dm-integrity: use the nop integrity profile

Use the block layer built-in nop profile instead of duplicating it.

Tested by:

$ dd if=/dev/urandom of=key.bin bs=512 count=1

$ cryptsetup luksFormat -q --type luks2 --integrity hmac-sha256 \
 	--integrity-no-wipe /dev/nvme0n1 key.bin
$ cryptsetup luksOpen /dev/nvme0n1 luks-integrity --key-file key.bin

and then doing mkfs.xfs and simple I/O on the mount file system.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240613084839.1044015-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

drivers/md/dm-crypt.c

@@ -1176,8 +1176,8 @@ static int crypt_integrity_ctr(struct crypt_config *cc, struct dm_target *ti)
 	struct blk_integrity *bi = blk_get_integrity(cc->dev->bdev->bd_disk);
 	struct mapped_device *md = dm_table_get_md(ti->table);
 
-	/* From now we require underlying device with our integrity profile */
-	if (!bi || strcasecmp(bi->profile->name, "DM-DIF-EXT-TAG")) {
+	/* We require an underlying device with non-PI metadata */
+	if (!bi || strcmp(bi->profile->name, "nop")) {
 		ti->error = "Integrity profile not supported.";
 		return -EINVAL;
 	}

drivers/md/dm-integrity.c

@@ -350,25 +350,6 @@ static struct kmem_cache *journal_io_cache;
 #define DEBUG_bytes(bytes, len, msg, ...)	do { } while (0)
 #endif
 
-static void dm_integrity_prepare(struct request *rq)
-{
-}
-
-static void dm_integrity_complete(struct request *rq, unsigned int nr_bytes)
-{
-}
-
-/*
- * DM Integrity profile, protection is performed layer above (dm-crypt)
- */
-static const struct blk_integrity_profile dm_integrity_profile = {
-	.name			= "DM-DIF-EXT-TAG",
-	.generate_fn		= NULL,
-	.verify_fn		= NULL,
-	.prepare_fn		= dm_integrity_prepare,
-	.complete_fn		= dm_integrity_complete,
-};
-
 static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map);
 static void integrity_bio_wait(struct work_struct *w);
 static void dm_integrity_dtr(struct dm_target *ti);
@@ -3656,7 +3637,6 @@ static void dm_integrity_set(struct dm_target *ti, struct dm_integrity_c *ic)
 	struct blk_integrity bi;
 
 	memset(&bi, 0, sizeof(bi));
-	bi.profile = &dm_integrity_profile;
 	bi.tuple_size = ic->tag_size;
 	bi.tag_size = bi.tuple_size;
 	bi.interval_exp = ic->sb->log2_sectors_per_block + SECTOR_SHIFT;