block: always assign default lock to queues

Move the assignment of a default lock below blk_init_queue() to
blk_queue_make_request(), so we also get to set the default lock
for ->make_request_fn() based drivers. This is important since the
queue flag locking requires a lock to be in place.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-settings.c b/block/blk-settings.c
index bd582a7..8a3ea3b 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -165,6 +165,13 @@
 	blk_set_default_limits(&q->limits);
 
 	/*
+	 * If the caller didn't supply a lock, fall back to our embedded
+	 * per-queue locks
+	 */
+	if (!q->queue_lock)
+		q->queue_lock = &q->__queue_lock;
+
+	/*
 	 * by default assume old behaviour and bounce for any highmem page
 	 */
 	blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);