Linux 3.8-rc7
[cris-mirror.git] / fs / jffs2 / compr_zlib.c
blob0b9a1e44e833e691e2fc8dd2ca3135274113aad3
1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
4 * Copyright © 2001-2007 Red Hat, Inc.
5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
7 * Created by David Woodhouse <dwmw2@infradead.org>
9 * For licensing information, see the file 'LICENCE' in this directory.
13 #if !defined(__KERNEL__) && !defined(__ECOS)
14 #error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
15 #endif
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 #include <linux/kernel.h>
20 #include <linux/zlib.h>
21 #include <linux/zutil.h>
22 #include "nodelist.h"
23 #include "compr.h"
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?
32 #define STREAM_END_SPACE 12
34 static DEFINE_MUTEX(deflate_mutex);
35 static DEFINE_MUTEX(inflate_mutex);
36 static z_stream inf_strm, def_strm;
38 #ifdef __KERNEL__ /* Linux-only */
39 #include <linux/vmalloc.h>
40 #include <linux/init.h>
41 #include <linux/mutex.h>
43 static int __init alloc_workspaces(void)
45 def_strm.workspace = vmalloc(zlib_deflate_workspacesize(MAX_WBITS,
46 MAX_MEM_LEVEL));
47 if (!def_strm.workspace)
48 return -ENOMEM;
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;
57 jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
58 zlib_inflate_workspacesize());
59 return 0;
62 static void free_workspaces(void)
64 vfree(def_strm.workspace);
65 vfree(inf_strm.workspace);
67 #else
68 #define alloc_workspaces() (0)
69 #define free_workspaces() do { } while(0)
70 #endif /* __KERNEL__ */
72 static int jffs2_zlib_compress(unsigned char *data_in,
73 unsigned char *cpage_out,
74 uint32_t *sourcelen, uint32_t *dstlen)
76 int ret;
78 if (*dstlen <= STREAM_END_SPACE)
79 return -1;
81 mutex_lock(&deflate_mutex);
83 if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
84 pr_warn("deflateInit failed\n");
85 mutex_unlock(&deflate_mutex);
86 return -1;
89 def_strm.next_in = data_in;
90 def_strm.total_in = 0;
92 def_strm.next_out = cpage_out;
93 def_strm.total_out = 0;
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((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
98 jffs2_dbg(1, "calling deflate with avail_in %d, avail_out %d\n",
99 def_strm.avail_in, def_strm.avail_out);
100 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
101 jffs2_dbg(1, "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
102 def_strm.avail_in, def_strm.avail_out,
103 def_strm.total_in, def_strm.total_out);
104 if (ret != Z_OK) {
105 jffs2_dbg(1, "deflate in loop returned %d\n", ret);
106 zlib_deflateEnd(&def_strm);
107 mutex_unlock(&deflate_mutex);
108 return -1;
111 def_strm.avail_out += STREAM_END_SPACE;
112 def_strm.avail_in = 0;
113 ret = zlib_deflate(&def_strm, Z_FINISH);
114 zlib_deflateEnd(&def_strm);
116 if (ret != Z_STREAM_END) {
117 jffs2_dbg(1, "final deflate returned %d\n", ret);
118 ret = -1;
119 goto out;
122 if (def_strm.total_out >= def_strm.total_in) {
123 jffs2_dbg(1, "zlib compressed %ld bytes into %ld; failing\n",
124 def_strm.total_in, def_strm.total_out);
125 ret = -1;
126 goto out;
129 jffs2_dbg(1, "zlib compressed %ld bytes into %ld\n",
130 def_strm.total_in, def_strm.total_out);
132 *dstlen = def_strm.total_out;
133 *sourcelen = def_strm.total_in;
134 ret = 0;
135 out:
136 mutex_unlock(&deflate_mutex);
137 return ret;
140 static int jffs2_zlib_decompress(unsigned char *data_in,
141 unsigned char *cpage_out,
142 uint32_t srclen, uint32_t destlen)
144 int ret;
145 int wbits = MAX_WBITS;
147 mutex_lock(&inflate_mutex);
149 inf_strm.next_in = data_in;
150 inf_strm.avail_in = srclen;
151 inf_strm.total_in = 0;
153 inf_strm.next_out = cpage_out;
154 inf_strm.avail_out = destlen;
155 inf_strm.total_out = 0;
157 /* If it's deflate, and it's got no preset dictionary, then
158 we can tell zlib to skip the adler32 check. */
159 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
160 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
161 !(((data_in[0]<<8) + data_in[1]) % 31)) {
163 jffs2_dbg(2, "inflate skipping adler32\n");
164 wbits = -((data_in[0] >> 4) + 8);
165 inf_strm.next_in += 2;
166 inf_strm.avail_in -= 2;
167 } else {
168 /* Let this remain D1 for now -- it should never happen */
169 jffs2_dbg(1, "inflate not skipping adler32\n");
173 if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
174 pr_warn("inflateInit failed\n");
175 mutex_unlock(&inflate_mutex);
176 return 1;
179 while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
181 if (ret != Z_STREAM_END) {
182 pr_notice("inflate returned %d\n", ret);
184 zlib_inflateEnd(&inf_strm);
185 mutex_unlock(&inflate_mutex);
186 return 0;
189 static struct jffs2_compressor jffs2_zlib_comp = {
190 .priority = JFFS2_ZLIB_PRIORITY,
191 .name = "zlib",
192 .compr = JFFS2_COMPR_ZLIB,
193 .compress = &jffs2_zlib_compress,
194 .decompress = &jffs2_zlib_decompress,
195 #ifdef JFFS2_ZLIB_DISABLED
196 .disabled = 1,
197 #else
198 .disabled = 0,
199 #endif
202 int __init jffs2_zlib_init(void)
204 int ret;
206 ret = alloc_workspaces();
207 if (ret)
208 return ret;
210 ret = jffs2_register_compressor(&jffs2_zlib_comp);
211 if (ret)
212 free_workspaces();
214 return ret;
217 void jffs2_zlib_exit(void)
219 jffs2_unregister_compressor(&jffs2_zlib_comp);
220 free_workspaces();