[PATCH] Fix on-the-fly switch from cfq i/o scheduler

Don't clear ->elevator_data on exit, if we are switching queues we are
overwriting the data of the new io scheduler.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/block/cfq-iosched.c

@@ -2059,10 +2059,8 @@ static void cfq_put_cfqd(struct cfq_data *cfqd)
 	if (!atomic_dec_and_test(&cfqd->ref))
 		return;
 
-	blk_put_queue(q);
-
 	cfq_shutdown_timer_wq(cfqd);
-	q->elevator->elevator_data = NULL;
+	blk_put_queue(q);
 
 	mempool_destroy(cfqd->crq_pool);
 	kfree(cfqd->crq_hash);