kernel26-2.6.12-alx-r9/crypto/scatterwalk.c

/*
 * Cryptographic API.
 *
 * Cipher operations.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *               2002 Adam J. Richter <adam@yggdrasil.com>
 *               2004 Jean-Luc Cooke <jlcooke@certainkey.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <asm/bug.h>
#include <asm/scatterlist.h>
#include "internal.h"
#include "scatterwalk.h"

enum km_type crypto_km_types[] = {
	KM_USER0,
	KM_USER1,
	KM_SOFTIRQ0,
	KM_SOFTIRQ1,
};

static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
{
	if (out)
		memcpy(sgdata, buf, nbytes);
	else
		memcpy(buf, sgdata, nbytes);
}

void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
{
	unsigned int rest_of_page;

	walk->sg = sg;

	walk->page = sg->page;
	walk->len_this_segment = sg->length;

	BUG_ON(!sg->length);

	rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
	walk->len_this_page = min(sg->length, rest_of_page);
	walk->offset = sg->offset;
}

void scatterwalk_map(struct scatter_walk *walk, int out)
{
	walk->data = crypto_kmap(walk->page, out) + walk->offset;
}

static inline void scatterwalk_unmap(struct scatter_walk *walk, int out)
{
	/* walk->data may be pointing the first byte of the next page;
	   however, we know we transfered at least one byte.  So,
	   walk->data - 1 will be a virtual address in the mapped page. */
	crypto_kunmap(walk->data - 1, out);
}

static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
				 unsigned int more)
{
	if (out)
		flush_dcache_page(walk->page);

	if (more) {
		walk->len_this_segment -= walk->len_this_page;

		if (walk->len_this_segment) {
			walk->page++;
			walk->len_this_page = min(walk->len_this_segment,
						  (unsigned)PAGE_CACHE_SIZE);
			walk->offset = 0;
		}
		else
			scatterwalk_start(walk, sg_next(walk->sg));
	}
}

void scatterwalk_done(struct scatter_walk *walk, int out, int more)
{
	scatterwalk_unmap(walk, out);
	if (walk->len_this_page == 0 || !more)
		scatterwalk_pagedone(walk, out, more);
}

/*
 * Do not call this unless the total length of all of the fragments
 * has been verified as multiple of the block size.
 */
int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
			   size_t nbytes, int out)
{
	do {
		memcpy_dir(buf, walk->data, walk->len_this_page, out);
		buf += walk->len_this_page;
		nbytes -= walk->len_this_page;

		scatterwalk_unmap(walk, out);
		scatterwalk_pagedone(walk, out, 1);
		scatterwalk_map(walk, out);
	} while (nbytes > walk->len_this_page);

	memcpy_dir(buf, walk->data, nbytes, out);
	return nbytes;
}
1	niro	628	/*
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>
18			#include <linux/pagemap.h>
19			#include <linux/highmem.h>
20			#include <asm/bug.h>
21			#include <asm/scatterlist.h>
22			#include "internal.h"
23			#include "scatterwalk.h"
24
25			enum km_type crypto_km_types[] = {
26			KM_USER0,
27			KM_USER1,
28			KM_SOFTIRQ0,
29			KM_SOFTIRQ1,
30			};
31
32			static void memcpy_dir(void buf, void sgdata, size_t nbytes, int out)
33			{
34			if (out)
35			memcpy(sgdata, buf, nbytes);
36			else
37			memcpy(buf, sgdata, nbytes);
38			}
39
40			void scatterwalk_start(struct scatter_walk walk, struct scatterlist sg)
41			{
42			unsigned int rest_of_page;
43
44			walk->sg = sg;
45
46			walk->page = sg->page;
47			walk->len_this_segment = sg->length;
48
49			BUG_ON(!sg->length);
50
51			rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
52			walk->len_this_page = min(sg->length, rest_of_page);
53			walk->offset = sg->offset;
54			}
55
56			void scatterwalk_map(struct scatter_walk *walk, int out)
57			{
58			walk->data = crypto_kmap(walk->page, out) + walk->offset;
59			}
60
61			static inline void scatterwalk_unmap(struct scatter_walk *walk, int out)
62			{
63			/* walk->data may be pointing the first byte of the next page;
64			however, we know we transfered at least one byte. So,
65			walk->data - 1 will be a virtual address in the mapped page. */
66			crypto_kunmap(walk->data - 1, out);
67			}
68
69			static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
70			unsigned int more)
71			{
72			if (out)
73			flush_dcache_page(walk->page);
74
75			if (more) {
76			walk->len_this_segment -= walk->len_this_page;
77
78			if (walk->len_this_segment) {
79			walk->page++;
80			walk->len_this_page = min(walk->len_this_segment,
81			(unsigned)PAGE_CACHE_SIZE);
82			walk->offset = 0;
83			}
84			else
85			scatterwalk_start(walk, sg_next(walk->sg));
86			}
87			}
88
89			void scatterwalk_done(struct scatter_walk *walk, int out, int more)
90			{
91			scatterwalk_unmap(walk, out);
92			if (walk->len_this_page == 0 \|\| !more)
93			scatterwalk_pagedone(walk, out, more);
94			}
95
96			/*
97			* Do not call this unless the total length of all of the fragments
98			* has been verified as multiple of the block size.
99			*/
100			int scatterwalk_copychunks(void buf, struct scatter_walk walk,
101			size_t nbytes, int out)
102			{
103			do {
104			memcpy_dir(buf, walk->data, walk->len_this_page, out);
105			buf += walk->len_this_page;
106			nbytes -= walk->len_this_page;
107
108			scatterwalk_unmap(walk, out);
109			scatterwalk_pagedone(walk, out, 1);
110			scatterwalk_map(walk, out);
111			} while (nbytes > walk->len_this_page);
112
113			memcpy_dir(buf, walk->data, nbytes, out);
114			return nbytes;
115			}