[linux-2.6-block.git] / include / crypto / scatterwalk.h

/*
 * Cryptographic scatter and gather helpers.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
 * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * 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.
 *
 */

#ifndef _CRYPTO_SCATTERWALK_H
#define _CRYPTO_SCATTERWALK_H

#include <crypto/algapi.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/scatterlist.h>

static inline void scatterwalk_crypto_chain(struct scatterlist *head,
					    struct scatterlist *sg, int num)
{
	if (sg)
		sg_chain(head, num, sg);
	else
		sg_mark_end(head);
}

static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
{
	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
	return len_this_page > len ? len : len_this_page;
}

static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
					     unsigned int nbytes)
{
	unsigned int len_this_page = scatterwalk_pagelen(walk);
	return nbytes > len_this_page ? len_this_page : nbytes;
}

static inline void scatterwalk_advance(struct scatter_walk *walk,
				       unsigned int nbytes)
{
	walk->offset += nbytes;
}

static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
					       unsigned int alignmask)
{
	return !(walk->offset & alignmask);
}

static inline struct page *scatterwalk_page(struct scatter_walk *walk)
{
	return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
}

static inline void scatterwalk_unmap(void *vaddr)
{
	kunmap_atomic(vaddr);
}

static inline void scatterwalk_start(struct scatter_walk *walk,
				     struct scatterlist *sg)
{
	walk->sg = sg;
	walk->offset = sg->offset;
}

static inline void *scatterwalk_map(struct scatter_walk *walk)
{
	return kmap_atomic(scatterwalk_page(walk)) +
	       offset_in_page(walk->offset);
}

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

		page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
		/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
		 * PageSlab cannot be optimised away per se due to
		 * use of volatile pointer.
		 */
		if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
			flush_dcache_page(page);
	}

	if (more && walk->offset >= walk->sg->offset + walk->sg->length)
		scatterwalk_start(walk, sg_next(walk->sg));
}

static inline void scatterwalk_done(struct scatter_walk *walk, int out,
				    int more)
{
	if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
	    !(walk->offset & (PAGE_SIZE - 1)))
		scatterwalk_pagedone(walk, out, more);
}

void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
			    size_t nbytes, int out);
void *scatterwalk_map(struct scatter_walk *walk);

void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
			      unsigned int start, unsigned int nbytes, int out);

struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
				     struct scatterlist *src,
				     unsigned int len);

#endif  /* _CRYPTO_SCATTERWALK_H */
Commit	Line	Data
1da177e4	1	/*
42c271c6	2	* Cryptographic scatter and gather helpers.
1da177e4 LT	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>
42c271c6	7	* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
1da177e4 LT	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
5c64097a	18
42c271c6	19	#include <crypto/algapi.h>
42c271c6 HX	20	#include <linux/highmem.h>
42c271c6 HX	21	#include <linux/kernel.h>
5c64097a	22	#include <linux/scatterlist.h>
1da177e4	23
079f2f74	24	static inline void scatterwalk_crypto_chain(struct scatterlist *head,
8c30fbe6	25	struct scatterlist *sg, int num)
079f2f74	26	{
079f2f74	27	if (sg)
c56f6d12	28	sg_chain(head, num, sg);
079f2f74 SK	29	else
	30	sg_mark_end(head);
	31	}
	32
5c64097a HX	33	static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
	34	{
	35	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
	36	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
	37	return len_this_page > len ? len : len_this_page;
1da177e4 LT	38	}
1da177e4 LT	39
c774e93e HX	40	static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
c774e93e HX	41	unsigned int nbytes)
1da177e4	42	{
5c64097a HX	43	unsigned int len_this_page = scatterwalk_pagelen(walk);
5c64097a HX	44	return nbytes > len_this_page ? len_this_page : nbytes;
1da177e4 LT	45	}
	46
	47	static inline void scatterwalk_advance(struct scatter_walk *walk,
	48	unsigned int nbytes)
	49	{
1da177e4	50	walk->offset += nbytes;
1da177e4 LT	51	}
1da177e4 LT	52
95477377 HX	53	static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
	54	unsigned int alignmask)
	55	{
	56	return !(walk->offset & alignmask);
	57	}
	58
5c64097a HX	59	static inline struct page scatterwalk_page(struct scatter_walk walk)
5c64097a HX	60	{
78c2f0b8	61	return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
5c64097a HX	62	}
5c64097a HX	63
f0dfc0b0	64	static inline void scatterwalk_unmap(void *vaddr)
5c64097a	65	{
f0dfc0b0	66	kunmap_atomic(vaddr);
5c64097a HX	67	}
5c64097a HX	68
ac027258 HX	69	static inline void scatterwalk_start(struct scatter_walk *walk,
	70	struct scatterlist *sg)
	71	{
	72	walk->sg = sg;
	73	walk->offset = sg->offset;
	74	}
	75
	76	static inline void scatterwalk_map(struct scatter_walk walk)
	77	{
	78	return kmap_atomic(scatterwalk_page(walk)) +
	79	offset_in_page(walk->offset);
	80	}
	81
	82	static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
	83	unsigned int more)
	84	{
	85	if (out) {
	86	struct page *page;
	87
	88	page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
	89	/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
	90	* PageSlab cannot be optimised away per se due to
	91	* use of volatile pointer.
	92	*/
	93	if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
	94	flush_dcache_page(page);
	95	}
	96
	97	if (more && walk->offset >= walk->sg->offset + walk->sg->length)
	98	scatterwalk_start(walk, sg_next(walk->sg));
	99	}
	100
	101	static inline void scatterwalk_done(struct scatter_walk *walk, int out,
	102	int more)
	103	{
	104	if (!more \|\| walk->offset >= walk->sg->offset + walk->sg->length \|\|
	105	!(walk->offset & (PAGE_SIZE - 1)))
	106	scatterwalk_pagedone(walk, out, more);
	107	}
	108
5c64097a HX	109	void scatterwalk_copychunks(void buf, struct scatter_walk walk,
5c64097a HX	110	size_t nbytes, int out);
f0dfc0b0	111	void scatterwalk_map(struct scatter_walk walk);
1da177e4	112
5fa0fea2 HX	113	void scatterwalk_map_and_copy(void buf, struct scatterlist sg,
	114	unsigned int start, unsigned int nbytes, int out);
	115
fc42bcba HX	116	struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
	117	struct scatterlist *src,
	118	unsigned int len);
	119
1da177e4	120	#endif /* _CRYPTO_SCATTERWALK_H */