Input: serport - use guard notation when acquiring spinlock

Using guard notation makes the code more compact and error handling
more robust by ensuring that locks 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/serio/serport.c

···
 static int serport_serio_open(struct serio *serio)
 {
 	struct serport *serport = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
 	set_bit(SERPORT_ACTIVE, &serport->flags);
-	spin_unlock_irqrestore(&serport->lock, flags);
 
 	return 0;
 }
···
 static void serport_serio_close(struct serio *serio)
 {
 	struct serport *serport = serio->port_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
 	clear_bit(SERPORT_ACTIVE, &serport->flags);
-	spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*
···
 				  const u8 *fp, size_t count)
 {
 	struct serport *serport = tty->disc_data;
-	unsigned long flags;
 	unsigned int ch_flags = 0;
 	int i;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
 
 	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
-		goto out;
+		return;
 
 	for (i = 0; i < count; i++) {
 		if (fp) {
···
 
 		serio_interrupt(serport->serio, cp[i], ch_flags);
 	}
-
-out:
-	spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*
···
 static void serport_ldisc_hangup(struct tty_struct *tty)
 {
 	struct serport *serport = tty->disc_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
-	set_bit(SERPORT_DEAD, &serport->flags);
-	spin_unlock_irqrestore(&serport->lock, flags);
+	scoped_guard(spinlock_irqsave, &serport->lock)
+		set_bit(SERPORT_DEAD, &serport->flags);
 
 	wake_up_interruptible(&serport->wait);
 }
···
 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 {
 	struct serport *serport = tty->disc_data;
-	unsigned long flags;
 
-	spin_lock_irqsave(&serport->lock, flags);
+	guard(spinlock_irqsave)(&serport->lock);
+
 	if (test_bit(SERPORT_ACTIVE, &serport->flags))
 		serio_drv_write_wakeup(serport->serio);
-	spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*