Re: [PATCH v2 6/6] blk-integrity: avoid sector_t in bip_{get,set}_seed()

[Christoph Hellwig <hch@lst.de>]

On Wed, Apr 15, 2026 at 06:22:14PM -0600, Caleb Sander Mateos wrote:
> 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 blk_integrity and 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.
> 
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> ---
>  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       | 14 ++++++++++++++
>  include/linux/bvec.h                |  1 +
>  7 files changed, 20 insertions(+), 19 deletions(-)
> 
> diff --git a/block/bio-integrity.c b/block/bio-integrity.c
> index 3ad6a6799f17..e9ae5db99f64 100644
> --- a/block/bio-integrity.c
> +++ b/block/bio-integrity.c
> @@ -103,13 +103,12 @@ 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(bip, bi, 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;
> @@ -472,11 +471,11 @@ 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..2c4b312f2f55 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(bip, bi, 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..4e0fa91a08fd 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(bip, bi, 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 af5178434ec6..edcd0855abba 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..3a2e55e809c5 100644
> --- a/include/linux/blk-integrity.h
> +++ b/include/linux/blk-integrity.h
> @@ -85,10 +85,24 @@ 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
> + * @bip:	struct bio_integrity_payload whose ref tag seed to set
> + * @bi:		struct blk_integrity profile for device
> + * @bio:	struct bio whose device address to use for the ref tag seed
> + */
> +static inline void bip_set_seed(struct bio_integrity_payload *bip,
> +				const struct blk_integrity *bi,
> +				const struct bio *bio)
> +{
> +	bip->bip_iter.bi_sector =
> +		bio_integrity_intervals(bi, bio->bi_iter.bi_sector);

The bip is pointed to by the bio, so we don't need to pass it separately.
Same for struct blk_integrity.