[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>

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 161e9aa872917da3cc3bb2cc4719850317e7b9e1..b1941b887f46fd6f7f5a991cbb969778ecd31c61 100644 (file)
--- 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))