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dm verity fec: fix block calculation

Message ID 1466532162-54016-1-git-send-email-samitolvanen@google.com (mailing list archive)
State Accepted, archived
Delegated to: Mike Snitzer
Headers show

Commit Message

Sami Tolvanen June 21, 2016, 6:02 p.m. UTC 
do_div was replaced with div64_u64 at some point, causing a bug
with block calculation due to incompatible semantics of the two
functions.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Fixes: a739ff3f543a ("dm verity: add support for forward error correction")
---
 drivers/md/dm-verity-fec.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
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Patch

diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c
index 459a9f8..0f0eb8a 100644
--- a/drivers/md/dm-verity-fec.c
+++ b/drivers/md/dm-verity-fec.c
@@ -453,9 +453,7 @@  int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
 	 */
 
 	offset = block << v->data_dev_block_bits;
-
-	res = offset;
-	div64_u64(res, v->fec->rounds << v->data_dev_block_bits);
+	res = div64_u64(offset, v->fec->rounds << v->data_dev_block_bits);
 
 	/*
 	 * The base RS block we can feed to the interleaver to find out all