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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 <asm/kmap_types.h>
#include <crypto/algapi.h>
#include <linux/hardirq.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/sched.h>
static inline void crypto_yield(u32 flags)
{
if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
cond_resched();
}
static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
struct scatterlist *sg2)
{
sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
sg1[num - 1].page_link &= ~0x02;
sg1[num - 1].page_link |= 0x01;
}
static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
{
if (sg_is_last(sg))
return NULL;
return (++sg)->length ? sg : sg_chain_ptr(sg);
}
static inline void scatterwalk_crypto_chain(struct scatterlist *head,
struct scatterlist *sg,
int chain, int num)
{
if (chain) {
head->length += sg->length;
sg = scatterwalk_sg_next(sg);
}
if (sg)
scatterwalk_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);
}
void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
size_t nbytes, int out);
void *scatterwalk_map(struct scatter_walk *walk);
void scatterwalk_done(struct scatter_walk *walk, int out, int more);
void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
unsigned int start, unsigned int nbytes, int out);
int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes);
#endif /* _CRYPTO_SCATTERWALK_H */
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