[PATCH] md: fix splitting of md/linear request that cross a device boundary

When a request crosses a boundary between devices, it needs to be split.
But where we should calculate the amount of the request before the boundary
to find the split-point, we care currently calculating the amount that is
*after* the boundary !!!

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 161e9aa87291..b1941b887f46 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -269,9 +269,8 @@ static int linear_make_request (request_queue_t *q, struct bio *bio)
                  * split it.
                  */
                 struct bio_pair *bp;
-                bp = bio_split(bio, bio_split_pool, 
-                               (bio->bi_sector + (bio->bi_size >> 9) -
-                                (tmp_dev->offset + tmp_dev->size))<<1);
+                bp = bio_split(bio, bio_split_pool,
+                               ((tmp_dev->offset + tmp_dev->size)<<1) - bio->bi_sector);
                 if (linear_make_request(q, &bp->bio1))
                         generic_make_request(&bp->bio1);
                 if (linear_make_request(q, &bp->bio2))