[ Upstream commit 787f1b2800464aa277236a66eb3c279535edd460 ]
"struct bvec_iter" is defined with the __packed attribute, so it is
aligned on a single byte. On X86 (and on other architectures that support
unaligned addresses in hardware), "struct bvec_iter" is accessed using the
8-byte and 4-byte memory instructions, however these instructions are less
efficient if they operate on unaligned addresses.
(on RISC machines that don't have unaligned access in hardware, GCC
generates byte-by-byte accesses that are very inefficient - see [1])
This commit reorders the entries in "struct dm_verity_io" and "struct
convert_context", so that "struct bvec_iter" is aligned on 8 bytes.
[1] https://lore.kernel.org/all/ZcLuWUNRZadJr0tQ@fedora/T/
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 38bc1ab135db87577695816b190e7d6d8ec75879 upstream.
dm_verity_fec_io is placed after the end of two hash digests. If the hash
digest has unaligned length, struct dm_verity_fec_io could be unaligned.
This commit fixes the placement of struct dm_verity_fec_io, so that it's
aligned.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Fixes: a739ff3f543a ("dm verity: add support for forward error correction")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
