[PATCH v2 3/7] dm-integrity: introduce integrity_kmap and integrity_kunmap

Mikulas Patocka
2025-09-08T13:18:01Z

This abstraction will be used later, for the asynchronous hash interface.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
---
drivers/md/dm-integrity.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)

Index: linux-2.6/drivers/md/dm-integrity.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-integrity.c 2025-08-21 18:21:12.000000000 +0200
+++ linux-2.6/drivers/md/dm-integrity.c 2025-08-21 18:22:00.000000000 +0200
@@ -1688,6 +1688,16 @@ failed:
get_random_bytes(result, ic->tag_size);
}

+static void *integrity_kmap(struct dm_integrity_c *ic, struct page *p)
+{
+ return kmap_local_page(p);
+}
+
+static void integrity_kunmap(struct dm_integrity_c *ic, const void *ptr)
+{
+ kunmap_local(ptr);
+}
+
static noinline void integrity_recheck(struct dm_integrity_io *dio, char *checksum)
{
struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
@@ -1838,7 +1848,7 @@ static void integrity_metadata(struct wo
char *mem, *checksums_ptr;

again:
- mem = kmap_local_page(bv_copy.bv_page);
+ mem = integrity_kmap(ic, bv_copy.bv_page);
pos = 0;
checksums_ptr = checksums;
do {
@@ -1848,7 +1858,7 @@ again:
pos += ic->sectors_per_block << SECTOR_SHIFT;
sector += ic->sectors_per_block;
} while (pos < bv_copy.bv_len && sectors_to_process && checksums != checksums_onstack);
- kunmap_local(mem);
+ integrity_kunmap(ic, mem);

r = dm_integrity_rw_tag(ic, checksums, &dio->metadata_block, &dio->metadata_offset,
checksums_ptr - checksums, dio->op == REQ_OP_READ ? TAG_CMP : TAG_WRITE);
@@ -2072,19 +2082,6 @@ retry_kmap:
js++;
mem_ptr += 1 << SECTOR_SHIFT;
} while (++s < ic->sectors_per_block);
-#ifdef INTERNAL_VERIFY
- if (ic->internal_hash) {
- char checksums_onstack[MAX_T(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
-
- integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack);
- if (unlikely(crypto_memneq(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) {
- DMERR_LIMIT("Checksum failed when reading from journal, at sector 0x%llx",
- logical_sector);
- dm_audit_log_bio(DM_MSG_PREFIX, "journal-checksum",
- bio, logical_sector, 0);
- }
- }
-#endif
}

if (!ic->internal_hash) {
@@ -2506,11 +2503,11 @@ skip_spinlock:
unsigned pos = 0;
while (dio->bio_details.bi_iter.bi_size) {
struct bio_vec bv = bio_iter_iovec(bio, dio->bio_details.bi_iter);
- const char *mem = kmap_local_page(bv.bv_page);
+ const char *mem = integrity_kmap(ic, bv.bv_page);
if (ic->tag_size < ic->tuple_size)
memset(dio->integrity_payload + pos + ic->tag_size, 0, ic->tuple_size - ic->tuple_size);
integrity_sector_checksum(ic, dio->bio_details.bi_iter.bi_sector, mem + bv.bv_offset, dio->integrity_payload + pos);
- kunmap_local(mem);
+ integrity_kunmap(ic, mem);
pos += ic->tuple_size;
bio_advance_iter_single(bio, &dio->bio_details.bi_iter, ic->sectors_per_block << SECTOR_SHIFT);
}
@@ -2626,17 +2623,17 @@ static int dm_integrity_end_io(struct dm
while (dio->bio_details.bi_iter.bi_size) {
char digest[HASH_MAX_DIGESTSIZE];
struct bio_vec bv = bio_iter_iovec(bio, dio->bio_details.bi_iter);
- char *mem = kmap_local_page(bv.bv_page);
+ char *mem = integrity_kmap(ic, bv.bv_page);
integrity_sector_checksum(ic, dio->bio_details.bi_iter.bi_sector, mem + bv.bv_offset, digest);
if (unlikely(crypto_memneq(digest, dio->integrity_payload + pos,
min(ic->internal_hash_digestsize, ic->tag_size)))) {
- kunmap_local(mem);
+ integrity_kunmap(ic, mem);
dm_integrity_free_payload(dio);
INIT_WORK(&dio->work, dm_integrity_inline_recheck);
queue_work(ic->offload_wq, &dio->work);
return DM_ENDIO_INCOMPLETE;
}
- kunmap_local(mem);
+ integrity_kunmap(ic, mem);
pos += ic->tuple_size;
bio_advance_iter_single(bio, &dio->bio_details.bi_iter, ic->sectors_per_block << SECTOR_SHIFT);
}