blk-integrity: avoid sector_t in bip_{get,set}_seed()

bip_set_seed() and big_get_seed() take/return a sector_t value that's
actually an integrity interval number. This is confusing, so pass
struct bio instead to bip_set_seed() and convert the bio's device
address to integrity intervals.

Open-code the access to bip->bip_iter.bi_sector in the one caller of
bip_set_seed() that doesn't use the bio device address for the seed.
Open-code bip_get_seed() in its one caller.

Add a comment to struct bvec_iter's bi_sector field explaining its
alternate use for bip_iter.

Suggested-by: Christoph Hellwig <[email protected]>
Signed-off-by: Caleb Sander Mateos <[email protected]>

Author: calebsander

block/bio-integrity.c

@@ -105,9 +105,8 @@ void bio_integrity_setup_default(struct bio *bio)
 {
 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 	struct bio_integrity_payload *bip = bio_integrity(bio);
-	u64 seed = bio->bi_iter.bi_sector >> (bi->interval_exp - SECTOR_SHIFT);
 
-	bip_set_seed(bip, seed);
+	bip_set_seed(bio);
 
 	if (bi->csum_type) {
 		bip->bip_flags |= BIP_CHECK_GUARD;
@@ -474,7 +473,7 @@ int bio_integrity_map_iter(struct bio *bio, struct uio_meta *meta)
 	ret = bio_integrity_map_user(bio, &it);
 	if (!ret) {
 		bio_uio_meta_to_bip(bio, meta);
-		bip_set_seed(bio_integrity(bio), meta->seed);
+		bio_integrity(bio)->bip_iter.bi_sector = meta->seed;
 		iov_iter_advance(&meta->iter, integrity_bytes);
 		meta->seed += bio_integrity_intervals(bi, bio_sectors(bio));
 	}

block/t10-pi.c

@@ -512,7 +512,7 @@ static void __blk_reftag_remap(struct bio *bio, struct blk_integrity *bi,
 {
 	struct bio_integrity_payload *bip = bio_integrity(bio);
 	struct bvec_iter iter = bip->bip_iter;
-	u64 virt = bip_get_seed(bip);
+	u64 virt = bip->bip_iter.bi_sector;
 	union pi_tuple *ptuple;
 	union pi_tuple tuple;
 

drivers/nvme/target/io-cmd-bdev.c

@@ -220,8 +220,7 @@ static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
 	}
 
 	/* virtual start sector must be in integrity interval units */
-	bip_set_seed(bip, bio->bi_iter.bi_sector >>
-		     (bi->interval_exp - SECTOR_SHIFT));
+	bip_set_seed(bio);
 
 	resid = bio_integrity_bytes(bi, bio_sectors(bio));
 	while (resid > 0 && sg_miter_next(miter)) {

drivers/target/target_core_iblock.c

@@ -708,8 +708,7 @@ iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio,
 	}
 
 	/* virtual start sector must be in integrity interval units */
-	bip_set_seed(bip, bio->bi_iter.bi_sector >>
-				  (bi->interval_exp - SECTOR_SHIFT));
+	bip_set_seed(bio);
 
 	pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
 		 (unsigned long long)bip->bip_iter.bi_sector);

include/linux/bio-integrity.h

@@ -58,17 +58,6 @@ static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 	return false;
 }
 
-static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
-{
-	return bip->bip_iter.bi_sector;
-}
-
-static inline void bip_set_seed(struct bio_integrity_payload *bip,
-				sector_t seed)
-{
-	bip->bip_iter.bi_sector = seed;
-}
-
 void bio_integrity_init(struct bio *bio, struct bio_integrity_payload *bip,
 		struct bio_vec *bvecs, unsigned int nr_vecs);
 struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, gfp_t gfp,

include/linux/blk-integrity.h

@@ -87,6 +87,19 @@ static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
 	return bio_integrity_intervals(bi, sectors) * bi->metadata_size;
 }
 
+/**
+ * bip_set_seed - Set bip reference tag seed from bio device address
+ * @bio:	struct bio whose integrity payload's ref tag seed to initialize
+ */
+static inline void bip_set_seed(struct bio *bio)
+{
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+
+	bip->bip_iter.bi_sector =
+		bio_integrity_intervals(bi, bio->bi_iter.bi_sector);
+}
+
 static inline bool blk_integrity_rq(const struct request *rq)
 {
 	return rq->cmd_flags & REQ_INTEGRITY;

include/linux/bvec.h

@@ -78,6 +78,7 @@ struct bvec_iter {
 	/*
 	 * Current device address in 512 byte sectors. Only updated by the bio
 	 * iter wrappers and not the bvec iterator helpers themselves.
+	 * For bip_iter, this is overloaded to represent the integrity interval.
 	 */
 	sector_t		bi_sector;