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authorEric Biggers <ebiggers@kernel.org>2024-07-02 16:39:13 +0200
committerMikulas Patocka <mpatocka@redhat.com>2024-07-03 21:33:17 +0200
commita7ddb3d49d16e1774b4d5b814d3469ee9c3830c0 (patch)
tree7d0aaa112f179be315d8bfb9000dda00370c5cd3 /drivers/md
parente41e52e59e51992368092a0555fd7b889662653f (diff)
dm-verity: make real_digest and want_digest fixed-length
Change the digest fields in struct dm_verity_io from variable-length to fixed-length, since their maximum length is fixed at HASH_MAX_DIGESTSIZE, i.e. 64 bytes, which is not too big. This is simpler and makes the fields a bit faster to access. (HASH_MAX_DIGESTSIZE did not exist when this code was written, which may explain why it wasn't used.) This makes the verity_io_real_digest() and verity_io_want_digest() functions trivial, but this patch leaves them in place temporarily since most of their callers will go away in a later patch anyway. Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-verity-target.c3
-rw-r--r--drivers/md/dm-verity.h17
2 files changed, 8 insertions, 12 deletions
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 796d85526696..4ef814a7faf4 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1529,8 +1529,7 @@ static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
- ti->per_io_data_size = sizeof(struct dm_verity_io) +
- v->ahash_reqsize + v->digest_size * 2;
+ ti->per_io_data_size = sizeof(struct dm_verity_io) + v->ahash_reqsize;
r = verity_fec_ctr(v);
if (r)
diff --git a/drivers/md/dm-verity.h b/drivers/md/dm-verity.h
index 20b1bcf03474..5d3da9f5fc95 100644
--- a/drivers/md/dm-verity.h
+++ b/drivers/md/dm-verity.h
@@ -91,15 +91,12 @@ struct dm_verity_io {
char *recheck_buffer;
+ u8 real_digest[HASH_MAX_DIGESTSIZE];
+ u8 want_digest[HASH_MAX_DIGESTSIZE];
+
/*
- * Three variably-size fields follow this struct:
- *
- * u8 hash_req[v->ahash_reqsize];
- * u8 real_digest[v->digest_size];
- * u8 want_digest[v->digest_size];
- *
- * To access them use: verity_io_hash_req(), verity_io_real_digest()
- * and verity_io_want_digest().
+ * This struct is followed by a variable-sized struct ahash_request of
+ * size v->ahash_reqsize. To access it, use verity_io_hash_req().
*/
};
@@ -112,13 +109,13 @@ static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,
static inline u8 *verity_io_real_digest(struct dm_verity *v,
struct dm_verity_io *io)
{
- return (u8 *)(io + 1) + v->ahash_reqsize;
+ return io->real_digest;
}
static inline u8 *verity_io_want_digest(struct dm_verity *v,
struct dm_verity_io *io)
{
- return (u8 *)(io + 1) + v->ahash_reqsize + v->digest_size;
+ return io->want_digest;
}
extern int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,