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_sg_chain(struct scatterlist *sg1, int num,
  29                                        struct scatterlist *sg2)
  30{
  31        sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
  32        sg1[num - 1].page_link &= ~0x02;
  33        sg1[num - 1].page_link |= 0x01;
  34}
  35
  36static inline void scatterwalk_crypto_chain(struct scatterlist *head,
  37                                            struct scatterlist *sg,
  38                                            int chain, int num)
  39{
  40        if (chain) {
  41                head->length += sg->length;
  42                sg = sg_next(sg);
  43        }
  44
  45        if (sg)
  46                scatterwalk_sg_chain(head, num, sg);
  47        else
  48                sg_mark_end(head);
  49}
  50
  51static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  52                                                struct scatter_walk *walk_out)
  53{
  54        return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
  55                 (int)(walk_in->offset - walk_out->offset));
  56}
  57
  58static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  59{
  60        unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  61        unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  62        return len_this_page > len ? len : len_this_page;
  63}
  64
  65static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  66                                             unsigned int nbytes)
  67{
  68        unsigned int len_this_page = scatterwalk_pagelen(walk);
  69        return nbytes > len_this_page ? len_this_page : nbytes;
  70}
  71
  72static inline void scatterwalk_advance(struct scatter_walk *walk,
  73                                       unsigned int nbytes)
  74{
  75        walk->offset += nbytes;
  76}
  77
  78static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  79                                               unsigned int alignmask)
  80{
  81        return !(walk->offset & alignmask);
  82}
  83
  84static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  85{
  86        return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  87}
  88
  89static inline void scatterwalk_unmap(void *vaddr)
  90{
  91        kunmap_atomic(vaddr);
  92}
  93
  94void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
  95void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  96                            size_t nbytes, int out);
  97void *scatterwalk_map(struct scatter_walk *walk);
  98void scatterwalk_done(struct scatter_walk *walk, int out, int more);
  99
 100void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 101                              unsigned int start, unsigned int nbytes, int out);
 102
 103int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes);
 104
 105#endif  /* _CRYPTO_SCATTERWALK_H */
 106