drivers/mtd/ubi/kapi.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  12  * the GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Author: Artem Bityutskiy (Битюцкий Артём)
  19  */
  20
  21 /* This file mostly implements UBI kernel API functions */
  22
  23 #include <linux/module.h>
  24 #include <linux/err.h>
  25 #include <linux/namei.h>
  26 #include <linux/fs.h>
  27 #include <asm/div64.h>
  28 #include "ubi.h"
  29
  30 /**
  31  * ubi_do_get_device_info - get information about UBI device.
  32  * @ubi: UBI device description object
  33  * @di: the information is stored here
  34  *
  35  * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
  36  * device is locked and cannot disappear.
  37  */
  38 void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
  39 {
  40         di->ubi_num = ubi->ubi_num;
  41         di->leb_size = ubi->leb_size;
  42         di->min_io_size = ubi->min_io_size;
  43         di->ro_mode = ubi->ro_mode;
  44         di->cdev = ubi->cdev.dev;
  45 }
  46 EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
  47
  48 /**
  49  * ubi_get_device_info - get information about UBI device.
  50  * @ubi_num: UBI device number
  51  * @di: the information is stored here
  52  *
  53  * This function returns %0 in case of success, %-EINVAL if the UBI device
  54  * number is invalid, and %-ENODEV if there is no such UBI device.
  55  */
  56 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
  57 {
  58         struct ubi_device *ubi;
  59
  60         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
  61                 return -EINVAL;
  62         ubi = ubi_get_device(ubi_num);
  63         if (!ubi)
  64                 return -ENODEV;
  65         ubi_do_get_device_info(ubi, di);
  66         ubi_put_device(ubi);
  67         return 0;
  68 }
  69 EXPORT_SYMBOL_GPL(ubi_get_device_info);
  70
  71 /**
  72  * ubi_do_get_volume_info - get information about UBI volume.
  73  * @ubi: UBI device description object
  74  * @vol: volume description object
  75  * @vi: the information is stored here
  76  */
  77 void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
  78                             struct ubi_volume_info *vi)
  79 {
  80         vi->vol_id = vol->vol_id;
  81         vi->ubi_num = ubi->ubi_num;
  82         vi->size = vol->reserved_pebs;
  83         vi->used_bytes = vol->used_bytes;
  84         vi->vol_type = vol->vol_type;
  85         vi->corrupted = vol->corrupted;
  86         vi->upd_marker = vol->upd_marker;
  87         vi->alignment = vol->alignment;
  88         vi->usable_leb_size = vol->usable_leb_size;
  89         vi->name_len = vol->name_len;
  90         vi->name = vol->name;
  91         vi->cdev = vol->cdev.dev;
  92 }
  93
  94 /**
  95  * ubi_get_volume_info - get information about UBI volume.
  96  * @desc: volume descriptor
  97  * @vi: the information is stored here
  98  */
  99 void ubi_get_volume_info(struct ubi_volume_desc *desc,
 100                          struct ubi_volume_info *vi)
 101 {
 102         ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
 103 }
 104 EXPORT_SYMBOL_GPL(ubi_get_volume_info);
 105
 106 /**
 107  * ubi_open_volume - open UBI volume.
 108  * @ubi_num: UBI device number
 109  * @vol_id: volume ID
 110  * @mode: open mode
 111  *
 112  * The @mode parameter specifies if the volume should be opened in read-only
 113  * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
 114  * nobody else will be able to open this volume. UBI allows to have many volume
 115  * readers and one writer at a time.
 116  *
 117  * If a static volume is being opened for the first time since boot, it will be
 118  * checked by this function, which means it will be fully read and the CRC
 119  * checksum of each logical eraseblock will be checked.
 120  *
 121  * This function returns volume descriptor in case of success and a negative
 122  * error code in case of failure.
 123  */
 124 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
 125 {
 126         int err;
 127         struct ubi_volume_desc *desc;
 128         struct ubi_device *ubi;
 129         struct ubi_volume *vol;
 130
 131         dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
 132
 133         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 134                 return ERR_PTR(-EINVAL);
 135
 136         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 137             mode != UBI_EXCLUSIVE)
 138                 return ERR_PTR(-EINVAL);
 139
 140         /*
 141          * First of all, we have to get the UBI device to prevent its removal.
 142          */
 143         ubi = ubi_get_device(ubi_num);
 144         if (!ubi)
 145                 return ERR_PTR(-ENODEV);
 146
 147         if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
 148                 err = -EINVAL;
 149                 goto out_put_ubi;
 150         }
 151
 152         desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 153         if (!desc) {
 154                 err = -ENOMEM;
 155                 goto out_put_ubi;
 156         }
 157
 158         err = -ENODEV;
 159         if (!try_module_get(THIS_MODULE))
 160                 goto out_free;
 161
 162         spin_lock(&ubi->volumes_lock);
 163         vol = ubi->volumes[vol_id];
 164         if (!vol)
 165                 goto out_unlock;
 166
 167         err = -EBUSY;
 168         switch (mode) {
 169         case UBI_READONLY:
 170                 if (vol->exclusive)
 171                         goto out_unlock;
 172                 vol->readers += 1;
 173                 break;
 174
 175         case UBI_READWRITE:
 176                 if (vol->exclusive || vol->writers > 0)
 177                         goto out_unlock;
 178                 vol->writers += 1;
 179                 break;
 180
 181         case UBI_EXCLUSIVE:
 182                 if (vol->exclusive || vol->writers || vol->readers)
 183                         goto out_unlock;
 184                 vol->exclusive = 1;
 185                 break;
 186         }
 187         get_device(&vol->dev);
 188         vol->ref_count += 1;
 189         spin_unlock(&ubi->volumes_lock);
 190
 191         desc->vol = vol;
 192         desc->mode = mode;
 193
 194         mutex_lock(&ubi->ckvol_mutex);
 195         if (!vol->checked) {
 196                 /* This is the first open - check the volume */
 197                 err = ubi_check_volume(ubi, vol_id);
 198                 if (err < 0) {
 199                         mutex_unlock(&ubi->ckvol_mutex);
 200                         ubi_close_volume(desc);
 201                         return ERR_PTR(err);
 202                 }
 203                 if (err == 1) {
 204                         ubi_warn("volume %d on UBI device %d is corrupted",
 205                                  vol_id, ubi->ubi_num);
 206                         vol->corrupted = 1;
 207                 }
 208                 vol->checked = 1;
 209         }
 210         mutex_unlock(&ubi->ckvol_mutex);
 211
 212         return desc;
 213
 214 out_unlock:
 215         spin_unlock(&ubi->volumes_lock);
 216         module_put(THIS_MODULE);
 217 out_free:
 218         kfree(desc);
 219 out_put_ubi:
 220         ubi_put_device(ubi);
 221         dbg_err("cannot open device %d, volume %d, error %d",
 222                 ubi_num, vol_id, err);
 223         return ERR_PTR(err);
 224 }
 225 EXPORT_SYMBOL_GPL(ubi_open_volume);
 226
 227 /**
 228  * ubi_open_volume_nm - open UBI volume by name.
 229  * @ubi_num: UBI device number
 230  * @name: volume name
 231  * @mode: open mode
 232  *
 233  * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 234  */
 235 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 236                                            int mode)
 237 {
 238         int i, vol_id = -1, len;
 239         struct ubi_device *ubi;
 240         struct ubi_volume_desc *ret;
 241
 242         dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
 243
 244         if (!name)
 245                 return ERR_PTR(-EINVAL);
 246
 247         len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 248         if (len > UBI_VOL_NAME_MAX)
 249                 return ERR_PTR(-EINVAL);
 250
 251         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 252                 return ERR_PTR(-EINVAL);
 253
 254         ubi = ubi_get_device(ubi_num);
 255         if (!ubi)
 256                 return ERR_PTR(-ENODEV);
 257
 258         spin_lock(&ubi->volumes_lock);
 259         /* Walk all volumes of this UBI device */
 260         for (i = 0; i < ubi->vtbl_slots; i++) {
 261                 struct ubi_volume *vol = ubi->volumes[i];
 262
 263                 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 264                         vol_id = i;
 265                         break;
 266                 }
 267         }
 268         spin_unlock(&ubi->volumes_lock);
 269
 270         if (vol_id >= 0)
 271                 ret = ubi_open_volume(ubi_num, vol_id, mode);
 272         else
 273                 ret = ERR_PTR(-ENODEV);
 274
 275         /*
 276          * We should put the UBI device even in case of success, because
 277          * 'ubi_open_volume()' took a reference as well.
 278          */
 279         ubi_put_device(ubi);
 280         return ret;
 281 }
 282 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 283
 284 /**
 285  * ubi_open_volume_path - open UBI volume by its character device node path.
 286  * @pathname: volume character device node path
 287  * @mode: open mode
 288  *
 289  * This function is similar to 'ubi_open_volume()', but opens a volume the path
 290  * to its character device node.
 291  */
 292 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
 293 {
 294         int error, ubi_num, vol_id;
 295         struct ubi_volume_desc *ret;
 296         struct inode *inode;
 297         struct path path;
 298
 299         dbg_gen("open volume %s, mode %d", pathname, mode);
 300
 301         if (!pathname || !*pathname)
 302                 return ERR_PTR(-EINVAL);
 303
 304         error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 305         if (error)
 306                 return ERR_PTR(error);
 307
 308         inode = path.dentry->d_inode;
 309         ubi_num = ubi_major2num(imajor(inode));
 310         vol_id = iminor(inode) - 1;
 311
 312         if (vol_id >= 0 && ubi_num >= 0)
 313                 ret = ubi_open_volume(ubi_num, vol_id, mode);
 314         else
 315                 ret = ERR_PTR(-ENODEV);
 316
 317         path_put(&path);
 318         return ret;
 319 }
 320 EXPORT_SYMBOL_GPL(ubi_open_volume_path);
 321
 322 /**
 323  * ubi_close_volume - close UBI volume.
 324  * @desc: volume descriptor
 325  */
 326 void ubi_close_volume(struct ubi_volume_desc *desc)
 327 {
 328         struct ubi_volume *vol = desc->vol;
 329         struct ubi_device *ubi = vol->ubi;
 330
 331         dbg_gen("close device %d, volume %d, mode %d",
 332                 ubi->ubi_num, vol->vol_id, desc->mode);
 333
 334         spin_lock(&ubi->volumes_lock);
 335         switch (desc->mode) {
 336         case UBI_READONLY:
 337                 vol->readers -= 1;
 338                 break;
 339         case UBI_READWRITE:
 340                 vol->writers -= 1;
 341                 break;
 342         case UBI_EXCLUSIVE:
 343                 vol->exclusive = 0;
 344         }
 345         vol->ref_count -= 1;
 346         spin_unlock(&ubi->volumes_lock);
 347
 348         kfree(desc);
 349         put_device(&vol->dev);
 350         ubi_put_device(ubi);
 351         module_put(THIS_MODULE);
 352 }
 353 EXPORT_SYMBOL_GPL(ubi_close_volume);
 354
 355 /**
 356  * ubi_leb_read - read data.
 357  * @desc: volume descriptor
 358  * @lnum: logical eraseblock number to read from
 359  * @buf: buffer where to store the read data
 360  * @offset: offset within the logical eraseblock to read from
 361  * @len: how many bytes to read
 362  * @check: whether UBI has to check the read data's CRC or not.
 363  *
 364  * This function reads data from offset @offset of logical eraseblock @lnum and
 365  * stores the data at @buf. When reading from static volumes, @check specifies
 366  * whether the data has to be checked or not. If yes, the whole logical
 367  * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 368  * checksum is per-eraseblock). So checking may substantially slow down the
 369  * read speed. The @check argument is ignored for dynamic volumes.
 370  *
 371  * In case of success, this function returns zero. In case of failure, this
 372  * function returns a negative error code.
 373  *
 374  * %-EBADMSG error code is returned:
 375  * o for both static and dynamic volumes if MTD driver has detected a data
 376  *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 377  * o for static volumes in case of data CRC mismatch.
 378  *
 379  * If the volume is damaged because of an interrupted update this function just
 380  * returns immediately with %-EBADF error code.
 381  */
 382 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 383                  int len, int check)
 384 {
 385         struct ubi_volume *vol = desc->vol;
 386         struct ubi_device *ubi = vol->ubi;
 387         int err, vol_id = vol->vol_id;
 388
 389         dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 390
 391         if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 392             lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 393             offset + len > vol->usable_leb_size)
 394                 return -EINVAL;
 395
 396         if (vol->vol_type == UBI_STATIC_VOLUME) {
 397                 if (vol->used_ebs == 0)
 398                         /* Empty static UBI volume */
 399                         return 0;
 400                 if (lnum == vol->used_ebs - 1 &&
 401                     offset + len > vol->last_eb_bytes)
 402                         return -EINVAL;
 403         }
 404
 405         if (vol->upd_marker)
 406                 return -EBADF;
 407         if (len == 0)
 408                 return 0;
 409
 410         err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
 411         if (err && err == -EBADMSG && vol->vol_type == UBI_STATIC_VOLUME) {
 412                 ubi_warn("mark volume %d as corrupted", vol_id);
 413                 vol->corrupted = 1;
 414         }
 415
 416         return err;
 417 }
 418 EXPORT_SYMBOL_GPL(ubi_leb_read);
 419
 420 /**
 421  * ubi_leb_write - write data.
 422  * @desc: volume descriptor
 423  * @lnum: logical eraseblock number to write to
 424  * @buf: data to write
 425  * @offset: offset within the logical eraseblock where to write
 426  * @len: how many bytes to write
 427  * @dtype: expected data type
 428  *
 429  * This function writes @len bytes of data from @buf to offset @offset of
 430  * logical eraseblock @lnum. The @dtype argument describes expected lifetime of
 431  * the data.
 432  *
 433  * This function takes care of physical eraseblock write failures. If write to
 434  * the physical eraseblock write operation fails, the logical eraseblock is
 435  * re-mapped to another physical eraseblock, the data is recovered, and the
 436  * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 437  *
 438  * If all the data were successfully written, zero is returned. If an error
 439  * occurred and UBI has not been able to recover from it, this function returns
 440  * a negative error code. Note, in case of an error, it is possible that
 441  * something was still written to the flash media, but that may be some
 442  * garbage.
 443  *
 444  * If the volume is damaged because of an interrupted update this function just
 445  * returns immediately with %-EBADF code.
 446  */
 447 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 448                   int offset, int len, int dtype)
 449 {
 450         struct ubi_volume *vol = desc->vol;
 451         struct ubi_device *ubi = vol->ubi;
 452         int vol_id = vol->vol_id;
 453
 454         dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 455
 456         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 457                 return -EINVAL;
 458
 459         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 460                 return -EROFS;
 461
 462         if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 463             offset + len > vol->usable_leb_size ||
 464             offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
 465                 return -EINVAL;
 466
 467         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 468             dtype != UBI_UNKNOWN)
 469                 return -EINVAL;
 470
 471         if (vol->upd_marker)
 472                 return -EBADF;
 473
 474         if (len == 0)
 475                 return 0;
 476
 477         return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len, dtype);
 478 }
 479 EXPORT_SYMBOL_GPL(ubi_leb_write);
 480
 481 /*
 482  * ubi_leb_change - change logical eraseblock atomically.
 483  * @desc: volume descriptor
 484  * @lnum: logical eraseblock number to change
 485  * @buf: data to write
 486  * @len: how many bytes to write
 487  * @dtype: expected data type
 488  *
 489  * This function changes the contents of a logical eraseblock atomically. @buf
 490  * has to contain new logical eraseblock data, and @len - the length of the
 491  * data, which has to be aligned. The length may be shorter then the logical
 492  * eraseblock size, ant the logical eraseblock may be appended to more times
 493  * later on. This function guarantees that in case of an unclean reboot the old
 494  * contents is preserved. Returns zero in case of success and a negative error
 495  * code in case of failure.
 496  */
 497 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 498                    int len, int dtype)
 499 {
 500         struct ubi_volume *vol = desc->vol;
 501         struct ubi_device *ubi = vol->ubi;
 502         int vol_id = vol->vol_id;
 503
 504         dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 505
 506         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 507                 return -EINVAL;
 508
 509         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 510                 return -EROFS;
 511
 512         if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 513             len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
 514                 return -EINVAL;
 515
 516         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 517             dtype != UBI_UNKNOWN)
 518                 return -EINVAL;
 519
 520         if (vol->upd_marker)
 521                 return -EBADF;
 522
 523         if (len == 0)
 524                 return 0;
 525
 526         return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len, dtype);
 527 }
 528 EXPORT_SYMBOL_GPL(ubi_leb_change);
 529
 530 /**
 531  * ubi_leb_erase - erase logical eraseblock.
 532  * @desc: volume descriptor
 533  * @lnum: logical eraseblock number
 534  *
 535  * This function un-maps logical eraseblock @lnum and synchronously erases the
 536  * correspondent physical eraseblock. Returns zero in case of success and a
 537  * negative error code in case of failure.
 538  *
 539  * If the volume is damaged because of an interrupted update this function just
 540  * returns immediately with %-EBADF code.
 541  */
 542 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 543 {
 544         struct ubi_volume *vol = desc->vol;
 545         struct ubi_device *ubi = vol->ubi;
 546         int err;
 547
 548         dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 549
 550         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 551                 return -EROFS;
 552
 553         if (lnum < 0 || lnum >= vol->reserved_pebs)
 554                 return -EINVAL;
 555
 556         if (vol->upd_marker)
 557                 return -EBADF;
 558
 559         err = ubi_eba_unmap_leb(ubi, vol, lnum);
 560         if (err)
 561                 return err;
 562
 563         return ubi_wl_flush(ubi);
 564 }
 565 EXPORT_SYMBOL_GPL(ubi_leb_erase);
 566
 567 /**
 568  * ubi_leb_unmap - un-map logical eraseblock.
 569  * @desc: volume descriptor
 570  * @lnum: logical eraseblock number
 571  *
 572  * This function un-maps logical eraseblock @lnum and schedules the
 573  * corresponding physical eraseblock for erasure, so that it will eventually be
 574  * physically erased in background. This operation is much faster then the
 575  * erase operation.
 576  *
 577  * Unlike erase, the un-map operation does not guarantee that the logical
 578  * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 579  * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 580  * happens after this, the logical eraseblocks will not necessarily be
 581  * un-mapped again when this MTD device is attached. They may actually be
 582  * mapped to the same physical eraseblocks again. So, this function has to be
 583  * used with care.
 584  *
 585  * In other words, when un-mapping a logical eraseblock, UBI does not store
 586  * any information about this on the flash media, it just marks the logical
 587  * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 588  * eraseblock is physically erased, it will be mapped again to the same logical
 589  * eraseblock when the MTD device is attached again.
 590  *
 591  * The main and obvious use-case of this function is when the contents of a
 592  * logical eraseblock has to be re-written. Then it is much more efficient to
 593  * first un-map it, then write new data, rather then first erase it, then write
 594  * new data. Note, once new data has been written to the logical eraseblock,
 595  * UBI guarantees that the old contents has gone forever. In other words, if an
 596  * unclean reboot happens after the logical eraseblock has been un-mapped and
 597  * then written to, it will contain the last written data.
 598  *
 599  * This function returns zero in case of success and a negative error code in
 600  * case of failure. If the volume is damaged because of an interrupted update
 601  * this function just returns immediately with %-EBADF code.
 602  */
 603 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 604 {
 605         struct ubi_volume *vol = desc->vol;
 606         struct ubi_device *ubi = vol->ubi;
 607
 608         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 609
 610         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 611                 return -EROFS;
 612
 613         if (lnum < 0 || lnum >= vol->reserved_pebs)
 614                 return -EINVAL;
 615
 616         if (vol->upd_marker)
 617                 return -EBADF;
 618
 619         return ubi_eba_unmap_leb(ubi, vol, lnum);
 620 }
 621 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 622
 623 /**
 624  * ubi_leb_map - map logical eraseblock to a physical eraseblock.
 625  * @desc: volume descriptor
 626  * @lnum: logical eraseblock number
 627  * @dtype: expected data type
 628  *
 629  * This function maps an un-mapped logical eraseblock @lnum to a physical
 630  * eraseblock. This means, that after a successful invocation of this
 631  * function the logical eraseblock @lnum will be empty (contain only %0xFF
 632  * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
 633  * happens.
 634  *
 635  * This function returns zero in case of success, %-EBADF if the volume is
 636  * damaged because of an interrupted update, %-EBADMSG if the logical
 637  * eraseblock is already mapped, and other negative error codes in case of
 638  * other failures.
 639  */
 640 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype)
 641 {
 642         struct ubi_volume *vol = desc->vol;
 643         struct ubi_device *ubi = vol->ubi;
 644
 645         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 646
 647         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 648                 return -EROFS;
 649
 650         if (lnum < 0 || lnum >= vol->reserved_pebs)
 651                 return -EINVAL;
 652
 653         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 654             dtype != UBI_UNKNOWN)
 655                 return -EINVAL;
 656
 657         if (vol->upd_marker)
 658                 return -EBADF;
 659
 660         if (vol->eba_tbl[lnum] >= 0)
 661                 return -EBADMSG;
 662
 663         return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0, dtype);
 664 }
 665 EXPORT_SYMBOL_GPL(ubi_leb_map);
 666
 667 /**
 668  * ubi_is_mapped - check if logical eraseblock is mapped.
 669  * @desc: volume descriptor
 670  * @lnum: logical eraseblock number
 671  *
 672  * This function checks if logical eraseblock @lnum is mapped to a physical
 673  * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 674  * mean it will still be un-mapped after the UBI device is re-attached. The
 675  * logical eraseblock may become mapped to the physical eraseblock it was last
 676  * mapped to.
 677  *
 678  * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 679  * error code in case of failure. If the volume is damaged because of an
 680  * interrupted update this function just returns immediately with %-EBADF error
 681  * code.
 682  */
 683 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 684 {
 685         struct ubi_volume *vol = desc->vol;
 686
 687         dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
 688
 689         if (lnum < 0 || lnum >= vol->reserved_pebs)
 690                 return -EINVAL;
 691
 692         if (vol->upd_marker)
 693                 return -EBADF;
 694
 695         return vol->eba_tbl[lnum] >= 0;
 696 }
 697 EXPORT_SYMBOL_GPL(ubi_is_mapped);
 698
 699 /**
 700  * ubi_sync - synchronize UBI device buffers.
 701  * @ubi_num: UBI device to synchronize
 702  *
 703  * The underlying MTD device may cache data in hardware or in software. This
 704  * function ensures the caches are flushed. Returns zero in case of success and
 705  * a negative error code in case of failure.
 706  */
 707 int ubi_sync(int ubi_num)
 708 {
 709         struct ubi_device *ubi;
 710
 711         ubi = ubi_get_device(ubi_num);
 712         if (!ubi)
 713                 return -ENODEV;
 714
 715         if (ubi->mtd->sync)
 716                 ubi->mtd->sync(ubi->mtd);
 717
 718         ubi_put_device(ubi);
 719         return 0;
 720 }
 721 EXPORT_SYMBOL_GPL(ubi_sync);
 722
 723 BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
 724
 725 /**
 726  * ubi_register_volume_notifier - register a volume notifier.
 727  * @nb: the notifier description object
 728  * @ignore_existing: if non-zero, do not send "added" notification for all
 729  *                   already existing volumes
 730  *
 731  * This function registers a volume notifier, which means that
 732  * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
 733  * removed, re-sized, re-named, or updated. The first argument of the function
 734  * is the notification type. The second argument is pointer to a
 735  * &struct ubi_notification object which describes the notification event.
 736  * Using UBI API from the volume notifier is prohibited.
 737  *
 738  * This function returns zero in case of success and a negative error code
 739  * in case of failure.
 740  */
 741 int ubi_register_volume_notifier(struct notifier_block *nb,
 742                                  int ignore_existing)
 743 {
 744         int err;
 745
 746         err = blocking_notifier_chain_register(&ubi_notifiers, nb);
 747         if (err != 0)
 748                 return err;
 749         if (ignore_existing)
 750                 return 0;
 751
 752         /*
 753          * We are going to walk all UBI devices and all volumes, and
 754          * notify the user about existing volumes by the %UBI_VOLUME_ADDED
 755          * event. We have to lock the @ubi_devices_mutex to make sure UBI
 756          * devices do not disappear.
 757          */
 758         mutex_lock(&ubi_devices_mutex);
 759         ubi_enumerate_volumes(nb);
 760         mutex_unlock(&ubi_devices_mutex);
 761
 762         return err;
 763 }
 764 EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
 765
 766 /**
 767  * ubi_unregister_volume_notifier - unregister the volume notifier.
 768  * @nb: the notifier description object
 769  *
 770  * This function unregisters volume notifier @nm and returns zero in case of
 771  * success and a negative error code in case of failure.
 772  */
 773 int ubi_unregister_volume_notifier(struct notifier_block *nb)
 774 {
 775         return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
 776 }
 777 EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);