dm cache policy mq: remove queue_shift_down()

queue_shift_down() didn't adjust the hit_counts to the new levels, so it
just had the effect of scrambling levels.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-cache-policy-mq.c

@@ -159,18 +159,6 @@ static void queue_remove(struct queue *q, struct list_head *elt)
 	list_del(elt);
 }
 
-/*
- * Shifts all regions down one level.  This has no effect on the order of
- * the queue.
- */
-static void queue_shift_down(struct queue *q)
-{
-	unsigned level;
-
-	for (level = 1; level < NR_QUEUE_LEVELS; level++)
-		list_splice_init(q->qs + level, q->qs + level - 1);
-}
-
 /*
  * Gives us the oldest entry of the lowest popoulated level.  If the first
  * level is emptied then we shift down one level.
@@ -193,10 +181,6 @@ static struct list_head *queue_pop(struct queue *q)
 	if (r) {
 		q->nr_elts--;
 		list_del(r);
-
-		/* have we just emptied the bottom level? */
-		if (list_empty(q->qs))
-			queue_shift_down(q);
 	}
 
 	return r;