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// SPDX-License-Identifier: GPL-2.0
/*
* t10_pi.c - Functions for generating and verifying T10 Protection
* Information.
*/
#include <linux/t10-pi.h>
#include <linux/blkdev.h>
#include <linux/crc-t10dif.h>
#include <linux/module.h>
#include <net/checksum.h>
typedef __be16 (csum_fn) (void *, unsigned int);
static __be16 t10_pi_crc_fn(void *data, unsigned int len)
{
return cpu_to_be16(crc_t10dif(data, len));
}
static __be16 t10_pi_ip_fn(void *data, unsigned int len)
{
return (__force __be16)ip_compute_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 blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
csum_fn *fn, enum t10_dif_type type)
{
unsigned int i;
for (i = 0 ; i < iter->data_size ; i += iter->interval) {
struct t10_pi_tuple *pi = iter->prot_buf;
pi->guard_tag = fn(iter->data_buf, iter->interval);
pi->app_tag = 0;
if (type == T10_PI_TYPE1_PROTECTION)
pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
else
pi->ref_tag = 0;
iter->data_buf += iter->interval;
iter->prot_buf += sizeof(struct t10_pi_tuple);
iter->seed++;
}
return BLK_STS_OK;
}
static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
csum_fn *fn, enum t10_dif_type type)
{
unsigned int i;
BUG_ON(type == T10_PI_TYPE0_PROTECTION);
for (i = 0 ; i < iter->data_size ; i += iter->interval) {
struct t10_pi_tuple *pi = iter->prot_buf;
__be16 csum;
if (type == T10_PI_TYPE1_PROTECTION ||
type == T10_PI_TYPE2_PROTECTION) {
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 (type == T10_PI_TYPE3_PROTECTION) {
if (pi->app_tag == T10_PI_APP_ESCAPE &&
pi->ref_tag == T10_PI_REF_ESCAPE)
goto next;
}
csum = fn(iter->data_buf, iter->interval);
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 += sizeof(struct t10_pi_tuple);
iter->seed++;
}
return BLK_STS_OK;
}
static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
{
return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
}
static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
{
return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
}
static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
{
return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
}
static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
{
return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
}
/**
* 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)
{
const int tuple_sz = rq->q->integrity.tuple_size;
u32 ref_tag = t10_pi_ref_tag(rq);
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) {
void *p, *pmap;
unsigned int j;
pmap = kmap_atomic(iv.bv_page);
p = pmap + iv.bv_offset;
for (j = 0; j < iv.bv_len; j += tuple_sz) {
struct t10_pi_tuple *pi = p;
if (be32_to_cpu(pi->ref_tag) == virt)
pi->ref_tag = cpu_to_be32(ref_tag);
virt++;
ref_tag++;
p += tuple_sz;
}
kunmap_atomic(pmap);
}
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)
{
unsigned intervals = nr_bytes >> rq->q->integrity.interval_exp;
const int tuple_sz = rq->q->integrity.tuple_size;
u32 ref_tag = t10_pi_ref_tag(rq);
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) {
void *p, *pmap;
unsigned int j;
pmap = kmap_atomic(iv.bv_page);
p = pmap + iv.bv_offset;
for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
struct t10_pi_tuple *pi = p;
if (be32_to_cpu(pi->ref_tag) == ref_tag)
pi->ref_tag = cpu_to_be32(virt);
virt++;
ref_tag++;
intervals--;
p += tuple_sz;
}
kunmap_atomic(pmap);
}
}
}
static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
{
return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
}
static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
{
return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
}
static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
{
return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
}
static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
{
return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
}
/* Type 3 does not have a reference tag so no remapping is required. */
static void t10_pi_type3_prepare(struct request *rq)
{
}
/* Type 3 does not have a reference tag so no remapping is required. */
static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
{
}
const struct blk_integrity_profile t10_pi_type1_crc = {
.name = "T10-DIF-TYPE1-CRC",
.generate_fn = t10_pi_type1_generate_crc,
.verify_fn = t10_pi_type1_verify_crc,
.prepare_fn = t10_pi_type1_prepare,
.complete_fn = t10_pi_type1_complete,
};
EXPORT_SYMBOL(t10_pi_type1_crc);
const struct blk_integrity_profile t10_pi_type1_ip = {
.name = "T10-DIF-TYPE1-IP",
.generate_fn = t10_pi_type1_generate_ip,
.verify_fn = t10_pi_type1_verify_ip,
.prepare_fn = t10_pi_type1_prepare,
.complete_fn = t10_pi_type1_complete,
};
EXPORT_SYMBOL(t10_pi_type1_ip);
const struct blk_integrity_profile t10_pi_type3_crc = {
.name = "T10-DIF-TYPE3-CRC",
.generate_fn = t10_pi_type3_generate_crc,
.verify_fn = t10_pi_type3_verify_crc,
.prepare_fn = t10_pi_type3_prepare,
.complete_fn = t10_pi_type3_complete,
};
EXPORT_SYMBOL(t10_pi_type3_crc);
const struct blk_integrity_profile t10_pi_type3_ip = {
.name = "T10-DIF-TYPE3-IP",
.generate_fn = t10_pi_type3_generate_ip,
.verify_fn = t10_pi_type3_verify_ip,
.prepare_fn = t10_pi_type3_prepare,
.complete_fn = t10_pi_type3_complete,
};
EXPORT_SYMBOL(t10_pi_type3_ip);
MODULE_LICENSE("GPL");