[CRYPTO] scatterwalk: Restore custom sg chaining for now
[linux-3.10.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 <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
27 static inline enum km_type crypto_kmap_type(int out)
28 {
29         enum km_type type;
30
31         if (in_softirq())
32                 type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0;
33         else
34                 type = out * (KM_USER1 - KM_USER0) + KM_USER0;
35
36         return type;
37 }
38
39 static inline void *crypto_kmap(struct page *page, int out)
40 {
41         return kmap_atomic(page, crypto_kmap_type(out));
42 }
43
44 static inline void crypto_kunmap(void *vaddr, int out)
45 {
46         kunmap_atomic(vaddr, crypto_kmap_type(out));
47 }
48
49 static inline void crypto_yield(u32 flags)
50 {
51         if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
52                 cond_resched();
53 }
54
55 static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
56                                         struct scatterlist *sg2)
57 {
58         sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
59 }
60
61 static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
62 {
63         return (++sg)->length ? sg : (void *)sg_page(sg);
64 }
65
66 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
67                                                 struct scatter_walk *walk_out)
68 {
69         return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
70                  (int)(walk_in->offset - walk_out->offset));
71 }
72
73 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
74 {
75         unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
76         unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
77         return len_this_page > len ? len : len_this_page;
78 }
79
80 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
81                                              unsigned int nbytes)
82 {
83         unsigned int len_this_page = scatterwalk_pagelen(walk);
84         return nbytes > len_this_page ? len_this_page : nbytes;
85 }
86
87 static inline void scatterwalk_advance(struct scatter_walk *walk,
88                                        unsigned int nbytes)
89 {
90         walk->offset += nbytes;
91 }
92
93 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
94                                                unsigned int alignmask)
95 {
96         return !(walk->offset & alignmask);
97 }
98
99 static inline struct page *scatterwalk_page(struct scatter_walk *walk)
100 {
101         return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
102 }
103
104 static inline void scatterwalk_unmap(void *vaddr, int out)
105 {
106         crypto_kunmap(vaddr, out);
107 }
108
109 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
110 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
111                             size_t nbytes, int out);
112 void *scatterwalk_map(struct scatter_walk *walk, int out);
113 void scatterwalk_done(struct scatter_walk *walk, int out, int more);
114
115 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
116                               unsigned int start, unsigned int nbytes, int out);
117
118 #endif  /* _CRYPTO_SCATTERWALK_H */