1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Cryptographic API.
 4 *
 5 * Cipher operations.
 6 *
 7 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 8 *               2002 Adam J. Richter <adam@yggdrasil.com>
 9 *               2004 Jean-Luc Cooke <jlcooke@certainkey.com>
 
 
 
 
 
 
10 */
11
12#include <crypto/scatterwalk.h>
13#include <linux/kernel.h>
14#include <linux/mm.h>
15#include <linux/module.h>
16#include <linux/scatterlist.h>
17
18static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
19{
20	void *src = out ? buf : sgdata;
21	void *dst = out ? sgdata : buf;
22
23	memcpy(dst, src, nbytes);
24}
25
26void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
27			    size_t nbytes, int out)
28{
29	for (;;) {
30		unsigned int len_this_page = scatterwalk_pagelen(walk);
31		u8 *vaddr;
32
33		if (len_this_page > nbytes)
34			len_this_page = nbytes;
35
36		if (out != 2) {
37			vaddr = scatterwalk_map(walk);
38			memcpy_dir(buf, vaddr, len_this_page, out);
39			scatterwalk_unmap(vaddr);
40		}
41
42		scatterwalk_advance(walk, len_this_page);
43
44		if (nbytes == len_this_page)
45			break;
46
47		buf += len_this_page;
48		nbytes -= len_this_page;
49
50		scatterwalk_pagedone(walk, out & 1, 1);
51	}
52}
53EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
54
55void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
56			      unsigned int start, unsigned int nbytes, int out)
57{
58	struct scatter_walk walk;
59	struct scatterlist tmp[2];
60
61	if (!nbytes)
62		return;
63
64	sg = scatterwalk_ffwd(tmp, sg, start);
65
66	scatterwalk_start(&walk, sg);
67	scatterwalk_copychunks(buf, &walk, nbytes, out);
68	scatterwalk_done(&walk, out, 0);
69}
70EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
71
72struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
73				     struct scatterlist *src,
74				     unsigned int len)
75{
76	for (;;) {
77		if (!len)
78			return src;
79
80		if (src->length > len)
81			break;
82
83		len -= src->length;
84		src = sg_next(src);
85	}
86
87	sg_init_table(dst, 2);
88	sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
89	scatterwalk_crypto_chain(dst, sg_next(src), 2);
90
91	return dst;
92}
93EXPORT_SYMBOL_GPL(scatterwalk_ffwd);

 
 1/*
 2 * Cryptographic API.
 3 *
 4 * Cipher operations.
 5 *
 6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 7 *               2002 Adam J. Richter <adam@yggdrasil.com>
 8 *               2004 Jean-Luc Cooke <jlcooke@certainkey.com>
 9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the Free
12 * Software Foundation; either version 2 of the License, or (at your option)
13 * any later version.
14 *
15 */
16
17#include <crypto/scatterwalk.h>
18#include <linux/kernel.h>
19#include <linux/mm.h>
20#include <linux/module.h>
21#include <linux/scatterlist.h>
22
23static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
24{
25	void *src = out ? buf : sgdata;
26	void *dst = out ? sgdata : buf;
27
28	memcpy(dst, src, nbytes);
29}
30
31void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
32			    size_t nbytes, int out)
33{
34	for (;;) {
35		unsigned int len_this_page = scatterwalk_pagelen(walk);
36		u8 *vaddr;
37
38		if (len_this_page > nbytes)
39			len_this_page = nbytes;
40
41		if (out != 2) {
42			vaddr = scatterwalk_map(walk);
43			memcpy_dir(buf, vaddr, len_this_page, out);
44			scatterwalk_unmap(vaddr);
45		}
46
47		scatterwalk_advance(walk, len_this_page);
48
49		if (nbytes == len_this_page)
50			break;
51
52		buf += len_this_page;
53		nbytes -= len_this_page;
54
55		scatterwalk_pagedone(walk, out & 1, 1);
56	}
57}
58EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
59
60void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
61			      unsigned int start, unsigned int nbytes, int out)
62{
63	struct scatter_walk walk;
64	struct scatterlist tmp[2];
65
66	if (!nbytes)
67		return;
68
69	sg = scatterwalk_ffwd(tmp, sg, start);
70
71	scatterwalk_start(&walk, sg);
72	scatterwalk_copychunks(buf, &walk, nbytes, out);
73	scatterwalk_done(&walk, out, 0);
74}
75EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
76
77struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
78				     struct scatterlist *src,
79				     unsigned int len)
80{
81	for (;;) {
82		if (!len)
83			return src;
84
85		if (src->length > len)
86			break;
87
88		len -= src->length;
89		src = sg_next(src);
90	}
91
92	sg_init_table(dst, 2);
93	sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
94	scatterwalk_crypto_chain(dst, sg_next(src), 0, 2);
95
96	return dst;
97}
98EXPORT_SYMBOL_GPL(scatterwalk_ffwd);