Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/crypto/scatterwalk.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 2898 byte(s)
Tag kernel26-2.6.12-alx-r9
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> |
20 | #include <asm/bug.h> |
21 | #include <asm/scatterlist.h> |
22 | #include "internal.h" |
23 | #include "scatterwalk.h" |
24 | |
25 | enum km_type crypto_km_types[] = { |
26 | KM_USER0, |
27 | KM_USER1, |
28 | KM_SOFTIRQ0, |
29 | KM_SOFTIRQ1, |
30 | }; |
31 | |
32 | static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) |
33 | { |
34 | if (out) |
35 | memcpy(sgdata, buf, nbytes); |
36 | else |
37 | memcpy(buf, sgdata, nbytes); |
38 | } |
39 | |
40 | void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) |
41 | { |
42 | unsigned int rest_of_page; |
43 | |
44 | walk->sg = sg; |
45 | |
46 | walk->page = sg->page; |
47 | walk->len_this_segment = sg->length; |
48 | |
49 | BUG_ON(!sg->length); |
50 | |
51 | rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1)); |
52 | walk->len_this_page = min(sg->length, rest_of_page); |
53 | walk->offset = sg->offset; |
54 | } |
55 | |
56 | void scatterwalk_map(struct scatter_walk *walk, int out) |
57 | { |
58 | walk->data = crypto_kmap(walk->page, out) + walk->offset; |
59 | } |
60 | |
61 | static inline void scatterwalk_unmap(struct scatter_walk *walk, int out) |
62 | { |
63 | /* walk->data may be pointing the first byte of the next page; |
64 | however, we know we transfered at least one byte. So, |
65 | walk->data - 1 will be a virtual address in the mapped page. */ |
66 | crypto_kunmap(walk->data - 1, out); |
67 | } |
68 | |
69 | static void scatterwalk_pagedone(struct scatter_walk *walk, int out, |
70 | unsigned int more) |
71 | { |
72 | if (out) |
73 | flush_dcache_page(walk->page); |
74 | |
75 | if (more) { |
76 | walk->len_this_segment -= walk->len_this_page; |
77 | |
78 | if (walk->len_this_segment) { |
79 | walk->page++; |
80 | walk->len_this_page = min(walk->len_this_segment, |
81 | (unsigned)PAGE_CACHE_SIZE); |
82 | walk->offset = 0; |
83 | } |
84 | else |
85 | scatterwalk_start(walk, sg_next(walk->sg)); |
86 | } |
87 | } |
88 | |
89 | void scatterwalk_done(struct scatter_walk *walk, int out, int more) |
90 | { |
91 | scatterwalk_unmap(walk, out); |
92 | if (walk->len_this_page == 0 || !more) |
93 | scatterwalk_pagedone(walk, out, more); |
94 | } |
95 | |
96 | /* |
97 | * Do not call this unless the total length of all of the fragments |
98 | * has been verified as multiple of the block size. |
99 | */ |
100 | int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, |
101 | size_t nbytes, int out) |
102 | { |
103 | do { |
104 | memcpy_dir(buf, walk->data, walk->len_this_page, out); |
105 | buf += walk->len_this_page; |
106 | nbytes -= walk->len_this_page; |
107 | |
108 | scatterwalk_unmap(walk, out); |
109 | scatterwalk_pagedone(walk, out, 1); |
110 | scatterwalk_map(walk, out); |
111 | } while (nbytes > walk->len_this_page); |
112 | |
113 | memcpy_dir(buf, walk->data, nbytes, out); |
114 | return nbytes; |
115 | } |