block: Use pointer to backing_dev_info from request_queue

We will want to have struct backing_dev_info allocated separately from
struct request_queue. As the first step add pointer to backing_dev_info
to request_queue and convert all users touching it. No functional
changes in this patch.

Change-Id: Ib99961747ed2d58cc2f9c0581c66c55a49aaee4b
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Git-commit: dc3b17cc8bf21307c7e076e7c778d5db756f7871
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
[riteshh@codeaurora.org: Resolved minor merge conflicts]
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 90fa4ac..b0d2cb7 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1276,7 +1276,7 @@
 	 		&& pd->bio_queue_size <= pd->write_congestion_off);
 	spin_unlock(&pd->lock);
 	if (wakeup) {
-		clear_bdi_congested(&pd->disk->queue->backing_dev_info,
+		clear_bdi_congested(pd->disk->queue->backing_dev_info,
 					BLK_RW_ASYNC);
 	}
 
@@ -2405,7 +2405,7 @@
 	spin_lock(&pd->lock);
 	if (pd->write_congestion_on > 0
 	    && pd->bio_queue_size >= pd->write_congestion_on) {
-		set_bdi_congested(&q->backing_dev_info, BLK_RW_ASYNC);
+		set_bdi_congested(q->backing_dev_info, BLK_RW_ASYNC);
 		do {
 			spin_unlock(&pd->lock);
 			congestion_wait(BLK_RW_ASYNC, HZ);