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Linux kernel mirror (for testing)
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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 <asm/kmap_types.h>
20#include <crypto/algapi.h>
21#include <linux/hardirq.h>
22#include <linux/highmem.h>
23#include <linux/kernel.h>
24#include <linux/mm.h>
25#include <linux/scatterlist.h>
26#include <linux/sched.h>
27
28static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
29 struct scatterlist *sg2)
30{
31 sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
32 sg1[num - 1].page_link &= ~0x02;
33 sg1[num - 1].page_link |= 0x01;
34}
35
36static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
37{
38 if (sg_is_last(sg))
39 return NULL;
40
41 return (++sg)->length ? sg : sg_chain_ptr(sg);
42}
43
44static inline void scatterwalk_crypto_chain(struct scatterlist *head,
45 struct scatterlist *sg,
46 int chain, int num)
47{
48 if (chain) {
49 head->length += sg->length;
50 sg = scatterwalk_sg_next(sg);
51 }
52
53 if (sg)
54 scatterwalk_sg_chain(head, num, sg);
55 else
56 sg_mark_end(head);
57}
58
59static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
60 struct scatter_walk *walk_out)
61{
62 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
63 (int)(walk_in->offset - walk_out->offset));
64}
65
66static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
67{
68 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
69 unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
70 return len_this_page > len ? len : len_this_page;
71}
72
73static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
74 unsigned int nbytes)
75{
76 unsigned int len_this_page = scatterwalk_pagelen(walk);
77 return nbytes > len_this_page ? len_this_page : nbytes;
78}
79
80static inline void scatterwalk_advance(struct scatter_walk *walk,
81 unsigned int nbytes)
82{
83 walk->offset += nbytes;
84}
85
86static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
87 unsigned int alignmask)
88{
89 return !(walk->offset & alignmask);
90}
91
92static inline struct page *scatterwalk_page(struct scatter_walk *walk)
93{
94 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
95}
96
97static inline void scatterwalk_unmap(void *vaddr)
98{
99 kunmap_atomic(vaddr);
100}
101
102void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
103void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
104 size_t nbytes, int out);
105void *scatterwalk_map(struct scatter_walk *walk);
106void scatterwalk_done(struct scatter_walk *walk, int out, int more);
107
108void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
109 unsigned int start, unsigned int nbytes, int out);
110
111int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes);
112
113#endif /* _CRYPTO_SCATTERWALK_H */