linux/block/t10-pi.c
Alexey Dobriyan a28dc358e2 block: constify ext_pi_ref_escape()
This function doesn't mutate data.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/d24611b3-dddf-473a-903d-39290db03b11@p183
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-08-13 06:20:02 -06:00

474 lines
12 KiB
C

// 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 <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(const u8 ref_tag[6])
{
static const 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);
}