ll_back_merge_fn 1144 block/blk-core.c 		if (!ll_back_merge_fn(q, req, bio))
ll_back_merge_fn   17 block/blk-map.c 	else if (!ll_back_merge_fn(q, rq, bio))
ll_back_merge_fn   59 block/blk.h    int ll_back_merge_fn(struct request_queue *q, struct request *req,