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 crypto_yield(u32 flags)
29{
30	if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
31		cond_resched();
32}
33
34static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
35					struct scatterlist *sg2)
36{
37	sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
38	sg1[num - 1].page_link &= ~0x02;
39}
40
41static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
42{
43	if (sg_is_last(sg))
44		return NULL;
45
46	return (++sg)->length ? sg : (void *)sg_page(sg);
47}
48
49static inline void scatterwalk_crypto_chain(struct scatterlist *head,
50					    struct scatterlist *sg,
51					    int chain, int num)
52{
53	if (chain) {
54		head->length += sg->length;
55		sg = scatterwalk_sg_next(sg);
56	}
57
58	if (sg)
59		scatterwalk_sg_chain(head, num, sg);
60	else
61		sg_mark_end(head);
62}
63
64static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
65						struct scatter_walk *walk_out)
66{
67	return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
68		 (int)(walk_in->offset - walk_out->offset));
69}
70
71static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
72{
73	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
74	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
75	return len_this_page > len ? len : len_this_page;
76}
77
78static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
79					     unsigned int nbytes)
80{
81	unsigned int len_this_page = scatterwalk_pagelen(walk);
82	return nbytes > len_this_page ? len_this_page : nbytes;
83}
84
85static inline void scatterwalk_advance(struct scatter_walk *walk,
86				       unsigned int nbytes)
87{
88	walk->offset += nbytes;
89}
90
91static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
92					       unsigned int alignmask)
93{
94	return !(walk->offset & alignmask);
95}
96
97static inline struct page *scatterwalk_page(struct scatter_walk *walk)
98{
99	return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
100}
101
102static inline void scatterwalk_unmap(void *vaddr)
103{
104	kunmap_atomic(vaddr);
105}
106
107void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
108void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
109			    size_t nbytes, int out);
110void *scatterwalk_map(struct scatter_walk *walk);
111void scatterwalk_done(struct scatter_walk *walk, int out, int more);
112
113void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
114			      unsigned int start, unsigned int nbytes, int out);
115
116#endif  /* _CRYPTO_SCATTERWALK_H */
117