1/*
2 * Copyright (C) 2014 Sergey Senozhatsky.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
9
10#include <linux/kernel.h>
11#include <linux/slab.h>
12#include <linux/lz4.h>
13#include <linux/vmalloc.h>
14#include <linux/mm.h>
15
16#include "zcomp_lz4.h"
17
18static void *zcomp_lz4_create(void)
19{
20	void *ret;
21
22	/*
23	 * This function can be called in swapout/fs write path
24	 * so we can't use GFP_FS|IO. And it assumes we already
25	 * have at least one stream in zram initialization so we
26	 * don't do best effort to allocate more stream in here.
27	 * A default stream will work well without further multiple
28	 * streams. That's why we use NORETRY | NOWARN.
29	 */
30	ret = kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
31					__GFP_NOWARN);
32	if (!ret)
33		ret = __vmalloc(LZ4_MEM_COMPRESS,
34				GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN |
35				__GFP_ZERO | __GFP_HIGHMEM,
36				PAGE_KERNEL);
37	return ret;
38}
39
40static void zcomp_lz4_destroy(void *private)
41{
42	kvfree(private);
43}
44
45static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
46		size_t *dst_len, void *private)
47{
48	/* return  : Success if return 0 */
49	return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
50}
51
52static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
53		unsigned char *dst)
54{
55	size_t dst_len = PAGE_SIZE;
56	/* return  : Success if return 0 */
57	return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
58}
59
60struct zcomp_backend zcomp_lz4 = {
61	.compress = zcomp_lz4_compress,
62	.decompress = zcomp_lz4_decompress,
63	.create = zcomp_lz4_create,
64	.destroy = zcomp_lz4_destroy,
65	.name = "lz4",
66};
67