summaryrefslogtreecommitdiffstats
path: root/drivers/block/zram/zcomp.h
blob: bd11d59c5dd161dfdd4bc69fb23b5dcd806836c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
/*
 * Copyright (C) 2014 Sergey Senozhatsky.
 *
 * 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 _ZCOMP_H_
#define _ZCOMP_H_

#include <linux/mutex.h>

struct zcomp_strm {
	/* compression/decompression buffer */
	void *buffer;
	/*
	 * The private data of the compression stream, only compression
	 * stream backend can touch this (e.g. compression algorithm
	 * working memory)
	 */
	void *private;
	/* used in multi stream backend, protected by backend strm_lock */
	struct list_head list;
};

/* static compression backend */
struct zcomp_backend {
	int (*compress)(const unsigned char *src, unsigned char *dst,
			size_t *dst_len, void *private);

	int (*decompress)(const unsigned char *src, size_t src_len,
			unsigned char *dst);

	void *(*create)(void);
	void (*destroy)(void *private);

	const char *name;
};

/* dynamic per-device compression frontend */
struct zcomp {
	void *stream;
	struct zcomp_backend *backend;

	struct zcomp_strm *(*strm_find)(struct zcomp *comp);
	void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
	int (*set_max_streams)(struct zcomp *comp, int num_strm);
	void (*destroy)(struct zcomp *comp);
};

struct zcomp *zcomp_create(const char *comp, int max_strm);
void zcomp_destroy(struct zcomp *comp);

struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);

int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
		const unsigned char *src, size_t *dst_len);

int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
		size_t src_len, unsigned char *dst);

int zcomp_set_max_streams(struct zcomp *comp, int num_strm);
#endif /* _ZCOMP_H_ */