blk-mq: move blk_mq_attempt_bio_merge out blk_mq_get_new_requests

blk_mq_attempt_bio_merge has nothing to do with allocating a new
request, it avoids allocating a new request.  Move the call out of
blk_mq_get_new_requests and into the only caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240124092658.2258309-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2dc0155..bc032d0 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2891,9 +2891,6 @@ static struct request *blk_mq_get_new_requests(struct request_queue *q,
        };
        struct request *rq;
 
-       if (blk_mq_attempt_bio_merge(q, bio, nsegs))
-               return NULL;
-
        rq_qos_throttle(q, bio);
 
        if (plug) {
@@ -2992,18 +2989,18 @@ void blk_mq_submit_bio(struct bio *bio)
                if (unlikely(bio_may_exceed_limits(bio, &q->limits))) {
                        bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
                        if (!bio)
-                               goto fail;
+                               goto queue_exit;
                }
                if (!bio_integrity_prep(bio))
-                       goto fail;
+                       goto queue_exit;
        }
 
+       if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
+               goto queue_exit;
+
        rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
-       if (unlikely(!rq)) {
-fail:
-               blk_queue_exit(q);
-               return;
-       }
+       if (unlikely(!rq))
+               goto queue_exit;
 
 done:
        trace_block_getrq(bio);
@@ -3036,6 +3033,10 @@ done:
        } else {
                blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
        }
+       return;
+
+queue_exit:
+       blk_queue_exit(q);
 }
 
 #ifdef CONFIG_BLK_MQ_STACKING