block/t10-pi.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * t10_pi.c - Functions for generating and verifying T10 Protection
  *	      Information.
  */

 #include <linux/t10-pi.h>
 #include <linux/blk-integrity.h>
 #include <linux/crc-t10dif.h>
 #include <linux/crc64.h>
 #include <linux/module.h>
 #include <net/checksum.h>
 #include <asm/unaligned.h>
 #include "blk.h"

 struct blk_integrity_iter {
 	void			*prot_buf;
 	void			*data_buf;
 	sector_t		seed;
 	unsigned int		data_size;
 	unsigned short		interval;
 	const char		*disk_name;
 };

 static __be16 t10_pi_csum(__be16 csum, void *data, unsigned int len,
 		unsigned char csum_type)
 {
 	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));
 }

 /*
  * 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.
  */
 static void t10_pi_generate(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;

 		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;

 		if (bi->flags & BLK_INTEGRITY_REF_TAG)
 			pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
 		else
 			pi->ref_tag = 0;

 		iter->data_buf += iter->interval;
 		iter->prot_buf += bi->tuple_size;
 		iter->seed++;
 	}
 }

 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;
 		}

 		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));
 			return BLK_STS_PROTECTION;
 		}

 next:
 		iter->data_buf += iter->interval;
 		iter->prot_buf += bi->tuple_size;
 		iter->seed++;
 	}

 	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)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;
 	const int tuple_sz = bi->tuple_size;
 	u32 ref_tag = t10_pi_ref_tag(rq);
 	u8 offset = bi->pi_offset;
 	struct bio *bio;

 	__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;

 		/* Already remapped? */
 		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
 			break;

 		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);
 		}

 		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 	}
 }

 /**
  * 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)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;
 	unsigned intervals = nr_bytes >> bi->interval_exp;
 	const int tuple_sz = bi->tuple_size;
 	u32 ref_tag = t10_pi_ref_tag(rq);
 	u8 offset = bi->pi_offset;
 	struct bio *bio;

 	__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 __be64 ext_pi_crc64(u64 crc, void *data, unsigned int len)
 {
 	return cpu_to_be64(crc64_rocksoft_update(crc, data, len));
 }

 static void ext_pi_crc64_generate(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;

 		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;

 		if (bi->flags & BLK_INTEGRITY_REF_TAG)
 			put_unaligned_be48(iter->seed, pi->ref_tag);
 		else
 			put_unaligned_be48(0ULL, pi->ref_tag);

 		iter->data_buf += iter->interval;
 		iter->prot_buf += bi->tuple_size;
 		iter->seed++;
 	}
 }

 static bool ext_pi_ref_escape(u8 *ref_tag)
 {
 	static u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

 	return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
 }

 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;
 		}

 		csum = ext_pi_crc64(0, iter->data_buf, iter->interval);
 		if (offset)
 			csum = ext_pi_crc64(be64_to_cpu(csum), iter->prot_buf,
 					    offset);

 		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;
 		}

 next:
 		iter->data_buf += iter->interval;
 		iter->prot_buf += bi->tuple_size;
 		iter->seed++;
 	}

 	return BLK_STS_OK;
 }

 static void ext_pi_type1_prepare(struct request *rq)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;
 	const int tuple_sz = bi->tuple_size;
 	u64 ref_tag = ext_pi_ref_tag(rq);
 	u8 offset = bi->pi_offset;
 	struct bio *bio;

 	__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;

 		/* Already remapped? */
 		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
 			break;

 		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);
 		}

 		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 	}
 }

 static void ext_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;
 	unsigned intervals = nr_bytes >> bi->interval_exp;
 	const int tuple_sz = bi->tuple_size;
 	u64 ref_tag = ext_pi_ref_tag(rq);
 	u8 offset = bi->pi_offset;
 	struct bio *bio;

 	__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);
 		}
 	}
 }

 void blk_integrity_generate(struct bio *bio)
 {
 	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);

 		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);
 	}
 }

 void blk_integrity_verify(struct bio *bio)
 {
 	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;

 	/*
 	 * 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 = bip->bio_iter.bi_sector;
 	iter.prot_buf = bvec_virt(bip->bip_vec);
 	__bio_for_each_segment(bv, bio, bviter, bip->bio_iter) {
 		void *kaddr = bvec_kmap_local(&bv);
 		blk_status_t ret = BLK_STS_OK;

 		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);

 		if (ret) {
 			bio->bi_status = ret;
 			return;
 		}
 	}
 }

 void blk_integrity_prepare(struct request *rq)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;

 	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);
 }

 void blk_integrity_complete(struct request *rq, unsigned int nr_bytes)
 {
 	struct blk_integrity *bi = &rq->q->limits.integrity;

 	if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
 		return;

 	if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
 		ext_pi_type1_complete(rq, nr_bytes);
 	else
 		t10_pi_type1_complete(rq, nr_bytes);
 }

 MODULE_DESCRIPTION("T10 Protection Information module");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* t10_pi.c - Functions for generating and verifying T10 Protection
	* Information.
	*/

	#include <linux/t10-pi.h>
	#include <linux/blk-integrity.h>
	#include <linux/crc-t10dif.h>
	#include <linux/crc64.h>
	#include <linux/module.h>
	#include <net/checksum.h>
	#include <asm/unaligned.h>
	#include "blk.h"

	struct blk_integrity_iter {
	void *prot_buf;
	void *data_buf;
	sector_t seed;
	unsigned int data_size;
	unsigned short interval;
	const char *disk_name;
	};

	static __be16 t10_pi_csum(__be16 csum, void *data, unsigned int len,
	unsigned char csum_type)
	{
	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));
	}

	/*
	* 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.
	*/
	static void t10_pi_generate(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;

	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;

	if (bi->flags & BLK_INTEGRITY_REF_TAG)
	pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
	else
	pi->ref_tag = 0;

	iter->data_buf += iter->interval;
	iter->prot_buf += bi->tuple_size;
	iter->seed++;
	}
	}

	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;
	}

	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));
	return BLK_STS_PROTECTION;
	}

	next:
	iter->data_buf += iter->interval;
	iter->prot_buf += bi->tuple_size;
	iter->seed++;
	}

	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)
	{
	struct blk_integrity *bi = &rq->q->limits.integrity;
	const int tuple_sz = bi->tuple_size;
	u32 ref_tag = t10_pi_ref_tag(rq);
	u8 offset = bi->pi_offset;
	struct bio *bio;

	__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;

	/* Already remapped? */
	if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
	break;

	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);
	}

	bip->bip_flags \|= BIP_MAPPED_INTEGRITY;
	}
	}

	/**
	* 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)
	{
	struct blk_integrity *bi = &rq->q->limits.integrity;
	unsigned intervals = nr_bytes >> bi->interval_exp;
	const int tuple_sz = bi->tuple_size;
	u32 ref_tag = t10_pi_ref_tag(rq);
	u8 offset = bi->pi_offset;
	struct bio *bio;

	__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 __be64 ext_pi_crc64(u64 crc, void *data, unsigned int len)
	{
	return cpu_to_be64(crc64_rocksoft_update(crc, data, len));
	}

	static void ext_pi_crc64_generate(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;

	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;

	if (bi->flags & BLK_INTEGRITY_REF_TAG)
	put_unaligned_be48(iter->seed, pi->ref_tag);
	else
	put_unaligned_be48(0ULL, pi->ref_tag);

	iter->data_buf += iter->interval;
	iter->prot_buf += bi->tuple_size;
	iter->seed++;
	}
	}

	static bool ext_pi_ref_escape(u8 *ref_tag)
	{
	static u8 ref_escape[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

	return memcmp(ref_tag, ref_escape, sizeof(ref_escape)) == 0;
	}

	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;
	}

	csum = ext_pi_crc64(0, iter->data_buf, iter->interval);
	if (offset)
	csum = ext_pi_crc64(be64_to_cpu(csum), iter->prot_buf,
	offset);

	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;
	}

	next:
	iter->data_buf += iter->interval;
	iter->prot_buf += bi->tuple_size;
	iter->seed++;
	}

	return BLK_STS_OK;
	}

	static void ext_pi_type1_prepare(struct request *rq)
	{
	struct blk_integrity *bi = &rq->q->limits.integrity;
	const int tuple_sz = bi->tuple_size;
	u64 ref_tag = ext_pi_ref_tag(rq);
	u8 offset = bi->pi_offset;
	struct bio *bio;

	__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;

	/* Already remapped? */
	if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
	break;

	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);
	}

	bip->bip_flags \|= BIP_MAPPED_INTEGRITY;
	}
	}

	static void ext_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
	{
	struct blk_integrity *bi = &rq->q->limits.integrity;
	unsigned intervals = nr_bytes >> bi->interval_exp;
	const int tuple_sz = bi->tuple_size;
	u64 ref_tag = ext_pi_ref_tag(rq);
	u8 offset = bi->pi_offset;
	struct bio *bio;

	__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);
	}
	}
	}

	void blk_integrity_generate(struct bio *bio)
	{
	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);

	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);
	}
	}

	void blk_integrity_verify(struct bio *bio)
	{
	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;

	/*
	* 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 = bip->bio_iter.bi_sector;
	iter.prot_buf = bvec_virt(bip->bip_vec);
	__bio_for_each_segment(bv, bio, bviter, bip->bio_iter) {
	void *kaddr = bvec_kmap_local(&bv);
	blk_status_t ret = BLK_STS_OK;

	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);

	if (ret) {
	bio->bi_status = ret;
	return;
	}
	}
	}

	void blk_integrity_prepare(struct request *rq)
	{
	struct blk_integrity *bi = &rq->q->limits.integrity;

	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);
	}

	void blk_integrity_complete(struct request *rq, unsigned int nr_bytes)
	{
	struct blk_integrity *bi = &rq->q->limits.integrity;

	if (!(bi->flags & BLK_INTEGRITY_REF_TAG))
	return;

	if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC64)
	ext_pi_type1_complete(rq, nr_bytes);
	else
	t10_pi_type1_complete(rq, nr_bytes);
	}

	MODULE_DESCRIPTION("T10 Protection Information module");
	MODULE_LICENSE("GPL");