Commit 8f9576b3 authored Jun 17, 2016 by Sami Tolvanen

ANDROID: dm verity fec: fix RS block calculation



A call to do_div was changed in Linux 4.5 to div64_u64 in
verity_fec_decode, which broke RS block calculation due to
incompatible semantics. This change fixes the computation.

Bug: 21893453
Change-Id: Idb88b901e0209c2cccc9c0796689f780592d58f9
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
(cherry picked from commit 879aac93eebcc2862d71afa9eca3a0c0f51b3b01)

parent c4d8e3e8

drivers/md/dm-verity-fec.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -463,9 +463,7 @@ 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