xref: /openbmc/linux/fs/jffs2/compr_zlib.c (revision d97b07c5)
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 #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 
34 static DEFINE_MUTEX(deflate_mutex);
35 static DEFINE_MUTEX(inflate_mutex);
36 static 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 
alloc_workspaces(void)43 static 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 
free_workspaces(void)62 static 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 
jffs2_zlib_compress(unsigned char * data_in,unsigned char * cpage_out,uint32_t * sourcelen,uint32_t * dstlen)72 static 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 
jffs2_zlib_decompress(unsigned char * data_in,unsigned char * cpage_out,uint32_t srclen,uint32_t destlen)141 static 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 
190 static 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 
jffs2_zlib_init(void)203 int __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 
jffs2_zlib_exit(void)218 void jffs2_zlib_exit(void)
219 {
220     jffs2_unregister_compressor(&jffs2_zlib_comp);
221     free_workspaces();
222 }
223