124 строки
2.9 KiB
C
124 строки
2.9 KiB
C
/*
|
|
* 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);
|