fs/partitions/check.c

   1 /*
   2  *  fs/partitions/check.c
   3  *
   4  *  Code extracted from drivers/block/genhd.c
   5  *  Copyright (C) 1991-1998  Linus Torvalds
   6  *  Re-organised Feb 1998 Russell King
   7  *
   8  *  We now have independent partition support from the
   9  *  block drivers, which allows all the partition code to
  10  *  be grouped in one location, and it to be mostly self
  11  *  contained.
  12  *
  13  *  Added needed MAJORS for new pairs, {hdi,hdj}, {hdk,hdl}
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/slab.h>
  20 #include <linux/kmod.h>
  21 #include <linux/ctype.h>
  22 #include <linux/genhd.h>
  23 #include <linux/blktrace_api.h>
  24
  25 #include "check.h"
  26
  27 #include "acorn.h"
  28 #include "amiga.h"
  29 #include "atari.h"
  30 #include "ldm.h"
  31 #include "mac.h"
  32 #include "msdos.h"
  33 #include "osf.h"
  34 #include "sgi.h"
  35 #include "sun.h"
  36 #include "ibm.h"
  37 #include "ultrix.h"
  38 #include "efi.h"
  39 #include "karma.h"
  40 #include "sysv68.h"
  41
  42 #ifdef CONFIG_BLK_DEV_MD
  43 extern void md_autodetect_dev(dev_t dev);
  44 #endif
  45
  46 int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
  47
  48 static int (*check_part[])(struct parsed_partitions *) = {
  49         /*
  50          * Probe partition formats with tables at disk address 0
  51          * that also have an ADFS boot block at 0xdc0.
  52          */
  53 #ifdef CONFIG_ACORN_PARTITION_ICS
  54         adfspart_check_ICS,
  55 #endif
  56 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
  57         adfspart_check_POWERTEC,
  58 #endif
  59 #ifdef CONFIG_ACORN_PARTITION_EESOX
  60         adfspart_check_EESOX,
  61 #endif
  62
  63         /*
  64          * Now move on to formats that only have partition info at
  65          * disk address 0xdc0.  Since these may also have stale
  66          * PC/BIOS partition tables, they need to come before
  67          * the msdos entry.
  68          */
  69 #ifdef CONFIG_ACORN_PARTITION_CUMANA
  70         adfspart_check_CUMANA,
  71 #endif
  72 #ifdef CONFIG_ACORN_PARTITION_ADFS
  73         adfspart_check_ADFS,
  74 #endif
  75
  76 #ifdef CONFIG_EFI_PARTITION
  77         efi_partition,          /* this must come before msdos */
  78 #endif
  79 #ifdef CONFIG_SGI_PARTITION
  80         sgi_partition,
  81 #endif
  82 #ifdef CONFIG_LDM_PARTITION
  83         ldm_partition,          /* this must come before msdos */
  84 #endif
  85 #ifdef CONFIG_MSDOS_PARTITION
  86         msdos_partition,
  87 #endif
  88 #ifdef CONFIG_OSF_PARTITION
  89         osf_partition,
  90 #endif
  91 #ifdef CONFIG_SUN_PARTITION
  92         sun_partition,
  93 #endif
  94 #ifdef CONFIG_AMIGA_PARTITION
  95         amiga_partition,
  96 #endif
  97 #ifdef CONFIG_ATARI_PARTITION
  98         atari_partition,
  99 #endif
 100 #ifdef CONFIG_MAC_PARTITION
 101         mac_partition,
 102 #endif
 103 #ifdef CONFIG_ULTRIX_PARTITION
 104         ultrix_partition,
 105 #endif
 106 #ifdef CONFIG_IBM_PARTITION
 107         ibm_partition,
 108 #endif
 109 #ifdef CONFIG_KARMA_PARTITION
 110         karma_partition,
 111 #endif
 112 #ifdef CONFIG_SYSV68_PARTITION
 113         sysv68_partition,
 114 #endif
 115         NULL
 116 };
 117
 118 /*
 119  * disk_name() is used by partition check code and the genhd driver.
 120  * It formats the devicename of the indicated disk into
 121  * the supplied buffer (of size at least 32), and returns
 122  * a pointer to that same buffer (for convenience).
 123  */
 124
 125 char *disk_name(struct gendisk *hd, int partno, char *buf)
 126 {
 127         if (!partno)
 128                 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
 129         else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
 130                 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
 131         else
 132                 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
 133
 134         return buf;
 135 }
 136
 137 const char *bdevname(struct block_device *bdev, char *buf)
 138 {
 139         return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
 140 }
 141
 142 EXPORT_SYMBOL(bdevname);
 143
 144 /*
 145  * There's very little reason to use this, you should really
 146  * have a struct block_device just about everywhere and use
 147  * bdevname() instead.
 148  */
 149 const char *__bdevname(dev_t dev, char *buffer)
 150 {
 151         scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
 152                                 MAJOR(dev), MINOR(dev));
 153         return buffer;
 154 }
 155
 156 EXPORT_SYMBOL(__bdevname);
 157
 158 static struct parsed_partitions *
 159 check_partition(struct gendisk *hd, struct block_device *bdev)
 160 {
 161         struct parsed_partitions *state;
 162         int i, res, err;
 163
 164         state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
 165         if (!state)
 166                 return NULL;
 167         state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
 168         if (!state->pp_buf) {
 169                 kfree(state);
 170                 return NULL;
 171         }
 172         state->pp_buf[0] = '\0';
 173
 174         state->bdev = bdev;
 175         disk_name(hd, 0, state->name);
 176         snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
 177         if (isdigit(state->name[strlen(state->name)-1]))
 178                 sprintf(state->name, "p");
 179
 180         state->limit = disk_max_parts(hd);
 181         i = res = err = 0;
 182         while (!res && check_part[i]) {
 183                 memset(&state->parts, 0, sizeof(state->parts));
 184                 res = check_part[i++](state);
 185                 if (res < 0) {
 186                         /* We have hit an I/O error which we don't report now.
 187                         * But record it, and let the others do their job.
 188                         */
 189                         err = res;
 190                         res = 0;
 191                 }
 192
 193         }
 194         if (res > 0) {
 195                 printk(KERN_INFO "%s", state->pp_buf);
 196
 197                 free_page((unsigned long)state->pp_buf);
 198                 return state;
 199         }
 200         if (state->access_beyond_eod)
 201                 err = -ENOSPC;
 202         if (err)
 203         /* The partition is unrecognized. So report I/O errors if there were any */
 204                 res = err;
 205         if (!res)
 206                 strlcat(state->pp_buf, " unknown partition table\n", PAGE_SIZE);
 207         else if (warn_no_part)
 208                 strlcat(state->pp_buf, " unable to read partition table\n", PAGE_SIZE);
 209
 210         printk(KERN_INFO "%s", state->pp_buf);
 211
 212         free_page((unsigned long)state->pp_buf);
 213         kfree(state);
 214         return ERR_PTR(res);
 215 }
 216
 217 static ssize_t part_partition_show(struct device *dev,
 218                                    struct device_attribute *attr, char *buf)
 219 {
 220         struct hd_struct *p = dev_to_part(dev);
 221
 222         return sprintf(buf, "%d\n", p->partno);
 223 }
 224
 225 static ssize_t part_start_show(struct device *dev,
 226                                struct device_attribute *attr, char *buf)
 227 {
 228         struct hd_struct *p = dev_to_part(dev);
 229
 230         return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
 231 }
 232
 233 ssize_t part_size_show(struct device *dev,
 234                        struct device_attribute *attr, char *buf)
 235 {
 236         struct hd_struct *p = dev_to_part(dev);
 237         return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
 238 }
 239
 240 ssize_t part_ro_show(struct device *dev,
 241                        struct device_attribute *attr, char *buf)
 242 {
 243         struct hd_struct *p = dev_to_part(dev);
 244         return sprintf(buf, "%d\n", p->policy ? 1 : 0);
 245 }
 246
 247 ssize_t part_alignment_offset_show(struct device *dev,
 248                                    struct device_attribute *attr, char *buf)
 249 {
 250         struct hd_struct *p = dev_to_part(dev);
 251         return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
 252 }
 253
 254 ssize_t part_discard_alignment_show(struct device *dev,
 255                                    struct device_attribute *attr, char *buf)
 256 {
 257         struct hd_struct *p = dev_to_part(dev);
 258         return sprintf(buf, "%u\n", p->discard_alignment);
 259 }
 260
 261 ssize_t part_stat_show(struct device *dev,
 262                        struct device_attribute *attr, char *buf)
 263 {
 264         struct hd_struct *p = dev_to_part(dev);
 265         int cpu;
 266
 267         cpu = part_stat_lock();
 268         part_round_stats(cpu, p);
 269         part_stat_unlock();
 270         return sprintf(buf,
 271                 "%8lu %8lu %8llu %8u "
 272                 "%8lu %8lu %8llu %8u "
 273                 "%8u %8u %8u"
 274                 "\n",
 275                 part_stat_read(p, ios[READ]),
 276                 part_stat_read(p, merges[READ]),
 277                 (unsigned long long)part_stat_read(p, sectors[READ]),
 278                 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
 279                 part_stat_read(p, ios[WRITE]),
 280                 part_stat_read(p, merges[WRITE]),
 281                 (unsigned long long)part_stat_read(p, sectors[WRITE]),
 282                 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
 283                 part_in_flight(p),
 284                 jiffies_to_msecs(part_stat_read(p, io_ticks)),
 285                 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
 286 }
 287
 288 ssize_t part_inflight_show(struct device *dev,
 289                         struct device_attribute *attr, char *buf)
 290 {
 291         struct hd_struct *p = dev_to_part(dev);
 292
 293         return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
 294                 atomic_read(&p->in_flight[1]));
 295 }
 296
 297 #ifdef CONFIG_FAIL_MAKE_REQUEST
 298 ssize_t part_fail_show(struct device *dev,
 299                        struct device_attribute *attr, char *buf)
 300 {
 301         struct hd_struct *p = dev_to_part(dev);
 302
 303         return sprintf(buf, "%d\n", p->make_it_fail);
 304 }
 305
 306 ssize_t part_fail_store(struct device *dev,
 307                         struct device_attribute *attr,
 308                         const char *buf, size_t count)
 309 {
 310         struct hd_struct *p = dev_to_part(dev);
 311         int i;
 312
 313         if (count > 0 && sscanf(buf, "%d", &i) > 0)
 314                 p->make_it_fail = (i == 0) ? 0 : 1;
 315
 316         return count;
 317 }
 318 #endif
 319
 320 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
 321 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
 322 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 323 static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
 324 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
 325 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
 326                    NULL);
 327 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 328 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
 329 #ifdef CONFIG_FAIL_MAKE_REQUEST
 330 static struct device_attribute dev_attr_fail =
 331         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 332 #endif
 333
 334 static struct attribute *part_attrs[] = {
 335         &dev_attr_partition.attr,
 336         &dev_attr_start.attr,
 337         &dev_attr_size.attr,
 338         &dev_attr_ro.attr,
 339         &dev_attr_alignment_offset.attr,
 340         &dev_attr_discard_alignment.attr,
 341         &dev_attr_stat.attr,
 342         &dev_attr_inflight.attr,
 343 #ifdef CONFIG_FAIL_MAKE_REQUEST
 344         &dev_attr_fail.attr,
 345 #endif
 346         NULL
 347 };
 348
 349 static struct attribute_group part_attr_group = {
 350         .attrs = part_attrs,
 351 };
 352
 353 static const struct attribute_group *part_attr_groups[] = {
 354         &part_attr_group,
 355 #ifdef CONFIG_BLK_DEV_IO_TRACE
 356         &blk_trace_attr_group,
 357 #endif
 358         NULL
 359 };
 360
 361 static void part_release(struct device *dev)
 362 {
 363         struct hd_struct *p = dev_to_part(dev);
 364         free_part_stats(p);
 365         free_part_info(p);
 366         kfree(p);
 367 }
 368
 369 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
 370 {
 371         struct hd_struct *part = dev_to_part(dev);
 372
 373         add_uevent_var(env, "PARTN=%u", part->partno);
 374         if (part->info && part->info->volname[0])
 375                 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
 376         return 0;
 377 }
 378
 379 struct device_type part_type = {
 380         .name           = "partition",
 381         .groups         = part_attr_groups,
 382         .release        = part_release,
 383         .uevent         = part_uevent,
 384 };
 385
 386 static void delete_partition_rcu_cb(struct rcu_head *head)
 387 {
 388         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
 389
 390         part->start_sect = 0;
 391         part->nr_sects = 0;
 392         part_stat_set_all(part, 0);
 393         put_device(part_to_dev(part));
 394 }
 395
 396 void __delete_partition(struct hd_struct *part)
 397 {
 398         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 399 }
 400
 401 void delete_partition(struct gendisk *disk, int partno)
 402 {
 403         struct disk_part_tbl *ptbl = disk->part_tbl;
 404         struct hd_struct *part;
 405
 406         if (partno >= ptbl->len)
 407                 return;
 408
 409         part = ptbl->part[partno];
 410         if (!part)
 411                 return;
 412
 413         blk_free_devt(part_devt(part));
 414         rcu_assign_pointer(ptbl->part[partno], NULL);
 415         rcu_assign_pointer(ptbl->last_lookup, NULL);
 416         kobject_put(part->holder_dir);
 417         device_del(part_to_dev(part));
 418
 419         hd_struct_put(part);
 420 }
 421
 422 static ssize_t whole_disk_show(struct device *dev,
 423                                struct device_attribute *attr, char *buf)
 424 {
 425         return 0;
 426 }
 427 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 428                    whole_disk_show, NULL);
 429
 430 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 431                                 sector_t start, sector_t len, int flags,
 432                                 struct partition_meta_info *info)
 433 {
 434         struct hd_struct *p;
 435         dev_t devt = MKDEV(0, 0);
 436         struct device *ddev = disk_to_dev(disk);
 437         struct device *pdev;
 438         struct disk_part_tbl *ptbl;
 439         const char *dname;
 440         int err;
 441
 442         err = disk_expand_part_tbl(disk, partno);
 443         if (err)
 444                 return ERR_PTR(err);
 445         ptbl = disk->part_tbl;
 446
 447         if (ptbl->part[partno])
 448                 return ERR_PTR(-EBUSY);
 449
 450         p = kzalloc(sizeof(*p), GFP_KERNEL);
 451         if (!p)
 452                 return ERR_PTR(-EBUSY);
 453
 454         if (!init_part_stats(p)) {
 455                 err = -ENOMEM;
 456                 goto out_free;
 457         }
 458         pdev = part_to_dev(p);
 459
 460         p->start_sect = start;
 461         p->alignment_offset =
 462                 queue_limit_alignment_offset(&disk->queue->limits, start);
 463         p->discard_alignment =
 464                 queue_limit_discard_alignment(&disk->queue->limits, start);
 465         p->nr_sects = len;
 466         p->partno = partno;
 467         p->policy = get_disk_ro(disk);
 468
 469         if (info) {
 470                 struct partition_meta_info *pinfo = alloc_part_info(disk);
 471                 if (!pinfo)
 472                         goto out_free_stats;
 473                 memcpy(pinfo, info, sizeof(*info));
 474                 p->info = pinfo;
 475         }
 476
 477         dname = dev_name(ddev);
 478         if (isdigit(dname[strlen(dname) - 1]))
 479                 dev_set_name(pdev, "%sp%d", dname, partno);
 480         else
 481                 dev_set_name(pdev, "%s%d", dname, partno);
 482
 483         device_initialize(pdev);
 484         pdev->class = &block_class;
 485         pdev->type = &part_type;
 486         pdev->parent = ddev;
 487
 488         err = blk_alloc_devt(p, &devt);
 489         if (err)
 490                 goto out_free_info;
 491         pdev->devt = devt;
 492
 493         /* delay uevent until 'holders' subdir is created */
 494         dev_set_uevent_suppress(pdev, 1);
 495         err = device_add(pdev);
 496         if (err)
 497                 goto out_put;
 498
 499         err = -ENOMEM;
 500         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
 501         if (!p->holder_dir)
 502                 goto out_del;
 503
 504         dev_set_uevent_suppress(pdev, 0);
 505         if (flags & ADDPART_FLAG_WHOLEDISK) {
 506                 err = device_create_file(pdev, &dev_attr_whole_disk);
 507                 if (err)
 508                         goto out_del;
 509         }
 510
 511         /* everything is up and running, commence */
 512         rcu_assign_pointer(ptbl->part[partno], p);
 513
 514         /* suppress uevent if the disk suppresses it */
 515         if (!dev_get_uevent_suppress(ddev))
 516                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 517
 518         hd_ref_init(p);
 519         return p;
 520
 521 out_free_info:
 522         free_part_info(p);
 523 out_free_stats:
 524         free_part_stats(p);
 525 out_free:
 526         kfree(p);
 527         return ERR_PTR(err);
 528 out_del:
 529         kobject_put(p->holder_dir);
 530         device_del(pdev);
 531 out_put:
 532         put_device(pdev);
 533         blk_free_devt(devt);
 534         return ERR_PTR(err);
 535 }
 536
 537 static bool disk_unlock_native_capacity(struct gendisk *disk)
 538 {
 539         const struct block_device_operations *bdops = disk->fops;
 540
 541         if (bdops->unlock_native_capacity &&
 542             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
 543                 printk(KERN_CONT "enabling native capacity\n");
 544                 bdops->unlock_native_capacity(disk);
 545                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
 546                 return true;
 547         } else {
 548                 printk(KERN_CONT "truncated\n");
 549                 return false;
 550         }
 551 }
 552
 553 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 554 {
 555         struct parsed_partitions *state = NULL;
 556         struct disk_part_iter piter;
 557         struct hd_struct *part;
 558         int p, highest, res;
 559 rescan:
 560         if (state && !IS_ERR(state)) {
 561                 kfree(state);
 562                 state = NULL;
 563         }
 564
 565         if (bdev->bd_part_count)
 566         {
 567         #if defined(CONFIG_SDMMC_RK29) && !defined(CONFIG_SDMMC_RK29_OLD)
 568             if(179 == MAJOR(bdev->bd_dev))
 569             {
 570                 printk(KERN_INFO "%s..%d.. The sdcard partition have been using.So device busy! \n",__FUNCTION__, __LINE__);
 571             }
 572         #endif
 573
 574                 return -EBUSY;
 575         }
 576         res = invalidate_partition(disk, 0);
 577         if (res)
 578                 return res;
 579
 580         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 581         while ((part = disk_part_iter_next(&piter)))
 582                 delete_partition(disk, part->partno);
 583         disk_part_iter_exit(&piter);
 584
 585         if (disk->fops->revalidate_disk)
 586                 disk->fops->revalidate_disk(disk);
 587         check_disk_size_change(disk, bdev);
 588         bdev->bd_invalidated = 0;
 589         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 590         {
 591         #if defined(CONFIG_SDMMC_RK29) && !defined(CONFIG_SDMMC_RK29_OLD)
 592             if(179 == MAJOR(bdev->bd_dev))
 593             {
 594                 printk(KERN_INFO "%s..%d... ==== check partition fail. partitionAddr=%x.\n",__FUNCTION__, __LINE__, state);
 595             }
 596          #endif
 597                 return 0;
 598         }
 599         if (IS_ERR(state)) {
 600                 /*
 601                  * I/O error reading the partition table.  If any
 602                  * partition code tried to read beyond EOD, retry
 603                  * after unlocking native capacity.
 604                  */
 605                 if (PTR_ERR(state) == -ENOSPC) {
 606                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
 607                                disk->disk_name);
 608                         if (disk_unlock_native_capacity(disk))
 609                                 goto rescan;
 610                 }
 611                 return -EIO;
 612         }
 613         /*
 614          * If any partition code tried to read beyond EOD, try
 615          * unlocking native capacity even if partition table is
 616          * successfully read as we could be missing some partitions.
 617          */
 618         if (state->access_beyond_eod) {
 619                 printk(KERN_WARNING
 620                        "%s: partition table partially beyond EOD, ",
 621                        disk->disk_name);
 622                 if (disk_unlock_native_capacity(disk))
 623                         goto rescan;
 624         }
 625
 626         /* tell userspace that the media / partition table may have changed */
 627         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 628
 629         /* Detect the highest partition number and preallocate
 630          * disk->part_tbl.  This is an optimization and not strictly
 631          * necessary.
 632          */
 633         for (p = 1, highest = 0; p < state->limit; p++)
 634                 if (state->parts[p].size)
 635                         highest = p;
 636
 637         disk_expand_part_tbl(disk, highest);
 638
 639         /* add partitions */
 640         for (p = 1; p < state->limit; p++) {
 641                 sector_t size, from;
 642                 struct partition_meta_info *info = NULL;
 643
 644                 size = state->parts[p].size;
 645                 if (!size)
 646                         continue;
 647
 648                 from = state->parts[p].from;
 649                 if (from >= get_capacity(disk)) {
 650                         printk(KERN_WARNING
 651                                "%s: p%d start %llu is beyond EOD, ",
 652                                disk->disk_name, p, (unsigned long long) from);
 653                         if (disk_unlock_native_capacity(disk))
 654                                 goto rescan;
 655                         continue;
 656                 }
 657
 658                 if (from + size > get_capacity(disk)) {
 659                         printk(KERN_WARNING
 660                                "%s: p%d size %llu extends beyond EOD, ",
 661                                disk->disk_name, p, (unsigned long long) size);
 662
 663                         if (disk_unlock_native_capacity(disk)) {
 664                                 /* free state and restart */
 665                                 goto rescan;
 666                         } else {
 667                                 /*
 668                                  * we can not ignore partitions of broken tables
 669                                  * created by for example camera firmware, but
 670                                  * we limit them to the end of the disk to avoid
 671                                  * creating invalid block devices
 672                                  */
 673                                 size = get_capacity(disk) - from;
 674                         }
 675                 }
 676
 677                 if (state->parts[p].has_info)
 678                         info = &state->parts[p].info;
 679                 part = add_partition(disk, p, from, size,
 680                                      state->parts[p].flags,
 681                                      &state->parts[p].info);
 682                 if (IS_ERR(part)) {
 683                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 684                                disk->disk_name, p, -PTR_ERR(part));
 685                         continue;
 686                 }
 687 #ifdef CONFIG_BLK_DEV_MD
 688                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
 689                         md_autodetect_dev(part_to_dev(part)->devt);
 690 #endif
 691         }
 692         kfree(state);
 693         return 0;
 694 }
 695
 696 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
 697 {
 698         struct address_space *mapping = bdev->bd_inode->i_mapping;
 699         struct page *page;
 700
 701         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
 702                                  NULL);
 703         if (!IS_ERR(page)) {
 704                 if (PageError(page))
 705                         goto fail;
 706                 p->v = page;
 707                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
 708 fail:
 709                 page_cache_release(page);
 710         }
 711         p->v = NULL;
 712         return NULL;
 713 }
 714
 715 EXPORT_SYMBOL(read_dev_sector);