SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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
  23 /* Define sg_next is an inline routine now in case we want to change
  24    scatterlist to a linked list later. */
  25 static inline struct scatterlist *sg_next(struct scatterlist *sg)
  26 {
  27         return sg + 1;
  28 }
  29
  30 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  31                                                 struct scatter_walk *walk_out)
  32 {
  33         return !(((walk_in->sg->page - walk_out->sg->page) << PAGE_SHIFT) +
  34                  (int)(walk_in->offset - walk_out->offset));
  35 }
  36
  37 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  38 {
  39         unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  40         unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  41         return len_this_page > len ? len : len_this_page;
  42 }
  43
  44 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  45                                              unsigned int nbytes)
  46 {
  47         unsigned int len_this_page = scatterwalk_pagelen(walk);
  48         return nbytes > len_this_page ? len_this_page : nbytes;
  49 }
  50
  51 static inline void scatterwalk_advance(struct scatter_walk *walk,
  52                                        unsigned int nbytes)
  53 {
  54         walk->offset += nbytes;
  55 }
  56
  57 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  58                                                unsigned int alignmask)
  59 {
  60         return !(walk->offset & alignmask);
  61 }
  62
  63 static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  64 {
  65         return walk->sg->page + (walk->offset >> PAGE_SHIFT);
  66 }
  67
  68 static inline void scatterwalk_unmap(void *vaddr, int out)
  69 {
  70         crypto_kunmap(vaddr, out);
  71 }
  72
  73 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
  74 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  75                             size_t nbytes, int out);
  76 void *scatterwalk_map(struct scatter_walk *walk, int out);
  77 void scatterwalk_done(struct scatter_walk *walk, int out, int more);
  78
  79 #endif  /* _CRYPTO_SCATTERWALK_H */