Root/fs/jffs2/compr_lzo.c

1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2007 Nokia Corporation. All rights reserved.
5 *
6 * Created by Richard Purdie <rpurdie@openedhand.com>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
11
12#include <linux/kernel.h>
13#include <linux/sched.h>
14#include <linux/slab.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(lzo_mem);
27    vfree(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        printk(KERN_WARNING "Failed to allocate lzo deflate workspace\n");
37        free_workspace();
38        return -ENOMEM;
39    }
40
41    return 0;
42}
43
44static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
45                  uint32_t *sourcelen, uint32_t *dstlen, void *model)
46{
47    size_t compress_size;
48    int ret;
49
50    mutex_lock(&deflate_mutex);
51    ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
52    if (ret != LZO_E_OK)
53        goto fail;
54
55    if (compress_size > *dstlen)
56        goto fail;
57
58    memcpy(cpage_out, lzo_compress_buf, compress_size);
59    mutex_unlock(&deflate_mutex);
60
61    *dstlen = compress_size;
62    return 0;
63
64 fail:
65    mutex_unlock(&deflate_mutex);
66    return -1;
67}
68
69static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
70                 uint32_t srclen, uint32_t destlen, void *model)
71{
72    size_t dl = destlen;
73    int ret;
74
75    ret = lzo1x_decompress_safe(data_in, srclen, cpage_out, &dl);
76
77    if (ret != LZO_E_OK || dl != destlen)
78        return -1;
79
80    return 0;
81}
82
83static struct jffs2_compressor jffs2_lzo_comp = {
84    .priority = JFFS2_LZO_PRIORITY,
85    .name = "lzo",
86    .compr = JFFS2_COMPR_LZO,
87    .compress = &jffs2_lzo_compress,
88    .decompress = &jffs2_lzo_decompress,
89    .disabled = 0,
90};
91
92int __init jffs2_lzo_init(void)
93{
94    int ret;
95
96    ret = alloc_workspace();
97    if (ret < 0)
98        return ret;
99
100    ret = jffs2_register_compressor(&jffs2_lzo_comp);
101    if (ret)
102        free_workspace();
103
104    return ret;
105}
106
107void jffs2_lzo_exit(void)
108{
109    jffs2_unregister_compressor(&jffs2_lzo_comp);
110    free_workspace();
111}
112

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