xref: /openbmc/linux/fs/jffs2/compr_zlib.c (revision 4800cd83)
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright © 2001-2007 Red Hat, Inc.
5  * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6  *
7  * Created by David Woodhouse <dwmw2@infradead.org>
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 #include <linux/kernel.h>
18 #include <linux/zlib.h>
19 #include <linux/zutil.h>
20 #include "nodelist.h"
21 #include "compr.h"
22 
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?
29 	*/
30 #define STREAM_END_SPACE 12
31 
32 static DEFINE_MUTEX(deflate_mutex);
33 static DEFINE_MUTEX(inflate_mutex);
34 static z_stream inf_strm, def_strm;
35 
36 #ifdef __KERNEL__ /* Linux-only */
37 #include <linux/vmalloc.h>
38 #include <linux/init.h>
39 #include <linux/mutex.h>
40 
41 static int __init alloc_workspaces(void)
42 {
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;
47 	}
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;
54 	}
55 	D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
56 	return 0;
57 }
58 
59 static void free_workspaces(void)
60 {
61 	vfree(def_strm.workspace);
62 	vfree(inf_strm.workspace);
63 }
64 #else
65 #define alloc_workspaces() (0)
66 #define free_workspaces() do { } while(0)
67 #endif /* __KERNEL__ */
68 
69 static int jffs2_zlib_compress(unsigned char *data_in,
70 			       unsigned char *cpage_out,
71 			       uint32_t *sourcelen, uint32_t *dstlen)
72 {
73 	int ret;
74 
75 	if (*dstlen <= STREAM_END_SPACE)
76 		return -1;
77 
78 	mutex_lock(&deflate_mutex);
79 
80 	if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
81 		printk(KERN_WARNING "deflateInit failed\n");
82 		mutex_unlock(&deflate_mutex);
83 		return -1;
84 	}
85 
86 	def_strm.next_in = data_in;
87 	def_strm.total_in = 0;
88 
89 	def_strm.next_out = cpage_out;
90 	def_strm.total_out = 0;
91 
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;
105 		}
106 	}
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);
111 
112 	if (ret != Z_STREAM_END) {
113 		D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
114 		ret = -1;
115 		goto out;
116 	}
117 
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;
123 	}
124 
125 	D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
126 		  def_strm.total_in, def_strm.total_out));
127 
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;
134 }
135 
136 static int jffs2_zlib_decompress(unsigned char *data_in,
137 				 unsigned char *cpage_out,
138 				 uint32_t srclen, uint32_t destlen)
139 {
140 	int ret;
141 	int wbits = MAX_WBITS;
142 
143 	mutex_lock(&inflate_mutex);
144 
145 	inf_strm.next_in = data_in;
146 	inf_strm.avail_in = srclen;
147 	inf_strm.total_in = 0;
148 
149 	inf_strm.next_out = cpage_out;
150 	inf_strm.avail_out = destlen;
151 	inf_strm.total_out = 0;
152 
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)) {
158 
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"));
166 	}
167 
168 
169 	if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
170 		printk(KERN_WARNING "inflateInit failed\n");
171 		mutex_unlock(&inflate_mutex);
172 		return 1;
173 	}
174 
175 	while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
176 		;
177 	if (ret != Z_STREAM_END) {
178 		printk(KERN_NOTICE "inflate returned %d\n", ret);
179 	}
180 	zlib_inflateEnd(&inf_strm);
181 	mutex_unlock(&inflate_mutex);
182 	return 0;
183 }
184 
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
196 };
197 
198 int __init jffs2_zlib_init(void)
199 {
200     int ret;
201 
202     ret = alloc_workspaces();
203     if (ret)
204 	    return ret;
205 
206     ret = jffs2_register_compressor(&jffs2_zlib_comp);
207     if (ret)
208 	    free_workspaces();
209 
210     return ret;
211 }
212 
213 void jffs2_zlib_exit(void)
214 {
215     jffs2_unregister_compressor(&jffs2_zlib_comp);
216     free_workspaces();
217 }
218