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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*/
#include <crypto/scatterwalk.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes)
{
struct scatterlist *sg = walk->sg;
nbytes += walk->offset - sg->offset;
while (nbytes > sg->length) {
nbytes -= sg->length;
sg = sg_next(sg);
}
walk->sg = sg;
walk->offset = sg->offset + nbytes;
}
EXPORT_SYMBOL_GPL(scatterwalk_skip);
inline void memcpy_from_scatterwalk(void *buf, struct scatter_walk *walk,
unsigned int nbytes)
{
do {
unsigned int to_copy;
to_copy = scatterwalk_next(walk, nbytes);
memcpy(buf, walk->addr, to_copy);
scatterwalk_done_src(walk, to_copy);
buf += to_copy;
nbytes -= to_copy;
} while (nbytes);
}
EXPORT_SYMBOL_GPL(memcpy_from_scatterwalk);
inline void memcpy_to_scatterwalk(struct scatter_walk *walk, const void *buf,
unsigned int nbytes)
{
do {
unsigned int to_copy;
to_copy = scatterwalk_next(walk, nbytes);
memcpy(walk->addr, buf, to_copy);
scatterwalk_done_dst(walk, to_copy);
buf += to_copy;
nbytes -= to_copy;
} while (nbytes);
}
EXPORT_SYMBOL_GPL(memcpy_to_scatterwalk);
void memcpy_from_sglist(void *buf, struct scatterlist *sg,
unsigned int start, unsigned int nbytes)
{
struct scatter_walk walk;
if (unlikely(nbytes == 0)) /* in case sg == NULL */
return;
scatterwalk_start_at_pos(&walk, sg, start);
memcpy_from_scatterwalk(buf, &walk, nbytes);
}
EXPORT_SYMBOL_GPL(memcpy_from_sglist);
void memcpy_to_sglist(struct scatterlist *sg, unsigned int start,
const void *buf, unsigned int nbytes)
{
struct scatter_walk walk;
if (unlikely(nbytes == 0)) /* in case sg == NULL */
return;
scatterwalk_start_at_pos(&walk, sg, start);
memcpy_to_scatterwalk(&walk, buf, nbytes);
}
EXPORT_SYMBOL_GPL(memcpy_to_sglist);
void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct scatter_walk swalk;
struct scatter_walk dwalk;
if (unlikely(nbytes == 0)) /* in case sg == NULL */
return;
scatterwalk_start(&swalk, src);
scatterwalk_start(&dwalk, dst);
do {
unsigned int slen, dlen;
unsigned int len;
slen = scatterwalk_next(&swalk, nbytes);
dlen = scatterwalk_next(&dwalk, nbytes);
len = min(slen, dlen);
memcpy(dwalk.addr, swalk.addr, len);
scatterwalk_done_dst(&dwalk, len);
scatterwalk_done_src(&swalk, len);
nbytes -= len;
} while (nbytes);
}
EXPORT_SYMBOL_GPL(memcpy_sglist);
struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
struct scatterlist *src,
unsigned int len)
{
for (;;) {
if (!len)
return src;
if (src->length > len)
break;
len -= src->length;
src = sg_next(src);
}
sg_init_table(dst, 2);
sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
scatterwalk_crypto_chain(dst, sg_next(src), 2);
return dst;
}
EXPORT_SYMBOL_GPL(scatterwalk_ffwd);
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