ALSA: seq: fifo: Use guard() for locking

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

Only the code refactoring, and no functional changes.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-13-tiwai@suse.de

sound/core/seq/seq_fifo.c

@@ -88,12 +88,11 @@ void snd_seq_fifo_clear(struct snd_seq_fifo *f)
 	atomic_set(&f->overflow, 0);
 
 	snd_use_lock_sync(&f->use_lock);
-	spin_lock_irq(&f->lock);
+	guard(spinlock_irq)(&f->lock);
 	/* drain the fifo */
 	while ((cell = fifo_cell_out(f)) != NULL) {
 		snd_seq_cell_free(cell);
 	}
-	spin_unlock_irq(&f->lock);
 }
 
 
@@ -102,7 +101,6 @@ int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
 			  struct snd_seq_event *event)
 {
 	struct snd_seq_event_cell *cell;
-	unsigned long flags;
 	int err;
 
 	if (snd_BUG_ON(!f))
@@ -118,15 +116,15 @@ int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
 	}
 		
 	/* append new cells to fifo */
-	spin_lock_irqsave(&f->lock, flags);
-	if (f->tail != NULL)
-		f->tail->next = cell;
-	f->tail = cell;
-	if (f->head == NULL)
-		f->head = cell;
-	cell->next = NULL;
-	f->cells++;
-	spin_unlock_irqrestore(&f->lock, flags);
+	scoped_guard(spinlock_irqsave, &f->lock) {
+		if (f->tail != NULL)
+			f->tail->next = cell;
+		f->tail = cell;
+		if (f->head == NULL)
+			f->head = cell;
+		cell->next = NULL;
+		f->cells++;
+	}
 
 	/* wakeup client */
 	if (waitqueue_active(&f->input_sleep))
@@ -199,16 +197,13 @@ int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
 void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
 			       struct snd_seq_event_cell *cell)
 {
-	unsigned long flags;
-
 	if (cell) {
-		spin_lock_irqsave(&f->lock, flags);
+		guard(spinlock_irqsave)(&f->lock);
 		cell->next = f->head;
 		f->head = cell;
 		if (!f->tail)
 			f->tail = cell;
 		f->cells++;
-		spin_unlock_irqrestore(&f->lock, flags);
 	}
 }
 
@@ -239,17 +234,17 @@ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
 		return -ENOMEM;
 	}
 
-	spin_lock_irq(&f->lock);
-	/* remember old pool */
-	oldpool = f->pool;
-	oldhead = f->head;
-	/* exchange pools */
-	f->pool = newpool;
-	f->head = NULL;
-	f->tail = NULL;
-	f->cells = 0;
-	/* NOTE: overflow flag is not cleared */
-	spin_unlock_irq(&f->lock);
+	scoped_guard(spinlock_irq, &f->lock) {
+		/* remember old pool */
+		oldpool = f->pool;
+		oldhead = f->head;
+		/* exchange pools */
+		f->pool = newpool;
+		f->head = NULL;
+		f->tail = NULL;
+		f->cells = 0;
+		/* NOTE: overflow flag is not cleared */
+	}
 
 	/* close the old pool and wait until all users are gone */
 	snd_seq_pool_mark_closing(oldpool);
@@ -268,16 +263,14 @@ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
 /* get the number of unused cells safely */
 int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f)
 {
-	unsigned long flags;
 	int cells;
 
 	if (!f)
 		return 0;
 
 	snd_use_lock_use(&f->use_lock);
-	spin_lock_irqsave(&f->lock, flags);
-	cells = snd_seq_unused_cells(f->pool);
-	spin_unlock_irqrestore(&f->lock, flags);
+	scoped_guard(spinlock_irqsave, &f->lock)
+		cells = snd_seq_unused_cells(f->pool);
 	snd_use_lock_free(&f->use_lock);
 	return cells;
 }