/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#include <linux/sched.h>
 27
 28static inline enum km_type crypto_kmap_type(int out)
 29{
 30	enum km_type type;
 31
 32	if (in_softirq())
 33		type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0;
 34	else
 35		type = out * (KM_USER1 - KM_USER0) + KM_USER0;
 36
 37	return type;
 38}
 39
 40static inline void *crypto_kmap(struct page *page, int out)
 41{
 42	return kmap_atomic(page, crypto_kmap_type(out));
 43}
 44
 45static inline void crypto_kunmap(void *vaddr, int out)
 46{
 47	kunmap_atomic(vaddr, crypto_kmap_type(out));
 48}
 49
 50static inline void crypto_yield(u32 flags)
 51{
 52	if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
 53		cond_resched();
 54}
 55
 56static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
 57					struct scatterlist *sg2)
 58{
 59	sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
 60	sg1[num - 1].page_link &= ~0x02;
 61}
 62
 63static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
 64{
 65	if (sg_is_last(sg))
 66		return NULL;
 67
 68	return (++sg)->length ? sg : (void *)sg_page(sg);
 69}
 70
 71static inline void scatterwalk_crypto_chain(struct scatterlist *head,
 72					    struct scatterlist *sg,
 73					    int chain, int num)
 74{
 75	if (chain) {
 76		head->length += sg->length;
 77		sg = scatterwalk_sg_next(sg);
 78	}
 79
 80	if (sg)
 81		scatterwalk_sg_chain(head, num, sg);
 82	else
 83		sg_mark_end(head);
 84}
 85
 86static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
 87						struct scatter_walk *walk_out)
 88{
 89	return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
 90		 (int)(walk_in->offset - walk_out->offset));
 91}
 92
 93static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
 94{
 95	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
 96	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
 97	return len_this_page > len ? len : len_this_page;
 98}
 99
100static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
101					     unsigned int nbytes)
102{
103	unsigned int len_this_page = scatterwalk_pagelen(walk);
104	return nbytes > len_this_page ? len_this_page : nbytes;
105}
106
107static inline void scatterwalk_advance(struct scatter_walk *walk,
108				       unsigned int nbytes)
109{
110	walk->offset += nbytes;
111}
112
113static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
114					       unsigned int alignmask)
115{
116	return !(walk->offset & alignmask);
117}
118
119static inline struct page *scatterwalk_page(struct scatter_walk *walk)
120{
121	return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
122}
123
124static inline void scatterwalk_unmap(void *vaddr, int out)
125{
126	crypto_kunmap(vaddr, out);
127}
128
129void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
130void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
131			    size_t nbytes, int out);
132void *scatterwalk_map(struct scatter_walk *walk, int out);
133void scatterwalk_done(struct scatter_walk *walk, int out, int more);
134
135void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
136			      unsigned int start, unsigned int nbytes, int out);
137
138#endif  /* _CRYPTO_SCATTERWALK_H */