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1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2001-2007 Red Hat, Inc.
5 * Copyright © 2004-2010 David Woodhouse <[email protected]>
6 *
7 * Created by David Woodhouse <[email protected]>
8 *
9 * For licensing information, see the file 'LICENCE' in this directory.
10 *
11 */
12
13#if !defined(__KERNEL__) && !defined(__ECOS)
14#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
15#endif
16
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/kernel.h>
20#include <linux/zlib.h>
21#include <linux/zutil.h>
22#include "nodelist.h"
23#include "compr.h"
24
25 /* Plan: call deflate() with avail_in == *sourcelen,
26 avail_out = *dstlen - 12 and flush == Z_FINISH.
27 If it doesn't manage to finish, call it again with
28 avail_in == 0 and avail_out set to the remaining 12
29 bytes for it to clean up.
30 Q: Is 12 bytes sufficient?
31 */
32#define STREAM_END_SPACE 12
33
34static DEFINE_MUTEX(deflate_mutex);
35static DEFINE_MUTEX(inflate_mutex);
36static z_stream inf_strm, def_strm;
37
38#ifdef __KERNEL__ /* Linux-only */
39#include <linux/vmalloc.h>
40#include <linux/init.h>
41#include <linux/mutex.h>
42
43static int __init alloc_workspaces(void)
44{
45 def_strm.workspace = vmalloc(zlib_deflate_workspacesize(MAX_WBITS,
46 MAX_MEM_LEVEL));
47 if (!def_strm.workspace)
48 return -ENOMEM;
49
50 jffs2_dbg(1, "Allocated %d bytes for deflate workspace\n",
51 zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL));
52 inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
53 if (!inf_strm.workspace) {
54 vfree(def_strm.workspace);
55 return -ENOMEM;
56 }
57 jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
58 zlib_inflate_workspacesize());
59 return 0;
60}
61
62static void free_workspaces(void)
63{
64 vfree(def_strm.workspace);
65 vfree(inf_strm.workspace);
66}
67#else
68#define alloc_workspaces() (0)
69#define free_workspaces() do { } while(0)
70#endif /* __KERNEL__ */
71
72static int jffs2_zlib_compress(unsigned char *data_in,
73 unsigned char *cpage_out,
74 uint32_t *sourcelen, uint32_t *dstlen)
75{
76 int ret;
77
78 if (*dstlen <= STREAM_END_SPACE)
79 return -1;
80
81 mutex_lock(&deflate_mutex);
82
83 if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
84 pr_warn("deflateInit failed\n");
85 mutex_unlock(&deflate_mutex);
86 return -1;
87 }
88
89 def_strm.next_in = data_in;
90 def_strm.total_in = 0;
91
92 def_strm.next_out = cpage_out;
93 def_strm.total_out = 0;
94
95 while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
96 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
97 def_strm.avail_in = min_t(unsigned long,
98 (*sourcelen-def_strm.total_in), def_strm.avail_out);
99 jffs2_dbg(1, "calling deflate with avail_in %ld, avail_out %ld\n",
100 def_strm.avail_in, def_strm.avail_out);
101 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
102 jffs2_dbg(1, "deflate returned with avail_in %ld, avail_out %ld, total_in %ld, total_out %ld\n",
103 def_strm.avail_in, def_strm.avail_out,
104 def_strm.total_in, def_strm.total_out);
105 if (ret != Z_OK) {
106 jffs2_dbg(1, "deflate in loop returned %d\n", ret);
107 zlib_deflateEnd(&def_strm);
108 mutex_unlock(&deflate_mutex);
109 return -1;
110 }
111 }
112 def_strm.avail_out += STREAM_END_SPACE;
113 def_strm.avail_in = 0;
114 ret = zlib_deflate(&def_strm, Z_FINISH);
115 zlib_deflateEnd(&def_strm);
116
117 if (ret != Z_STREAM_END) {
118 jffs2_dbg(1, "final deflate returned %d\n", ret);
119 ret = -1;
120 goto out;
121 }
122
123 if (def_strm.total_out >= def_strm.total_in) {
124 jffs2_dbg(1, "zlib compressed %ld bytes into %ld; failing\n",
125 def_strm.total_in, def_strm.total_out);
126 ret = -1;
127 goto out;
128 }
129
130 jffs2_dbg(1, "zlib compressed %ld bytes into %ld\n",
131 def_strm.total_in, def_strm.total_out);
132
133 *dstlen = def_strm.total_out;
134 *sourcelen = def_strm.total_in;
135 ret = 0;
136 out:
137 mutex_unlock(&deflate_mutex);
138 return ret;
139}
140
141static int jffs2_zlib_decompress(unsigned char *data_in,
142 unsigned char *cpage_out,
143 uint32_t srclen, uint32_t destlen)
144{
145 int ret;
146 int wbits = MAX_WBITS;
147
148 mutex_lock(&inflate_mutex);
149
150 inf_strm.next_in = data_in;
151 inf_strm.avail_in = srclen;
152 inf_strm.total_in = 0;
153
154 inf_strm.next_out = cpage_out;
155 inf_strm.avail_out = destlen;
156 inf_strm.total_out = 0;
157
158 /* If it's deflate, and it's got no preset dictionary, then
159 we can tell zlib to skip the adler32 check. */
160 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
161 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
162 !(((data_in[0]<<8) + data_in[1]) % 31)) {
163
164 jffs2_dbg(2, "inflate skipping adler32\n");
165 wbits = -((data_in[0] >> 4) + 8);
166 inf_strm.next_in += 2;
167 inf_strm.avail_in -= 2;
168 } else {
169 /* Let this remain D1 for now -- it should never happen */
170 jffs2_dbg(1, "inflate not skipping adler32\n");
171 }
172
173
174 if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
175 pr_warn("inflateInit failed\n");
176 mutex_unlock(&inflate_mutex);
177 return 1;
178 }
179
180 while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
181 ;
182 if (ret != Z_STREAM_END) {
183 pr_notice("inflate returned %d\n", ret);
184 }
185 zlib_inflateEnd(&inf_strm);
186 mutex_unlock(&inflate_mutex);
187 return 0;
188}
189
190static struct jffs2_compressor jffs2_zlib_comp = {
191 .priority = JFFS2_ZLIB_PRIORITY,
192 .name = "zlib",
193 .compr = JFFS2_COMPR_ZLIB,
194 .compress = &jffs2_zlib_compress,
195 .decompress = &jffs2_zlib_decompress,
196#ifdef JFFS2_ZLIB_DISABLED
197 .disabled = 1,
198#else
199 .disabled = 0,
200#endif
201};
202
203int __init jffs2_zlib_init(void)
204{
205 int ret;
206
207 ret = alloc_workspaces();
208 if (ret)
209 return ret;
210
211 ret = jffs2_register_compressor(&jffs2_zlib_comp);
212 if (ret)
213 free_workspaces();
214
215 return ret;
216}
217
218void jffs2_zlib_exit(void)
219{
220 jffs2_unregister_compressor(&jffs2_zlib_comp);
221 free_workspaces();
222}