]>
Commit | Line | Data |
---|---|---|
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 | ||
25 | static 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 | ||
33 | void 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 | } | |
41 | EXPORT_SYMBOL_GPL(scatterwalk_start); | |
42 | ||
43 | void *scatterwalk_map(struct scatter_walk *walk, int out) | |
44 | { | |
45 | return crypto_kmap(scatterwalk_page(walk), out) + | |
46 | offset_in_page(walk->offset); | |
47 | } | |
48 | EXPORT_SYMBOL_GPL(scatterwalk_map); | |
49 | ||
50 | static 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 | if (!PageSlab(page)) | |
58 | flush_dcache_page(page); | |
59 | } | |
60 | ||
61 | if (more) { | |
62 | walk->offset += PAGE_SIZE - 1; | |
63 | walk->offset &= PAGE_MASK; | |
64 | if (walk->offset >= walk->sg->offset + walk->sg->length) | |
65 | scatterwalk_start(walk, scatterwalk_sg_next(walk->sg)); | |
66 | } | |
67 | } | |
68 | ||
69 | void scatterwalk_done(struct scatter_walk *walk, int out, int more) | |
70 | { | |
71 | if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more) | |
72 | scatterwalk_pagedone(walk, out, more); | |
73 | } | |
74 | EXPORT_SYMBOL_GPL(scatterwalk_done); | |
75 | ||
76 | void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, | |
77 | size_t nbytes, int out) | |
78 | { | |
79 | for (;;) { | |
80 | unsigned int len_this_page = scatterwalk_pagelen(walk); | |
81 | u8 *vaddr; | |
82 | ||
83 | if (len_this_page > nbytes) | |
84 | len_this_page = nbytes; | |
85 | ||
86 | vaddr = scatterwalk_map(walk, out); | |
87 | memcpy_dir(buf, vaddr, len_this_page, out); | |
88 | scatterwalk_unmap(vaddr, out); | |
89 | ||
90 | scatterwalk_advance(walk, len_this_page); | |
91 | ||
92 | if (nbytes == len_this_page) | |
93 | break; | |
94 | ||
95 | buf += len_this_page; | |
96 | nbytes -= len_this_page; | |
97 | ||
98 | scatterwalk_pagedone(walk, out, 1); | |
99 | } | |
100 | } | |
101 | EXPORT_SYMBOL_GPL(scatterwalk_copychunks); | |
102 | ||
103 | void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, | |
104 | unsigned int start, unsigned int nbytes, int out) | |
105 | { | |
106 | struct scatter_walk walk; | |
107 | unsigned int offset = 0; | |
108 | ||
109 | if (!nbytes) | |
110 | return; | |
111 | ||
112 | for (;;) { | |
113 | scatterwalk_start(&walk, sg); | |
114 | ||
115 | if (start < offset + sg->length) | |
116 | break; | |
117 | ||
118 | offset += sg->length; | |
119 | sg = scatterwalk_sg_next(sg); | |
120 | } | |
121 | ||
122 | scatterwalk_advance(&walk, start - offset); | |
123 | scatterwalk_copychunks(buf, &walk, nbytes, out); | |
124 | scatterwalk_done(&walk, out, 0); | |
125 | } | |
126 | EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); |