bfq-iosched: don't worry about reserved tags in limit_depth

Reserved tags are used for error handling, we don't need to
care about them for regular IO. The core won't call us for these
anyway.
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bfq-iosched.c

@@ -542,14 +542,7 @@ static void bfq_limit_depth(unsigned int op, struct blk_mq_alloc_data *data)
 	if (op_is_sync(op) && !op_is_write(op))
 		return;
 
-	if (data->flags & BLK_MQ_REQ_RESERVED) {
-		if (unlikely(!tags->nr_reserved_tags)) {
-			WARN_ON_ONCE(1);
-			return;
-		}
-		bt = &tags->breserved_tags;
-	} else
-		bt = &tags->bitmap_tags;
+	bt = &tags->bitmap_tags;
 
 	if (unlikely(bfqd->sb_shift != bt->sb.shift))
 		bfq_update_depths(bfqd, bt);