Input: n64joy - use guard notation when acquiring mutex

Using guard notation makes the code more compact and error handling
more robust by ensuring that mutexes are released in all code paths
when control leaves critical section.

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

drivers/input/joystick/n64joy.c

···
 static int n64joy_open(struct input_dev *dev)
 {
 	struct n64joy_priv *priv = input_get_drvdata(dev);
-	int err;
 
-	err = mutex_lock_interruptible(&priv->n64joy_mutex);
-	if (err)
-		return err;
+	scoped_guard(mutex_intr, &priv->n64joy_mutex) {
+		if (!priv->n64joy_opened) {
+			/*
+			 * We could use the vblank irq, but it's not important
+			 * if the poll point slightly changes.
+			 */
+			timer_setup(&priv->timer, n64joy_poll, 0);
+			mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
+		}
 
-	if (!priv->n64joy_opened) {
-		/*
-		 * We could use the vblank irq, but it's not important if
-		 * the poll point slightly changes.
-		 */
-		timer_setup(&priv->timer, n64joy_poll, 0);
-		mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
+		priv->n64joy_opened++;
+		return 0;
 	}
 
-	priv->n64joy_opened++;
-
-	mutex_unlock(&priv->n64joy_mutex);
-	return err;
+	return -EINTR;
 }
 
 static void n64joy_close(struct input_dev *dev)
 {
 	struct n64joy_priv *priv = input_get_drvdata(dev);
 
-	mutex_lock(&priv->n64joy_mutex);
+	guard(mutex)(&priv->n64joy_mutex);
+
 	if (!--priv->n64joy_opened)
 		del_timer_sync(&priv->timer);
-	mutex_unlock(&priv->n64joy_mutex);
 }
 
 static const u64 __initconst scandata[] ____cacheline_aligned = {