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1da177e4 LT |
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 | */ | |
42c271c6 HX |
16 | |
17 | #include <crypto/scatterwalk.h> | |
1da177e4 LT |
18 | #include <linux/kernel.h> |
19 | #include <linux/mm.h> | |
5c64097a | 20 | #include <linux/module.h> |
1da177e4 LT |
21 | #include <linux/pagemap.h> |
22 | #include <linux/highmem.h> | |
5c64097a HX |
23 | #include <linux/scatterlist.h> |
24 | ||
5c64097a | 25 | static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) |
1da177e4 | 26 | { |
5c64097a HX |
27 | void *src = out ? buf : sgdata; |
28 | void *dst = out ? sgdata : buf; | |
29 | ||
30 | memcpy(dst, src, nbytes); | |
1da177e4 LT |
31 | } |
32 | ||
33 | void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) | |
34 | { | |
1da177e4 LT |
35 | walk->sg = sg; |
36 | ||
1da177e4 LT |
37 | BUG_ON(!sg->length); |
38 | ||
1da177e4 LT |
39 | walk->offset = sg->offset; |
40 | } | |
5c64097a | 41 | EXPORT_SYMBOL_GPL(scatterwalk_start); |
1da177e4 | 42 | |
f0dfc0b0 | 43 | void *scatterwalk_map(struct scatter_walk *walk) |
1da177e4 | 44 | { |
f0dfc0b0 | 45 | return kmap_atomic(scatterwalk_page(walk)) + |
5c64097a | 46 | offset_in_page(walk->offset); |
1da177e4 | 47 | } |
5c64097a | 48 | EXPORT_SYMBOL_GPL(scatterwalk_map); |
1da177e4 LT |
49 | |
50 | static void scatterwalk_pagedone(struct scatter_walk *walk, int out, | |
51 | unsigned int more) | |
52 | { | |
9f116727 HX |
53 | if (out) { |
54 | struct page *page; | |
55 | ||
78c2f0b8 | 56 | page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT); |
4f3e797a HX |
57 | if (!PageSlab(page)) |
58 | flush_dcache_page(page); | |
9f116727 | 59 | } |
1da177e4 LT |
60 | |
61 | if (more) { | |
5c64097a HX |
62 | walk->offset += PAGE_SIZE - 1; |
63 | walk->offset &= PAGE_MASK; | |
64 | if (walk->offset >= walk->sg->offset + walk->sg->length) | |
b2ab4a57 | 65 | scatterwalk_start(walk, scatterwalk_sg_next(walk->sg)); |
1da177e4 LT |
66 | } |
67 | } | |
68 | ||
69 | void scatterwalk_done(struct scatter_walk *walk, int out, int more) | |
70 | { | |
801b100b HX |
71 | if (!more || walk->offset >= walk->sg->offset + walk->sg->length || |
72 | !(walk->offset & (PAGE_SIZE - 1))) | |
1da177e4 LT |
73 | scatterwalk_pagedone(walk, out, more); |
74 | } | |
5c64097a | 75 | EXPORT_SYMBOL_GPL(scatterwalk_done); |
1da177e4 | 76 | |
5c64097a HX |
77 | void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, |
78 | size_t nbytes, int out) | |
1da177e4 | 79 | { |
5c64097a HX |
80 | for (;;) { |
81 | unsigned int len_this_page = scatterwalk_pagelen(walk); | |
82 | u8 *vaddr; | |
83 | ||
84 | if (len_this_page > nbytes) | |
85 | len_this_page = nbytes; | |
86 | ||
f0dfc0b0 | 87 | vaddr = scatterwalk_map(walk); |
5c64097a | 88 | memcpy_dir(buf, vaddr, len_this_page, out); |
f0dfc0b0 | 89 | scatterwalk_unmap(vaddr); |
5c64097a | 90 | |
4ee531a3 | 91 | scatterwalk_advance(walk, len_this_page); |
f70ee5ec | 92 | |
5c64097a HX |
93 | if (nbytes == len_this_page) |
94 | break; | |
95 | ||
96 | buf += len_this_page; | |
97 | nbytes -= len_this_page; | |
1da177e4 | 98 | |
1da177e4 | 99 | scatterwalk_pagedone(walk, out, 1); |
c774e93e | 100 | } |
1da177e4 | 101 | } |
5c64097a | 102 | EXPORT_SYMBOL_GPL(scatterwalk_copychunks); |
5fa0fea2 HX |
103 | |
104 | void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, | |
105 | unsigned int start, unsigned int nbytes, int out) | |
106 | { | |
107 | struct scatter_walk walk; | |
108 | unsigned int offset = 0; | |
109 | ||
6e050778 HX |
110 | if (!nbytes) |
111 | return; | |
112 | ||
5fa0fea2 HX |
113 | for (;;) { |
114 | scatterwalk_start(&walk, sg); | |
115 | ||
116 | if (start < offset + sg->length) | |
117 | break; | |
118 | ||
119 | offset += sg->length; | |
b2ab4a57 | 120 | sg = scatterwalk_sg_next(sg); |
5fa0fea2 HX |
121 | } |
122 | ||
123 | scatterwalk_advance(&walk, start - offset); | |
124 | scatterwalk_copychunks(buf, &walk, nbytes, out); | |
125 | scatterwalk_done(&walk, out, 0); | |
126 | } | |
127 | EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); |