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/*
* Cryptographic scatter and gather helpers.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
* Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
* Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#ifndef _CRYPTO_SCATTERWALK_H
#define _CRYPTO_SCATTERWALK_H
#include <crypto/algapi.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/scatterlist.h>
static inline void scatterwalk_crypto_chain(struct scatterlist *head,
struct scatterlist *sg, int num)
{
if (sg)
sg_chain(head, num, sg);
else
sg_mark_end(head);
}
static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
struct scatter_walk *walk_out)
{
return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
(int)(walk_in->offset - walk_out->offset));
}
static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
{
unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
return len_this_page > len ? len : len_this_page;
}
static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
unsigned int nbytes)
{
unsigned int len_this_page = scatterwalk_pagelen(walk);
return nbytes > len_this_page ? len_this_page : nbytes;
}
static inline void scatterwalk_advance(struct scatter_walk *walk,
unsigned int nbytes)
{
walk->offset += nbytes;
}
static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
unsigned int alignmask)
{
return !(walk->offset & alignmask);
}
static inline struct page *scatterwalk_page(struct scatter_walk *walk)
{
return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
}
static inline void scatterwalk_unmap(void *vaddr)
{
kunmap_atomic(vaddr);
}
static inline void scatterwalk_start(struct scatter_walk *walk,
struct scatterlist *sg)
{
walk->sg = sg;
walk->offset = sg->offset;
}
static inline void *scatterwalk_map(struct scatter_walk *walk)
{
return kmap_atomic(scatterwalk_page(walk)) +
offset_in_page(walk->offset);
}
static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
unsigned int more)
{
if (out) {
struct page *page;
page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
* PageSlab cannot be optimised away per se due to
* use of volatile pointer.
*/
if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
flush_dcache_page(page);
}
if (more && walk->offset >= walk->sg->offset + walk->sg->length)
scatterwalk_start(walk, sg_next(walk->sg));
}
static inline void scatterwalk_done(struct scatter_walk *walk, int out,
int more)
{
if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
!(walk->offset & (PAGE_SIZE - 1)))
scatterwalk_pagedone(walk, out, more);
}
void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
size_t nbytes, int out);
void *scatterwalk_map(struct scatter_walk *walk);
void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
unsigned int start, unsigned int nbytes, int out);
struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
struct scatterlist *src,
unsigned int len);
#endif /* _CRYPTO_SCATTERWALK_H */
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