Subversion Repositories test_project

/*

 * Cryptographic API.

 *

 * Cipher operations.

 *

 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>

 *               2002 Adam J. Richter <adam@yggdrasil.com>

 *               2004 Jean-Luc Cooke <jlcooke@certainkey.com>

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the Free

 * Software Foundation; either version 2 of the License, or (at your option)

 * any later version.

 *

 */

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/module.h>

#include <linux/pagemap.h>

#include <linux/highmem.h>

#include <linux/scatterlist.h>

#include "internal.h"

#include "scatterwalk.h"

static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)

{

        void *src = out ? buf : sgdata;

        void *dst = out ? sgdata : buf;

        memcpy(dst, src, nbytes);

}

void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)

{

        walk->sg = sg;

        BUG_ON(!sg->length);

        walk->offset = sg->offset;

}

EXPORT_SYMBOL_GPL(scatterwalk_start);

void *scatterwalk_map(struct scatter_walk *walk, int out)

{

        return crypto_kmap(scatterwalk_page(walk), out) +

               offset_in_page(walk->offset);

}

EXPORT_SYMBOL_GPL(scatterwalk_map);

static void scatterwalk_pagedone(struct scatter_walk *walk, int out,

                                 unsigned int more)

{

        if (out) {

                struct page *page;

                page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);

                flush_dcache_page(page);

        }

        if (more) {

                walk->offset += PAGE_SIZE - 1;

                walk->offset &= PAGE_MASK;

                if (walk->offset >= walk->sg->offset + walk->sg->length)

                        scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));

        }

}

void scatterwalk_done(struct scatter_walk *walk, int out, int more)

{

        if (!offset_in_page(walk->offset) || !more)

                scatterwalk_pagedone(walk, out, more);

}

EXPORT_SYMBOL_GPL(scatterwalk_done);

void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,

                            size_t nbytes, int out)

{

        for (;;) {

                unsigned int len_this_page = scatterwalk_pagelen(walk);

                u8 *vaddr;

                if (len_this_page > nbytes)

                        len_this_page = nbytes;

                vaddr = scatterwalk_map(walk, out);

                memcpy_dir(buf, vaddr, len_this_page, out);

                scatterwalk_unmap(vaddr, out);

                scatterwalk_advance(walk, len_this_page);

                if (nbytes == len_this_page)

                        break;

                buf += len_this_page;

                nbytes -= len_this_page;

                scatterwalk_pagedone(walk, out, 1);

        }

}

EXPORT_SYMBOL_GPL(scatterwalk_copychunks);

void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,

                              unsigned int start, unsigned int nbytes, int out)

{

        struct scatter_walk walk;

        unsigned int offset = 0;

        for (;;) {

                scatterwalk_start(&walk, sg);

                if (start < offset + sg->length)

                        break;

                offset += sg->length;

                sg = sg_next(sg);

        }

        scatterwalk_advance(&walk, start - offset);

        scatterwalk_copychunks(buf, &walk, nbytes, out);

        scatterwalk_done(&walk, out, 0);

}

EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);