Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm...
[linux-3.10.git] / fs / jffs2 / compr_lzo.c
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
20 static void *lzo_mem;
21 static void *lzo_compress_buf;
22 static DEFINE_MUTEX(deflate_mutex);     /* for lzo_mem and lzo_compress_buf */
23
24 static void free_workspace(void)
25 {
26         vfree(lzo_mem);
27         vfree(lzo_compress_buf);
28 }
29
30 static 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
43 static 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(data_in, *sourcelen, lzo_compress_buf, &compress_size, 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(&deflate_mutex);
59
60         *dstlen = compress_size;
61         return 0;
62
63  fail:
64         mutex_unlock(&deflate_mutex);
65         return -1;
66 }
67
68 static 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(data_in, srclen, cpage_out, &dl);
75
76         if (ret != LZO_E_OK || dl != destlen)
77                 return -1;
78
79         return 0;
80 }
81
82 static 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
91 int __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(&jffs2_lzo_comp);
100         if (ret)
101                 free_workspace();
102
103         return ret;
104 }
105
106 void jffs2_lzo_exit(void)
107 {
108         jffs2_unregister_compressor(&jffs2_lzo_comp);
109         free_workspace();
110 }