LXR linux/crypto/scatterwalk.h

   1/*
   2 * Cryptographic API.
   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 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms of the GNU General Public License as published by the Free
  10 * Software Foundation; either version 2 of the License, or (at your option)
  11 * any later version.
  12 *
  13 */
  14
  15#ifndef _CRYPTO_SCATTERWALK_H
  16#define _CRYPTO_SCATTERWALK_H
  17
  18#include <linux/mm.h>
  19#include <linux/scatterlist.h>
  20
  21#include "internal.h"
  22
  23static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
  24{
  25        return (++sg)->length ? sg : (void *) sg_page(sg);
  26}
  27
  28static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  29                                                struct scatter_walk *walk_out)
  30{
  31        return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
  32                 (int)(walk_in->offset - walk_out->offset));
  33}
  34
  35static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  36{
  37        unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  38        unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  39        return len_this_page > len ? len : len_this_page;
  40}
  41
  42static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  43                                             unsigned int nbytes)
  44{
  45        unsigned int len_this_page = scatterwalk_pagelen(walk);
  46        return nbytes > len_this_page ? len_this_page : nbytes;
  47}
  48
  49static inline void scatterwalk_advance(struct scatter_walk *walk,
  50                                       unsigned int nbytes)
  51{
  52        walk->offset += nbytes;
  53}
  54
  55static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  56                                               unsigned int alignmask)
  57{
  58        return !(walk->offset & alignmask);
  59}
  60
  61static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  62{
  63        return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  64}
  65
  66static inline void scatterwalk_unmap(void *vaddr, int out)
  67{
  68        crypto_kunmap(vaddr, out);
  69}
  70
  71void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
  72void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  73                            size_t nbytes, int out);
  74void *scatterwalk_map(struct scatter_walk *walk, int out);
  75void scatterwalk_done(struct scatter_walk *walk, int out, int more);
  76
  77void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
  78                              unsigned int start, unsigned int nbytes, int out);
  79
  80#endif  /* _CRYPTO_SCATTERWALK_H */
  81