blk-mq: simplify blk_mq_make_request()

Move the blk_mq_bio_to_request() call in front of the if-statement.

Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -1971,10 +1971,10 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 
 	cookie = request_to_qc_t(data.hctx, rq);
 
-	plug = current->plug;
-	if (unlikely(is_flush_fua)) {
 	blk_mq_bio_to_request(rq, bio, nr_segs);
 
+	plug = current->plug;
+	if (unlikely(is_flush_fua)) {
 		/* bypass scheduler for flush rq */
 		blk_insert_flush(rq);
 		blk_mq_run_hw_queue(data.hctx, true);
@@ -1986,8 +1986,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 		unsigned int request_count = plug->rq_count;
 		struct request *last = NULL;
 
-		blk_mq_bio_to_request(rq, bio, nr_segs);
-
 		if (!request_count)
 			trace_block_plug(q);
 		else
@@ -2001,8 +1999,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 
 		blk_add_rq_to_plug(plug, rq);
 	} else if (plug && !blk_queue_nomerges(q)) {
-		blk_mq_bio_to_request(rq, bio, nr_segs);
-
 		/*
 		 * We do limited plugging. If the bio can be merged, do that.
 		 * Otherwise the existing request in the plug list will be
@@ -2027,10 +2023,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 		}
 	} else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator &&
 			!data.hctx->dispatch_busy)) {
-		blk_mq_bio_to_request(rq, bio, nr_segs);
 		blk_mq_try_issue_directly(data.hctx, rq, &cookie);
 	} else {
-		blk_mq_bio_to_request(rq, bio, nr_segs);
 		blk_mq_sched_insert_request(rq, false, true, true);
 	}