block: add a missing BIOVEC_SEG_BOUNDARY check in bio_add_pc_page

The actual recaculation of segments in __blk_recalc_rq_segments will
do this check, so there is no point in forcing it if we know it won't
succeed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bio.c b/block/bio.c
index 81d90b8..c254e5a 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -731,7 +731,9 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
        }
 
        /* If we may be able to merge these biovecs, force a recount */
-       if (bio->bi_vcnt > 1 && biovec_phys_mergeable(bvec-1, bvec))
+       if (bio->bi_vcnt > 1 &&
+           biovec_phys_mergeable(bvec - 1, bvec) &&
+           BIOVEC_SEG_BOUNDARY(q, bvec - 1, bvec))
                bio_clear_flag(bio, BIO_SEG_VALID);
 
  done: