dm: convert wait loops to use autoremove_wake_function()

Use autoremove_wake_function() instead of default_wake_function()
to make the dm wait loops more similar to other wait loops in the
kernel.  This patch does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-mpath.c

@@ -1193,21 +1193,17 @@ static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv)
 
 static void multipath_wait_for_pg_init_completion(struct multipath *m)
 {
-	DECLARE_WAITQUEUE(wait, current);
-
-	add_wait_queue(&m->pg_init_wait, &wait);
+	DEFINE_WAIT(wait);
 
 	while (1) {
-		set_current_state(TASK_UNINTERRUPTIBLE);
+		prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE);
 
 		if (!atomic_read(&m->pg_init_in_progress))
 			break;
 
 		io_schedule();
 	}
-	set_current_state(TASK_RUNNING);
-
-	remove_wait_queue(&m->pg_init_wait, &wait);
+	finish_wait(&m->pg_init_wait, &wait);
 }
 
 static void flush_multipath_work(struct multipath *m)

drivers/md/dm.c

@@ -1944,12 +1944,10 @@ EXPORT_SYMBOL_GPL(dm_put);
 static int dm_wait_for_completion(struct mapped_device *md, long task_state)
 {
 	int r = 0;
-	DECLARE_WAITQUEUE(wait, current);
-
-	add_wait_queue(&md->wait, &wait);
+	DEFINE_WAIT(wait);
 
 	while (1) {
-		set_current_state(task_state);
+		prepare_to_wait(&md->wait, &wait, task_state);
 
 		if (!md_in_flight(md))
 			break;
@@ -1961,9 +1959,7 @@ static int dm_wait_for_completion(struct mapped_device *md, long task_state)
 
 		io_schedule();
 	}
-	set_current_state(TASK_RUNNING);
-
-	remove_wait_queue(&md->wait, &wait);
+	finish_wait(&md->wait, &wait);
 
 	return r;
 }