Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Cryptographic API. |
| 3 | * |
| 4 | * Cipher operations. |
| 5 | * |
| 6 | * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> |
| 7 | * 2002 Adam J. Richter <adam@yggdrasil.com> |
| 8 | * 2004 Jean-Luc Cooke <jlcooke@certainkey.com> |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify it |
| 11 | * under the terms of the GNU General Public License as published by the Free |
| 12 | * Software Foundation; either version 2 of the License, or (at your option) |
| 13 | * any later version. |
| 14 | * |
| 15 | */ |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/mm.h> |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 18 | #include <linux/module.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/pagemap.h> |
| 20 | #include <linux/highmem.h> |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 21 | #include <linux/scatterlist.h> |
| 22 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include "internal.h" |
| 24 | #include "scatterwalk.h" |
| 25 | |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 26 | static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | { |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 28 | void *src = out ? buf : sgdata; |
| 29 | void *dst = out ? sgdata : buf; |
| 30 | |
| 31 | memcpy(dst, src, nbytes); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | } |
| 33 | |
| 34 | void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg) |
| 35 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | walk->sg = sg; |
| 37 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | BUG_ON(!sg->length); |
| 39 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | walk->offset = sg->offset; |
| 41 | } |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 42 | EXPORT_SYMBOL_GPL(scatterwalk_start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 44 | void *scatterwalk_map(struct scatter_walk *walk, int out) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | { |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 46 | return crypto_kmap(scatterwalk_page(walk), out) + |
| 47 | offset_in_page(walk->offset); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | } |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 49 | EXPORT_SYMBOL_GPL(scatterwalk_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | |
| 51 | static void scatterwalk_pagedone(struct scatter_walk *walk, int out, |
| 52 | unsigned int more) |
| 53 | { |
Herbert Xu | 9f11672 | 2007-03-31 12:58:20 +1000 | [diff] [blame] | 54 | if (out) { |
| 55 | struct page *page; |
| 56 | |
Jens Axboe | 78c2f0b | 2007-10-22 19:40:16 +0200 | [diff] [blame^] | 57 | page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT); |
Herbert Xu | 9f11672 | 2007-03-31 12:58:20 +1000 | [diff] [blame] | 58 | flush_dcache_page(page); |
| 59 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | |
| 61 | if (more) { |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 62 | walk->offset += PAGE_SIZE - 1; |
| 63 | walk->offset &= PAGE_MASK; |
| 64 | if (walk->offset >= walk->sg->offset + walk->sg->length) |
Jens Axboe | ab83407 | 2007-05-09 08:58:32 +0200 | [diff] [blame] | 65 | scatterwalk_start(walk, scatterwalk_sg_next(walk->sg)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | } |
| 67 | } |
| 68 | |
| 69 | void scatterwalk_done(struct scatter_walk *walk, int out, int more) |
| 70 | { |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 71 | if (!offset_in_page(walk->offset) || !more) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | scatterwalk_pagedone(walk, out, more); |
| 73 | } |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 74 | EXPORT_SYMBOL_GPL(scatterwalk_done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 76 | void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, |
| 77 | size_t nbytes, int out) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | { |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 79 | for (;;) { |
| 80 | unsigned int len_this_page = scatterwalk_pagelen(walk); |
| 81 | u8 *vaddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 83 | if (len_this_page > nbytes) |
| 84 | len_this_page = nbytes; |
| 85 | |
| 86 | vaddr = scatterwalk_map(walk, out); |
| 87 | memcpy_dir(buf, vaddr, len_this_page, out); |
| 88 | scatterwalk_unmap(vaddr, out); |
| 89 | |
Herbert Xu | 4ee531a | 2007-03-31 12:16:20 +1000 | [diff] [blame] | 90 | scatterwalk_advance(walk, len_this_page); |
J. Bruce Fields | f70ee5e | 2007-03-21 08:50:12 +1100 | [diff] [blame] | 91 | |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 92 | if (nbytes == len_this_page) |
| 93 | break; |
| 94 | |
| 95 | buf += len_this_page; |
| 96 | nbytes -= len_this_page; |
| 97 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | scatterwalk_pagedone(walk, out, 1); |
Herbert Xu | c774e93 | 2005-07-06 13:51:31 -0700 | [diff] [blame] | 99 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | } |
Herbert Xu | 5c64097 | 2006-08-12 21:56:17 +1000 | [diff] [blame] | 101 | EXPORT_SYMBOL_GPL(scatterwalk_copychunks); |
Herbert Xu | 5fa0fea | 2007-08-29 16:31:34 +0800 | [diff] [blame] | 102 | |
| 103 | void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, |
| 104 | unsigned int start, unsigned int nbytes, int out) |
| 105 | { |
| 106 | struct scatter_walk walk; |
| 107 | unsigned int offset = 0; |
| 108 | |
| 109 | for (;;) { |
| 110 | scatterwalk_start(&walk, sg); |
| 111 | |
| 112 | if (start < offset + sg->length) |
| 113 | break; |
| 114 | |
| 115 | offset += sg->length; |
| 116 | sg = sg_next(sg); |
| 117 | } |
| 118 | |
| 119 | scatterwalk_advance(&walk, start - offset); |
| 120 | scatterwalk_copychunks(buf, &walk, nbytes, out); |
| 121 | scatterwalk_done(&walk, out, 0); |
| 122 | } |
| 123 | EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy); |