block: remove blk_rq_bio_prep

There is not real point in a helper just to assign three values to four
fields, especially when the surrounding code is working on the
neighbor fields directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Link: https://lore.kernel.org/r/20250103073417.459715-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-map.c

@@ -490,17 +490,19 @@ int blk_rq_append_bio(struct request *rq, struct bio *bio)
 		return ret;
 	}
 
-	if (!rq->bio) {
-		blk_rq_bio_prep(rq, bio, nr_segs);
-	} else {
+	if (rq->bio) {
 		if (!ll_back_merge_fn(rq, bio, nr_segs))
 			return -EINVAL;
 		rq->biotail->bi_next = bio;
 		rq->biotail = bio;
-		rq->__data_len += (bio)->bi_iter.bi_size;
+		rq->__data_len += bio->bi_iter.bi_size;
 		bio_crypt_free_ctx(bio);
+		return 0;
 	}
 
+	rq->nr_phys_segments = nr_segs;
+	rq->bio = rq->biotail = bio;
+	rq->__data_len = bio->bi_iter.bi_size;
 	return 0;
 }
 EXPORT_SYMBOL(blk_rq_append_bio);

block/blk-mq.c

@@ -2658,8 +2658,10 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
 	if (bio->bi_opf & REQ_RAHEAD)
 		rq->cmd_flags |= REQ_FAILFAST_MASK;
 
+	rq->bio = rq->biotail = bio;
 	rq->__sector = bio->bi_iter.bi_sector;
-	blk_rq_bio_prep(rq, bio, nr_segs);
+	rq->__data_len = bio->bi_iter.bi_size;
+	rq->nr_phys_segments = nr_segs;
 	if (bio_integrity(bio))
 		rq->nr_integrity_segments = blk_rq_count_integrity_sg(rq->q,
 								      bio);

include/linux/blk-mq.h

@@ -978,14 +978,6 @@ static inline void blk_mq_cleanup_rq(struct request *rq)
 		rq->q->mq_ops->cleanup_rq(rq);
 }
 
-static inline void blk_rq_bio_prep(struct request *rq, struct bio *bio,
-		unsigned int nr_segs)
-{
-	rq->nr_phys_segments = nr_segs;
-	rq->__data_len = bio->bi_iter.bi_size;
-	rq->bio = rq->biotail = bio;
-}
-
 void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx,
 		struct lock_class_key *key);