1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2007 Nokia Corporation. All rights reserved.
5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6 *
7 * Created by Richard Purdie <rpurdie@openedhand.com>
8 *
9 * For licensing information, see the file 'LICENCE' in this directory.
10 *
11 */
12
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/vmalloc.h>
16#include <linux/init.h>
17#include <linux/lzo.h>
18#include "compr.h"
19
20static void *lzo_mem;
21static void *lzo_compress_buf;
22static DEFINE_MUTEX(deflate_mutex); /* for lzo_mem and lzo_compress_buf */
23
24static void free_workspace(void)
25{
26 vfree(addr: lzo_mem);
27 vfree(addr: lzo_compress_buf);
28}
29
30static int __init alloc_workspace(void)
31{
32 lzo_mem = vmalloc(LZO1X_MEM_COMPRESS);
33 lzo_compress_buf = vmalloc(lzo1x_worst_compress(PAGE_SIZE));
34
35 if (!lzo_mem || !lzo_compress_buf) {
36 free_workspace();
37 return -ENOMEM;
38 }
39
40 return 0;
41}
42
43static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
44 uint32_t *sourcelen, uint32_t *dstlen)
45{
46 size_t compress_size;
47 int ret;
48
49 mutex_lock(&deflate_mutex);
50 ret = lzo1x_1_compress(src: data_in, src_len: *sourcelen, dst: lzo_compress_buf, dst_len: &compress_size, wrkmem: lzo_mem);
51 if (ret != LZO_E_OK)
52 goto fail;
53
54 if (compress_size > *dstlen)
55 goto fail;
56
57 memcpy(cpage_out, lzo_compress_buf, compress_size);
58 mutex_unlock(lock: &deflate_mutex);
59
60 *dstlen = compress_size;
61 return 0;
62
63 fail:
64 mutex_unlock(lock: &deflate_mutex);
65 return -1;
66}
67
68static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
69 uint32_t srclen, uint32_t destlen)
70{
71 size_t dl = destlen;
72 int ret;
73
74 ret = lzo1x_decompress_safe(src: data_in, src_len: srclen, dst: cpage_out, dst_len: &dl);
75
76 if (ret != LZO_E_OK || dl != destlen)
77 return -1;
78
79 return 0;
80}
81
82static struct jffs2_compressor jffs2_lzo_comp = {
83 .priority = JFFS2_LZO_PRIORITY,
84 .name = "lzo",
85 .compr = JFFS2_COMPR_LZO,
86 .compress = &jffs2_lzo_compress,
87 .decompress = &jffs2_lzo_decompress,
88 .disabled = 0,
89};
90
91int __init jffs2_lzo_init(void)
92{
93 int ret;
94
95 ret = alloc_workspace();
96 if (ret < 0)
97 return ret;
98
99 ret = jffs2_register_compressor(comp: &jffs2_lzo_comp);
100 if (ret)
101 free_workspace();
102
103 return ret;
104}
105
106void jffs2_lzo_exit(void)
107{
108 jffs2_unregister_compressor(comp: &jffs2_lzo_comp);
109 free_workspace();
110}
111

source code of linux/fs/jffs2/compr_lzo.c