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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
2 * Cryptographic scatter and gather helpers.
3 *
4 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
5 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
6 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
7 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16#ifndef _CRYPTO_SCATTERWALK_H
17#define _CRYPTO_SCATTERWALK_H
18
19#include <crypto/algapi.h>
20#include <linux/highmem.h>
21#include <linux/kernel.h>
22#include <linux/scatterlist.h>
23
24static inline void scatterwalk_crypto_chain(struct scatterlist *head,
25 struct scatterlist *sg,
26 int chain, int num)
27{
28 if (chain) {
29 head->length += sg->length;
30 sg = sg_next(sg);
31 }
32
33 if (sg)
34 sg_chain(head, num, sg);
35 else
36 sg_mark_end(head);
37}
38
39static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
40 struct scatter_walk *walk_out)
41{
42 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
43 (int)(walk_in->offset - walk_out->offset));
44}
45
46static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
47{
48 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
49 unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
50 return len_this_page > len ? len : len_this_page;
51}
52
53static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
54 unsigned int nbytes)
55{
56 unsigned int len_this_page = scatterwalk_pagelen(walk);
57 return nbytes > len_this_page ? len_this_page : nbytes;
58}
59
60static inline void scatterwalk_advance(struct scatter_walk *walk,
61 unsigned int nbytes)
62{
63 walk->offset += nbytes;
64}
65
66static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
67 unsigned int alignmask)
68{
69 return !(walk->offset & alignmask);
70}
71
72static inline struct page *scatterwalk_page(struct scatter_walk *walk)
73{
74 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
75}
76
77static inline void scatterwalk_unmap(void *vaddr)
78{
79 kunmap_atomic(vaddr);
80}
81
82static inline void scatterwalk_start(struct scatter_walk *walk,
83 struct scatterlist *sg)
84{
85 walk->sg = sg;
86 walk->offset = sg->offset;
87}
88
89static inline void *scatterwalk_map(struct scatter_walk *walk)
90{
91 return kmap_atomic(scatterwalk_page(walk)) +
92 offset_in_page(walk->offset);
93}
94
95static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
96 unsigned int more)
97{
98 if (out) {
99 struct page *page;
100
101 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
102 /* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
103 * PageSlab cannot be optimised away per se due to
104 * use of volatile pointer.
105 */
106 if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
107 flush_dcache_page(page);
108 }
109
110 if (more && walk->offset >= walk->sg->offset + walk->sg->length)
111 scatterwalk_start(walk, sg_next(walk->sg));
112}
113
114static inline void scatterwalk_done(struct scatter_walk *walk, int out,
115 int more)
116{
117 if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
118 !(walk->offset & (PAGE_SIZE - 1)))
119 scatterwalk_pagedone(walk, out, more);
120}
121
122void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
123 size_t nbytes, int out);
124void *scatterwalk_map(struct scatter_walk *walk);
125
126void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
127 unsigned int start, unsigned int nbytes, int out);
128
129struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
130 struct scatterlist *src,
131 unsigned int len);
132
133#endif /* _CRYPTO_SCATTERWALK_H */