Char: genrtc, use wait_event_interruptible

genrtc, use wait_event_interruptible

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/genrtc.c

@@ -173,7 +173,6 @@ static void gen_rtc_interrupt(unsigned long arg)
 static ssize_t gen_rtc_read(struct file *file, char __user *buf,
 			size_t count, loff_t *ppos)
 {
-	DECLARE_WAITQUEUE(wait, current);
 	unsigned long data;
 	ssize_t retval;
 
@@ -183,18 +182,10 @@ static ssize_t gen_rtc_read(struct file *file, char __user *buf,
 	if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data)
 		return -EAGAIN;
 
-	add_wait_queue(&gen_rtc_wait, &wait);
-	retval = -ERESTARTSYS;
-
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		data = xchg(&gen_rtc_irq_data, 0);
-		if (data)
-			break;
-		if (signal_pending(current))
-			goto out;
-		schedule();
-	}
+	retval = wait_event_interruptible(gen_rtc_wait,
+			(data = xchg(&gen_rtc_irq_data, 0)));
+	if (retval)
+		goto out;
 
 	/* first test allows optimizer to nuke this case for 32-bit machines */
 	if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) {
@@ -206,10 +197,7 @@ static ssize_t gen_rtc_read(struct file *file, char __user *buf,
 		retval = put_user(data, (unsigned long __user *)buf) ?:
 			sizeof(unsigned long);
 	}
- out:
-	__set_current_state(TASK_RUNNING);
-	remove_wait_queue(&gen_rtc_wait, &wait);
-
+out:
 	return retval;
 }