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   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
  27 static inline enum km_type crypto_kmap_type(int out)
  28 {
  29         enum km_type type;
  30
  31         if (in_softirq())
  32                 type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0;
  33         else
  34                 type = out * (KM_USER1 - KM_USER0) + KM_USER0;
  35
  36         return type;
  37 }
  38
  39 static inline void *crypto_kmap(struct page *page, int out)
  40 {
  41         return kmap_atomic(page, crypto_kmap_type(out));
  42 }
  43
  44 static inline void crypto_kunmap(void *vaddr, int out)
  45 {
  46         kunmap_atomic(vaddr, crypto_kmap_type(out));
  47 }
  48
  49 static inline void crypto_yield(u32 flags)
  50 {
  51         if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
  52                 cond_resched();
  53 }
  54
  55 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  56                                                 struct scatter_walk *walk_out)
  57 {
  58         return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +
  59                  (int)(walk_in->offset - walk_out->offset));
  60 }
  61
  62 static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  63 {
  64         unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  65         unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  66         return len_this_page > len ? len : len_this_page;
  67 }
  68
  69 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  70                                              unsigned int nbytes)
  71 {
  72         unsigned int len_this_page = scatterwalk_pagelen(walk);
  73         return nbytes > len_this_page ? len_this_page : nbytes;
  74 }
  75
  76 static inline void scatterwalk_advance(struct scatter_walk *walk,
  77                                        unsigned int nbytes)
  78 {
  79         walk->offset += nbytes;
  80 }
  81
  82 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  83                                                unsigned int alignmask)
  84 {
  85         return !(walk->offset & alignmask);
  86 }
  87
  88 static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  89 {
  90         return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
  91 }
  92
  93 static inline void scatterwalk_unmap(void *vaddr, int out)
  94 {
  95         crypto_kunmap(vaddr, out);
  96 }
  97
  98 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
  99 void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
 100                             size_t nbytes, int out);
 101 void *scatterwalk_map(struct scatter_walk *walk, int out);
 102 void scatterwalk_done(struct scatter_walk *walk, int out, int more);
 103
 104 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 105                               unsigned int start, unsigned int nbytes, int out);
 106
 107 #endif  /* _CRYPTO_SCATTERWALK_H */