Commit | Line | Data |
---|---|---|
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 | */ | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/highmem.h> | |
1da177e4 LT |
20 | #include <asm/scatterlist.h> |
21 | #include "internal.h" | |
22 | #include "scatterwalk.h" | |
23 | ||
24 | enum km_type crypto_km_types[] = { | |
25 | KM_USER0, | |
26 | KM_USER1, | |
27 | KM_SOFTIRQ0, | |
28 | KM_SOFTIRQ1, | |
29 | }; | |
30 | ||
31 | static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) | |
32 | { | |
33 | if (out) | |
34 | memcpy(sgdata, buf, nbytes); | |
35 | else | |
36 | memcpy(buf, sgdata, nbytes); | |
37 | } | |
38 | ||
39 | void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) | |
40 | { | |
41 | unsigned int rest_of_page; | |
42 | ||
43 | walk->sg = sg; | |
44 | ||
45 | walk->page = sg->page; | |
46 | walk->len_this_segment = sg->length; | |
47 | ||
48 | BUG_ON(!sg->length); | |
49 | ||
50 | rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1)); | |
51 | walk->len_this_page = min(sg->length, rest_of_page); | |
52 | walk->offset = sg->offset; | |
53 | } | |
54 | ||
55 | void scatterwalk_map(struct scatter_walk *walk, int out) | |
56 | { | |
57 | walk->data = crypto_kmap(walk->page, out) + walk->offset; | |
58 | } | |
59 | ||
60 | static inline void scatterwalk_unmap(struct scatter_walk *walk, int out) | |
61 | { | |
62 | /* walk->data may be pointing the first byte of the next page; | |
63 | however, we know we transfered at least one byte. So, | |
64 | walk->data - 1 will be a virtual address in the mapped page. */ | |
65 | crypto_kunmap(walk->data - 1, out); | |
66 | } | |
67 | ||
68 | static void scatterwalk_pagedone(struct scatter_walk *walk, int out, | |
69 | unsigned int more) | |
70 | { | |
71 | if (out) | |
72 | flush_dcache_page(walk->page); | |
73 | ||
74 | if (more) { | |
75 | walk->len_this_segment -= walk->len_this_page; | |
76 | ||
77 | if (walk->len_this_segment) { | |
78 | walk->page++; | |
79 | walk->len_this_page = min(walk->len_this_segment, | |
80 | (unsigned)PAGE_CACHE_SIZE); | |
81 | walk->offset = 0; | |
82 | } | |
83 | else | |
84 | scatterwalk_start(walk, sg_next(walk->sg)); | |
85 | } | |
86 | } | |
87 | ||
88 | void scatterwalk_done(struct scatter_walk *walk, int out, int more) | |
89 | { | |
90 | scatterwalk_unmap(walk, out); | |
91 | if (walk->len_this_page == 0 || !more) | |
92 | scatterwalk_pagedone(walk, out, more); | |
93 | } | |
94 | ||
95 | /* | |
96 | * Do not call this unless the total length of all of the fragments | |
97 | * has been verified as multiple of the block size. | |
98 | */ | |
99 | int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, | |
100 | size_t nbytes, int out) | |
101 | { | |
c774e93e | 102 | while (nbytes > walk->len_this_page) { |
1da177e4 LT |
103 | memcpy_dir(buf, walk->data, walk->len_this_page, out); |
104 | buf += walk->len_this_page; | |
105 | nbytes -= walk->len_this_page; | |
106 | ||
107 | scatterwalk_unmap(walk, out); | |
108 | scatterwalk_pagedone(walk, out, 1); | |
109 | scatterwalk_map(walk, out); | |
c774e93e | 110 | } |
1da177e4 LT |
111 | |
112 | memcpy_dir(buf, walk->data, nbytes, out); | |
113 | return nbytes; | |
114 | } |