blk-mq: set the nr_integrity_segments from bio

This value is used for merging considerations, so it needs to be
accurate.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20240913182854.2445457-3-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: keithbusch

block/blk-mq.c

@@ -2544,6 +2544,9 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
 	rq->__sector = bio->bi_iter.bi_sector;
 	rq->write_hint = bio->bi_write_hint;
 	blk_rq_bio_prep(rq, bio, nr_segs);
+	if (bio_integrity(bio))
+		rq->nr_integrity_segments = blk_rq_count_integrity_sg(rq->q,
+								      bio);
 
 	/* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
 	err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);