bfq: Remove pointless bfq_init_rq() calls

We call bfq_init_rq() from request merging functions where requests we
get should have already gone through bfq_init_rq() during insert and
anyway we want to do anything only if the request is already tracked by
BFQ. So replace calls to bfq_init_rq() with RQ_BFQQ() instead to simply
skip requests untracked by BFQ. We move bfq_init_rq() call in
bfq_insert_request() a bit earlier to cover request merging and thus
can transfer FIFO position in case of a merge.

CC: stable@vger.kernel.org
Tested-by: "yukuai (C)" <yukuai3@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220401102752.8599-6-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bfq-iosched.c

@@ -2497,8 +2497,6 @@ static int bfq_request_merge(struct request_queue *q, struct request **req,
 	return ELEVATOR_NO_MERGE;
 }
 
-static struct bfq_queue *bfq_init_rq(struct request *rq);
-
 static void bfq_request_merged(struct request_queue *q, struct request *req,
 			       enum elv_merge type)
 {
@@ -2507,7 +2505,7 @@ static void bfq_request_merged(struct request_queue *q, struct request *req,
 	    blk_rq_pos(req) <
 	    blk_rq_pos(container_of(rb_prev(&req->rb_node),
 				    struct request, rb_node))) {
-		struct bfq_queue *bfqq = bfq_init_rq(req);
+		struct bfq_queue *bfqq = RQ_BFQQ(req);
 		struct bfq_data *bfqd;
 		struct request *prev, *next_rq;
 
@@ -2559,8 +2557,8 @@ static void bfq_request_merged(struct request_queue *q, struct request *req,
 static void bfq_requests_merged(struct request_queue *q, struct request *rq,
 				struct request *next)
 {
-	struct bfq_queue *bfqq = bfq_init_rq(rq),
-		*next_bfqq = bfq_init_rq(next);
+	struct bfq_queue *bfqq = RQ_BFQQ(rq),
+		*next_bfqq = RQ_BFQQ(next);
 
 	if (!bfqq)
 		goto remove;
@@ -6129,6 +6127,8 @@ static inline void bfq_update_insert_stats(struct request_queue *q,
 					   unsigned int cmd_flags) {}
 #endif /* CONFIG_BFQ_CGROUP_DEBUG */
 
+static struct bfq_queue *bfq_init_rq(struct request *rq);
+
 static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 			       bool at_head)
 {
@@ -6144,6 +6144,7 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		bfqg_stats_update_legacy_io(q, rq);
 #endif
 	spin_lock_irq(&bfqd->lock);
+	bfqq = bfq_init_rq(rq);
 	if (blk_mq_sched_try_insert_merge(q, rq, &free)) {
 		spin_unlock_irq(&bfqd->lock);
 		blk_mq_free_requests(&free);
@@ -6152,7 +6153,6 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 
 	trace_block_rq_insert(rq);
 
-	bfqq = bfq_init_rq(rq);
 	if (!bfqq || at_head) {
 		if (at_head)
 			list_add(&rq->queuelist, &bfqd->dispatch);