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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Herbert Xu42c271c2007-12-07 18:52:49 +08002 * Cryptographic scatter and gather helpers.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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>
Herbert Xu42c271c2007-12-07 18:52:49 +08007 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Herbert Xu42c271c2007-12-07 18:52:49 +080019#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>
Herbert Xu5c640972006-08-12 21:56:17 +100024#include <linux/mm.h>
25#include <linux/scatterlist.h>
Herbert Xu1c5dfe62007-12-24 08:54:24 +080026#include <linux/sched.h>
Herbert Xu5c640972006-08-12 21:56:17 +100027
Herbert Xu42c271c2007-12-07 18:52:49 +080028static inline void crypto_yield(u32 flags)
29{
30 if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
31 cond_resched();
32}
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Herbert Xub2ab4a52007-12-05 20:59:25 +110034static 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);
Herbert Xu8ec970d2008-04-29 21:53:52 +080038 sg1[num - 1].page_link &= ~0x02;
Herbert Xub2ab4a52007-12-05 20:59:25 +110039}
40
41static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
42{
Herbert Xu8ec970d2008-04-29 21:53:52 +080043 if (sg_is_last(sg))
44 return NULL;
45
Herbert Xub2ab4a52007-12-05 20:59:25 +110046 return (++sg)->length ? sg : (void *)sg_page(sg);
47}
48
Steffen Klassert079f2f72010-11-22 11:25:50 +010049static 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
Herbert Xu5c640972006-08-12 21:56:17 +100064static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
65 struct scatter_walk *walk_out)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066{
Jens Axboe78c2f0b2007-10-22 19:40:16 +020067 return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
Herbert Xu5c640972006-08-12 21:56:17 +100068 (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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076}
77
Herbert Xuc774e932005-07-06 13:51:31 -070078static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
79 unsigned int nbytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080{
Herbert Xu5c640972006-08-12 21:56:17 +100081 unsigned int len_this_page = scatterwalk_pagelen(walk);
82 return nbytes > len_this_page ? len_this_page : nbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -070083}
84
85static inline void scatterwalk_advance(struct scatter_walk *walk,
86 unsigned int nbytes)
87{
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 walk->offset += nbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089}
90
Herbert Xu95477372005-07-06 13:52:09 -070091static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
92 unsigned int alignmask)
93{
94 return !(walk->offset & alignmask);
95}
96
Herbert Xu5c640972006-08-12 21:56:17 +100097static inline struct page *scatterwalk_page(struct scatter_walk *walk)
98{
Jens Axboe78c2f0b2007-10-22 19:40:16 +020099 return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
Herbert Xu5c640972006-08-12 21:56:17 +1000100}
101
Cong Wangf0dfc0b2011-11-25 23:14:17 +0800102static inline void scatterwalk_unmap(void *vaddr)
Herbert Xu5c640972006-08-12 21:56:17 +1000103{
Cong Wangf0dfc0b2011-11-25 23:14:17 +0800104 kunmap_atomic(vaddr);
Herbert Xu5c640972006-08-12 21:56:17 +1000105}
106
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
Herbert Xu5c640972006-08-12 21:56:17 +1000108void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
109 size_t nbytes, int out);
Cong Wangf0dfc0b2011-11-25 23:14:17 +0800110void *scatterwalk_map(struct scatter_walk *walk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111void scatterwalk_done(struct scatter_walk *walk, int out, int more);
112
Herbert Xu5fa0fea2007-08-29 16:31:34 +0800113void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
114 unsigned int start, unsigned int nbytes, int out);
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116#endif /* _CRYPTO_SCATTERWALK_H */