linux-imx

/*

 * 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 __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 == 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;

            }