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 static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
  24 {
  25         return (++sg)->length ? sg : (void *) sg_page(sg);
  26 }
  27
  28 static 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
  35 static 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
  42 static 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
  49 static inline void scatterwalk_advance(struct scatter_walk *walk,
  50                                        unsigned int nbytes)
  51 {
  52         walk->offset += nbytes;
  53 }
  54
  55 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  56                                                unsigned int alignmask)
  57 {
  58         return !(walk->offset & alignmask);
  59 }
  60
  61 static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  62 {
  63         return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  64 }
  65
  66 static inline void scatterwalk_unmap(void *vaddr, int out)
  67 {
  68         crypto_kunmap(vaddr, out);
  69 }
  70
  71 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
  72 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  73                             size_t nbytes, int out);
  74 void *scatterwalk_map(struct scatter_walk *walk, int out);
  75 void scatterwalk_done(struct scatter_walk *walk, int out, int more);
  76
  77 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
  78                               unsigned int start, unsigned int nbytes, int out);
  79
  80 #endif  /* _CRYPTO_SCATTERWALK_H */