[PATCH 4.4 70/74] block: get the 1st and last bvec via helpers

Greg Kroah-Hartman
2016-03-08T00:05:28Z

From: Ming Lei <ming.lei@canonical.com>

commit 25e71a99f10e444cd00bb2ebccb11e1c9fb672b1 upstream.

This patch applies the two introduced helpers to
figure out the 1st and last bvec, and fixes the
original way after bio splitting.

Reported-by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/blkdev.h | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1389,11 +1389,16 @@ static inline bool bvec_gap_to_prev(stru
static inline bool bio_will_gap(struct request_queue *q, struct bio *prev,
struct bio *next)
{
- if (!bio_has_data(prev) || !queue_virt_boundary(q))
- return false;
+ if (bio_has_data(prev) && queue_virt_boundary(q)) {
+ struct bio_vec pb, nb;

- return __bvec_gap_to_prev(q, &prev->bi_io_vec[prev->bi_vcnt - 1],
- next->bi_io_vec[0].bv_offset);
+ bio_get_last_bvec(prev, &pb);
+ bio_get_first_bvec(next, &nb);
+
+ return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
+ }
+
+ return false;
}

static inline bool req_gap_back_merge(struct request *req, struct bio *bio)