GNU Linux-libre 4.9.304-gnu1
[releases.git] / include / crypto / scatterwalk.h
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
24 static 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
39 static 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
46 static 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
53 static 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
60 static inline void scatterwalk_advance(struct scatter_walk *walk,
61                                        unsigned int nbytes)
62 {
63         walk->offset += nbytes;
64 }
65
66 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
67                                                unsigned int alignmask)
68 {
69         return !(walk->offset & alignmask);
70 }
71
72 static inline struct page *scatterwalk_page(struct scatter_walk *walk)
73 {
74         return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
75 }
76
77 static inline void scatterwalk_unmap(void *vaddr)
78 {
79         kunmap_atomic(vaddr);
80 }
81
82 static inline void scatterwalk_start(struct scatter_walk *walk,
83                                      struct scatterlist *sg)
84 {
85         walk->sg = sg;
86         walk->offset = sg->offset;
87 }
88
89 static inline void *scatterwalk_map(struct scatter_walk *walk)
90 {
91         return kmap_atomic(scatterwalk_page(walk)) +
92                offset_in_page(walk->offset);
93 }
94
95 static 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
114 static 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
122 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
123                             size_t nbytes, int out);
124 void *scatterwalk_map(struct scatter_walk *walk);
125
126 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
127                               unsigned int start, unsigned int nbytes, int out);
128
129 struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
130                                      struct scatterlist *src,
131                                      unsigned int len);
132
133 #endif  /* _CRYPTO_SCATTERWALK_H */