block: get the 1st and last bvec via helpers

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>

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7f2f0f61d156bb852e714c1a6299df9fab4479b7..168755791ec88ac895c4cc0eb267638ba459e39e 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1389,11 +1389,16 @@ static inline bool bvec_gap_to_prev(struct request_queue *q,
 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;
+
+               bio_get_last_bvec(prev, &pb);
+               bio_get_first_bvec(next, &nb);
 
-       return __bvec_gap_to_prev(q, &prev->bi_io_vec[prev->bi_vcnt - 1],
-                                 next->bi_io_vec[0].bv_offset);
+               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)