[mirror_ubuntu-artful-kernel.git] / block / t10-pi.c

/*
 * t10_pi.c - Functions for generating and verifying T10 Protection
 *	      Information.
 *
 * Copyright (C) 2007, 2008, 2014 Oracle Corporation
 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA.
 *
 */

#include <linux/t10-pi.h>
#include <linux/blkdev.h>
#include <linux/crc-t10dif.h>
#include <net/checksum.h>

typedef __be16 (csum_fn) (void *, unsigned int);

static const __be16 APP_ESCAPE = (__force __be16) 0xffff;
static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff;

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, unsigned int 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 == 1)
			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, unsigned int type)
{
	unsigned int i;

	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
		struct t10_pi_tuple *pi = iter->prot_buf;
		__be16 csum;

		switch (type) {
		case 1:
		case 2:
			if (pi->app_tag == 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;
			}
			break;
		case 3:
			if (pi->app_tag == APP_ESCAPE &&
			    pi->ref_tag == REF_ESCAPE)
				goto next;
			break;
		}

		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, 1);
}

static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_ip_fn, 1);
}

static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_crc_fn, 1);
}

static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_ip_fn, 1);
}

static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_crc_fn, 3);
}

static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_ip_fn, 3);
}

static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_crc_fn, 3);
}

static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_ip_fn, 3);
}

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,
};
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,
};
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,
};
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,
};
EXPORT_SYMBOL(t10_pi_type3_ip);
Commit	Line	Data
2341c2f8 MP	1	/*
	2	* t10_pi.c - Functions for generating and verifying T10 Protection
	3	* Information.
	4	*
	5	* Copyright (C) 2007, 2008, 2014 Oracle Corporation
	6	* Written by: Martin K. Petersen <martin.petersen@oracle.com>
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License version
	10	* 2 as published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful, but
	13	* WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; see the file COPYING. If not, write to
	19	* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
	20	* USA.
	21	*
	22	*/
	23
	24	#include <linux/t10-pi.h>
	25	#include <linux/blkdev.h>
	26	#include <linux/crc-t10dif.h>
	27	#include <net/checksum.h>
	28
	29	typedef __be16 (csum_fn) (void *, unsigned int);
	30
	31	static const __be16 APP_ESCAPE = (__force __be16) 0xffff;
	32	static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff;
	33
	34	static __be16 t10_pi_crc_fn(void *data, unsigned int len)
	35	{
	36	return cpu_to_be16(crc_t10dif(data, len));
	37	}
	38
	39	static __be16 t10_pi_ip_fn(void *data, unsigned int len)
	40	{
	41	return (__force __be16)ip_compute_csum(data, len);
	42	}
	43
	44	/*
	45	* Type 1 and Type 2 protection use the same format: 16 bit guard tag,
	46	* 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
	47	* tag.
	48	*/
4e4cbee9 CH	49	static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
4e4cbee9 CH	50	csum_fn *fn, unsigned int type)
2341c2f8 MP	51	{
	52	unsigned int i;
	53
	54	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
	55	struct t10_pi_tuple *pi = iter->prot_buf;
	56
	57	pi->guard_tag = fn(iter->data_buf, iter->interval);
	58	pi->app_tag = 0;
	59
	60	if (type == 1)
	61	pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
	62	else
	63	pi->ref_tag = 0;
	64
	65	iter->data_buf += iter->interval;
	66	iter->prot_buf += sizeof(struct t10_pi_tuple);
	67	iter->seed++;
	68	}
	69
4e4cbee9	70	return BLK_STS_OK;
2341c2f8 MP	71	}
2341c2f8 MP	72
4e4cbee9 CH	73	static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
4e4cbee9 CH	74	csum_fn *fn, unsigned int type)
2341c2f8 MP	75	{
	76	unsigned int i;
	77
	78	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
	79	struct t10_pi_tuple *pi = iter->prot_buf;
	80	__be16 csum;
	81
	82	switch (type) {
	83	case 1:
	84	case 2:
	85	if (pi->app_tag == APP_ESCAPE)
	86	goto next;
	87
	88	if (be32_to_cpu(pi->ref_tag) !=
	89	lower_32_bits(iter->seed)) {
	90	pr_err("%s: ref tag error at location %llu " \
	91	"(rcvd %u)\n", iter->disk_name,
	92	(unsigned long long)
	93	iter->seed, be32_to_cpu(pi->ref_tag));
a462b950	94	return BLK_STS_PROTECTION;
2341c2f8 MP	95	}
	96	break;
	97	case 3:
	98	if (pi->app_tag == APP_ESCAPE &&
	99	pi->ref_tag == REF_ESCAPE)
	100	goto next;
	101	break;
	102	}
	103
	104	csum = fn(iter->data_buf, iter->interval);
	105
	106	if (pi->guard_tag != csum) {
	107	pr_err("%s: guard tag error at sector %llu " \
	108	"(rcvd %04x, want %04x)\n", iter->disk_name,
	109	(unsigned long long)iter->seed,
	110	be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
4e4cbee9	111	return BLK_STS_PROTECTION;
2341c2f8 MP	112	}
	113
	114	next:
	115	iter->data_buf += iter->interval;
	116	iter->prot_buf += sizeof(struct t10_pi_tuple);
	117	iter->seed++;
	118	}
	119
4e4cbee9	120	return BLK_STS_OK;
2341c2f8 MP	121	}
2341c2f8 MP	122
4e4cbee9	123	static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
2341c2f8 MP	124	{
	125	return t10_pi_generate(iter, t10_pi_crc_fn, 1);
	126	}
	127
4e4cbee9	128	static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
2341c2f8 MP	129	{
	130	return t10_pi_generate(iter, t10_pi_ip_fn, 1);
	131	}
	132
4e4cbee9	133	static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
2341c2f8 MP	134	{
	135	return t10_pi_verify(iter, t10_pi_crc_fn, 1);
	136	}
	137
4e4cbee9	138	static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
2341c2f8 MP	139	{
	140	return t10_pi_verify(iter, t10_pi_ip_fn, 1);
	141	}
	142
4e4cbee9	143	static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
2341c2f8 MP	144	{
	145	return t10_pi_generate(iter, t10_pi_crc_fn, 3);
	146	}
	147
4e4cbee9	148	static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
2341c2f8 MP	149	{
	150	return t10_pi_generate(iter, t10_pi_ip_fn, 3);
	151	}
	152
4e4cbee9	153	static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
2341c2f8 MP	154	{
	155	return t10_pi_verify(iter, t10_pi_crc_fn, 3);
	156	}
	157
4e4cbee9	158	static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
2341c2f8 MP	159	{
	160	return t10_pi_verify(iter, t10_pi_ip_fn, 3);
	161	}
	162
869ab90f	163	const struct blk_integrity_profile t10_pi_type1_crc = {
2341c2f8 MP	164	.name = "T10-DIF-TYPE1-CRC",
	165	.generate_fn = t10_pi_type1_generate_crc,
	166	.verify_fn = t10_pi_type1_verify_crc,
2341c2f8 MP	167	};
	168	EXPORT_SYMBOL(t10_pi_type1_crc);
	169
869ab90f	170	const struct blk_integrity_profile t10_pi_type1_ip = {
2341c2f8 MP	171	.name = "T10-DIF-TYPE1-IP",
	172	.generate_fn = t10_pi_type1_generate_ip,
	173	.verify_fn = t10_pi_type1_verify_ip,
2341c2f8 MP	174	};
	175	EXPORT_SYMBOL(t10_pi_type1_ip);
	176
869ab90f	177	const struct blk_integrity_profile t10_pi_type3_crc = {
2341c2f8 MP	178	.name = "T10-DIF-TYPE3-CRC",
	179	.generate_fn = t10_pi_type3_generate_crc,
	180	.verify_fn = t10_pi_type3_verify_crc,
2341c2f8 MP	181	};
	182	EXPORT_SYMBOL(t10_pi_type3_crc);
	183
869ab90f	184	const struct blk_integrity_profile t10_pi_type3_ip = {
2341c2f8 MP	185	.name = "T10-DIF-TYPE3-IP",
	186	.generate_fn = t10_pi_type3_generate_ip,
	187	.verify_fn = t10_pi_type3_verify_ip,
2341c2f8 MP	188	};
2341c2f8 MP	189	EXPORT_SYMBOL(t10_pi_type3_ip);