[PATCH v2 1/7] dm-integrity: use internal variable for digestsize

Mikulas Patocka
2025-09-08T13:17:50Z

Instead of calling digestsize() each time the digestsize for
the internal hash is needed, store the digestsize in a new
field internal_hash_digestsize within struct dm_integrity_c
once and use this value when needed.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
---
drivers/md/dm-integrity.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)

Index: linux-2.6/drivers/md/dm-integrity.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-integrity.c 2025-08-15 17:31:52.000000000 +0200
+++ linux-2.6/drivers/md/dm-integrity.c 2025-08-15 17:33:14.000000000 +0200
@@ -223,6 +223,7 @@ struct dm_integrity_c {
int failed;

struct crypto_shash *internal_hash;
+ unsigned int internal_hash_digestsize;

struct dm_target *ti;

@@ -1676,7 +1677,7 @@ static void integrity_sector_checksum(st
goto failed;
}

- digest_size = crypto_shash_digestsize(ic->internal_hash);
+ digest_size = ic->internal_hash_digestsize;
if (unlikely(digest_size < ic->tag_size))
memset(result + digest_size, 0, ic->tag_size - digest_size);

@@ -1776,7 +1777,7 @@ static void integrity_metadata(struct wo
if (ic->internal_hash) {
struct bvec_iter iter;
struct bio_vec bv;
- unsigned int digest_size = crypto_shash_digestsize(ic->internal_hash);
+ unsigned int digest_size = ic->internal_hash_digestsize;
struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
char *checksums;
unsigned int extra_space = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0;
@@ -2124,7 +2125,7 @@ retry_kmap:
} while (++s < ic->sectors_per_block);

if (ic->internal_hash) {
- unsigned int digest_size = crypto_shash_digestsize(ic->internal_hash);
+ unsigned int digest_size = ic->internal_hash_digestsize;

if (unlikely(digest_size > ic->tag_size)) {
char checksums_onstack[HASH_MAX_DIGESTSIZE];
@@ -2428,7 +2429,7 @@ retry:
if (!dio->integrity_payload) {
unsigned digest_size, extra_size;
dio->payload_len = ic->tuple_size * (bio_sectors(bio) >> ic->sb->log2_sectors_per_block);
- digest_size = crypto_shash_digestsize(ic->internal_hash);
+ digest_size = ic->internal_hash_digestsize;
extra_size = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0;
dio->payload_len += extra_size;
dio->integrity_payload = kmalloc(dio->payload_len, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
@@ -2589,7 +2590,7 @@ static void dm_integrity_inline_recheck(
bio_put(outgoing_bio);

integrity_sector_checksum(ic, dio->bio_details.bi_iter.bi_sector, outgoing_data, digest);
- if (unlikely(crypto_memneq(digest, dio->integrity_payload, min(crypto_shash_digestsize(ic->internal_hash), ic->tag_size)))) {
+ if (unlikely(crypto_memneq(digest, dio->integrity_payload, min(ic->internal_hash_digestsize, ic->tag_size)))) {
DMERR_LIMIT("%pg: Checksum failed at sector 0x%llx",
ic->dev->bdev, dio->bio_details.bi_iter.bi_sector);
atomic64_inc(&ic->number_of_mismatches);
@@ -2629,7 +2630,7 @@ static int dm_integrity_end_io(struct dm
//memset(mem, 0xff, ic->sectors_per_block << SECTOR_SHIFT);
integrity_sector_checksum(ic, dio->bio_details.bi_iter.bi_sector, mem, digest);
if (unlikely(crypto_memneq(digest, dio->integrity_payload + pos,
- min(crypto_shash_digestsize(ic->internal_hash), ic->tag_size)))) {
+ min(ic->internal_hash_digestsize, ic->tag_size)))) {
kunmap_local(mem);
dm_integrity_free_payload(dio);
INIT_WORK(&dio->work, dm_integrity_inline_recheck);
@@ -3011,8 +3012,8 @@ oom:
goto free_ret;
}
recalc_tags_size = (recalc_sectors >> ic->sb->log2_sectors_per_block) * ic->tag_size;
- if (crypto_shash_digestsize(ic->internal_hash) > ic->tag_size)
- recalc_tags_size += crypto_shash_digestsize(ic->internal_hash) - ic->tag_size;
+ if (ic->internal_hash_digestsize > ic->tag_size)
+ recalc_tags_size += ic->internal_hash_digestsize - ic->tag_size;
recalc_tags = kvmalloc(recalc_tags_size, GFP_NOIO);
if (!recalc_tags) {
vfree(recalc_buffer);
@@ -3171,8 +3172,8 @@ oom:
}

recalc_tags_size = (recalc_sectors >> ic->sb->log2_sectors_per_block) * ic->tuple_size;
- if (crypto_shash_digestsize(ic->internal_hash) > ic->tuple_size)
- recalc_tags_size += crypto_shash_digestsize(ic->internal_hash) - ic->tuple_size;
+ if (ic->internal_hash_digestsize > ic->tuple_size)
+ recalc_tags_size += ic->internal_hash_digestsize - ic->tuple_size;
recalc_tags = kmalloc(recalc_tags_size, GFP_NOIO | __GFP_NOWARN);
if (!recalc_tags) {
kfree(recalc_buffer);
@@ -4694,6 +4695,8 @@ static int dm_integrity_ctr(struct dm_ta
"Invalid internal hash", "Error setting internal hash key");
if (r)
goto bad;
+ if (ic->internal_hash)
+ ic->internal_hash_digestsize = crypto_shash_digestsize(ic->internal_hash);

r = get_mac(&ic->journal_mac, &ic->journal_mac_alg, &ti->error,
"Invalid journal mac", "Error setting journal mac key");
@@ -4706,7 +4709,7 @@ static int dm_integrity_ctr(struct dm_ta
r = -EINVAL;
goto bad;
}
- ic->tag_size = crypto_shash_digestsize(ic->internal_hash);
+ ic->tag_size = ic->internal_hash_digestsize;
}
if (ic->tag_size > MAX_TAG_SIZE) {
ti->error = "Too big tag size";