Merge branch 'v6v7' into devel
[linux/fpc-iii.git] / fs / jffs2 / compr_zlib.c
blobfd05a0b9431df3e2bb37ed3b4bed29a131c37ffd
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 #include <linux/kernel.h>
18 #include <linux/zlib.h>
19 #include <linux/zutil.h>
20 #include "nodelist.h"
21 #include "compr.h"
23 /* Plan: call deflate() with avail_in == *sourcelen,
24 avail_out = *dstlen - 12 and flush == Z_FINISH.
25 If it doesn't manage to finish, call it again with
26 avail_in == 0 and avail_out set to the remaining 12
27 bytes for it to clean up.
28 Q: Is 12 bytes sufficient?
30 #define STREAM_END_SPACE 12
32 static DEFINE_MUTEX(deflate_mutex);
33 static DEFINE_MUTEX(inflate_mutex);
34 static z_stream inf_strm, def_strm;
36 #ifdef __KERNEL__ /* Linux-only */
37 #include <linux/vmalloc.h>
38 #include <linux/init.h>
39 #include <linux/mutex.h>
41 static int __init alloc_workspaces(void)
43 def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
44 if (!def_strm.workspace) {
45 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
46 return -ENOMEM;
48 D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
49 inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
50 if (!inf_strm.workspace) {
51 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
52 vfree(def_strm.workspace);
53 return -ENOMEM;
55 D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
56 return 0;
59 static void free_workspaces(void)
61 vfree(def_strm.workspace);
62 vfree(inf_strm.workspace);
64 #else
65 #define alloc_workspaces() (0)
66 #define free_workspaces() do { } while(0)
67 #endif /* __KERNEL__ */
69 static int jffs2_zlib_compress(unsigned char *data_in,
70 unsigned char *cpage_out,
71 uint32_t *sourcelen, uint32_t *dstlen)
73 int ret;
75 if (*dstlen <= STREAM_END_SPACE)
76 return -1;
78 mutex_lock(&deflate_mutex);
80 if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
81 printk(KERN_WARNING "deflateInit failed\n");
82 mutex_unlock(&deflate_mutex);
83 return -1;
86 def_strm.next_in = data_in;
87 def_strm.total_in = 0;
89 def_strm.next_out = cpage_out;
90 def_strm.total_out = 0;
92 while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
93 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
94 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
95 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
96 def_strm.avail_in, def_strm.avail_out));
97 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
98 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
99 def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
100 if (ret != Z_OK) {
101 D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
102 zlib_deflateEnd(&def_strm);
103 mutex_unlock(&deflate_mutex);
104 return -1;
107 def_strm.avail_out += STREAM_END_SPACE;
108 def_strm.avail_in = 0;
109 ret = zlib_deflate(&def_strm, Z_FINISH);
110 zlib_deflateEnd(&def_strm);
112 if (ret != Z_STREAM_END) {
113 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
114 ret = -1;
115 goto out;
118 if (def_strm.total_out >= def_strm.total_in) {
119 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
120 def_strm.total_in, def_strm.total_out));
121 ret = -1;
122 goto out;
125 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
126 def_strm.total_in, def_strm.total_out));
128 *dstlen = def_strm.total_out;
129 *sourcelen = def_strm.total_in;
130 ret = 0;
131 out:
132 mutex_unlock(&deflate_mutex);
133 return ret;
136 static int jffs2_zlib_decompress(unsigned char *data_in,
137 unsigned char *cpage_out,
138 uint32_t srclen, uint32_t destlen)
140 int ret;
141 int wbits = MAX_WBITS;
143 mutex_lock(&inflate_mutex);
145 inf_strm.next_in = data_in;
146 inf_strm.avail_in = srclen;
147 inf_strm.total_in = 0;
149 inf_strm.next_out = cpage_out;
150 inf_strm.avail_out = destlen;
151 inf_strm.total_out = 0;
153 /* If it's deflate, and it's got no preset dictionary, then
154 we can tell zlib to skip the adler32 check. */
155 if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
156 ((data_in[0] & 0x0f) == Z_DEFLATED) &&
157 !(((data_in[0]<<8) + data_in[1]) % 31)) {
159 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
160 wbits = -((data_in[0] >> 4) + 8);
161 inf_strm.next_in += 2;
162 inf_strm.avail_in -= 2;
163 } else {
164 /* Let this remain D1 for now -- it should never happen */
165 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
169 if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
170 printk(KERN_WARNING "inflateInit failed\n");
171 mutex_unlock(&inflate_mutex);
172 return 1;
175 while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
177 if (ret != Z_STREAM_END) {
178 printk(KERN_NOTICE "inflate returned %d\n", ret);
180 zlib_inflateEnd(&inf_strm);
181 mutex_unlock(&inflate_mutex);
182 return 0;
185 static struct jffs2_compressor jffs2_zlib_comp = {
186 .priority = JFFS2_ZLIB_PRIORITY,
187 .name = "zlib",
188 .compr = JFFS2_COMPR_ZLIB,
189 .compress = &jffs2_zlib_compress,
190 .decompress = &jffs2_zlib_decompress,
191 #ifdef JFFS2_ZLIB_DISABLED
192 .disabled = 1,
193 #else
194 .disabled = 0,
195 #endif
198 int __init jffs2_zlib_init(void)
200 int ret;
202 ret = alloc_workspaces();
203 if (ret)
204 return ret;
206 ret = jffs2_register_compressor(&jffs2_zlib_comp);
207 if (ret)
208 free_workspaces();
210 return ret;
213 void jffs2_zlib_exit(void)
215 jffs2_unregister_compressor(&jffs2_zlib_comp);
216 free_workspaces();