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   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 Red Hat, Inc.
   5  * Created by Arjan van de Ven <arjanv@redhat.com>
   6  *
   7  * Copyright (C) 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  * $Id: compr.c,v 1.46 2005/11/07 11:14:38 gleixner Exp $
  13  *
  14  */
  15
  16 #include "compr.h"
  17
  18 static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
  19
  20 /* Available compressors are on this list */
  21 static LIST_HEAD(jffs2_compressor_list);
  22
  23 /* Actual compression mode */
  24 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
  25
  26 /* Statistics for blocks stored without compression */
  27 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
  28
  29 /* jffs2_compress:
  30  * @data: Pointer to uncompressed data
  31  * @cdata: Pointer to returned pointer to buffer for compressed data
  32  * @datalen: On entry, holds the amount of data available for compression.
  33  *      On exit, expected to hold the amount of data actually compressed.
  34  * @cdatalen: On entry, holds the amount of space available for compressed
  35  *      data. On exit, expected to hold the actual size of the compressed
  36  *      data.
  37  *
  38  * Returns: Lower byte to be stored with data indicating compression type used.
  39  * Zero is used to show that the data could not be compressed - the
  40  * compressed version was actually larger than the original.
  41  * Upper byte will be used later. (soon)
  42  *
  43  * If the cdata buffer isn't large enough to hold all the uncompressed data,
  44  * jffs2_compress should compress as much as will fit, and should set
  45  * *datalen accordingly to show the amount of data which were compressed.
  46  */
  47 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
  48                              unsigned char *data_in, unsigned char **cpage_out,
  49                              uint32_t *datalen, uint32_t *cdatalen)
  50 {
  51         int ret = JFFS2_COMPR_NONE;
  52         int compr_ret;
  53         struct jffs2_compressor *this, *best=NULL;
  54         unsigned char *output_buf = NULL, *tmp_buf;
  55         uint32_t orig_slen, orig_dlen;
  56         uint32_t best_slen=0, best_dlen=0;
  57
  58         switch (jffs2_compression_mode) {
  59         case JFFS2_COMPR_MODE_NONE:
  60                 break;
  61         case JFFS2_COMPR_MODE_PRIORITY:
  62                 output_buf = kmalloc(*cdatalen,GFP_KERNEL);
  63                 if (!output_buf) {
  64                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
  65                         goto out;
  66                 }
  67                 orig_slen = *datalen;
  68                 orig_dlen = *cdatalen;
  69                 spin_lock(&jffs2_compressor_list_lock);
  70                 list_for_each_entry(this, &jffs2_compressor_list, list) {
  71                         /* Skip decompress-only backwards-compatibility and disabled modules */
  72                         if ((!this->compress)||(this->disabled))
  73                                 continue;
  74
  75                         this->usecount++;
  76                         spin_unlock(&jffs2_compressor_list_lock);
  77                         *datalen  = orig_slen;
  78                         *cdatalen = orig_dlen;
  79                         compr_ret = this->compress(data_in, output_buf, datalen, cdatalen, NULL);
  80                         spin_lock(&jffs2_compressor_list_lock);
  81                         this->usecount--;
  82                         if (!compr_ret) {
  83                                 ret = this->compr;
  84                                 this->stat_compr_blocks++;
  85                                 this->stat_compr_orig_size += *datalen;
  86                                 this->stat_compr_new_size  += *cdatalen;
  87                                 break;
  88                         }
  89                 }
  90                 spin_unlock(&jffs2_compressor_list_lock);
  91                 if (ret == JFFS2_COMPR_NONE) kfree(output_buf);
  92                 break;
  93         case JFFS2_COMPR_MODE_SIZE:
  94                 orig_slen = *datalen;
  95                 orig_dlen = *cdatalen;
  96                 spin_lock(&jffs2_compressor_list_lock);
  97                 list_for_each_entry(this, &jffs2_compressor_list, list) {
  98                         /* Skip decompress-only backwards-compatibility and disabled modules */
  99                         if ((!this->compress)||(this->disabled))
 100                                 continue;
 101                         /* Allocating memory for output buffer if necessary */
 102                         if ((this->compr_buf_size<orig_dlen)&&(this->compr_buf)) {
 103                                 spin_unlock(&jffs2_compressor_list_lock);
 104                                 kfree(this->compr_buf);
 105                                 spin_lock(&jffs2_compressor_list_lock);
 106                                 this->compr_buf_size=0;
 107                                 this->compr_buf=NULL;
 108                         }
 109                         if (!this->compr_buf) {
 110                                 spin_unlock(&jffs2_compressor_list_lock);
 111                                 tmp_buf = kmalloc(orig_dlen,GFP_KERNEL);
 112                                 spin_lock(&jffs2_compressor_list_lock);
 113                                 if (!tmp_buf) {
 114                                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n",orig_dlen);
 115                                         continue;
 116                                 }
 117                                 else {
 118                                         this->compr_buf = tmp_buf;
 119                                         this->compr_buf_size = orig_dlen;
 120                                 }
 121                         }
 122                         this->usecount++;
 123                         spin_unlock(&jffs2_compressor_list_lock);
 124                         *datalen  = orig_slen;
 125                         *cdatalen = orig_dlen;
 126                         compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen, NULL);
 127                         spin_lock(&jffs2_compressor_list_lock);
 128                         this->usecount--;
 129                         if (!compr_ret) {
 130                                 if ((!best_dlen)||(best_dlen>*cdatalen)) {
 131                                         best_dlen = *cdatalen;
 132                                         best_slen = *datalen;
 133                                         best = this;
 134                                 }
 135                         }
 136                 }
 137                 if (best_dlen) {
 138                         *cdatalen = best_dlen;
 139                         *datalen  = best_slen;
 140                         output_buf = best->compr_buf;
 141                         best->compr_buf = NULL;
 142                         best->compr_buf_size = 0;
 143                         best->stat_compr_blocks++;
 144                         best->stat_compr_orig_size += best_slen;
 145                         best->stat_compr_new_size  += best_dlen;
 146                         ret = best->compr;
 147                 }
 148                 spin_unlock(&jffs2_compressor_list_lock);
 149                 break;
 150         default:
 151                 printk(KERN_ERR "JFFS2: unknow compression mode.\n");
 152         }
 153  out:
 154         if (ret == JFFS2_COMPR_NONE) {
 155                 *cpage_out = data_in;
 156                 *datalen = *cdatalen;
 157                 none_stat_compr_blocks++;
 158                 none_stat_compr_size += *datalen;
 159         }
 160         else {
 161                 *cpage_out = output_buf;
 162         }
 163         return ret;
 164 }
 165
 166 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
 167                      uint16_t comprtype, unsigned char *cdata_in,
 168                      unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
 169 {
 170         struct jffs2_compressor *this;
 171         int ret;
 172
 173         /* Older code had a bug where it would write non-zero 'usercompr'
 174            fields. Deal with it. */
 175         if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
 176                 comprtype &= 0xff;
 177
 178         switch (comprtype & 0xff) {
 179         case JFFS2_COMPR_NONE:
 180                 /* This should be special-cased elsewhere, but we might as well deal with it */
 181                 memcpy(data_out, cdata_in, datalen);
 182                 none_stat_decompr_blocks++;
 183                 break;
 184         case JFFS2_COMPR_ZERO:
 185                 memset(data_out, 0, datalen);
 186                 break;
 187         default:
 188                 spin_lock(&jffs2_compressor_list_lock);
 189                 list_for_each_entry(this, &jffs2_compressor_list, list) {
 190                         if (comprtype == this->compr) {
 191                                 this->usecount++;
 192                                 spin_unlock(&jffs2_compressor_list_lock);
 193                                 ret = this->decompress(cdata_in, data_out, cdatalen, datalen, NULL);
 194                                 spin_lock(&jffs2_compressor_list_lock);
 195                                 if (ret) {
 196                                         printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
 197                                 }
 198                                 else {
 199                                         this->stat_decompr_blocks++;
 200                                 }
 201                                 this->usecount--;
 202                                 spin_unlock(&jffs2_compressor_list_lock);
 203                                 return ret;
 204                         }
 205                 }
 206                 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
 207                 spin_unlock(&jffs2_compressor_list_lock);
 208                 return -EIO;
 209         }
 210         return 0;
 211 }
 212
 213 int jffs2_register_compressor(struct jffs2_compressor *comp)
 214 {
 215         struct jffs2_compressor *this;
 216
 217         if (!comp->name) {
 218                 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
 219                 return -1;
 220         }
 221         comp->compr_buf_size=0;
 222         comp->compr_buf=NULL;
 223         comp->usecount=0;
 224         comp->stat_compr_orig_size=0;
 225         comp->stat_compr_new_size=0;
 226         comp->stat_compr_blocks=0;
 227         comp->stat_decompr_blocks=0;
 228         D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));
 229
 230         spin_lock(&jffs2_compressor_list_lock);
 231
 232         list_for_each_entry(this, &jffs2_compressor_list, list) {
 233                 if (this->priority < comp->priority) {
 234                         list_add(&comp->list, this->list.prev);
 235                         goto out;
 236                 }
 237         }
 238         list_add_tail(&comp->list, &jffs2_compressor_list);
 239 out:
 240         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
 241                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
 242         })
 243
 244         spin_unlock(&jffs2_compressor_list_lock);
 245
 246         return 0;
 247 }
 248
 249 int jffs2_unregister_compressor(struct jffs2_compressor *comp)
 250 {
 251         D2(struct jffs2_compressor *this;)
 252
 253         D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
 254
 255         spin_lock(&jffs2_compressor_list_lock);
 256
 257         if (comp->usecount) {
 258                 spin_unlock(&jffs2_compressor_list_lock);
 259                 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");
 260                 return -1;
 261         }
 262         list_del(&comp->list);
 263
 264         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
 265                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
 266         })
 267         spin_unlock(&jffs2_compressor_list_lock);
 268         return 0;
 269 }
 270
 271 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
 272 {
 273         if (orig != comprbuf)
 274                 kfree(comprbuf);
 275 }
 276
 277 int __init jffs2_compressors_init(void)
 278 {
 279 /* Registering compressors */
 280 #ifdef CONFIG_JFFS2_ZLIB
 281         jffs2_zlib_init();
 282 #endif
 283 #ifdef CONFIG_JFFS2_RTIME
 284         jffs2_rtime_init();
 285 #endif
 286 #ifdef CONFIG_JFFS2_RUBIN
 287         jffs2_rubinmips_init();
 288         jffs2_dynrubin_init();
 289 #endif
 290 /* Setting default compression mode */
 291 #ifdef CONFIG_JFFS2_CMODE_NONE
 292         jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
 293         D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)
 294 #else
 295 #ifdef CONFIG_JFFS2_CMODE_SIZE
 296         jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
 297         D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)
 298 #else
 299         D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)
 300 #endif
 301 #endif
 302         return 0;
 303 }
 304
 305 int jffs2_compressors_exit(void)
 306 {
 307 /* Unregistering compressors */
 308 #ifdef CONFIG_JFFS2_RUBIN
 309         jffs2_dynrubin_exit();
 310         jffs2_rubinmips_exit();
 311 #endif
 312 #ifdef CONFIG_JFFS2_RTIME
 313         jffs2_rtime_exit();
 314 #endif
 315 #ifdef CONFIG_JFFS2_ZLIB
 316         jffs2_zlib_exit();
 317 #endif
 318         return 0;
 319 }