Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
[linux-2.6-microblaze.git] / include / 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
19 static 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
28 static 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
35 static 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
42 static inline void scatterwalk_advance(struct scatter_walk *walk,
43                                        unsigned int nbytes)
44 {
45         walk->offset += nbytes;
46 }
47
48 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
49                                                unsigned int alignmask)
50 {
51         return !(walk->offset & alignmask);
52 }
53
54 static inline struct page *scatterwalk_page(struct scatter_walk *walk)
55 {
56         return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
57 }
58
59 static inline void scatterwalk_unmap(void *vaddr)
60 {
61         kunmap_atomic(vaddr);
62 }
63
64 static inline void scatterwalk_start(struct scatter_walk *walk,
65                                      struct scatterlist *sg)
66 {
67         walk->sg = sg;
68         walk->offset = sg->offset;
69 }
70
71 static inline void *scatterwalk_map(struct scatter_walk *walk)
72 {
73         return kmap_atomic(scatterwalk_page(walk)) +
74                offset_in_page(walk->offset);
75 }
76
77 static 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
91 static 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
99 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
100                             size_t nbytes, int out);
101 void *scatterwalk_map(struct scatter_walk *walk);
102
103 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
104                               unsigned int start, unsigned int nbytes, int out);
105
106 struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
107                                      struct scatterlist *src,
108                                      unsigned int len);
109
110 #endif  /* _CRYPTO_SCATTERWALK_H */