parport: fix interruptible_sleep_on race

The interruptible_sleep_on function is can still lead to the
deadlock mentioned in the comment above the caller, and we want
to remove it soon, so replace it now with the race-free
wait_event_interruptible.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/parport/share.c

@@ -905,7 +905,8 @@ int parport_claim_or_block(struct pardevice *dev)
 		/* If dev->waiting is clear now, an interrupt
 		   gave us the port and we would deadlock if we slept.  */
 		if (dev->waiting) {
-			interruptible_sleep_on (&dev->wait_q);
+			wait_event_interruptible(dev->wait_q,
+						 !dev->waiting);
 			if (signal_pending (current)) {
 				return -EINTR;
 			}