1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright (C) 2001-2003 Red Hat, Inc. 5 * 6 * Created by David Woodhouse <dwmw2@infradead.org> 7 * 8 * For licensing information, see the file 'LICENCE' in this directory. 9 * 10 * $Id: compr_zlib.c,v 1.29 2004/11/16 20:36:11 dwmw2 Exp $ 11 * 12 */ 13 14 #if !defined(__KERNEL__) && !defined(__ECOS) 15 #error "The userspace support got too messy and was removed. Update your mkfs.jffs2" 16 #endif 17 18 #include <linux/config.h> 19 #include <linux/kernel.h> 20 #include <linux/slab.h> 21 #include <linux/zlib.h> 22 #include <linux/zutil.h> 23 #include <asm/semaphore.h> 24 #include "nodelist.h" 25 #include "compr.h" 26 27 /* Plan: call deflate() with avail_in == *sourcelen, 28 avail_out = *dstlen - 12 and flush == Z_FINISH. 29 If it doesn't manage to finish, call it again with 30 avail_in == 0 and avail_out set to the remaining 12 31 bytes for it to clean up. 32 Q: Is 12 bytes sufficient? 33 */ 34 #define STREAM_END_SPACE 12 35 36 static DECLARE_MUTEX(deflate_sem); 37 static DECLARE_MUTEX(inflate_sem); 38 static z_stream inf_strm, def_strm; 39 40 #ifdef __KERNEL__ /* Linux-only */ 41 #include <linux/vmalloc.h> 42 #include <linux/init.h> 43 44 static int __init alloc_workspaces(void) 45 { 46 def_strm.workspace = vmalloc(zlib_deflate_workspacesize()); 47 if (!def_strm.workspace) { 48 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize()); 49 return -ENOMEM; 50 } 51 D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize())); 52 inf_strm.workspace = vmalloc(zlib_inflate_workspacesize()); 53 if (!inf_strm.workspace) { 54 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize()); 55 vfree(def_strm.workspace); 56 return -ENOMEM; 57 } 58 D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize())); 59 return 0; 60 } 61 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 72 static int jffs2_zlib_compress(unsigned char *data_in, 73 unsigned char *cpage_out, 74 uint32_t *sourcelen, uint32_t *dstlen, 75 void *model) 76 { 77 int ret; 78 79 if (*dstlen <= STREAM_END_SPACE) 80 return -1; 81 82 down(&deflate_sem); 83 84 if (Z_OK != zlib_deflateInit(&def_strm, 3)) { 85 printk(KERN_WARNING "deflateInit failed\n"); 86 up(&deflate_sem); 87 return -1; 88 } 89 90 def_strm.next_in = data_in; 91 def_strm.total_in = 0; 92 93 def_strm.next_out = cpage_out; 94 def_strm.total_out = 0; 95 96 while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) { 97 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE); 98 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out); 99 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n", 100 def_strm.avail_in, def_strm.avail_out)); 101 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH); 102 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n", 103 def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out)); 104 if (ret != Z_OK) { 105 D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret)); 106 zlib_deflateEnd(&def_strm); 107 up(&deflate_sem); 108 return -1; 109 } 110 } 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); 115 116 if (ret != Z_STREAM_END) { 117 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret)); 118 ret = -1; 119 goto out; 120 } 121 122 if (def_strm.total_out >= def_strm.total_in) { 123 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n", 124 def_strm.total_in, def_strm.total_out)); 125 ret = -1; 126 goto out; 127 } 128 129 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n", 130 def_strm.total_in, def_strm.total_out)); 131 132 *dstlen = def_strm.total_out; 133 *sourcelen = def_strm.total_in; 134 ret = 0; 135 out: 136 up(&deflate_sem); 137 return ret; 138 } 139 140 static int jffs2_zlib_decompress(unsigned char *data_in, 141 unsigned char *cpage_out, 142 uint32_t srclen, uint32_t destlen, 143 void *model) 144 { 145 int ret; 146 int wbits = MAX_WBITS; 147 148 down(&inflate_sem); 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 D2(printk(KERN_DEBUG "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 D1(printk(KERN_DEBUG "inflate not skipping adler32\n")); 171 } 172 173 174 if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) { 175 printk(KERN_WARNING "inflateInit failed\n"); 176 up(&inflate_sem); 177 return 1; 178 } 179 180 while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK) 181 ; 182 if (ret != Z_STREAM_END) { 183 printk(KERN_NOTICE "inflate returned %d\n", ret); 184 } 185 zlib_inflateEnd(&inf_strm); 186 up(&inflate_sem); 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 }; 202 203 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 } 217 218 void jffs2_zlib_exit(void) 219 { 220 jffs2_unregister_compressor(&jffs2_zlib_comp); 221 free_workspaces(); 222 } 223