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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Cryptographic scatter and gather helpers.
4 *
5 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
6 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
7 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
8 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
9 */
10
11#ifndef _CRYPTO_SCATTERWALK_H
12#define _CRYPTO_SCATTERWALK_H
13
14#include <crypto/algapi.h>
15
16#include <linux/highmem.h>
17#include <linux/mm.h>
18#include <linux/scatterlist.h>
19
20static inline void scatterwalk_crypto_chain(struct scatterlist *head,
21 struct scatterlist *sg, int num)
22{
23 if (sg)
24 sg_chain(head, num, sg);
25 else
26 sg_mark_end(head);
27}
28
29static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
30{
31 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
32 unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
33 return len_this_page > len ? len : len_this_page;
34}
35
36static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
37 unsigned int nbytes)
38{
39 unsigned int len_this_page = scatterwalk_pagelen(walk);
40 return nbytes > len_this_page ? len_this_page : nbytes;
41}
42
43static inline void scatterwalk_advance(struct scatter_walk *walk,
44 unsigned int nbytes)
45{
46 walk->offset += nbytes;
47}
48
49static inline struct page *scatterwalk_page(struct scatter_walk *walk)
50{
51 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
52}
53
54static inline void scatterwalk_unmap(void *vaddr)
55{
56 kunmap_local(vaddr);
57}
58
59static inline void scatterwalk_start(struct scatter_walk *walk,
60 struct scatterlist *sg)
61{
62 walk->sg = sg;
63 walk->offset = sg->offset;
64}
65
66static inline void *scatterwalk_map(struct scatter_walk *walk)
67{
68 return kmap_local_page(scatterwalk_page(walk)) +
69 offset_in_page(walk->offset);
70}
71
72static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
73 unsigned int more)
74{
75 if (out) {
76 struct page *page;
77
78 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
79 flush_dcache_page(page);
80 }
81
82 if (more && walk->offset >= walk->sg->offset + walk->sg->length)
83 scatterwalk_start(walk, sg_next(walk->sg));
84}
85
86static inline void scatterwalk_done(struct scatter_walk *walk, int out,
87 int more)
88{
89 if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
90 !(walk->offset & (PAGE_SIZE - 1)))
91 scatterwalk_pagedone(walk, out, more);
92}
93
94void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
95 size_t nbytes, int out);
96
97void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
98 unsigned int start, unsigned int nbytes, int out);
99
100struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
101 struct scatterlist *src,
102 unsigned int len);
103
104#endif /* _CRYPTO_SCATTERWALK_H */
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Cryptographic scatter and gather helpers.
4 *
5 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
6 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
7 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
8 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
9 */
10
11#ifndef _CRYPTO_SCATTERWALK_H
12#define _CRYPTO_SCATTERWALK_H
13
14#include <crypto/algapi.h>
15#include <linux/highmem.h>
16#include <linux/kernel.h>
17#include <linux/scatterlist.h>
18
19static inline void scatterwalk_crypto_chain(struct scatterlist *head,
20 struct scatterlist *sg, int num)
21{
22 if (sg)
23 sg_chain(head, num, sg);
24 else
25 sg_mark_end(head);
26}
27
28static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
29{
30 unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
31 unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
32 return len_this_page > len ? len : len_this_page;
33}
34
35static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
36 unsigned int nbytes)
37{
38 unsigned int len_this_page = scatterwalk_pagelen(walk);
39 return nbytes > len_this_page ? len_this_page : nbytes;
40}
41
42static inline void scatterwalk_advance(struct scatter_walk *walk,
43 unsigned int nbytes)
44{
45 walk->offset += nbytes;
46}
47
48static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
49 unsigned int alignmask)
50{
51 return !(walk->offset & alignmask);
52}
53
54static inline struct page *scatterwalk_page(struct scatter_walk *walk)
55{
56 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
57}
58
59static inline void scatterwalk_unmap(void *vaddr)
60{
61 kunmap_atomic(vaddr);
62}
63
64static inline void scatterwalk_start(struct scatter_walk *walk,
65 struct scatterlist *sg)
66{
67 walk->sg = sg;
68 walk->offset = sg->offset;
69}
70
71static inline void *scatterwalk_map(struct scatter_walk *walk)
72{
73 return kmap_atomic(scatterwalk_page(walk)) +
74 offset_in_page(walk->offset);
75}
76
77static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
78 unsigned int more)
79{
80 if (out) {
81 struct page *page;
82
83 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
84 flush_dcache_page(page);
85 }
86
87 if (more && walk->offset >= walk->sg->offset + walk->sg->length)
88 scatterwalk_start(walk, sg_next(walk->sg));
89}
90
91static inline void scatterwalk_done(struct scatter_walk *walk, int out,
92 int more)
93{
94 if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
95 !(walk->offset & (PAGE_SIZE - 1)))
96 scatterwalk_pagedone(walk, out, more);
97}
98
99void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
100 size_t nbytes, int out);
101void *scatterwalk_map(struct scatter_walk *walk);
102
103void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
104 unsigned int start, unsigned int nbytes, int out);
105
106struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
107 struct scatterlist *src,
108 unsigned int len);
109
110#endif /* _CRYPTO_SCATTERWALK_H */