drivers/mtd/ubi/kapi.c

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  *
   6  * Author: Artem Bityutskiy (Битюцкий Артём)
   7  */
   8
   9 /* This file mostly implements UBI kernel API functions */
  10
  11 #define __UBOOT__
  12 #ifndef __UBOOT__
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/namei.h>
  16 #include <linux/fs.h>
  17 #include <asm/div64.h>
  18 #else
  19 #include <ubi_uboot.h>
  20 #endif
  21 #include <linux/err.h>
  22
  23 #include "ubi.h"
  24
  25 /**
  26  * ubi_do_get_device_info - get information about UBI device.
  27  * @ubi: UBI device description object
  28  * @di: the information is stored here
  29  *
  30  * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
  31  * device is locked and cannot disappear.
  32  */
  33 void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
  34 {
  35         di->ubi_num = ubi->ubi_num;
  36         di->leb_size = ubi->leb_size;
  37         di->leb_start = ubi->leb_start;
  38         di->min_io_size = ubi->min_io_size;
  39         di->max_write_size = ubi->max_write_size;
  40         di->ro_mode = ubi->ro_mode;
  41 #ifndef __UBOOT__
  42         di->cdev = ubi->cdev.dev;
  43 #endif
  44 }
  45 EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
  46
  47 /**
  48  * ubi_get_device_info - get information about UBI device.
  49  * @ubi_num: UBI device number
  50  * @di: the information is stored here
  51  *
  52  * This function returns %0 in case of success, %-EINVAL if the UBI device
  53  * number is invalid, and %-ENODEV if there is no such UBI device.
  54  */
  55 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
  56 {
  57         struct ubi_device *ubi;
  58
  59         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
  60                 return -EINVAL;
  61         ubi = ubi_get_device(ubi_num);
  62         if (!ubi)
  63                 return -ENODEV;
  64         ubi_do_get_device_info(ubi, di);
  65         ubi_put_device(ubi);
  66         return 0;
  67 }
  68 EXPORT_SYMBOL_GPL(ubi_get_device_info);
  69
  70 /**
  71  * ubi_do_get_volume_info - get information about UBI volume.
  72  * @ubi: UBI device description object
  73  * @vol: volume description object
  74  * @vi: the information is stored here
  75  */
  76 void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
  77                             struct ubi_volume_info *vi)
  78 {
  79         vi->vol_id = vol->vol_id;
  80         vi->ubi_num = ubi->ubi_num;
  81         vi->size = vol->reserved_pebs;
  82         vi->used_bytes = vol->used_bytes;
  83         vi->vol_type = vol->vol_type;
  84         vi->corrupted = vol->corrupted;
  85         vi->upd_marker = vol->upd_marker;
  86         vi->alignment = vol->alignment;
  87         vi->usable_leb_size = vol->usable_leb_size;
  88         vi->name_len = vol->name_len;
  89         vi->name = vol->name;
  90         vi->cdev = vol->cdev.dev;
  91 }
  92
  93 /**
  94  * ubi_get_volume_info - get information about UBI volume.
  95  * @desc: volume descriptor
  96  * @vi: the information is stored here
  97  */
  98 void ubi_get_volume_info(struct ubi_volume_desc *desc,
  99                          struct ubi_volume_info *vi)
 100 {
 101         ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
 102 }
 103 EXPORT_SYMBOL_GPL(ubi_get_volume_info);
 104
 105 /**
 106  * ubi_open_volume - open UBI volume.
 107  * @ubi_num: UBI device number
 108  * @vol_id: volume ID
 109  * @mode: open mode
 110  *
 111  * The @mode parameter specifies if the volume should be opened in read-only
 112  * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
 113  * nobody else will be able to open this volume. UBI allows to have many volume
 114  * readers and one writer at a time.
 115  *
 116  * If a static volume is being opened for the first time since boot, it will be
 117  * checked by this function, which means it will be fully read and the CRC
 118  * checksum of each logical eraseblock will be checked.
 119  *
 120  * This function returns volume descriptor in case of success and a negative
 121  * error code in case of failure.
 122  */
 123 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
 124 {
 125         int err;
 126         struct ubi_volume_desc *desc;
 127         struct ubi_device *ubi;
 128         struct ubi_volume *vol;
 129
 130         dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
 131
 132         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 133                 return ERR_PTR(-EINVAL);
 134
 135         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 136             mode != UBI_EXCLUSIVE)
 137                 return ERR_PTR(-EINVAL);
 138
 139         /*
 140          * First of all, we have to get the UBI device to prevent its removal.
 141          */
 142         ubi = ubi_get_device(ubi_num);
 143         if (!ubi)
 144                 return ERR_PTR(-ENODEV);
 145
 146         if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
 147                 err = -EINVAL;
 148                 goto out_put_ubi;
 149         }
 150
 151         desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 152         if (!desc) {
 153                 err = -ENOMEM;
 154                 goto out_put_ubi;
 155         }
 156
 157         err = -ENODEV;
 158         if (!try_module_get(THIS_MODULE))
 159                 goto out_free;
 160
 161         spin_lock(&ubi->volumes_lock);
 162         vol = ubi->volumes[vol_id];
 163         if (!vol)
 164                 goto out_unlock;
 165
 166         err = -EBUSY;
 167         switch (mode) {
 168         case UBI_READONLY:
 169                 if (vol->exclusive)
 170                         goto out_unlock;
 171                 vol->readers += 1;
 172                 break;
 173
 174         case UBI_READWRITE:
 175                 if (vol->exclusive || vol->writers > 0)
 176                         goto out_unlock;
 177                 vol->writers += 1;
 178                 break;
 179
 180         case UBI_EXCLUSIVE:
 181                 if (vol->exclusive || vol->writers || vol->readers)
 182                         goto out_unlock;
 183                 vol->exclusive = 1;
 184                 break;
 185         }
 186         get_device(&vol->dev);
 187         vol->ref_count += 1;
 188         spin_unlock(&ubi->volumes_lock);
 189
 190         desc->vol = vol;
 191         desc->mode = mode;
 192
 193         mutex_lock(&ubi->ckvol_mutex);
 194         if (!vol->checked) {
 195                 /* This is the first open - check the volume */
 196                 err = ubi_check_volume(ubi, vol_id);
 197                 if (err < 0) {
 198                         mutex_unlock(&ubi->ckvol_mutex);
 199                         ubi_close_volume(desc);
 200                         return ERR_PTR(err);
 201                 }
 202                 if (err == 1) {
 203                         ubi_warn("volume %d on UBI device %d is corrupted",
 204                                  vol_id, ubi->ubi_num);
 205                         vol->corrupted = 1;
 206                 }
 207                 vol->checked = 1;
 208         }
 209         mutex_unlock(&ubi->ckvol_mutex);
 210
 211         return desc;
 212
 213 out_unlock:
 214         spin_unlock(&ubi->volumes_lock);
 215         module_put(THIS_MODULE);
 216 out_free:
 217         kfree(desc);
 218 out_put_ubi:
 219         ubi_put_device(ubi);
 220         ubi_err("cannot open device %d, volume %d, error %d",
 221                 ubi_num, vol_id, err);
 222         return ERR_PTR(err);
 223 }
 224 EXPORT_SYMBOL_GPL(ubi_open_volume);
 225
 226 /**
 227  * ubi_open_volume_nm - open UBI volume by name.
 228  * @ubi_num: UBI device number
 229  * @name: volume name
 230  * @mode: open mode
 231  *
 232  * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 233  */
 234 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 235                                            int mode)
 236 {
 237         int i, vol_id = -1, len;
 238         struct ubi_device *ubi;
 239         struct ubi_volume_desc *ret;
 240
 241         dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
 242
 243         if (!name)
 244                 return ERR_PTR(-EINVAL);
 245
 246         len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 247         if (len > UBI_VOL_NAME_MAX)
 248                 return ERR_PTR(-EINVAL);
 249
 250         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 251                 return ERR_PTR(-EINVAL);
 252
 253         ubi = ubi_get_device(ubi_num);
 254         if (!ubi)
 255                 return ERR_PTR(-ENODEV);
 256
 257         spin_lock(&ubi->volumes_lock);
 258         /* Walk all volumes of this UBI device */
 259         for (i = 0; i < ubi->vtbl_slots; i++) {
 260                 struct ubi_volume *vol = ubi->volumes[i];
 261
 262                 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 263                         vol_id = i;
 264                         break;
 265                 }
 266         }
 267         spin_unlock(&ubi->volumes_lock);
 268
 269         if (vol_id >= 0)
 270                 ret = ubi_open_volume(ubi_num, vol_id, mode);
 271         else
 272                 ret = ERR_PTR(-ENODEV);
 273
 274         /*
 275          * We should put the UBI device even in case of success, because
 276          * 'ubi_open_volume()' took a reference as well.
 277          */
 278         ubi_put_device(ubi);
 279         return ret;
 280 }
 281 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 282
 283 #ifndef __UBOOT__
 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, mod;
 295         struct inode *inode;
 296         struct path path;
 297
 298         dbg_gen("open volume %s, mode %d", pathname, mode);
 299
 300         if (!pathname || !*pathname)
 301                 return ERR_PTR(-EINVAL);
 302
 303         error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 304         if (error)
 305                 return ERR_PTR(error);
 306
 307         inode = path.dentry->d_inode;
 308         mod = inode->i_mode;
 309         ubi_num = ubi_major2num(imajor(inode));
 310         vol_id = iminor(inode) - 1;
 311         path_put(&path);
 312
 313         if (!S_ISCHR(mod))
 314                 return ERR_PTR(-EINVAL);
 315         if (vol_id >= 0 && ubi_num >= 0)
 316                 return ubi_open_volume(ubi_num, vol_id, mode);
 317         return ERR_PTR(-ENODEV);
 318 }
 319 EXPORT_SYMBOL_GPL(ubi_open_volume_path);
 320 #endif
 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 && mtd_is_eccerr(err) && 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  *
 428  * This function writes @len bytes of data from @buf to offset @offset of
 429  * logical eraseblock @lnum.
 430  *
 431  * This function takes care of physical eraseblock write failures. If write to
 432  * the physical eraseblock write operation fails, the logical eraseblock is
 433  * re-mapped to another physical eraseblock, the data is recovered, and the
 434  * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 435  *
 436  * If all the data were successfully written, zero is returned. If an error
 437  * occurred and UBI has not been able to recover from it, this function returns
 438  * a negative error code. Note, in case of an error, it is possible that
 439  * something was still written to the flash media, but that may be some
 440  * garbage.
 441  *
 442  * If the volume is damaged because of an interrupted update this function just
 443  * returns immediately with %-EBADF code.
 444  */
 445 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 446                   int offset, int len)
 447 {
 448         struct ubi_volume *vol = desc->vol;
 449         struct ubi_device *ubi = vol->ubi;
 450         int vol_id = vol->vol_id;
 451
 452         dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 453
 454         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 455                 return -EINVAL;
 456
 457         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 458                 return -EROFS;
 459
 460         if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 461             offset + len > vol->usable_leb_size ||
 462             offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
 463                 return -EINVAL;
 464
 465         if (vol->upd_marker)
 466                 return -EBADF;
 467
 468         if (len == 0)
 469                 return 0;
 470
 471         return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
 472 }
 473 EXPORT_SYMBOL_GPL(ubi_leb_write);
 474
 475 /*
 476  * ubi_leb_change - change logical eraseblock atomically.
 477  * @desc: volume descriptor
 478  * @lnum: logical eraseblock number to change
 479  * @buf: data to write
 480  * @len: how many bytes to write
 481  *
 482  * This function changes the contents of a logical eraseblock atomically. @buf
 483  * has to contain new logical eraseblock data, and @len - the length of the
 484  * data, which has to be aligned. The length may be shorter than the logical
 485  * eraseblock size, ant the logical eraseblock may be appended to more times
 486  * later on. This function guarantees that in case of an unclean reboot the old
 487  * contents is preserved. Returns zero in case of success and a negative error
 488  * code in case of failure.
 489  */
 490 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 491                    int len)
 492 {
 493         struct ubi_volume *vol = desc->vol;
 494         struct ubi_device *ubi = vol->ubi;
 495         int vol_id = vol->vol_id;
 496
 497         dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 498
 499         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 500                 return -EINVAL;
 501
 502         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 503                 return -EROFS;
 504
 505         if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 506             len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
 507                 return -EINVAL;
 508
 509         if (vol->upd_marker)
 510                 return -EBADF;
 511
 512         if (len == 0)
 513                 return 0;
 514
 515         return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
 516 }
 517 EXPORT_SYMBOL_GPL(ubi_leb_change);
 518
 519 /**
 520  * ubi_leb_erase - erase logical eraseblock.
 521  * @desc: volume descriptor
 522  * @lnum: logical eraseblock number
 523  *
 524  * This function un-maps logical eraseblock @lnum and synchronously erases the
 525  * correspondent physical eraseblock. Returns zero in case of success and a
 526  * negative error code in case of failure.
 527  *
 528  * If the volume is damaged because of an interrupted update this function just
 529  * returns immediately with %-EBADF code.
 530  */
 531 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 532 {
 533         struct ubi_volume *vol = desc->vol;
 534         struct ubi_device *ubi = vol->ubi;
 535         int err;
 536
 537         dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 538
 539         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 540                 return -EROFS;
 541
 542         if (lnum < 0 || lnum >= vol->reserved_pebs)
 543                 return -EINVAL;
 544
 545         if (vol->upd_marker)
 546                 return -EBADF;
 547
 548         err = ubi_eba_unmap_leb(ubi, vol, lnum);
 549         if (err)
 550                 return err;
 551
 552         return ubi_wl_flush(ubi, vol->vol_id, lnum);
 553 }
 554 EXPORT_SYMBOL_GPL(ubi_leb_erase);
 555
 556 /**
 557  * ubi_leb_unmap - un-map logical eraseblock.
 558  * @desc: volume descriptor
 559  * @lnum: logical eraseblock number
 560  *
 561  * This function un-maps logical eraseblock @lnum and schedules the
 562  * corresponding physical eraseblock for erasure, so that it will eventually be
 563  * physically erased in background. This operation is much faster than the
 564  * erase operation.
 565  *
 566  * Unlike erase, the un-map operation does not guarantee that the logical
 567  * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 568  * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 569  * happens after this, the logical eraseblocks will not necessarily be
 570  * un-mapped again when this MTD device is attached. They may actually be
 571  * mapped to the same physical eraseblocks again. So, this function has to be
 572  * used with care.
 573  *
 574  * In other words, when un-mapping a logical eraseblock, UBI does not store
 575  * any information about this on the flash media, it just marks the logical
 576  * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 577  * eraseblock is physically erased, it will be mapped again to the same logical
 578  * eraseblock when the MTD device is attached again.
 579  *
 580  * The main and obvious use-case of this function is when the contents of a
 581  * logical eraseblock has to be re-written. Then it is much more efficient to
 582  * first un-map it, then write new data, rather than first erase it, then write
 583  * new data. Note, once new data has been written to the logical eraseblock,
 584  * UBI guarantees that the old contents has gone forever. In other words, if an
 585  * unclean reboot happens after the logical eraseblock has been un-mapped and
 586  * then written to, it will contain the last written data.
 587  *
 588  * This function returns zero in case of success and a negative error code in
 589  * case of failure. If the volume is damaged because of an interrupted update
 590  * this function just returns immediately with %-EBADF code.
 591  */
 592 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 593 {
 594         struct ubi_volume *vol = desc->vol;
 595         struct ubi_device *ubi = vol->ubi;
 596
 597         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 598
 599         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 600                 return -EROFS;
 601
 602         if (lnum < 0 || lnum >= vol->reserved_pebs)
 603                 return -EINVAL;
 604
 605         if (vol->upd_marker)
 606                 return -EBADF;
 607
 608         return ubi_eba_unmap_leb(ubi, vol, lnum);
 609 }
 610 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 611
 612 /**
 613  * ubi_leb_map - map logical eraseblock to a physical eraseblock.
 614  * @desc: volume descriptor
 615  * @lnum: logical eraseblock number
 616  *
 617  * This function maps an un-mapped logical eraseblock @lnum to a physical
 618  * eraseblock. This means, that after a successful invocation of this
 619  * function the logical eraseblock @lnum will be empty (contain only %0xFF
 620  * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
 621  * happens.
 622  *
 623  * This function returns zero in case of success, %-EBADF if the volume is
 624  * damaged because of an interrupted update, %-EBADMSG if the logical
 625  * eraseblock is already mapped, and other negative error codes in case of
 626  * other failures.
 627  */
 628 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
 629 {
 630         struct ubi_volume *vol = desc->vol;
 631         struct ubi_device *ubi = vol->ubi;
 632
 633         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 634
 635         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 636                 return -EROFS;
 637
 638         if (lnum < 0 || lnum >= vol->reserved_pebs)
 639                 return -EINVAL;
 640
 641         if (vol->upd_marker)
 642                 return -EBADF;
 643
 644         if (vol->eba_tbl[lnum] >= 0)
 645                 return -EBADMSG;
 646
 647         return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
 648 }
 649 EXPORT_SYMBOL_GPL(ubi_leb_map);
 650
 651 /**
 652  * ubi_is_mapped - check if logical eraseblock is mapped.
 653  * @desc: volume descriptor
 654  * @lnum: logical eraseblock number
 655  *
 656  * This function checks if logical eraseblock @lnum is mapped to a physical
 657  * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 658  * mean it will still be un-mapped after the UBI device is re-attached. The
 659  * logical eraseblock may become mapped to the physical eraseblock it was last
 660  * mapped to.
 661  *
 662  * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 663  * error code in case of failure. If the volume is damaged because of an
 664  * interrupted update this function just returns immediately with %-EBADF error
 665  * code.
 666  */
 667 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 668 {
 669         struct ubi_volume *vol = desc->vol;
 670
 671         dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
 672
 673         if (lnum < 0 || lnum >= vol->reserved_pebs)
 674                 return -EINVAL;
 675
 676         if (vol->upd_marker)
 677                 return -EBADF;
 678
 679         return vol->eba_tbl[lnum] >= 0;
 680 }
 681 EXPORT_SYMBOL_GPL(ubi_is_mapped);
 682
 683 /**
 684  * ubi_sync - synchronize UBI device buffers.
 685  * @ubi_num: UBI device to synchronize
 686  *
 687  * The underlying MTD device may cache data in hardware or in software. This
 688  * function ensures the caches are flushed. Returns zero in case of success and
 689  * a negative error code in case of failure.
 690  */
 691 int ubi_sync(int ubi_num)
 692 {
 693         struct ubi_device *ubi;
 694
 695         ubi = ubi_get_device(ubi_num);
 696         if (!ubi)
 697                 return -ENODEV;
 698
 699         mtd_sync(ubi->mtd);
 700         ubi_put_device(ubi);
 701         return 0;
 702 }
 703 EXPORT_SYMBOL_GPL(ubi_sync);
 704
 705 /**
 706  * ubi_flush - flush UBI work queue.
 707  * @ubi_num: UBI device to flush work queue
 708  * @vol_id: volume id to flush for
 709  * @lnum: logical eraseblock number to flush for
 710  *
 711  * This function executes all pending works for a particular volume id / logical
 712  * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
 713  * a wildcard for all of the corresponding volume numbers or logical
 714  * eraseblock numbers. It returns zero in case of success and a negative error
 715  * code in case of failure.
 716  */
 717 int ubi_flush(int ubi_num, int vol_id, int lnum)
 718 {
 719         struct ubi_device *ubi;
 720         int err = 0;
 721
 722         ubi = ubi_get_device(ubi_num);
 723         if (!ubi)
 724                 return -ENODEV;
 725
 726         err = ubi_wl_flush(ubi, vol_id, lnum);
 727         ubi_put_device(ubi);
 728         return err;
 729 }
 730 EXPORT_SYMBOL_GPL(ubi_flush);
 731
 732 #ifndef __UBOOT__
 733 BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
 734
 735 /**
 736  * ubi_register_volume_notifier - register a volume notifier.
 737  * @nb: the notifier description object
 738  * @ignore_existing: if non-zero, do not send "added" notification for all
 739  *                   already existing volumes
 740  *
 741  * This function registers a volume notifier, which means that
 742  * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
 743  * removed, re-sized, re-named, or updated. The first argument of the function
 744  * is the notification type. The second argument is pointer to a
 745  * &struct ubi_notification object which describes the notification event.
 746  * Using UBI API from the volume notifier is prohibited.
 747  *
 748  * This function returns zero in case of success and a negative error code
 749  * in case of failure.
 750  */
 751 int ubi_register_volume_notifier(struct notifier_block *nb,
 752                                  int ignore_existing)
 753 {
 754         int err;
 755
 756         err = blocking_notifier_chain_register(&ubi_notifiers, nb);
 757         if (err != 0)
 758                 return err;
 759         if (ignore_existing)
 760                 return 0;
 761
 762         /*
 763          * We are going to walk all UBI devices and all volumes, and
 764          * notify the user about existing volumes by the %UBI_VOLUME_ADDED
 765          * event. We have to lock the @ubi_devices_mutex to make sure UBI
 766          * devices do not disappear.
 767          */
 768         mutex_lock(&ubi_devices_mutex);
 769         ubi_enumerate_volumes(nb);
 770         mutex_unlock(&ubi_devices_mutex);
 771
 772         return err;
 773 }
 774 EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
 775
 776 /**
 777  * ubi_unregister_volume_notifier - unregister the volume notifier.
 778  * @nb: the notifier description object
 779  *
 780  * This function unregisters volume notifier @nm and returns zero in case of
 781  * success and a negative error code in case of failure.
 782  */
 783 int ubi_unregister_volume_notifier(struct notifier_block *nb)
 784 {
 785         return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
 786 }
 787 EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
 788 #endif