This is a note to let you know that I've just added the patch titled
dm-verity, dm-crypt: align "struct bvec_iter" correctly
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-verity-dm-crypt-align-struct-bvec_iter-correctly.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7089a433a187c2234ed43f0001780d009b151036
Author: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Date: Tue Feb 20 19:11:51 2024 +0100
dm-verity, dm-crypt: align "struct bvec_iter" correctly
[ 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@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 5904af05f6057..a3db76dcdb3ec 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -49,11 +49,11 @@
struct convert_context {
struct completion restart;
struct bio *bio_in;
- struct bio *bio_out;
struct bvec_iter iter_in;
+ struct bio *bio_out;
struct bvec_iter iter_out;
- u64 cc_sector;
atomic_t cc_pending;
+ u64 cc_sector;
union {
struct skcipher_request *req;
struct aead_request *req_aead;
diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h
index 78d1e51195ada..f61c89c79cf5b 100644
--- a/drivers/md/dm-verity.h
+++ b/drivers/md/dm-verity.h
@@ -74,11 +74,11 @@ struct dm_verity_io {
/* original value of bio->bi_end_io */
bio_end_io_t *orig_bi_end_io;
+ struct bvec_iter iter;
+
sector_t block;
unsigned n_blocks;
- struct bvec_iter iter;
-
struct work_struct work;
/*
