drivers/mtd/mtd_blkdevs.c

   1 /*
   2  * Interface to Linux block layer for MTD 'translation layers'.
   3  *
   4  * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/list.h>
  26 #include <linux/fs.h>
  27 #include <linux/mtd/blktrans.h>
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/blkdev.h>
  30 #include <linux/blkpg.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/hdreg.h>
  33 #include <linux/init.h>
  34 #include <linux/mutex.h>
  35 #include <linux/kthread.h>
  36 #include <asm/uaccess.h>
  37
  38 #include "mtdcore.h"
  39
  40 static LIST_HEAD(blktrans_majors);
  41 static DEFINE_MUTEX(blktrans_ref_mutex);
  42
  43 #define MTD_MERGE                       1
  44 static void blktrans_dev_release(struct kref *kref)
  45 {
  46         struct mtd_blktrans_dev *dev =
  47                 container_of(kref, struct mtd_blktrans_dev, ref);
  48
  49         dev->disk->private_data = NULL;
  50         blk_cleanup_queue(dev->rq);
  51         put_disk(dev->disk);
  52         list_del(&dev->list);
  53         kfree(dev);
  54 }
  55
  56 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
  57 {
  58         struct mtd_blktrans_dev *dev;
  59
  60         mutex_lock(&blktrans_ref_mutex);
  61         dev = disk->private_data;
  62
  63         if (!dev)
  64                 goto unlock;
  65         kref_get(&dev->ref);
  66 unlock:
  67         mutex_unlock(&blktrans_ref_mutex);
  68         return dev;
  69 }
  70
  71 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
  72 {
  73         mutex_lock(&blktrans_ref_mutex);
  74         kref_put(&dev->ref, blktrans_dev_release);
  75         mutex_unlock(&blktrans_ref_mutex);
  76 }
  77
  78 #if(MTD_MERGE == 0)
  79 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
  80                                struct mtd_blktrans_dev *dev,
  81                                struct request *req)
  82 {
  83         unsigned long block, nsect;
  84         char *buf;
  85 #if 0
  86         block = blk_rq_pos(req) << 9 >> tr->blkshift;
  87         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
  88 #else  //modify by zyf for cap>=4GB 20110120
  89         block = blk_rq_pos(req);
  90         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
  91     if(tr->blkshift != 9)
  92     {
  93         if(tr->blkshift > 9)
  94         {
  95             block = blk_rq_pos(req) >> (tr->blkshift - 9);
  96         }
  97         else
  98         {
  99                 block = blk_rq_pos(req) << (9 - tr->blkshift);
 100         }
 101     }
 102 #endif
 103
 104         buf = req->buffer;
 105
 106         if (req->cmd_type != REQ_TYPE_FS)
 107                 return -EIO;
 108
 109         if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
 110             get_capacity(req->rq_disk))
 111                 return -EIO;
 112
 113         if (req->cmd_flags & REQ_DISCARD)
 114                 return tr->discard(dev, block, nsect);
 115
 116         switch(rq_data_dir(req)) {
 117         case READ:
 118                 //for (; nsect > 0; nsect--, block++, buf += tr->blksize)
 119                         if (tr->readsect(dev, block,nsect, buf))
 120                                 return -EIO;
 121                 rq_flush_dcache_pages(req);
 122                 return 0;
 123         case WRITE:
 124                 if (!tr->writesect)
 125                         return -EIO;
 126
 127                 rq_flush_dcache_pages(req);
 128                 //for (; nsect > 0; nsect--, block++, buf += tr->blksize)
 129                         if (tr->writesect(dev, block,nsect, buf))
 130                                 return -EIO;
 131                 return 0;
 132         default:
 133                 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
 134                 return -EIO;
 135         }
 136 }
 137
 138 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
 139 {
 140         if (kthread_should_stop())
 141                 return 1;
 142
 143         return dev->bg_stop;
 144 }
 145 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
 146
 147 static int mtd_blktrans_thread(void *arg)
 148 {
 149         struct mtd_blktrans_dev *dev = arg;
 150         struct mtd_blktrans_ops *tr = dev->tr;
 151         struct request_queue *rq = dev->rq;
 152         struct request *req = NULL;
 153         int background_done = 0;
 154
 155         spin_lock_irq(rq->queue_lock);
 156
 157         while (!kthread_should_stop()) {
 158                 int res;
 159
 160                 dev->bg_stop = false;
 161                 if (!req && !(req = blk_fetch_request(rq))) {
 162                         if (tr->background && !background_done) {
 163                                 spin_unlock_irq(rq->queue_lock);
 164                                 mutex_lock(&dev->lock);
 165                                 tr->background(dev);
 166                                 mutex_unlock(&dev->lock);
 167                                 spin_lock_irq(rq->queue_lock);
 168                                 /*
 169                                  * Do background processing just once per idle
 170                                  * period.
 171                                  */
 172                                 background_done = !dev->bg_stop;
 173                                 continue;
 174                         }
 175                         set_current_state(TASK_INTERRUPTIBLE);
 176
 177                         if (kthread_should_stop())
 178                                 set_current_state(TASK_RUNNING);
 179
 180                         spin_unlock_irq(rq->queue_lock);
 181                         schedule();
 182                         spin_lock_irq(rq->queue_lock);
 183                         continue;
 184                 }
 185
 186                 spin_unlock_irq(rq->queue_lock);
 187
 188                 mutex_lock(&dev->lock);
 189                 res = do_blktrans_request(dev->tr, dev, req);
 190                 mutex_unlock(&dev->lock);
 191
 192                 spin_lock_irq(rq->queue_lock);
 193
 194                 if (!__blk_end_request_cur(req, res))
 195                         req = NULL;
 196
 197                 background_done = 0;
 198         }
 199
 200         if (req)
 201                 __blk_end_request_all(req, -EIO);
 202
 203         spin_unlock_irq(rq->queue_lock);
 204
 205         return 0;
 206 }
 207 #else
 208
 209 #define MTD_RW_SECTORS  (2048)     // 2048 (BLK_SAFE_MAX_SECTORS+1)
 210 static char * mtd_rw_buffer;       //[MTD_RW_SECTORS*512]   __attribute__((aligned(4096)));
 211 struct mutex  mtd_rw_buffer_lock;
 212 static int req_check_buffer_align(struct request *req,char **pbuf)
 213 {
 214     int    nr_vec = 0;
 215     struct bio_vec *bv;
 216     struct req_iterator iter;
 217     char *buffer;
 218     void *firstbuf = 0;
 219     char *nextbuffer = 0;
 220         unsigned long block, nsect;
 221         block = blk_rq_pos(req);
 222         nsect = blk_rq_cur_bytes(req) >> 9;
 223         rq_for_each_segment(bv, req, iter)
 224         {
 225             buffer = page_address(bv->bv_page) + bv->bv_offset;
 226             if( firstbuf == 0 )
 227             {
 228             firstbuf = buffer;
 229             }
 230         nr_vec++;
 231         if(nextbuffer!=0)
 232         {
 233             if(nextbuffer!=buffer)
 234             {
 235                 return 0;
 236             }
 237         }
 238         nextbuffer = buffer+bv->bv_len;
 239         }
 240         *pbuf = firstbuf;
 241         return 1;
 242 }
 243
 244
 245 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
 246 {
 247         if (kthread_should_stop())
 248                 return 1;
 249
 250         return dev->bg_stop;
 251 }
 252 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
 253
 254 static int mtd_blktrans_thread(void *arg)
 255 {
 256         struct mtd_blktrans_dev *dev = arg;
 257         struct mtd_blktrans_ops *tr = dev->tr;
 258         struct request_queue *rq = dev->rq;
 259         struct request *req = NULL;
 260         int background_done = 0;
 261
 262         unsigned long block, data_len;
 263         char *buf = NULL;
 264         struct req_iterator rq_iter;
 265         struct bio_vec *bvec;
 266         int cmd_flag;
 267
 268     set_user_nice(current,-20);
 269         spin_lock_irq(rq->queue_lock);
 270
 271         while (!kthread_should_stop()) {
 272                 int res;
 273
 274                 dev->bg_stop = false;
 275                 if (!req && !(req = blk_fetch_request(rq))) {
 276                         if (tr->background && !background_done) {
 277                                 spin_unlock_irq(rq->queue_lock);
 278                                 mutex_lock(&dev->lock);
 279                                 tr->background(dev);
 280                                 mutex_unlock(&dev->lock);
 281                                 spin_lock_irq(rq->queue_lock);
 282                                 /*
 283                                  * Do background processing just once per idle
 284                                  * period.
 285                                  */
 286                                 background_done = !dev->bg_stop;
 287                                 continue;
 288                         }
 289                         set_current_state(TASK_INTERRUPTIBLE);
 290
 291                         if (kthread_should_stop())
 292                                 set_current_state(TASK_RUNNING);
 293
 294                         spin_unlock_irq(rq->queue_lock);
 295                         schedule();
 296                         spin_lock_irq(rq->queue_lock);
 297                         continue;
 298                 }
 299         if ((req->cmd_type != REQ_TYPE_FS) || (blk_rq_pos(req) + blk_rq_sectors(req) > get_capacity(req->rq_disk)))
 300         {
 301             __blk_end_request_all(req, -EIO);
 302                 req = NULL;
 303                     background_done = 0;
 304                 continue;
 305         }
 306                 spin_unlock_irq(rq->queue_lock);
 307         mutex_lock(&dev->lock);
 308
 309             block = blk_rq_pos(req);
 310             data_len = 0;
 311                 buf = 0;
 312                 res = 0;
 313             cmd_flag = rq_data_dir(req);
 314             //i = 0;
 315         if(cmd_flag == READ && mtd_rw_buffer)
 316         {
 317                 unsigned long nsect;
 318             buf = mtd_rw_buffer;
 319             req_check_buffer_align(req,&buf);
 320             nsect = req->__data_len >> 9;
 321             if( nsect > MTD_RW_SECTORS ) {
 322                 printk("%s..%d::nsect=%d,too large , may be error!\n",__FILE__,__LINE__, nsect );
 323                 nsect = MTD_RW_SECTORS;
 324                 while(1);
 325             }
 326                         if(buf == mtd_rw_buffer )
 327                 mutex_lock(&mtd_rw_buffer_lock);
 328                 if (tr->readsect(dev, block,nsect, buf))
 329                     res = -EIO;
 330             if( buf == mtd_rw_buffer )
 331             {
 332                 char *p = buf;
 333                     rq_for_each_segment(bvec, req, rq_iter)
 334                 {
 335                     memcpy( page_address(bvec->bv_page) + bvec->bv_offset , p , bvec->bv_len );
 336                     flush_dcache_page(bvec->bv_page); //zyf rq_flush_dcache_pages(req);
 337                     p += bvec->bv_len;
 338                 }
 339                 mutex_unlock(&mtd_rw_buffer_lock);
 340             }
 341             //rq_flush_dcache_pages(req);
 342         }
 343         else
 344         {
 345                 rq_for_each_segment(bvec, req, rq_iter)
 346                 {
 347                 //printk("%d buf = %x, lba = %llx , nsec=%x ,offset = %x\n",i,page_address(bvec->bv_page) + bvec->bv_offset,((rq_iter.bio)->bi_sector),(bvec->bv_len),(bvec->bv_offset));
 348                 //i++;
 349                 flush_dcache_page(bvec->bv_page); //zyf rq_flush_dcache_pages(req);
 350                 if((page_address(bvec->bv_page) + bvec->bv_offset) == (buf + data_len))
 351                 {
 352                     data_len += bvec->bv_len;
 353                 }
 354                 else
 355                 {
 356                     if(data_len)
 357                     {
 358                         //printk("buf = %x, lba = %lx , nsec=%x \n",buf,block,data_len);
 359                         switch(cmd_flag)
 360                         {
 361                         case READ:
 362                                         if (tr->readsect(dev, block,data_len>>9, buf))
 363                                                 res = -EIO;
 364                                 //rq_flush_dcache_pages(req);
 365                                 break;
 366                         case WRITE:
 367                                 //if (!tr->writesect)
 368                                 //      res = -EIO;
 369                                 //rq_flush_dcache_pages(req);
 370                                         if (tr->writesect(dev, block,data_len>>9, buf))
 371                                                 res = -EIO;
 372                                 break;
 373                         default:
 374                                 //printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
 375                                         res = -EIO;
 376                                 break;
 377                         }
 378                     }
 379                                 block += data_len>>9;
 380                                 buf = (page_address(bvec->bv_page) + bvec->bv_offset);
 381                                 data_len = bvec->bv_len;
 382                 }
 383                 }
 384
 385             if(data_len)
 386             {
 387                 //printk("buf = %x, lba = %lx , nsec=%x \n",buf,block,data_len);
 388                 switch(cmd_flag)
 389                 {
 390                 case READ:
 391                                 if (tr->readsect(dev, block,data_len>>9, buf))
 392                                         res = -EIO;
 393                         //rq_flush_dcache_pages(req);
 394                         break;
 395                 case WRITE:
 396                         //if (!tr->writesect)
 397                         //      res = -EIO;
 398                         //rq_flush_dcache_pages(req);
 399                                 if (tr->writesect(dev, block,data_len>>9, buf))
 400                                         res = -EIO;
 401                         break;
 402                 default:
 403                         //printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
 404                                 res = -EIO;
 405                         break;
 406                 }
 407             }
 408         }
 409         mutex_unlock(&dev->lock);
 410                 spin_lock_irq(rq->queue_lock);
 411                 //printk("__blk_end_request_all %d\n",res);
 412                 __blk_end_request_all(req, res);
 413                 req = NULL;
 414                 background_done = 0;
 415         }
 416
 417         if (req)
 418                 __blk_end_request_all(req, -EIO);
 419
 420         spin_unlock_irq(rq->queue_lock);
 421
 422         return 0;
 423 }
 424 #endif
 425 static void mtd_blktrans_request(struct request_queue *rq)
 426 {
 427         struct mtd_blktrans_dev *dev;
 428         struct request *req = NULL;
 429
 430         dev = rq->queuedata;
 431
 432         if (!dev)
 433                 while ((req = blk_fetch_request(rq)) != NULL)
 434                         __blk_end_request_all(req, -ENODEV);
 435         else {
 436                 dev->bg_stop = true;
 437                 wake_up_process(dev->thread);
 438         }
 439 }
 440
 441 static int blktrans_open(struct block_device *bdev, fmode_t mode)
 442 {
 443         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
 444         int ret = 0;
 445
 446         if (!dev)
 447                 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
 448
 449         mutex_lock(&dev->lock);
 450
 451         if (dev->open)
 452                 goto unlock;
 453
 454         kref_get(&dev->ref);
 455         __module_get(dev->tr->owner);
 456
 457         if (!dev->mtd)
 458                 goto unlock;
 459
 460         if (dev->tr->open) {
 461                 ret = dev->tr->open(dev);
 462                 if (ret)
 463                         goto error_put;
 464         }
 465
 466         ret = __get_mtd_device(dev->mtd);
 467         if (ret)
 468                 goto error_release;
 469
 470 unlock:
 471         dev->open++;
 472         mutex_unlock(&dev->lock);
 473         blktrans_dev_put(dev);
 474         return ret;
 475
 476 error_release:
 477         if (dev->tr->release)
 478                 dev->tr->release(dev);
 479 error_put:
 480         module_put(dev->tr->owner);
 481         kref_put(&dev->ref, blktrans_dev_release);
 482         mutex_unlock(&dev->lock);
 483         blktrans_dev_put(dev);
 484         return ret;
 485 }
 486
 487 static int blktrans_release(struct gendisk *disk, fmode_t mode)
 488 {
 489         struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
 490         int ret = 0;
 491
 492         if (!dev)
 493                 return ret;
 494
 495         mutex_lock(&dev->lock);
 496
 497         if (--dev->open)
 498                 goto unlock;
 499
 500         kref_put(&dev->ref, blktrans_dev_release);
 501         module_put(dev->tr->owner);
 502
 503         if (dev->mtd) {
 504                 ret = dev->tr->release ? dev->tr->release(dev) : 0;
 505                 __put_mtd_device(dev->mtd);
 506         }
 507 unlock:
 508         mutex_unlock(&dev->lock);
 509         blktrans_dev_put(dev);
 510         return ret;
 511 }
 512
 513 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 514 {
 515         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
 516         int ret = -ENXIO;
 517
 518         if (!dev)
 519                 return ret;
 520
 521         mutex_lock(&dev->lock);
 522
 523         if (!dev->mtd)
 524                 goto unlock;
 525
 526         ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
 527 unlock:
 528         mutex_unlock(&dev->lock);
 529         blktrans_dev_put(dev);
 530         return ret;
 531 }
 532
 533 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
 534                               unsigned int cmd, unsigned long arg)
 535 {
 536         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
 537         int ret = -ENXIO;
 538
 539         if (!dev)
 540                 return ret;
 541
 542         mutex_lock(&dev->lock);
 543
 544         if (!dev->mtd)
 545                 goto unlock;
 546
 547         switch (cmd) {
 548         case BLKFLSBUF:
 549                 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
 550                 break;
 551         default:
 552                 ret = -ENOTTY;
 553         }
 554 unlock:
 555         mutex_unlock(&dev->lock);
 556         blktrans_dev_put(dev);
 557         return ret;
 558 }
 559
 560 static const struct block_device_operations mtd_blktrans_ops = {
 561         .owner          = THIS_MODULE,
 562         .open           = blktrans_open,
 563         .release        = blktrans_release,
 564         .ioctl          = blktrans_ioctl,
 565         .getgeo         = blktrans_getgeo,
 566 };
 567
 568 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 569 {
 570         struct mtd_blktrans_ops *tr = new->tr;
 571         struct mtd_blktrans_dev *d;
 572         int last_devnum = -1;
 573         struct gendisk *gd;
 574         int ret;
 575
 576         if (mutex_trylock(&mtd_table_mutex)) {
 577                 mutex_unlock(&mtd_table_mutex);
 578                 BUG();
 579         }
 580
 581         mutex_lock(&blktrans_ref_mutex);
 582         list_for_each_entry(d, &tr->devs, list) {
 583                 if (new->devnum == -1) {
 584                         /* Use first free number */
 585                         if (d->devnum != last_devnum+1) {
 586                                 /* Found a free devnum. Plug it in here */
 587                                 new->devnum = last_devnum+1;
 588                                 list_add_tail(&new->list, &d->list);
 589                                 goto added;
 590                         }
 591                 } else if (d->devnum == new->devnum) {
 592                         /* Required number taken */
 593                         mutex_unlock(&blktrans_ref_mutex);
 594                         return -EBUSY;
 595                 } else if (d->devnum > new->devnum) {
 596                         /* Required number was free */
 597                         list_add_tail(&new->list, &d->list);
 598                         goto added;
 599                 }
 600                 last_devnum = d->devnum;
 601         }
 602
 603         ret = -EBUSY;
 604         if (new->devnum == -1)
 605                 new->devnum = last_devnum+1;
 606
 607         /* Check that the device and any partitions will get valid
 608          * minor numbers and that the disk naming code below can cope
 609          * with this number. */
 610         if (new->devnum > (MINORMASK >> tr->part_bits) ||
 611             (tr->part_bits && new->devnum >= 27 * 26)) {
 612                 mutex_unlock(&blktrans_ref_mutex);
 613                 goto error1;
 614         }
 615
 616         list_add_tail(&new->list, &tr->devs);
 617  added:
 618         mutex_unlock(&blktrans_ref_mutex);
 619
 620         mutex_init(&new->lock);
 621         kref_init(&new->ref);
 622         if (!tr->writesect)
 623                 new->readonly = 1;
 624
 625         /* Create gendisk */
 626         ret = -ENOMEM;
 627         gd = alloc_disk(1 << tr->part_bits);
 628
 629         if (!gd)
 630                 goto error2;
 631
 632         new->disk = gd;
 633         gd->private_data = new;
 634         gd->major = tr->major;
 635         gd->first_minor = (new->devnum) << tr->part_bits;
 636         gd->fops = &mtd_blktrans_ops;
 637
 638         if (tr->part_bits)
 639                 if (new->devnum < 26)
 640                         snprintf(gd->disk_name, sizeof(gd->disk_name),
 641                                  "%s%c", tr->name, 'a' + new->devnum);
 642                 else
 643                         snprintf(gd->disk_name, sizeof(gd->disk_name),
 644                                  "%s%c%c", tr->name,
 645                                  'a' - 1 + new->devnum / 26,
 646                                  'a' + new->devnum % 26);
 647         else
 648                 snprintf(gd->disk_name, sizeof(gd->disk_name),
 649                          "%s%d", tr->name, new->devnum);
 650
 651         /* 2.5 has capacity in units of 512 bytes while still
 652            having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
 653         //set_capacity(gd, (new->size * tr->blksize) >> 9);
 654         set_capacity(gd, (new->size >> 9) * tr->blksize);   //modify by zyf for cap>=4GB 20110120
 655
 656         /* Create the request queue */
 657         spin_lock_init(&new->queue_lock);
 658         new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
 659
 660         if (!new->rq)
 661                 goto error3;
 662
 663         new->rq->queuedata = new;
 664         blk_queue_logical_block_size(new->rq, tr->blksize);
 665
 666 #if (MTD_MERGE == 1)
 667     blk_queue_max_hw_sectors(new->rq,MTD_RW_SECTORS);
 668         //blk_queue_max_segment_size(new->rq,MTD_RW_SECTORS);
 669         blk_queue_max_segments(new->rq, MTD_RW_SECTORS);// /PAGE_CACHE_SIZE
 670 #endif
 671
 672         if (tr->discard) {
 673                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq);
 674                 new->rq->limits.max_discard_sectors = UINT_MAX;
 675         }
 676
 677         gd->queue = new->rq;
 678
 679         /* Create processing thread */
 680         /* TODO: workqueue ? */
 681         new->thread = kthread_run(mtd_blktrans_thread, new,
 682                         "%s%d", tr->name, new->mtd->index);
 683         if (IS_ERR(new->thread)) {
 684                 ret = PTR_ERR(new->thread);
 685                 goto error4;
 686         }
 687         gd->driverfs_dev = &new->mtd->dev;
 688
 689         if (new->readonly)
 690                 set_disk_ro(gd, 1);
 691
 692         add_disk(gd);
 693
 694         if (new->disk_attributes) {
 695                 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
 696                                         new->disk_attributes);
 697                 WARN_ON(ret);
 698         }
 699         return 0;
 700 error4:
 701         blk_cleanup_queue(new->rq);
 702 error3:
 703         put_disk(new->disk);
 704 error2:
 705         list_del(&new->list);
 706 error1:
 707         return ret;
 708 }
 709
 710 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
 711 {
 712         unsigned long flags;
 713
 714         if (mutex_trylock(&mtd_table_mutex)) {
 715                 mutex_unlock(&mtd_table_mutex);
 716                 BUG();
 717         }
 718
 719         if (old->disk_attributes)
 720                 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
 721                                                 old->disk_attributes);
 722
 723         /* Stop new requests to arrive */
 724         del_gendisk(old->disk);
 725
 726
 727         /* Stop the thread */
 728         kthread_stop(old->thread);
 729
 730         /* Kill current requests */
 731         spin_lock_irqsave(&old->queue_lock, flags);
 732         old->rq->queuedata = NULL;
 733         blk_start_queue(old->rq);
 734         spin_unlock_irqrestore(&old->queue_lock, flags);
 735
 736         /* If the device is currently open, tell trans driver to close it,
 737                 then put mtd device, and don't touch it again */
 738         mutex_lock(&old->lock);
 739         if (old->open) {
 740                 if (old->tr->release)
 741                         old->tr->release(old);
 742                 __put_mtd_device(old->mtd);
 743         }
 744
 745         old->mtd = NULL;
 746
 747         mutex_unlock(&old->lock);
 748         blktrans_dev_put(old);
 749         return 0;
 750 }
 751
 752 static void blktrans_notify_remove(struct mtd_info *mtd)
 753 {
 754         struct mtd_blktrans_ops *tr;
 755         struct mtd_blktrans_dev *dev, *next;
 756
 757         list_for_each_entry(tr, &blktrans_majors, list)
 758                 list_for_each_entry_safe(dev, next, &tr->devs, list)
 759                         if (dev->mtd == mtd)
 760                                 tr->remove_dev(dev);
 761 }
 762
 763 static void blktrans_notify_add(struct mtd_info *mtd)
 764 {
 765         struct mtd_blktrans_ops *tr;
 766
 767         if (mtd->type == MTD_ABSENT)
 768                 return;
 769
 770         list_for_each_entry(tr, &blktrans_majors, list)
 771                 tr->add_mtd(tr, mtd);
 772 }
 773
 774 static struct mtd_notifier blktrans_notifier = {
 775         .add = blktrans_notify_add,
 776         .remove = blktrans_notify_remove,
 777 };
 778
 779 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 780 {
 781         struct mtd_info *mtd;
 782         int ret;
 783 #if(MTD_MERGE != 0)
 784         mutex_init(&mtd_rw_buffer_lock);
 785     mtd_rw_buffer = kmalloc(MTD_RW_SECTORS*512, GFP_KERNEL | GFP_DMA);
 786 #endif
 787         /* Register the notifier if/when the first device type is
 788            registered, to prevent the link/init ordering from fucking
 789            us over. */
 790         if (!blktrans_notifier.list.next)
 791                 register_mtd_user(&blktrans_notifier);
 792
 793
 794         mutex_lock(&mtd_table_mutex);
 795
 796         ret = register_blkdev(tr->major, tr->name);
 797         if (ret < 0) {
 798                 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
 799                        tr->name, tr->major, ret);
 800                 mutex_unlock(&mtd_table_mutex);
 801                 return ret;
 802         }
 803
 804         if (ret)
 805                 tr->major = ret;
 806
 807         tr->blkshift = ffs(tr->blksize) - 1;
 808
 809         INIT_LIST_HEAD(&tr->devs);
 810         list_add(&tr->list, &blktrans_majors);
 811
 812         mtd_for_each_device(mtd)
 813                 if (mtd->type != MTD_ABSENT)
 814                         tr->add_mtd(tr, mtd);
 815
 816         mutex_unlock(&mtd_table_mutex);
 817         return 0;
 818 }
 819
 820 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
 821 {
 822         struct mtd_blktrans_dev *dev, *next;
 823
 824         mutex_lock(&mtd_table_mutex);
 825
 826         /* Remove it from the list of active majors */
 827         list_del(&tr->list);
 828
 829         list_for_each_entry_safe(dev, next, &tr->devs, list)
 830                 tr->remove_dev(dev);
 831
 832         unregister_blkdev(tr->major, tr->name);
 833         mutex_unlock(&mtd_table_mutex);
 834
 835         BUG_ON(!list_empty(&tr->devs));
 836         return 0;
 837 }
 838
 839 static void __exit mtd_blktrans_exit(void)
 840 {
 841         /* No race here -- if someone's currently in register_mtd_blktrans
 842            we're screwed anyway. */
 843         if (blktrans_notifier.list.next)
 844                 unregister_mtd_user(&blktrans_notifier);
 845 }
 846
 847 module_exit(mtd_blktrans_exit);
 848
 849 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
 850 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
 851 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
 852 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
 853
 854 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 855 MODULE_LICENSE("GPL");
 856 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");