1 /* 2 * JFFS2 -- Journalling Flash File System, Version 2. 3 * 4 * Copyright © 2001-2007 Red Hat, Inc. 5 * Created by Arjan van de Ven <arjanv@redhat.com> 6 * 7 * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>, 8 * University of Szeged, Hungary 9 * 10 * For licensing information, see the file 'LICENCE' in this directory. 11 * 12 */ 13 14 #include "compr.h" 15 16 static DEFINE_SPINLOCK(jffs2_compressor_list_lock); 17 18 /* Available compressors are on this list */ 19 static LIST_HEAD(jffs2_compressor_list); 20 21 /* Actual compression mode */ 22 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY; 23 24 /* Statistics for blocks stored without compression */ 25 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0; 26 27 28 /* 29 * Return 1 to use this compression 30 */ 31 static int jffs2_is_best_compression(struct jffs2_compressor *this, 32 struct jffs2_compressor *best, uint32_t size, uint32_t bestsize) 33 { 34 switch (jffs2_compression_mode) { 35 case JFFS2_COMPR_MODE_SIZE: 36 if (bestsize > size) 37 return 1; 38 return 0; 39 case JFFS2_COMPR_MODE_FAVOURLZO: 40 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size)) 41 return 1; 42 if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size)) 43 return 1; 44 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100))) 45 return 1; 46 if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size) 47 return 1; 48 49 return 0; 50 } 51 /* Shouldn't happen */ 52 return 0; 53 } 54 55 /* jffs2_compress: 56 * @data_in: Pointer to uncompressed data 57 * @cpage_out: Pointer to returned pointer to buffer for compressed data 58 * @datalen: On entry, holds the amount of data available for compression. 59 * On exit, expected to hold the amount of data actually compressed. 60 * @cdatalen: On entry, holds the amount of space available for compressed 61 * data. On exit, expected to hold the actual size of the compressed 62 * data. 63 * 64 * Returns: Lower byte to be stored with data indicating compression type used. 65 * Zero is used to show that the data could not be compressed - the 66 * compressed version was actually larger than the original. 67 * Upper byte will be used later. (soon) 68 * 69 * If the cdata buffer isn't large enough to hold all the uncompressed data, 70 * jffs2_compress should compress as much as will fit, and should set 71 * *datalen accordingly to show the amount of data which were compressed. 72 */ 73 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 74 unsigned char *data_in, unsigned char **cpage_out, 75 uint32_t *datalen, uint32_t *cdatalen) 76 { 77 int ret = JFFS2_COMPR_NONE; 78 int compr_ret; 79 struct jffs2_compressor *this, *best=NULL; 80 unsigned char *output_buf = NULL, *tmp_buf; 81 uint32_t orig_slen, orig_dlen; 82 uint32_t best_slen=0, best_dlen=0; 83 84 switch (jffs2_compression_mode) { 85 case JFFS2_COMPR_MODE_NONE: 86 break; 87 case JFFS2_COMPR_MODE_PRIORITY: 88 output_buf = kmalloc(*cdatalen,GFP_KERNEL); 89 if (!output_buf) { 90 printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n"); 91 goto out; 92 } 93 orig_slen = *datalen; 94 orig_dlen = *cdatalen; 95 spin_lock(&jffs2_compressor_list_lock); 96 list_for_each_entry(this, &jffs2_compressor_list, list) { 97 /* Skip decompress-only backwards-compatibility and disabled modules */ 98 if ((!this->compress)||(this->disabled)) 99 continue; 100 101 this->usecount++; 102 spin_unlock(&jffs2_compressor_list_lock); 103 *datalen = orig_slen; 104 *cdatalen = orig_dlen; 105 compr_ret = this->compress(data_in, output_buf, datalen, cdatalen, NULL); 106 spin_lock(&jffs2_compressor_list_lock); 107 this->usecount--; 108 if (!compr_ret) { 109 ret = this->compr; 110 this->stat_compr_blocks++; 111 this->stat_compr_orig_size += *datalen; 112 this->stat_compr_new_size += *cdatalen; 113 break; 114 } 115 } 116 spin_unlock(&jffs2_compressor_list_lock); 117 if (ret == JFFS2_COMPR_NONE) 118 kfree(output_buf); 119 break; 120 case JFFS2_COMPR_MODE_SIZE: 121 case JFFS2_COMPR_MODE_FAVOURLZO: 122 orig_slen = *datalen; 123 orig_dlen = *cdatalen; 124 spin_lock(&jffs2_compressor_list_lock); 125 list_for_each_entry(this, &jffs2_compressor_list, list) { 126 /* Skip decompress-only backwards-compatibility and disabled modules */ 127 if ((!this->compress)||(this->disabled)) 128 continue; 129 /* Allocating memory for output buffer if necessary */ 130 if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) { 131 spin_unlock(&jffs2_compressor_list_lock); 132 kfree(this->compr_buf); 133 spin_lock(&jffs2_compressor_list_lock); 134 this->compr_buf_size=0; 135 this->compr_buf=NULL; 136 } 137 if (!this->compr_buf) { 138 spin_unlock(&jffs2_compressor_list_lock); 139 tmp_buf = kmalloc(orig_slen, GFP_KERNEL); 140 spin_lock(&jffs2_compressor_list_lock); 141 if (!tmp_buf) { 142 printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n", orig_slen); 143 continue; 144 } 145 else { 146 this->compr_buf = tmp_buf; 147 this->compr_buf_size = orig_slen; 148 } 149 } 150 this->usecount++; 151 spin_unlock(&jffs2_compressor_list_lock); 152 *datalen = orig_slen; 153 *cdatalen = orig_dlen; 154 compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen, NULL); 155 spin_lock(&jffs2_compressor_list_lock); 156 this->usecount--; 157 if (!compr_ret) { 158 if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen)) 159 && (*cdatalen < *datalen)) { 160 best_dlen = *cdatalen; 161 best_slen = *datalen; 162 best = this; 163 } 164 } 165 } 166 if (best_dlen) { 167 *cdatalen = best_dlen; 168 *datalen = best_slen; 169 output_buf = best->compr_buf; 170 best->compr_buf = NULL; 171 best->compr_buf_size = 0; 172 best->stat_compr_blocks++; 173 best->stat_compr_orig_size += best_slen; 174 best->stat_compr_new_size += best_dlen; 175 ret = best->compr; 176 } 177 spin_unlock(&jffs2_compressor_list_lock); 178 break; 179 default: 180 printk(KERN_ERR "JFFS2: unknown compression mode.\n"); 181 } 182 out: 183 if (ret == JFFS2_COMPR_NONE) { 184 *cpage_out = data_in; 185 *datalen = *cdatalen; 186 none_stat_compr_blocks++; 187 none_stat_compr_size += *datalen; 188 } 189 else { 190 *cpage_out = output_buf; 191 } 192 return ret; 193 } 194 195 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f, 196 uint16_t comprtype, unsigned char *cdata_in, 197 unsigned char *data_out, uint32_t cdatalen, uint32_t datalen) 198 { 199 struct jffs2_compressor *this; 200 int ret; 201 202 /* Older code had a bug where it would write non-zero 'usercompr' 203 fields. Deal with it. */ 204 if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB) 205 comprtype &= 0xff; 206 207 switch (comprtype & 0xff) { 208 case JFFS2_COMPR_NONE: 209 /* This should be special-cased elsewhere, but we might as well deal with it */ 210 memcpy(data_out, cdata_in, datalen); 211 none_stat_decompr_blocks++; 212 break; 213 case JFFS2_COMPR_ZERO: 214 memset(data_out, 0, datalen); 215 break; 216 default: 217 spin_lock(&jffs2_compressor_list_lock); 218 list_for_each_entry(this, &jffs2_compressor_list, list) { 219 if (comprtype == this->compr) { 220 this->usecount++; 221 spin_unlock(&jffs2_compressor_list_lock); 222 ret = this->decompress(cdata_in, data_out, cdatalen, datalen, NULL); 223 spin_lock(&jffs2_compressor_list_lock); 224 if (ret) { 225 printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret); 226 } 227 else { 228 this->stat_decompr_blocks++; 229 } 230 this->usecount--; 231 spin_unlock(&jffs2_compressor_list_lock); 232 return ret; 233 } 234 } 235 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype); 236 spin_unlock(&jffs2_compressor_list_lock); 237 return -EIO; 238 } 239 return 0; 240 } 241 242 int jffs2_register_compressor(struct jffs2_compressor *comp) 243 { 244 struct jffs2_compressor *this; 245 246 if (!comp->name) { 247 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n"); 248 return -1; 249 } 250 comp->compr_buf_size=0; 251 comp->compr_buf=NULL; 252 comp->usecount=0; 253 comp->stat_compr_orig_size=0; 254 comp->stat_compr_new_size=0; 255 comp->stat_compr_blocks=0; 256 comp->stat_decompr_blocks=0; 257 D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name)); 258 259 spin_lock(&jffs2_compressor_list_lock); 260 261 list_for_each_entry(this, &jffs2_compressor_list, list) { 262 if (this->priority < comp->priority) { 263 list_add(&comp->list, this->list.prev); 264 goto out; 265 } 266 } 267 list_add_tail(&comp->list, &jffs2_compressor_list); 268 out: 269 D2(list_for_each_entry(this, &jffs2_compressor_list, list) { 270 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); 271 }) 272 273 spin_unlock(&jffs2_compressor_list_lock); 274 275 return 0; 276 } 277 278 int jffs2_unregister_compressor(struct jffs2_compressor *comp) 279 { 280 D2(struct jffs2_compressor *this;) 281 282 D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name)); 283 284 spin_lock(&jffs2_compressor_list_lock); 285 286 if (comp->usecount) { 287 spin_unlock(&jffs2_compressor_list_lock); 288 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n"); 289 return -1; 290 } 291 list_del(&comp->list); 292 293 D2(list_for_each_entry(this, &jffs2_compressor_list, list) { 294 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority); 295 }) 296 spin_unlock(&jffs2_compressor_list_lock); 297 return 0; 298 } 299 300 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig) 301 { 302 if (orig != comprbuf) 303 kfree(comprbuf); 304 } 305 306 int __init jffs2_compressors_init(void) 307 { 308 /* Registering compressors */ 309 #ifdef CONFIG_JFFS2_ZLIB 310 jffs2_zlib_init(); 311 #endif 312 #ifdef CONFIG_JFFS2_RTIME 313 jffs2_rtime_init(); 314 #endif 315 #ifdef CONFIG_JFFS2_RUBIN 316 jffs2_rubinmips_init(); 317 jffs2_dynrubin_init(); 318 #endif 319 #ifdef CONFIG_JFFS2_LZO 320 jffs2_lzo_init(); 321 #endif 322 /* Setting default compression mode */ 323 #ifdef CONFIG_JFFS2_CMODE_NONE 324 jffs2_compression_mode = JFFS2_COMPR_MODE_NONE; 325 D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");) 326 #else 327 #ifdef CONFIG_JFFS2_CMODE_SIZE 328 jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE; 329 D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");) 330 #else 331 #ifdef CONFIG_JFFS2_CMODE_FAVOURLZO 332 jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO; 333 D1(printk(KERN_INFO "JFFS2: default compression mode: favourlzo\n");) 334 #else 335 D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");) 336 #endif 337 #endif 338 #endif 339 return 0; 340 } 341 342 int jffs2_compressors_exit(void) 343 { 344 /* Unregistering compressors */ 345 #ifdef CONFIG_JFFS2_LZO 346 jffs2_lzo_exit(); 347 #endif 348 #ifdef CONFIG_JFFS2_RUBIN 349 jffs2_dynrubin_exit(); 350 jffs2_rubinmips_exit(); 351 #endif 352 #ifdef CONFIG_JFFS2_RTIME 353 jffs2_rtime_exit(); 354 #endif 355 #ifdef CONFIG_JFFS2_ZLIB 356 jffs2_zlib_exit(); 357 #endif 358 return 0; 359 } 360