From: Sagi Grimberg <sagi@grimberg.me>

Date: Thu, 14 Jan 2021 13:15:26 -0800

Subject: [PATCH] nvme-tcp: pass multipage bvec to request iov_iter

Git-commit: 0dc9edaf80ea3c48231d94cd482355699d453888

Patch-mainline: v5.12-rc1

References: git-fixes

iov_iter uses the right helpers so we should be able

to pass in a multipage bvec. Right now the iov_iter is

initialized with more segments that it needs which doesn't

fail because the iov_iter is capped by byte count, but it

is better to use a full multipage bvec iter.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Hannes Reinecke <hare@suse.com>

---

 drivers/nvme/host/tcp.c | 13 +++++++++----

 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c

index f2f3471faed3..4c13c7110dbe 100644

--- a/drivers/nvme/host/tcp.c

+++ b/drivers/nvme/host/tcp.c

@@ -224,24 +224,29 @@ static void nvme_tcp_init_iter(struct nvme_tcp_request *req,

 	struct request *rq = blk_mq_rq_from_pdu(req);

 	struct bio_vec *vec;

 	unsigned int size;

-	int nsegs;

+	int nr_bvec;

 	size_t offset;

 	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD) {

 		vec = &rq->special_vec;

-		nsegs = 1;

+		nr_bvec = 1;

 		size = blk_rq_payload_bytes(rq);

 		offset = 0;

 	} else {

 		struct bio *bio = req->curr_bio;

+		struct bvec_iter bi;

+		struct bio_vec bv;

 		vec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);

-		nsegs = bio_segments(bio);

+		nr_bvec = 0;

+		bio_for_each_bvec(bv, bio, bi) {

+			nr_bvec++;

+		}

 		size = bio->bi_iter.bi_size;

 		offset = bio->bi_iter.bi_bvec_done;

 	}

-	iov_iter_bvec(&req->iter, dir, vec, nsegs, size);

+	iov_iter_bvec(&req->iter, dir, vec, nr_bvec, size);

 	req->iter.iov_offset = offset;

 }

-- 

2.29.2