LXR linux/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 void scatterwalk_crypto_chain(struct scatterlist *head,
  29                                            struct scatterlist *sg,
  30                                            int chain, int num)
  31{
  32        if (chain) {
  33                head->length += sg->length;
  34                sg = sg_next(sg);
  35        }
  36
  37        if (sg)
  38                sg_chain(head, num, sg);
  39        else
  40                sg_mark_end(head);
  41}
  42
  43static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  44                                                struct scatter_walk *walk_out)
  45{
  46        return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
  47                 (int)(walk_in->offset - walk_out->offset));
  48}
  49
  50static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  51{
  52        unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  53        unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  54        return len_this_page > len ? len : len_this_page;
  55}
  56
  57static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  58                                             unsigned int nbytes)
  59{
  60        unsigned int len_this_page = scatterwalk_pagelen(walk);
  61        return nbytes > len_this_page ? len_this_page : nbytes;
  62}
  63
  64static inline void scatterwalk_advance(struct scatter_walk *walk,
  65                                       unsigned int nbytes)
  66{
  67        walk->offset += nbytes;
  68}
  69
  70static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  71                                               unsigned int alignmask)
  72{
  73        return !(walk->offset & alignmask);
  74}
  75
  76static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  77{
  78        return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  79}
  80
  81static inline void scatterwalk_unmap(void *vaddr)
  82{
  83        kunmap_atomic(vaddr);
  84}
  85
  86void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
  87void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  88                            size_t nbytes, int out);
  89void *scatterwalk_map(struct scatter_walk *walk);
  90void scatterwalk_done(struct scatter_walk *walk, int out, int more);
  91
  92void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
  93                              unsigned int start, unsigned int nbytes, int out);
  94
  95int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes);
  96
  97struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
  98                                     struct scatterlist *src,
  99                                     unsigned int len);
 100
 101#endif  /* _CRYPTO_SCATTERWALK_H */
 102