tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/pagemap.h>
22#include <linux/highmem.h>
23#include <linux/scatterlist.h>
24
25static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
26{
27 void *src = out ? buf : sgdata;
28 void *dst = out ? sgdata : buf;
29
30 memcpy(dst, src, nbytes);
31}
32
33void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
34{
35 walk->sg = sg;
36
37 BUG_ON(!sg->length);
38
39 walk->offset = sg->offset;
40}
41EXPORT_SYMBOL_GPL(scatterwalk_start);
42
43void *scatterwalk_map(struct scatter_walk *walk, int out)
44{
45 return crypto_kmap(scatterwalk_page(walk), out) +
46 offset_in_page(walk->offset);
47}
48EXPORT_SYMBOL_GPL(scatterwalk_map);
49
50static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
51 unsigned int more)
52{
53 if (out) {
54 struct page *page;
55
56 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
57 flush_dcache_page(page);
58 }
59
60 if (more) {
61 walk->offset += PAGE_SIZE - 1;
62 walk->offset &= PAGE_MASK;
63 if (walk->offset >= walk->sg->offset + walk->sg->length)
64 scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));
65 }
66}
67
68void scatterwalk_done(struct scatter_walk *walk, int out, int more)
69{
70 if (!offset_in_page(walk->offset) || !more)
71 scatterwalk_pagedone(walk, out, more);
72}
73EXPORT_SYMBOL_GPL(scatterwalk_done);
74
75void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
76 size_t nbytes, int out)
77{
78 for (;;) {
79 unsigned int len_this_page = scatterwalk_pagelen(walk);
80 u8 *vaddr;
81
82 if (len_this_page > nbytes)
83 len_this_page = nbytes;
84
85 vaddr = scatterwalk_map(walk, out);
86 memcpy_dir(buf, vaddr, len_this_page, out);
87 scatterwalk_unmap(vaddr, out);
88
89 scatterwalk_advance(walk, len_this_page);
90
91 if (nbytes == len_this_page)
92 break;
93
94 buf += len_this_page;
95 nbytes -= len_this_page;
96
97 scatterwalk_pagedone(walk, out, 1);
98 }
99}
100EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
101
102void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
103 unsigned int start, unsigned int nbytes, int out)
104{
105 struct scatter_walk walk;
106 unsigned int offset = 0;
107
108 if (!nbytes)
109 return;
110
111 for (;;) {
112 scatterwalk_start(&walk, sg);
113
114 if (start < offset + sg->length)
115 break;
116
117 offset += sg->length;
118 sg = scatterwalk_sg_next(sg);
119 }
120
121 scatterwalk_advance(&walk, start - offset);
122 scatterwalk_copychunks(buf, &walk, nbytes, out);
123 scatterwalk_done(&walk, out, 0);
124}
125EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);