linux-imx

/*

 * blk-integrity.c - Block layer data integrity extensions

 *

 * Copyright (C) 2007, 2008 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/blkdev.h>

#include <linux/backing-dev.h>

#include <linux/mempool.h>

#include <linux/bio.h>

#include <linux/scatterlist.h>

#include <linux/export.h>

#include <linux/slab.h>

​

#include "blk.h"

​

/**

 * blk_rq_count_integrity_sg - Count number of integrity scatterlist elements

 * @q:      request queue

 * @bio:    bio with integrity metadata attached

 *

 * Description: Returns the number of elements required in a

 * scatterlist corresponding to the integrity metadata in a bio.

 */

int blk_rq_count_integrity_sg(struct request_queue *q, struct bio *bio)

{

    struct bio_vec iv, ivprv = { NULL };

    unsigned int segments = 0;

    unsigned int seg_size = 0;

    struct bvec_iter iter;

    int prev = 0;

​

    bio_for_each_integrity_vec(iv, bio, iter) {

​

        if (prev) {

            if (!biovec_phys_mergeable(q, &ivprv, &iv))

                goto new_segment;

            if (seg_size + iv.bv_len > queue_max_segment_size(q))

                goto new_segment;

​

            seg_size += iv.bv_len;

        } else {

new_segment:

            segments++;

            seg_size = iv.bv_len;

        }

​

        prev = 1;

        ivprv = iv;

    }

​

    return segments;

}

EXPORT_SYMBOL(blk_rq_count_integrity_sg);

​

/**

 * blk_rq_map_integrity_sg - Map integrity metadata into a scatterlist

 * @q:      request queue

 * @bio:    bio with integrity metadata attached

 * @sglist: target scatterlist

 *

 * Description: Map the integrity vectors in request into a

 * scatterlist.  The scatterlist must be big enough to hold all

 * elements.  I.e. sized using blk_rq_count_integrity_sg().

 */

int blk_rq_map_integrity_sg(struct request_queue *q, struct bio *bio,

                struct scatterlist *sglist)

{

    struct bio_vec iv, ivprv = { NULL };

    struct scatterlist *sg = NULL;

    unsigned int segments = 0;

    struct bvec_iter iter;

    int prev = 0;

​

    bio_for_each_integrity_vec(iv, bio, iter) {

​