[PATCH] dm: don't enable bouncing by default

DM doesn't need to bounce bio's on its own, but the block layer defaults
to that in blk_queue_make_request(). The lower level drivers should
bounce ios themselves, that is what they need to do if not layered below
dm anyways.
Signed-off-by: NJens Axboe <axboe@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/md/dm.c

@@ -768,6 +768,7 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
 	md->queue->backing_dev_info.congested_fn = dm_any_congested;
 	md->queue->backing_dev_info.congested_data = md;
 	blk_queue_make_request(md->queue, dm_request);
+	blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
 	md->queue->unplug_fn = dm_unplug_all;
 	md->queue->issue_flush_fn = dm_flush_all;