[PATCH] md: make md threads interruptible again

Despite the fact that md threads don't need to be signalled, and won't
respond to signals anyway, we need to have an 'interruptible' wait, else
they stay in 'D' state and add to the load average.

(akpm: the signal_pending() test is unneeded - we'll fix that up in the next
round.  For now, leave it there because that's how the code used to be).
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/md/md.c

@@ -3437,10 +3437,19 @@ static int md_thread(void * arg)
 	allow_signal(SIGKILL);
 	while (!kthread_should_stop()) {
 
-		wait_event_timeout(thread->wqueue,
-				   test_bit(THREAD_WAKEUP, &thread->flags)
-				   || kthread_should_stop(),
-				   thread->timeout);
+		/* We need to wait INTERRUPTIBLE so that
+		 * we don't add to the load-average.
+		 * That means we need to be sure no signals are
+		 * pending
+		 */
+		if (signal_pending(current))
+			flush_signals(current);
+
+		wait_event_interruptible_timeout
+			(thread->wqueue,
+			 test_bit(THREAD_WAKEUP, &thread->flags)
+			 || kthread_should_stop(),
+			 thread->timeout);
 		try_to_freeze();
 
 		clear_bit(THREAD_WAKEUP, &thread->flags);