[PATCH v4 5/5] blk-integrity: avoid sector_t in bip_{get,set}_seed()

[Caleb Sander Mateos <csander@purestorage.com>]

bip_set_seed() and bip_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 <hch@infradead.org>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
 block/bio-integrity.c               |  5 ++---
 block/t10-pi.c                      |  2 +-
 drivers/nvme/target/io-cmd-bdev.c   |  3 +--
 drivers/target/target_core_iblock.c |  3 +--
 include/linux/bio-integrity.h       | 11 -----------
 include/linux/blk-integrity.h       | 13 +++++++++++++
 include/linux/bvec.h                |  1 +
 7 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index d20f9002c7c9..7e5fb9b44848 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -102,13 +102,12 @@ void bio_integrity_free_buf(struct bio_integrity_payload *bip)
 
 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;
 		if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
 			bip->bip_flags |= BIP_IP_CHECKSUM;
@@ -488,11 +487,11 @@ int bio_integrity_map_iter(struct bio *bio, struct uio_meta *meta)
 
 	it.count = integrity_bytes;
 	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));
 	}
 	return ret;
 }
diff --git a/block/t10-pi.c b/block/t10-pi.c
index 787950dec50a..71367fd082bd 100644
--- a/block/t10-pi.c
+++ b/block/t10-pi.c
@@ -510,11 +510,11 @@ static void blk_reftag_remap_prepare(struct blk_integrity *bi,
 static void __blk_reftag_remap(struct bio *bio, struct blk_integrity *bi,
 			       unsigned *intervals, u64 *ref, bool prep)
 {
 	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;
 
 	if (prep && bip->bip_flags & BIP_MAPPED_INTEGRITY) {
 		*ref += bio->bi_iter.bi_size >> bi->interval_exp;
diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index f2d9e8901df4..65fce51b024a 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -218,12 +218,11 @@ static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
 		pr_err("Unable to allocate bio_integrity_payload\n");
 		return PTR_ERR(bip);
 	}
 
 	/* 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)) {
 		len = min_t(size_t, miter->length, resid);
 		rc = bio_integrity_add_page(bio, miter->page, len,
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 1087d1d17c36..1aeb5be529a8 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -706,12 +706,11 @@ iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio,
 		pr_err("Unable to allocate bio_integrity_payload\n");
 		return PTR_ERR(bip);
 	}
 
 	/* 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);
 
 	resid = bio_integrity_bytes(bi, bio_sectors(bio));
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index c3dda32fd803..992cb1622c2c 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -56,21 +56,10 @@ static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 		return bip->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,
 		unsigned int nr);
 int bio_integrity_add_page(struct bio *bio, struct page *page, unsigned int len,
diff --git a/include/linux/blk-integrity.h b/include/linux/blk-integrity.h
index 825d777c078b..c82b2f6fe194 100644
--- a/include/linux/blk-integrity.h
+++ b/include/linux/blk-integrity.h
@@ -85,10 +85,23 @@ static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
 					       unsigned int sectors)
 {
 	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;
 }
 
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 92837e2743f1..22bded380bbf 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -91,10 +91,11 @@ static inline struct folio *bvec_folio(const struct bio_vec *bv)
 
 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;
 
 	/*
 	 * Remaining size in bytes.
-- 
2.54.0