blob: 35f99b68d037066b987a90ae24b6b6ba5bd00d09 [file] [log] [blame]
* Cryptographic scatter and gather helpers.
* Copyright (c) 2002 James Morris <>
* Copyright (c) 2002 Adam J. Richter <>
* Copyright (c) 2004 Jean-Luc Cooke <>
* Copyright (c) 2007 Herbert Xu <>
* 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.
#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 scatterwalk_crypto_chain(struct scatterlist *head,
struct scatterlist *sg,
int chain, int num)
if (chain) {
head->length += sg->length;
sg = sg_next(sg);
if (sg)
sg_chain(head, num, sg);
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)
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);
struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
struct scatterlist *src,
unsigned int len);