[PATCHv8 1/2] blk-integrity: support arbitrary buffer alignment

[Keith Busch <kbusch@meta.com>]

From: Keith Busch <kbusch@kernel.org>

A bio segment may have partial interval block data with the rest
continuing into the next segments because direct-io data payloads only
need to align in memory to the device's DMA limits.

At the same time, the protection information may also be split in
multiple segments. The most likely way that may happen is if two
requests merge, or if we're directly using the io_uring user metadata.
The generate/verify, however, only ever accessed the first bip_vec.

Further, it may be possible to unalign the protection fields from the
user space buffer, or if there are odd additional opaque bytes in front
or in back of the protection information metadata region.

Change up the iteration to allow spanning multiple segments. This patch
is mostly a re-write of the protection information handling to allow any
arbitrary alignments, so it's probably easier to review the end result
rather than the diff.

Many controllers are not able to handle interval data composed of
multiple segments when PI is used, so this patch introduces a new
integrity limit that a low level driver can set to notify that it is
capable, default to false. The nvme driver is the first one to enable it
in this patch. Everyone else will force DMA alignment to the logical
block size as before to ensure interval data is always aligned within a
single segment.

Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 block/blk-settings.c          |  12 +-
 block/t10-pi.c                | 816 +++++++++++++++++++---------------
 drivers/nvme/host/core.c      |   1 +
 include/linux/blk-integrity.h |   1 +
 4 files changed, 465 insertions(+), 365 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index dabfab97fbab0..78c83817b9d36 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -189,11 +189,11 @@ static int blk_validate_integrity_limits(struct queue_limits *lim)
 	}
 
 	/*
-	 * The PI generation / validation helpers do not expect intervals to
-	 * straddle multiple bio_vecs.  Enforce alignment so that those are
+	 * Some IO controllers can not handle data intervals straddling
+	 * multiple bio_vecs.  For those, enforce alignment so that those are
 	 * never generated, and that each buffer is aligned as expected.
 	 */
-	if (bi->csum_type) {
+	if (!(bi->flags & BLK_SPLIT_INTERVAL_CAPABLE) && bi->csum_type) {
 		lim->dma_alignment = max(lim->dma_alignment,
 					(1U << bi->interval_exp) - 1);
 	}
@@ -992,10 +992,14 @@ bool queue_limits_stack_integrity(struct queue_limits *t,
 		if ((ti->flags & BLK_INTEGRITY_REF_TAG) !=
 		    (bi->flags & BLK_INTEGRITY_REF_TAG))
 			goto incompatible;
+		if ((ti->flags & BLK_SPLIT_INTERVAL_CAPABLE) &&
+		    !(bi->flags & BLK_SPLIT_INTERVAL_CAPABLE))
+			ti->flags &= ~BLK_SPLIT_INTERVAL_CAPABLE;
 	} else {
 		ti->flags = BLK_INTEGRITY_STACKED;
 		ti->flags |= (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) |
-			     (bi->flags & BLK_INTEGRITY_REF_TAG);
+			     (bi->flags & BLK_INTEGRITY_REF_TAG) |
+			     (bi->flags & BLK_SPLIT_INTERVAL_CAPABLE);
 		ti->csum_type = bi->csum_type;
 		ti->pi_tuple_size = bi->pi_tuple_size;
 		ti->metadata_size = bi->metadata_size;
diff --git a/block/t10-pi.c b/block/t10-pi.c
index d27be6041fd31..a19b4e102a837 100644
--- a/block/t10-pi.c
+++ b/block/t10-pi.c
@@ -12,462 +12,556 @@
 #include <linux/unaligned.h>
 #include "blk.h"
 
+#define APP_TAG_ESCAPE 0xffff
+#define REF_TAG_ESCAPE 0xffffffff
+
+/*
+ * This union is used for onstack allocations when the pi field is split across
+ * segments. blk_validate_integrity_limits() guarantees pi_tuple_size matches
+ * the sizeof one of these two types.
+ */
+union pi_tuple {
+	struct crc64_pi_tuple	crc64_pi;
+	struct t10_pi_tuple	t10_pi;
+};
+
 struct blk_integrity_iter {
-	void			*prot_buf;
-	void			*data_buf;
-	sector_t		seed;
-	unsigned int		data_size;
-	unsigned short		interval;
-	const char		*disk_name;
+	struct bio			*bio;
+	struct bio_integrity_payload	*bip;
+	struct blk_integrity		*bi;
+	struct bvec_iter		data_iter;
+	struct bvec_iter		prot_iter;
+	unsigned int			interval_remaining;
+	u64				seed;
+	u64				csum;
 };
 
-static __be16 t10_pi_csum(__be16 csum, void *data, unsigned int len,
-		unsigned char csum_type)
+static void blk_calculate_guard(struct blk_integrity_iter *iter, void *data,
+				unsigned int len)
 {
-	if (csum_type == BLK_INTEGRITY_CSUM_IP)
-		return (__force __be16)ip_compute_csum(data, len);
-	return cpu_to_be16(crc_t10dif_update(be16_to_cpu(csum), data, len));
+	switch (iter->bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+		iter->csum = crc64_nvme(iter->csum, data, len);
+		break;
+	case BLK_INTEGRITY_CSUM_CRC:
+		iter->csum = crc_t10dif_update(iter->csum, data, len);
+		break;
+	case BLK_INTEGRITY_CSUM_IP:
+		iter->csum = (__force u32)csum_partial(data, len,
+						(__force __wsum)iter->csum);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		iter->csum = U64_MAX;
+		break;
+	}
+}
+
+static void blk_integrity_csum_finish(struct blk_integrity_iter *iter)
+{
+	switch (iter->bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_IP:
+		iter->csum = (__force u16)csum_fold((__force __wsum)iter->csum);
+		break;
+	default:
+		break;
+	}
 }
 
 /*
- * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
- * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
- * tag.
+ * Update the csum for formats that have metadata padding in front of the data
+ * integrity field
  */
-static void t10_pi_generate(struct blk_integrity_iter *iter,
-		struct blk_integrity *bi)
+static void blk_integrity_csum_offset(struct blk_integrity_iter *iter)
 {
-	u8 offset = bi->pi_offset;
-	unsigned int i;
+	unsigned int offset = iter->bi->pi_offset;
+	struct bio_vec *bvec = iter->bip->bip_vec;
+
+	while (offset > 0) {
+		struct bio_vec pbv = bvec_iter_bvec(bvec, iter->prot_iter);
+		unsigned int len = min(pbv.bv_len, offset);
+		void *prot_buf = bvec_kmap_local(&pbv);
+
+		blk_calculate_guard(iter, prot_buf, len);
+		kunmap_local(prot_buf);
+		offset -= len;
+		bvec_iter_advance_single(bvec, &iter->prot_iter, len);
+	}
+	blk_integrity_csum_finish(iter);
+}
 
-	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
-		struct t10_pi_tuple *pi = iter->prot_buf + offset;
+static void blk_integrity_copy_from_tuple(struct bio_integrity_payload *bip,
+					  struct bvec_iter *iter, void *tuple,
+					  unsigned int tuple_size)
+{
+	while (tuple_size) {
+		struct bio_vec pbv = bvec_iter_bvec(bip->bip_vec, *iter);
+		unsigned int len = min(tuple_size, pbv.bv_len);
+		void *prot_buf = bvec_kmap_local(&pbv);
+
+		memcpy(prot_buf, tuple, len);
+		kunmap_local(prot_buf);
+		bvec_iter_advance_single(bip->bip_vec, iter, len);
+		tuple_size -= len;
+		tuple += len;
+	}
+}
 
-		pi->guard_tag = t10_pi_csum(0, iter->data_buf, iter->interval,
-				bi->csum_type);
-		if (offset)
-			pi->guard_tag = t10_pi_csum(pi->guard_tag,
-					iter->prot_buf, offset, bi->csum_type);
-		pi->app_tag = 0;
+static void blk_integrity_copy_to_tuple(struct bio_integrity_payload *bip,
+					struct bvec_iter *iter, void *tuple,
+					unsigned int tuple_size)
+{
+	while (tuple_size) {
+		struct bio_vec pbv = bvec_iter_bvec(bip->bip_vec, *iter);
+		unsigned int len = min(tuple_size, pbv.bv_len);
+		void *prot_buf = bvec_kmap_local(&pbv);
+
+		memcpy(tuple, prot_buf, len);
+		kunmap_local(prot_buf);
+		bvec_iter_advance_single(bip->bip_vec, iter, len);
+		tuple_size -= len;
+		tuple += len;
+	}
+}
 
-		if (bi->flags & BLK_INTEGRITY_REF_TAG)
-			pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
-		else
-			pi->ref_tag = 0;
+static bool ext_pi_ref_escape(const u8 ref_tag[6])
+{
+	static const u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
-		iter->data_buf += iter->interval;
-		iter->prot_buf += bi->metadata_size;
-		iter->seed++;
-	}
+	return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
 }
 
-static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
-		struct blk_integrity *bi)
-{
-	u8 offset = bi->pi_offset;
-	unsigned int i;
-
-	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
-		struct t10_pi_tuple *pi = iter->prot_buf + offset;
-		__be16 csum;
-
-		if (bi->flags & BLK_INTEGRITY_REF_TAG) {
-			if (pi->app_tag == T10_PI_APP_ESCAPE)
-				goto next;
-
-			if (be32_to_cpu(pi->ref_tag) !=
-			    lower_32_bits(iter->seed)) {
-				pr_err("%s: ref tag error at location %llu " \
-				       "(rcvd %u)\n", iter->disk_name,
-				       (unsigned long long)
-				       iter->seed, be32_to_cpu(pi->ref_tag));
-				return BLK_STS_PROTECTION;
-			}
-		} else {
-			if (pi->app_tag == T10_PI_APP_ESCAPE &&
-			    pi->ref_tag == T10_PI_REF_ESCAPE)
-				goto next;
+static blk_status_t blk_verify_ext_pi(struct blk_integrity_iter *iter,
+				      struct crc64_pi_tuple *pi)
+{
+	u64 seed = lower_48_bits(iter->seed);
+	u64 guard = get_unaligned_be64(&pi->guard_tag);
+	u64 ref = get_unaligned_be48(pi->ref_tag);
+	u16 app = get_unaligned_be16(&pi->app_tag);
+
+	if (iter->bi->flags & BLK_INTEGRITY_REF_TAG) {
+		if (app == APP_TAG_ESCAPE)
+			return BLK_STS_OK;
+		if (ref != seed) {
+			pr_err("%s: ref tag error at location %llu (rcvd %llu)\n",
+				iter->bio->bi_bdev->bd_disk->disk_name, seed,
+				ref);
+			return BLK_STS_PROTECTION;
 		}
+	} else if (app == APP_TAG_ESCAPE && ext_pi_ref_escape(pi->ref_tag)) {
+		return BLK_STS_OK;
+	}
+
+	if (guard != iter->csum) {
+		pr_err("%s: guard tag error at sector %llu (rcvd %016llx, want %016llx)\n",
+			iter->bio->bi_bdev->bd_disk->disk_name, iter->seed,
+			guard, iter->csum);
+		return BLK_STS_PROTECTION;
+	}
+
+	return BLK_STS_OK;
+}
 
-		csum = t10_pi_csum(0, iter->data_buf, iter->interval,
-				bi->csum_type);
-		if (offset)
-			csum = t10_pi_csum(csum, iter->prot_buf, offset,
-					bi->csum_type);
-
-		if (pi->guard_tag != csum) {
-			pr_err("%s: guard tag error at sector %llu " \
-			       "(rcvd %04x, want %04x)\n", iter->disk_name,
-			       (unsigned long long)iter->seed,
-			       be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
+static blk_status_t blk_verify_pi(struct blk_integrity_iter *iter,
+				      struct t10_pi_tuple *pi, u16 guard)
+{
+	u32 seed = lower_32_bits(iter->seed);
+	u32 ref = get_unaligned_be32(&pi->ref_tag);
+	u16 app = get_unaligned_be16(&pi->app_tag);
+
+	if (iter->bi->flags & BLK_INTEGRITY_REF_TAG) {
+		if (app == APP_TAG_ESCAPE)
+			return BLK_STS_OK;
+		if (ref != seed) {
+			pr_err("%s: ref tag error at location %u (rcvd %u)\n",
+				iter->bio->bi_bdev->bd_disk->disk_name, seed,
+				ref);
 			return BLK_STS_PROTECTION;
 		}
+	} else if (app == APP_TAG_ESCAPE && ref == REF_TAG_ESCAPE) {
+		return BLK_STS_OK;
+	}
 
-next:
-		iter->data_buf += iter->interval;
-		iter->prot_buf += bi->metadata_size;
-		iter->seed++;
+	if (guard != (u16)iter->csum) {
+		pr_err("%s: guard tag error at sector %llu (rcvd %04x, want %04x)\n",
+			iter->bio->bi_bdev->bd_disk->disk_name, iter->seed,
+			guard, (u16)iter->csum);
+		return BLK_STS_PROTECTION;
 	}
 
 	return BLK_STS_OK;
 }
 
-/**
- * t10_pi_type1_prepare - prepare PI prior submitting request to device
- * @rq:              request with PI that should be prepared
- *
- * For Type 1/Type 2, the virtual start sector is the one that was
- * originally submitted by the block layer for the ref_tag usage. Due to
- * partitioning, MD/DM cloning, etc. the actual physical start sector is
- * likely to be different. Remap protection information to match the
- * physical LBA.
- */
-static void t10_pi_type1_prepare(struct request *rq)
+static blk_status_t blk_verify_t10_pi(struct blk_integrity_iter *iter,
+				      struct t10_pi_tuple *pi)
 {
-	struct blk_integrity *bi = &rq->q->limits.integrity;
-	const int tuple_sz = bi->metadata_size;
-	u32 ref_tag = t10_pi_ref_tag(rq);
-	u8 offset = bi->pi_offset;
-	struct bio *bio;
+	u16 guard = get_unaligned_be16(&pi->guard_tag);
 
-	__rq_for_each_bio(bio, rq) {
-		struct bio_integrity_payload *bip = bio_integrity(bio);
-		u32 virt = bip_get_seed(bip) & 0xffffffff;
-		struct bio_vec iv;
-		struct bvec_iter iter;
+	return blk_verify_pi(iter, pi, guard);
+}
 
-		/* Already remapped? */
-		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
-			break;
+static blk_status_t blk_verify_ip_pi(struct blk_integrity_iter *iter,
+				     struct t10_pi_tuple *pi)
+{
+	u16 guard = get_unaligned((u16 *)&pi->guard_tag);
 
-		bip_for_each_vec(iv, bip, iter) {
-			unsigned int j;
-			void *p;
-
-			p = bvec_kmap_local(&iv);
-			for (j = 0; j < iv.bv_len; j += tuple_sz) {
-				struct t10_pi_tuple *pi = p + offset;
-
-				if (be32_to_cpu(pi->ref_tag) == virt)
-					pi->ref_tag = cpu_to_be32(ref_tag);
-				virt++;
-				ref_tag++;
-				p += tuple_sz;
-			}
-			kunmap_local(p);
-		}
+	return blk_verify_pi(iter, pi, guard);
+}
 
-		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
+static blk_status_t blk_integrity_verify(struct blk_integrity_iter *iter,
+					 union pi_tuple *tuple)
+{
+	switch (iter->bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+		return blk_verify_ext_pi(iter, &tuple->crc64_pi);
+	case BLK_INTEGRITY_CSUM_CRC:
+		return blk_verify_t10_pi(iter, &tuple->t10_pi);
+	case BLK_INTEGRITY_CSUM_IP:
+		return blk_verify_ip_pi(iter, &tuple->t10_pi);
+	default:
+		return BLK_STS_OK;
 	}
 }
 
-/**
- * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
- * @rq:              request with PI that should be prepared
- * @nr_bytes:        total bytes to prepare
- *
- * For Type 1/Type 2, the virtual start sector is the one that was
- * originally submitted by the block layer for the ref_tag usage. Due to
- * partitioning, MD/DM cloning, etc. the actual physical start sector is
- * likely to be different. Since the physical start sector was submitted
- * to the device, we should remap it back to virtual values expected by the
- * block layer.
- */
-static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
+static void blk_set_ext_pi(struct blk_integrity_iter *iter,
+			   struct crc64_pi_tuple *pi)
 {
-	struct blk_integrity *bi = &rq->q->limits.integrity;
-	unsigned intervals = nr_bytes >> bi->interval_exp;
-	const int tuple_sz = bi->metadata_size;
-	u32 ref_tag = t10_pi_ref_tag(rq);
-	u8 offset = bi->pi_offset;
-	struct bio *bio;
+	put_unaligned_be64(iter->csum, &pi->guard_tag);
+	put_unaligned_be16(0, &pi->app_tag);
+	put_unaligned_be48(iter->seed, &pi->ref_tag);
+}
 
-	__rq_for_each_bio(bio, rq) {
-		struct bio_integrity_payload *bip = bio_integrity(bio);
-		u32 virt = bip_get_seed(bip) & 0xffffffff;
-		struct bio_vec iv;
-		struct bvec_iter iter;
-
-		bip_for_each_vec(iv, bip, iter) {
-			unsigned int j;
-			void *p;
-
-			p = bvec_kmap_local(&iv);
-			for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
-				struct t10_pi_tuple *pi = p + offset;
-
-				if (be32_to_cpu(pi->ref_tag) == ref_tag)
-					pi->ref_tag = cpu_to_be32(virt);
-				virt++;
-				ref_tag++;
-				intervals--;
-				p += tuple_sz;
-			}
-			kunmap_local(p);
-		}
-	}
+static void blk_set_pi(struct blk_integrity_iter *iter,
+		       struct t10_pi_tuple *pi, __be16 csum)
+{
+	put_unaligned(csum, &pi->guard_tag);
+	put_unaligned_be16(0, &pi->app_tag);
+	put_unaligned_be32(iter->seed, &pi->ref_tag);
 }
 
-static __be64 ext_pi_crc64(u64 crc, void *data, unsigned int len)
+static void blk_set_t10_pi(struct blk_integrity_iter *iter,
+			   struct t10_pi_tuple *pi)
 {
-	return cpu_to_be64(crc64_nvme(crc, data, len));
+	blk_set_pi(iter, pi, cpu_to_be16((u16)iter->csum));
 }
 
-static void ext_pi_crc64_generate(struct blk_integrity_iter *iter,
-		struct blk_integrity *bi)
+static void blk_set_ip_pi(struct blk_integrity_iter *iter,
+			  struct t10_pi_tuple *pi)
 {
-	u8 offset = bi->pi_offset;
-	unsigned int i;
+	blk_set_pi(iter, pi, (__force __be16)(u16)iter->csum);
+}
 
-	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
-		struct crc64_pi_tuple *pi = iter->prot_buf + offset;
+static void blk_integrity_set(struct blk_integrity_iter *iter,
+			      union pi_tuple *tuple)
+{
+	switch (iter->bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+		return blk_set_ext_pi(iter, &tuple->crc64_pi);
+	case BLK_INTEGRITY_CSUM_CRC:
+		return blk_set_t10_pi(iter, &tuple->t10_pi);
+	case BLK_INTEGRITY_CSUM_IP:
+		return blk_set_ip_pi(iter, &tuple->t10_pi);
+	default:
+		WARN_ON_ONCE(1);
+		return;
+	}
+}
 
-		pi->guard_tag = ext_pi_crc64(0, iter->data_buf, iter->interval);
-		if (offset)
-			pi->guard_tag = ext_pi_crc64(be64_to_cpu(pi->guard_tag),
-					iter->prot_buf, offset);
-		pi->app_tag = 0;
+static blk_status_t blk_integrity_interval(struct blk_integrity_iter *iter,
+					   bool verify)
+{
+	blk_status_t ret = BLK_STS_OK;
+	union pi_tuple tuple;
+	void *ptuple = &tuple;
+	struct bio_vec pbv;
+
+	blk_integrity_csum_offset(iter);
+	pbv = bvec_iter_bvec(iter->bip->bip_vec, iter->prot_iter);
+	if (pbv.bv_len >= iter->bi->pi_tuple_size) {
+		ptuple = bvec_kmap_local(&pbv);
+		bvec_iter_advance_single(iter->bip->bip_vec, &iter->prot_iter,
+				iter->bi->metadata_size - iter->bi->pi_offset);
+	} else if (verify) {
+		blk_integrity_copy_to_tuple(iter->bip, &iter->prot_iter,
+				ptuple, iter->bi->pi_tuple_size);
+	}
 
-		if (bi->flags & BLK_INTEGRITY_REF_TAG)
-			put_unaligned_be48(iter->seed, pi->ref_tag);
-		else
-			put_unaligned_be48(0ULL, pi->ref_tag);
+	if (verify)
+		ret = blk_integrity_verify(iter, ptuple);
+	else
+		blk_integrity_set(iter, ptuple);
 
-		iter->data_buf += iter->interval;
-		iter->prot_buf += bi->metadata_size;
-		iter->seed++;
+	if (likely(ptuple != &tuple)) {
+		kunmap_local(ptuple);
+	} else if (!verify) {
+		blk_integrity_copy_from_tuple(iter->bip, &iter->prot_iter,
+				ptuple, iter->bi->pi_tuple_size);
 	}
+
+	iter->interval_remaining = 1 << iter->bi->interval_exp;
+	iter->csum = 0;
+	iter->seed++;
+	return ret;
 }
 
-static bool ext_pi_ref_escape(const u8 ref_tag[6])
+static blk_status_t blk_integrity_iterate(struct bio *bio,
+					  struct bvec_iter *data_iter,
+					  bool verify)
 {
-	static const u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+	struct blk_integrity_iter iter = {
+		.bio = bio,
+		.bip = bip,
+		.bi = bi,
+		.data_iter = *data_iter,
+		.prot_iter = bip->bip_iter,
+		.interval_remaining = 1 << bi->interval_exp,
+		.seed = data_iter->bi_sector,
+		.csum = 0,
+	};
+	blk_status_t ret = BLK_STS_OK;
+
+	while (iter.data_iter.bi_size && ret == BLK_STS_OK) {
+		struct bio_vec bv = bvec_iter_bvec(iter.bio->bi_io_vec,
+						   iter.data_iter);
+		void *kaddr = bvec_kmap_local(&bv);
+		void *data = kaddr;
+		unsigned int len;
+
+		bvec_iter_advance_single(iter.bio->bi_io_vec, &iter.data_iter,
+					 bv.bv_len);
+		while (bv.bv_len && ret == BLK_STS_OK) {
+			len = min(iter.interval_remaining, bv.bv_len);
+			blk_calculate_guard(&iter, data, len);
+			bv.bv_len -= len;
+			data += len;
+			iter.interval_remaining -= len;
+			if (!iter.interval_remaining)
+				ret = blk_integrity_interval(&iter, verify);
+		}
+		kunmap_local(kaddr);
+	}
 
-	return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
+	return ret;
 }
 
-static blk_status_t ext_pi_crc64_verify(struct blk_integrity_iter *iter,
-		struct blk_integrity *bi)
-{
-	u8 offset = bi->pi_offset;
-	unsigned int i;
-
-	for (i = 0; i < iter->data_size; i += iter->interval) {
-		struct crc64_pi_tuple *pi = iter->prot_buf + offset;
-		u64 ref, seed;
-		__be64 csum;
-
-		if (bi->flags & BLK_INTEGRITY_REF_TAG) {
-			if (pi->app_tag == T10_PI_APP_ESCAPE)
-				goto next;
-
-			ref = get_unaligned_be48(pi->ref_tag);
-			seed = lower_48_bits(iter->seed);
-			if (ref != seed) {
-				pr_err("%s: ref tag error at location %llu (rcvd %llu)\n",
-					iter->disk_name, seed, ref);
-				return BLK_STS_PROTECTION;
-			}
-		} else {
-			if (pi->app_tag == T10_PI_APP_ESCAPE &&
-			    ext_pi_ref_escape(pi->ref_tag))
-				goto next;
-		}
+void bio_integrity_generate(struct bio *bio)
+{
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 
-		csum = ext_pi_crc64(0, iter->data_buf, iter->interval);
-		if (offset)
-			csum = ext_pi_crc64(be64_to_cpu(csum), iter->prot_buf,
-					    offset);
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+	case BLK_INTEGRITY_CSUM_CRC:
+	case BLK_INTEGRITY_CSUM_IP:
+		blk_integrity_iterate(bio, &bio->bi_iter, false);
+		break;
+	default:
+		break;
+	}
+}
 
-		if (pi->guard_tag != csum) {
-			pr_err("%s: guard tag error at sector %llu " \
-			       "(rcvd %016llx, want %016llx)\n",
-				iter->disk_name, (unsigned long long)iter->seed,
-				be64_to_cpu(pi->guard_tag), be64_to_cpu(csum));
-			return BLK_STS_PROTECTION;
-		}
+blk_status_t bio_integrity_verify(struct bio *bio, struct bvec_iter *saved_iter)
+{
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 
-next:
-		iter->data_buf += iter->interval;
-		iter->prot_buf += bi->metadata_size;
-		iter->seed++;
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+	case BLK_INTEGRITY_CSUM_CRC:
+	case BLK_INTEGRITY_CSUM_IP:
+		return blk_integrity_iterate(bio, saved_iter, true);
+	default:
+		break;
 	}
 
 	return BLK_STS_OK;
 }
 
-static void ext_pi_type1_prepare(struct request *rq)
+/*
+ * Advance @iter past the protection offset for protection formats that
+ * contain front padding on the metadata region.
+ */
+static void blk_pi_advance_offset(struct blk_integrity *bi,
+				  struct bio_integrity_payload *bip,
+				  struct bvec_iter *iter)
 {
-	struct blk_integrity *bi = &rq->q->limits.integrity;
-	const int tuple_sz = bi->metadata_size;
-	u64 ref_tag = ext_pi_ref_tag(rq);
-	u8 offset = bi->pi_offset;
-	struct bio *bio;
+	unsigned int offset = bi->pi_offset;
 
-	__rq_for_each_bio(bio, rq) {
-		struct bio_integrity_payload *bip = bio_integrity(bio);
-		u64 virt = lower_48_bits(bip_get_seed(bip));
-		struct bio_vec iv;
-		struct bvec_iter iter;
+	while (offset > 0) {
+		struct bio_vec bv = mp_bvec_iter_bvec(bip->bip_vec, *iter);
+		unsigned int len = min(bv.bv_len, offset);
 
-		/* Already remapped? */
-		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
-			break;
+		bvec_iter_advance_single(bip->bip_vec, iter, len);
+		offset -= len;
+	}
+}
 
-		bip_for_each_vec(iv, bip, iter) {
-			unsigned int j;
-			void *p;
-
-			p = bvec_kmap_local(&iv);
-			for (j = 0; j < iv.bv_len; j += tuple_sz) {
-				struct crc64_pi_tuple *pi = p +  offset;
-				u64 ref = get_unaligned_be48(pi->ref_tag);
-
-				if (ref == virt)
-					put_unaligned_be48(ref_tag, pi->ref_tag);
-				virt++;
-				ref_tag++;
-				p += tuple_sz;
-			}
-			kunmap_local(p);
-		}
+static void *blk_tuple_remap_begin(union pi_tuple *tuple,
+				   struct blk_integrity *bi,
+				   struct bio_integrity_payload *bip,
+				   struct bvec_iter *iter)
+{
+	struct bvec_iter titer;
+	struct bio_vec pbv;
 
-		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
+	blk_pi_advance_offset(bi, bip, iter);
+	pbv = bvec_iter_bvec(bip->bip_vec, *iter);
+	if (likely(pbv.bv_len >= bi->pi_tuple_size))
+		return bvec_kmap_local(&pbv);
+
+	/*
+	 * We need to preserve the state of the original iter for the
+	 * copy_from_tuple at the end, so make a temp iter for here.
+	 */
+	titer = *iter;
+	blk_integrity_copy_to_tuple(bip, &titer, tuple, bi->pi_tuple_size);
+	return tuple;
+}
+
+static void blk_tuple_remap_end(union pi_tuple *tuple, void *ptuple,
+				struct blk_integrity *bi,
+				struct bio_integrity_payload *bip,
+				struct bvec_iter *iter)
+{
+	unsigned int len = bi->metadata_size - bi->pi_offset;
+
+	if (likely(ptuple != tuple)) {
+		kunmap_local(ptuple);
+	} else {
+		blk_integrity_copy_from_tuple(bip, iter, ptuple,
+				bi->pi_tuple_size);
+		len -= bi->pi_tuple_size;
 	}
+
+	bvec_iter_advance(bip->bip_vec, iter, len);
 }
 
-static void ext_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
+static void blk_set_ext_unmap_ref(struct crc64_pi_tuple *pi, u64 virt,
+				  u64 ref_tag)
 {
-	struct blk_integrity *bi = &rq->q->limits.integrity;
-	unsigned intervals = nr_bytes >> bi->interval_exp;
-	const int tuple_sz = bi->metadata_size;
-	u64 ref_tag = ext_pi_ref_tag(rq);
-	u8 offset = bi->pi_offset;
-	struct bio *bio;
+	u64 ref = get_unaligned_be48(&pi->ref_tag);
 
-	__rq_for_each_bio(bio, rq) {
-		struct bio_integrity_payload *bip = bio_integrity(bio);
-		u64 virt = lower_48_bits(bip_get_seed(bip));
-		struct bio_vec iv;
-		struct bvec_iter iter;
-
-		bip_for_each_vec(iv, bip, iter) {
-			unsigned int j;
-			void *p;
-
-			p = bvec_kmap_local(&iv);
-			for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
-				struct crc64_pi_tuple *pi = p + offset;
-				u64 ref = get_unaligned_be48(pi->ref_tag);
-
-				if (ref == ref_tag)
-					put_unaligned_be48(virt, pi->ref_tag);
-				virt++;
-				ref_tag++;
-				intervals--;
-				p += tuple_sz;
-			}
-			kunmap_local(p);
-		}
+	if (ref == lower_48_bits(ref_tag) && ref != lower_48_bits(virt))
+		put_unaligned_be48(virt, pi->ref_tag);
+}
+
+static void blk_set_t10_unmap_ref(struct t10_pi_tuple *pi, u32 virt,
+				  u32 ref_tag)
+{
+	u32 ref = get_unaligned_be32(&pi->ref_tag);
+
+	if (ref == ref_tag && ref != virt)
+		put_unaligned_be32(virt, &pi->ref_tag);
+}
+
+static void blk_reftag_remap_complete(struct blk_integrity *bi,
+				      union pi_tuple *tuple, u64 virt, u64 ref)
+{
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+		blk_set_ext_unmap_ref(&tuple->crc64_pi, virt, ref);
+		break;
+	case BLK_INTEGRITY_CSUM_CRC:
+	case BLK_INTEGRITY_CSUM_IP:
+		blk_set_t10_unmap_ref(&tuple->t10_pi, virt, ref);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
 	}
 }
 
-void bio_integrity_generate(struct bio *bio)
+static void blk_set_ext_map_ref(struct crc64_pi_tuple *pi, u64 virt,
+				u64 ref_tag)
 {
-	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
-	struct bio_integrity_payload *bip = bio_integrity(bio);
-	struct blk_integrity_iter iter;
-	struct bvec_iter bviter;
-	struct bio_vec bv;
-
-	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
-	iter.interval = 1 << bi->interval_exp;
-	iter.seed = bio->bi_iter.bi_sector;
-	iter.prot_buf = bvec_virt(bip->bip_vec);
-	bio_for_each_segment(bv, bio, bviter) {
-		void *kaddr = bvec_kmap_local(&bv);
+	u64 ref = get_unaligned_be48(&pi->ref_tag);
 
-		iter.data_buf = kaddr;
-		iter.data_size = bv.bv_len;
-		switch (bi->csum_type) {
-		case BLK_INTEGRITY_CSUM_CRC64:
-			ext_pi_crc64_generate(&iter, bi);
-			break;
-		case BLK_INTEGRITY_CSUM_CRC:
-		case BLK_INTEGRITY_CSUM_IP:
-			t10_pi_generate(&iter, bi);
-			break;
-		default:
-			break;
-		}
-		kunmap_local(kaddr);
+	if (ref == lower_48_bits(virt) && ref != ref_tag)
+		put_unaligned_be48(ref_tag, pi->ref_tag);
+}
+
+static void blk_set_t10_map_ref(struct t10_pi_tuple *pi, u32 virt, u32 ref_tag)
+{
+	u32 ref = get_unaligned_be32(&pi->ref_tag);
+
+	if (ref == virt && ref != ref_tag)
+		put_unaligned_be32(ref_tag, &pi->ref_tag);
+}
+
+static void blk_reftag_remap_prepare(struct blk_integrity *bi,
+				     union pi_tuple *tuple,
+				     u64 virt, u64 ref)
+{
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_CRC64:
+		blk_set_ext_map_ref(&tuple->crc64_pi, virt, ref);
+		break;
+	case BLK_INTEGRITY_CSUM_CRC:
+	case BLK_INTEGRITY_CSUM_IP:
+		blk_set_t10_map_ref(&tuple->t10_pi, virt, ref);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
 	}
 }
 
-blk_status_t bio_integrity_verify(struct bio *bio, struct bvec_iter *saved_iter)
+static void __blk_reftag_remap(struct bio *bio, struct blk_integrity *bi,
+			       unsigned *intervals, u64 *ref, bool prep)
 {
-	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 	struct bio_integrity_payload *bip = bio_integrity(bio);
-	struct blk_integrity_iter iter;
-	struct bvec_iter bviter;
-	struct bio_vec bv;
+	struct bvec_iter iter = bip->bip_iter;
+	u64 virt = bip_get_seed(bip);
+	union pi_tuple *ptuple;
+	union pi_tuple tuple;
 
-	/*
-	 * At the moment verify is called bi_iter has been advanced during split
-	 * and completion, so use the copy created during submission here.
-	 */
-	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
-	iter.interval = 1 << bi->interval_exp;
-	iter.seed = saved_iter->bi_sector;
-	iter.prot_buf = bvec_virt(bip->bip_vec);
-	__bio_for_each_segment(bv, bio, bviter, *saved_iter) {
-		void *kaddr = bvec_kmap_local(&bv);
-		blk_status_t ret = BLK_STS_OK;
+	if (prep && bip->bip_flags & BIP_MAPPED_INTEGRITY) {
+		*ref += bio->bi_iter.bi_size >> bi->interval_exp;
+		return;
+	}
 
-		iter.data_buf = kaddr;
-		iter.data_size = bv.bv_len;
-		switch (bi->csum_type) {
-		case BLK_INTEGRITY_CSUM_CRC64:
-			ret = ext_pi_crc64_verify(&iter, bi);
-			break;
-		case BLK_INTEGRITY_CSUM_CRC:
-		case BLK_INTEGRITY_CSUM_IP:
-			ret = t10_pi_verify(&iter, bi);
-			break;
-		default:
-			break;
-		}
-		kunmap_local(kaddr);
+	while (iter.bi_size && *intervals) {
+		ptuple = blk_tuple_remap_begin(&tuple, bi, bip, &iter);
+
+		if (prep)
+			blk_reftag_remap_prepare(bi, ptuple, virt, *ref);
+		else
+			blk_reftag_remap_complete(bi, ptuple, virt, *ref);
 
-		if (ret)
-			return ret;
+		blk_tuple_remap_end(&tuple, ptuple, bi, bip, &iter);
+		(*intervals)--;
+		(*ref)++;
+		virt++;
 	}
 
-	return BLK_STS_OK;
+	if (prep)
+		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 }
 
-void blk_integrity_prepare(struct request *rq)
+static void blk_integrity_remap(struct request *rq, unsigned int nr_bytes,
+				bool prep)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;
+	u64 ref = blk_rq_pos(rq) >> (bi->interval_exp - SECTOR_SHIFT);
+	unsigned intervals = nr_bytes >> bi->interval_exp;
+	struct bio *bio;
 
 	if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
 		return;
 
-	if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
-		ext_pi_type1_prepare(rq);
-	else
-		t10_pi_type1_prepare(rq);
+	__rq_for_each_bio(bio, rq) {
+		__blk_reftag_remap(bio, bi, &intervals, &ref, prep);
+		if (!intervals)
+			break;
+	}
 }
 
-void blk_integrity_complete(struct request *rq, unsigned int nr_bytes)
+void blk_integrity_prepare(struct request *rq)
 {
-	struct blk_integrity *bi = &rq->q->limits.integrity;
-
-	if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
-		return;
+	blk_integrity_remap(rq, blk_rq_bytes(rq), true);
+}
 
-	if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
-		ext_pi_type1_complete(rq, nr_bytes);
-	else
-		t10_pi_type1_complete(rq, nr_bytes);
+void blk_integrity_complete(struct request *rq, unsigned int nr_bytes)
+{
+	blk_integrity_remap(rq, nr_bytes, false);
 }
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f5ebcaa2f859c..31ae380489b3e 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1875,6 +1875,7 @@ static bool nvme_init_integrity(struct nvme_ns_head *head,
 		break;
 	}
 
+	bi->flags |= BLK_SPLIT_INTERVAL_CAPABLE;
 	bi->metadata_size = head->ms;
 	if (bi->csum_type) {
 		bi->pi_tuple_size = head->pi_size;
diff --git a/include/linux/blk-integrity.h b/include/linux/blk-integrity.h
index ea6d7d322ae3b..b1b530613c342 100644
--- a/include/linux/blk-integrity.h
+++ b/include/linux/blk-integrity.h
@@ -14,6 +14,7 @@ enum blk_integrity_flags {
 	BLK_INTEGRITY_DEVICE_CAPABLE	= 1 << 2,
 	BLK_INTEGRITY_REF_TAG		= 1 << 3,
 	BLK_INTEGRITY_STACKED		= 1 << 4,
+	BLK_SPLIT_INTERVAL_CAPABLE	= 1 << 5,
 };
 
 const char *blk_integrity_profile_name(struct blk_integrity *bi);
-- 
2.52.0