeof(ginfo->id));
-		strscpy(ginfo->name, t->name, sizeof(ginfo->name));
-		spin_lock_irq(&t->lock);
+	if (!t)
+		return -ENODEV;
+	ginfo->card = t->card ? t->card->number : -1;
+	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
+		ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
+	strscpy(ginfo->id, t->id, sizeof(ginfo->id));
+	strscpy(ginfo->name, t->name, sizeof(ginfo->name));
+	scoped_guard(spinlock_irq, &t->lock)
 		ginfo->resolution = snd_timer_hw_resolution(t);
-		spin_unlock_irq(&t->lock);
-		if (t->hw.resolution_min > 0) {
-			ginfo->resolution_min = t->hw.resolution_min;
-			ginfo->resolution_max = t->hw.resolution_max;
-		}
-		list_for_each(p, &t->open_list_head) {
-			ginfo->clients++;
-		}
-	} else {
-		err = -ENODEV;
+	if (t->hw.resolution_min > 0) {
+		ginfo->resolution_min = t->hw.resolution_min;
+		ginfo->resolution_max = t->hw.resolution_max;
 	}
-	mutex_unlock(&register_mutex);
-	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
-		err = -EFAULT;
-	return err;
+	list_for_each(p, &t->open_list_head) {
+		ginfo->clients++;
+	}
+	if (copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
+		return -EFAULT;
+	return 0;
 }
 
 static int timer_set_gparams(struct snd_timer_gparams *gparams)
 {
 	struct snd_timer *t;
-	int err;
 
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	t = snd_timer_find(&gparams->tid);
-	if (!t) {
-		err = -ENODEV;
-		goto _error;
-	}
-	if (!list_empty(&t->open_list_head)) {
-		err = -EBUSY;
-		goto _error;
-	}
-	if (!t->hw.set_period) {
-		err = -ENOSYS;
-		goto _error;
-	}
-	err = t->hw.set_period(t, gparams->period_num, gparams->period_den);
-_error:
-	mutex_unlock(&register_mutex);
-	return err;
+	if (!t)
+		return -ENODEV;
+	if (!list_empty(&t->open_list_head))
+		return -EBUSY;
+	if (!t->hw.set_period)
+		return -ENOSYS;
+	return t->hw.set_period(t, gparams->period_num, gparams->period_den);
 }
 
 static int snd_timer_user_gparams(struct file *file,
···
 	tid = gstatus.tid;
 	memset(&gstatus, 0, sizeof(gstatus));
 	gstatus.tid = tid;
-	mutex_lock(&register_mutex);
+	guard(mutex)(&register_mutex);
 	t = snd_timer_find(&tid);
 	if (t != NULL) {
-		spin_lock_irq(&t->lock);
+		guard(spinlock_irq)(&t->lock);
 		gstatus.resolution = snd_timer_hw_resolution(t);
 		if (t->hw.precise_resolution) {
 			t->hw.precise_resolution(t, &gstatus.resolution_num,
···
 			gstatus.resolution_num = gstatus.resolution;
 			gstatus.resolution_den = 1000000000uL;
 		}
-		spin_unlock_irq(&t->lock);
 	} else {
 		err = -ENODEV;
 	}
-	mutex_unlock(&register_mutex);
 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
 		err = -EFAULT;
 	return err;
···
 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
 	strscpy(info->id, t->id, sizeof(info->id));
 	strscpy(info->name, t->name, sizeof(info->name));
-	spin_lock_irq(&t->lock);
-	info->resolution = snd_timer_hw_resolution(t);
-	spin_unlock_irq(&t->lock);
+	scoped_guard(spinlock_irq, &t->lock)
+		info->resolution = snd_timer_hw_resolution(t);
 	if (copy_to_user(_info, info, sizeof(*_info)))
 		return -EFAULT;
 	return 0;
···
 		goto _end;
 	}
 	snd_timer_stop(tu->timeri);
-	spin_lock_irq(&t->lock);
-	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
-			       SNDRV_TIMER_IFLG_EXCLUSIVE|
-			       SNDRV_TIMER_IFLG_EARLY_EVENT);
-	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
-		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
-	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
-		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
-	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
-		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
-	spin_unlock_irq(&t->lock);
+	scoped_guard(spinlock_irq, &t->lock) {
+		tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
+				       SNDRV_TIMER_IFLG_EXCLUSIVE|
+				       SNDRV_TIMER_IFLG_EARLY_EVENT);
+		if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
+			tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
+		if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
+			tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
+		if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
+			tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
+	}
 	if (params.queue_size > 0 &&
 	    (unsigned int)tu->queue_size != params.queue_size) {
 		err = realloc_user_queue(tu, params.queue_size);
 		if (err < 0)
 			goto _end;
 	}
-	spin_lock_irq(&tu->qlock);
-	tu->qhead = tu->qtail = tu->qused = 0;
-	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
-		if (tu->tread) {
-			struct snd_timer_tread64 tread;
-			memset(&tread, 0, sizeof(tread));
-			tread.event = SNDRV_TIMER_EVENT_EARLY;
-			tread.tstamp_sec = 0;
-			tread.tstamp_nsec = 0;
-			tread.val = 0;
-			snd_timer_user_append_to_tqueue(tu, &tread);
-		} else {
-			struct snd_timer_read *r = &tu->queue[0];
-			r->resolution = 0;
-			r->ticks = 0;
-			tu->qused++;
-			tu->qtail++;
+	scoped_guard(spinlock_irq, &tu->qlock) {
+		tu->qhead = tu->qtail = tu->qused = 0;
+		if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
+			if (tu->tread) {
+				struct snd_timer_tread64 tread;
+
+				memset(&tread, 0, sizeof(tread));
+				tread.event = SNDRV_TIMER_EVENT_EARLY;
+				tread.tstamp_sec = 0;
+				tread.tstamp_nsec = 0;
+				tread.val = 0;
+				snd_timer_user_append_to_tqueue(tu, &tread);
+			} else {
+				struct snd_timer_read *r = &tu->queue[0];
+
+				r->resolution = 0;
+				r->ticks = 0;
+				tu->qused++;
+				tu->qtail++;
+			}
 		}
+		tu->filter = params.filter;
+		tu->ticks = params.ticks;
 	}
-	tu->filter = params.filter;
-	tu->ticks = params.ticks;
-	spin_unlock_irq(&tu->qlock);
 	err = 0;
  _end:
 	if (copy_to_user(_params, &params, sizeof(params)))
···
 	status.resolution = snd_timer_resolution(tu->timeri);
 	status.lost = tu->timeri->lost;
 	status.overrun = tu->overrun;
-	spin_lock_irq(&tu->qlock);
-	status.queue = tu->qused;
-	spin_unlock_irq(&tu->qlock);
+	scoped_guard(spinlock_irq, &tu->qlock)
+		status.queue = tu->qused;
 	if (copy_to_user(_status, &status, sizeof(status)))
 		return -EFAULT;
 	return 0;
···
 	status.resolution = snd_timer_resolution(tu->timeri);
 	status.lost = tu->timeri->lost;
 	status.overrun = tu->overrun;
-	spin_lock_irq(&tu->qlock);
-	status.queue = tu->qused;
-	spin_unlock_irq(&tu->qlock);
+	scoped_guard(spinlock_irq, &tu->qlock)
+		status.queue = tu->qused;
 	if (copy_to_user(_status, &status, sizeof(status)))
 		return -EFAULT;
 	return 0;
···
 				 unsigned long arg)
 {
 	struct snd_timer_user *tu = file->private_data;
-	long ret;
 
-	mutex_lock(&tu->ioctl_lock);
-	ret = __snd_timer_user_ioctl(file, cmd, arg, false);
-	mutex_unlock(&tu->ioctl_lock);
-	return ret;
+	guard(mutex)(&tu->ioctl_lock);
+	return __snd_timer_user_ioctl(file, cmd, arg, false);
 }
 
 static int snd_timer_user_fasync(int fd, struct file * file, int on)
···
         poll_wait(file, &tu->qchange_sleep, wait);
 
 	mask = 0;
-	spin_lock_irq(&tu->qlock);
+	guard(spinlock_irq)(&tu->qlock);
 	if (tu->qused)
 		mask |= EPOLLIN | EPOLLRDNORM;
 	if (tu->disconnected)
 		mask |= EPOLLERR;
-	spin_unlock_irq(&tu->qlock);
 
 	return mask;
 }

sound/core/timer_compat.c

···
 					unsigned long arg)
 {
 	struct snd_timer_user *tu = file->private_data;
-	long ret;
 
-	mutex_lock(&tu->ioctl_lock);
-	ret = __snd_timer_user_ioctl_compat(file, cmd, arg);
-	mutex_unlock(&tu->ioctl_lock);
-	return ret;
+	guard(mutex)(&tu->ioctl_lock);
+	return __snd_timer_user_ioctl_compat(file, cmd, arg);
 }