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/slab.h>
  26 #include <linux/namei.h>
  27 #include <linux/fs.h>
  28 #include <asm/div64.h>
  29 #include "ubi.h"
  30
  31 /**
  32  * ubi_do_get_device_info - get information about UBI device.
  33  * @ubi: UBI device description object
  34  * @di: the information is stored here
  35  *
  36  * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
  37  * device is locked and cannot disappear.
  38  */
  39 void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
  40 {
  41         di->ubi_num = ubi->ubi_num;
  42         di->leb_size = ubi->leb_size;
  43         di->leb_start = ubi->leb_start;
  44         di->min_io_size = ubi->min_io_size;
  45         di->max_write_size = ubi->max_write_size;
  46         di->ro_mode = ubi->ro_mode;
  47         di->cdev = ubi->cdev.dev;
  48 }
  49 EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
  50
  51 /**
  52  * ubi_get_device_info - get information about UBI device.
  53  * @ubi_num: UBI device number
  54  * @di: the information is stored here
  55  *
  56  * This function returns %0 in case of success, %-EINVAL if the UBI device
  57  * number is invalid, and %-ENODEV if there is no such UBI device.
  58  */
  59 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
  60 {
  61         struct ubi_device *ubi;
  62
  63         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
  64                 return -EINVAL;
  65         ubi = ubi_get_device(ubi_num);
  66         if (!ubi)
  67                 return -ENODEV;
  68         ubi_do_get_device_info(ubi, di);
  69         ubi_put_device(ubi);
  70         return 0;
  71 }
  72 EXPORT_SYMBOL_GPL(ubi_get_device_info);
  73
  74 /**
  75  * ubi_do_get_volume_info - get information about UBI volume.
  76  * @ubi: UBI device description object
  77  * @vol: volume description object
  78  * @vi: the information is stored here
  79  */
  80 void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
  81                             struct ubi_volume_info *vi)
  82 {
  83         vi->vol_id = vol->vol_id;
  84         vi->ubi_num = ubi->ubi_num;
  85         vi->size = vol->reserved_pebs;
  86         vi->used_bytes = vol->used_bytes;
  87         vi->vol_type = vol->vol_type;
  88         vi->corrupted = vol->corrupted;
  89         vi->upd_marker = vol->upd_marker;
  90         vi->alignment = vol->alignment;
  91         vi->usable_leb_size = vol->usable_leb_size;
  92         vi->name_len = vol->name_len;
  93         vi->name = vol->name;
  94         vi->cdev = vol->cdev.dev;
  95 }
  96
  97 /**
  98  * ubi_get_volume_info - get information about UBI volume.
  99  * @desc: volume descriptor
 100  * @vi: the information is stored here
 101  */
 102 void ubi_get_volume_info(struct ubi_volume_desc *desc,
 103                          struct ubi_volume_info *vi)
 104 {
 105         ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
 106 }
 107 EXPORT_SYMBOL_GPL(ubi_get_volume_info);
 108
 109 /**
 110  * ubi_open_volume - open UBI volume.
 111  * @ubi_num: UBI device number
 112  * @vol_id: volume ID
 113  * @mode: open mode
 114  *
 115  * The @mode parameter specifies if the volume should be opened in read-only
 116  * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
 117  * nobody else will be able to open this volume. UBI allows to have many volume
 118  * readers and one writer at a time.
 119  *
 120  * If a static volume is being opened for the first time since boot, it will be
 121  * checked by this function, which means it will be fully read and the CRC
 122  * checksum of each logical eraseblock will be checked.
 123  *
 124  * This function returns volume descriptor in case of success and a negative
 125  * error code in case of failure.
 126  */
 127 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
 128 {
 129         int err;
 130         struct ubi_volume_desc *desc;
 131         struct ubi_device *ubi;
 132         struct ubi_volume *vol;
 133
 134         dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
 135
 136         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 137                 return ERR_PTR(-EINVAL);
 138
 139         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 140             mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
 141                 return ERR_PTR(-EINVAL);
 142
 143         /*
 144          * First of all, we have to get the UBI device to prevent its removal.
 145          */
 146         ubi = ubi_get_device(ubi_num);
 147         if (!ubi)
 148                 return ERR_PTR(-ENODEV);
 149
 150         if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
 151                 err = -EINVAL;
 152                 goto out_put_ubi;
 153         }
 154
 155         desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 156         if (!desc) {
 157                 err = -ENOMEM;
 158                 goto out_put_ubi;
 159         }
 160
 161         err = -ENODEV;
 162         if (!try_module_get(THIS_MODULE))
 163                 goto out_free;
 164
 165         spin_lock(&ubi->volumes_lock);
 166         vol = ubi->volumes[vol_id];
 167         if (!vol)
 168                 goto out_unlock;
 169
 170         err = -EBUSY;
 171         switch (mode) {
 172         case UBI_READONLY:
 173                 if (vol->exclusive)
 174                         goto out_unlock;
 175                 vol->readers += 1;
 176                 break;
 177
 178         case UBI_READWRITE:
 179                 if (vol->exclusive || vol->writers > 0)
 180                         goto out_unlock;
 181                 vol->writers += 1;
 182                 break;
 183
 184         case UBI_EXCLUSIVE:
 185                 if (vol->exclusive || vol->writers || vol->readers ||
 186                     vol->metaonly)
 187                         goto out_unlock;
 188                 vol->exclusive = 1;
 189                 break;
 190
 191         case UBI_METAONLY:
 192                 if (vol->metaonly || vol->exclusive)
 193                         goto out_unlock;
 194                 vol->metaonly = 1;
 195                 break;
 196         }
 197         get_device(&vol->dev);
 198         vol->ref_count += 1;
 199         spin_unlock(&ubi->volumes_lock);
 200
 201         desc->vol = vol;
 202         desc->mode = mode;
 203
 204         mutex_lock(&ubi->ckvol_mutex);
 205         if (!vol->checked) {
 206                 /* This is the first open - check the volume */
 207                 err = ubi_check_volume(ubi, vol_id);
 208                 if (err < 0) {
 209                         mutex_unlock(&ubi->ckvol_mutex);
 210                         ubi_close_volume(desc);
 211                         return ERR_PTR(err);
 212                 }
 213                 if (err == 1) {
 214                         ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
 215                                  vol_id, ubi->ubi_num);
 216                         vol->corrupted = 1;
 217                 }
 218                 vol->checked = 1;
 219         }
 220         mutex_unlock(&ubi->ckvol_mutex);
 221
 222         return desc;
 223
 224 out_unlock:
 225         spin_unlock(&ubi->volumes_lock);
 226         module_put(THIS_MODULE);
 227 out_free:
 228         kfree(desc);
 229 out_put_ubi:
 230         ubi_put_device(ubi);
 231         ubi_err(ubi, "cannot open device %d, volume %d, error %d",
 232                 ubi_num, vol_id, err);
 233         return ERR_PTR(err);
 234 }
 235 EXPORT_SYMBOL_GPL(ubi_open_volume);
 236
 237 /**
 238  * ubi_open_volume_nm - open UBI volume by name.
 239  * @ubi_num: UBI device number
 240  * @name: volume name
 241  * @mode: open mode
 242  *
 243  * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 244  */
 245 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 246                                            int mode)
 247 {
 248         int i, vol_id = -1, len;
 249         struct ubi_device *ubi;
 250         struct ubi_volume_desc *ret;
 251
 252         dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
 253
 254         if (!name)
 255                 return ERR_PTR(-EINVAL);
 256
 257         len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 258         if (len > UBI_VOL_NAME_MAX)
 259                 return ERR_PTR(-EINVAL);
 260
 261         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 262                 return ERR_PTR(-EINVAL);
 263
 264         ubi = ubi_get_device(ubi_num);
 265         if (!ubi)
 266                 return ERR_PTR(-ENODEV);
 267
 268         spin_lock(&ubi->volumes_lock);
 269         /* Walk all volumes of this UBI device */
 270         for (i = 0; i < ubi->vtbl_slots; i++) {
 271                 struct ubi_volume *vol = ubi->volumes[i];
 272
 273                 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 274                         vol_id = i;
 275                         break;
 276                 }
 277         }
 278         spin_unlock(&ubi->volumes_lock);
 279
 280         if (vol_id >= 0)
 281                 ret = ubi_open_volume(ubi_num, vol_id, mode);
 282         else
 283                 ret = ERR_PTR(-ENODEV);
 284
 285         /*
 286          * We should put the UBI device even in case of success, because
 287          * 'ubi_open_volume()' took a reference as well.
 288          */
 289         ubi_put_device(ubi);
 290         return ret;
 291 }
 292 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 293
 294 /**
 295  * ubi_open_volume_path - open UBI volume by its character device node path.
 296  * @pathname: volume character device node path
 297  * @mode: open mode
 298  *
 299  * This function is similar to 'ubi_open_volume()', but opens a volume the path
 300  * to its character device node.
 301  */
 302 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
 303 {
 304         int error, ubi_num, vol_id, mod;
 305         struct inode *inode;
 306         struct path path;
 307
 308         dbg_gen("open volume %s, mode %d", pathname, mode);
 309
 310         if (!pathname || !*pathname)
 311                 return ERR_PTR(-EINVAL);
 312
 313         error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 314         if (error)
 315                 return ERR_PTR(error);
 316
 317         inode = d_backing_inode(path.dentry);
 318         mod = inode->i_mode;
 319         ubi_num = ubi_major2num(imajor(inode));
 320         vol_id = iminor(inode) - 1;
 321         path_put(&path);
 322
 323         if (!S_ISCHR(mod))
 324                 return ERR_PTR(-EINVAL);
 325         if (vol_id >= 0 && ubi_num >= 0)
 326                 return ubi_open_volume(ubi_num, vol_id, mode);
 327         return ERR_PTR(-ENODEV);
 328 }
 329 EXPORT_SYMBOL_GPL(ubi_open_volume_path);
 330
 331 /**
 332  * ubi_close_volume - close UBI volume.
 333  * @desc: volume descriptor
 334  */
 335 void ubi_close_volume(struct ubi_volume_desc *desc)
 336 {
 337         struct ubi_volume *vol = desc->vol;
 338         struct ubi_device *ubi = vol->ubi;
 339
 340         dbg_gen("close device %d, volume %d, mode %d",
 341                 ubi->ubi_num, vol->vol_id, desc->mode);
 342
 343         spin_lock(&ubi->volumes_lock);
 344         switch (desc->mode) {
 345         case UBI_READONLY:
 346                 vol->readers -= 1;
 347                 break;
 348         case UBI_READWRITE:
 349                 vol->writers -= 1;
 350                 break;
 351         case UBI_EXCLUSIVE:
 352                 vol->exclusive = 0;
 353                 break;
 354         case UBI_METAONLY:
 355                 vol->metaonly = 0;
 356                 break;
 357         }
 358         vol->ref_count -= 1;
 359         spin_unlock(&ubi->volumes_lock);
 360
 361         kfree(desc);
 362         put_device(&vol->dev);
 363         ubi_put_device(ubi);
 364         module_put(THIS_MODULE);
 365 }
 366 EXPORT_SYMBOL_GPL(ubi_close_volume);
 367
 368 /**
 369  * leb_read_sanity_check - does sanity checks on read requests.
 370  * @desc: volume descriptor
 371  * @lnum: logical eraseblock number to read from
 372  * @offset: offset within the logical eraseblock to read from
 373  * @len: how many bytes to read
 374  *
 375  * This function is used by ubi_leb_read() and ubi_leb_read_sg()
 376  * to perform sanity checks.
 377  */
 378 static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
 379                                  int offset, int len)
 380 {
 381         struct ubi_volume *vol = desc->vol;
 382         struct ubi_device *ubi = vol->ubi;
 383         int vol_id = vol->vol_id;
 384
 385         if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 386             lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 387             offset + len > vol->usable_leb_size)
 388                 return -EINVAL;
 389
 390         if (vol->vol_type == UBI_STATIC_VOLUME) {
 391                 if (vol->used_ebs == 0)
 392                         /* Empty static UBI volume */
 393                         return 0;
 394                 if (lnum == vol->used_ebs - 1 &&
 395                     offset + len > vol->last_eb_bytes)
 396                         return -EINVAL;
 397         }
 398
 399         if (vol->upd_marker)
 400                 return -EBADF;
 401
 402         return 0;
 403 }
 404
 405 /**
 406  * ubi_leb_read - read data.
 407  * @desc: volume descriptor
 408  * @lnum: logical eraseblock number to read from
 409  * @buf: buffer where to store the read data
 410  * @offset: offset within the logical eraseblock to read from
 411  * @len: how many bytes to read
 412  * @check: whether UBI has to check the read data's CRC or not.
 413  *
 414  * This function reads data from offset @offset of logical eraseblock @lnum and
 415  * stores the data at @buf. When reading from static volumes, @check specifies
 416  * whether the data has to be checked or not. If yes, the whole logical
 417  * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 418  * checksum is per-eraseblock). So checking may substantially slow down the
 419  * read speed. The @check argument is ignored for dynamic volumes.
 420  *
 421  * In case of success, this function returns zero. In case of failure, this
 422  * function returns a negative error code.
 423  *
 424  * %-EBADMSG error code is returned:
 425  * o for both static and dynamic volumes if MTD driver has detected a data
 426  *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 427  * o for static volumes in case of data CRC mismatch.
 428  *
 429  * If the volume is damaged because of an interrupted update this function just
 430  * returns immediately with %-EBADF error code.
 431  */
 432 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 433                  int len, int check)
 434 {
 435         struct ubi_volume *vol = desc->vol;
 436         struct ubi_device *ubi = vol->ubi;
 437         int err, vol_id = vol->vol_id;
 438
 439         dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 440
 441         err = leb_read_sanity_check(desc, lnum, offset, len);
 442         if (err < 0)
 443                 return err;
 444
 445         if (len == 0)
 446                 return 0;
 447
 448         err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
 449         if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 450                 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
 451                 vol->corrupted = 1;
 452         }
 453
 454         return err;
 455 }
 456 EXPORT_SYMBOL_GPL(ubi_leb_read);
 457
 458
 459 /**
 460  * ubi_leb_read_sg - read data into a scatter gather list.
 461  * @desc: volume descriptor
 462  * @lnum: logical eraseblock number to read from
 463  * @buf: buffer where to store the read data
 464  * @offset: offset within the logical eraseblock to read from
 465  * @len: how many bytes to read
 466  * @check: whether UBI has to check the read data's CRC or not.
 467  *
 468  * This function works exactly like ubi_leb_read_sg(). But instead of
 469  * storing the read data into a buffer it writes to an UBI scatter gather
 470  * list.
 471  */
 472 int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
 473                     int offset, int len, int check)
 474 {
 475         struct ubi_volume *vol = desc->vol;
 476         struct ubi_device *ubi = vol->ubi;
 477         int err, vol_id = vol->vol_id;
 478
 479         dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 480
 481         err = leb_read_sanity_check(desc, lnum, offset, len);
 482         if (err < 0)
 483                 return err;
 484
 485         if (len == 0)
 486                 return 0;
 487
 488         err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
 489         if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 490                 ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
 491                 vol->corrupted = 1;
 492         }
 493
 494         return err;
 495 }
 496 EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
 497
 498 /**
 499  * ubi_leb_write - write data.
 500  * @desc: volume descriptor
 501  * @lnum: logical eraseblock number to write to
 502  * @buf: data to write
 503  * @offset: offset within the logical eraseblock where to write
 504  * @len: how many bytes to write
 505  *
 506  * This function writes @len bytes of data from @buf to offset @offset of
 507  * logical eraseblock @lnum.
 508  *
 509  * This function takes care of physical eraseblock write failures. If write to
 510  * the physical eraseblock write operation fails, the logical eraseblock is
 511  * re-mapped to another physical eraseblock, the data is recovered, and the
 512  * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 513  *
 514  * If all the data were successfully written, zero is returned. If an error
 515  * occurred and UBI has not been able to recover from it, this function returns
 516  * a negative error code. Note, in case of an error, it is possible that
 517  * something was still written to the flash media, but that may be some
 518  * garbage.
 519  *
 520  * If the volume is damaged because of an interrupted update this function just
 521  * returns immediately with %-EBADF code.
 522  */
 523 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 524                   int offset, int len)
 525 {
 526         struct ubi_volume *vol = desc->vol;
 527         struct ubi_device *ubi = vol->ubi;
 528         int vol_id = vol->vol_id;
 529
 530         dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 531
 532         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 533                 return -EINVAL;
 534
 535         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 536                 return -EROFS;
 537
 538         if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 539             offset + len > vol->usable_leb_size ||
 540             offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
 541                 return -EINVAL;
 542
 543         if (vol->upd_marker)
 544                 return -EBADF;
 545
 546         if (len == 0)
 547                 return 0;
 548
 549         return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
 550 }
 551 EXPORT_SYMBOL_GPL(ubi_leb_write);
 552
 553 /*
 554  * ubi_leb_change - change logical eraseblock atomically.
 555  * @desc: volume descriptor
 556  * @lnum: logical eraseblock number to change
 557  * @buf: data to write
 558  * @len: how many bytes to write
 559  *
 560  * This function changes the contents of a logical eraseblock atomically. @buf
 561  * has to contain new logical eraseblock data, and @len - the length of the
 562  * data, which has to be aligned. The length may be shorter than the logical
 563  * eraseblock size, ant the logical eraseblock may be appended to more times
 564  * later on. This function guarantees that in case of an unclean reboot the old
 565  * contents is preserved. Returns zero in case of success and a negative error
 566  * code in case of failure.
 567  */
 568 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 569                    int len)
 570 {
 571         struct ubi_volume *vol = desc->vol;
 572         struct ubi_device *ubi = vol->ubi;
 573         int vol_id = vol->vol_id;
 574
 575         dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 576
 577         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 578                 return -EINVAL;
 579
 580         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 581                 return -EROFS;
 582
 583         if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 584             len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
 585                 return -EINVAL;
 586
 587         if (vol->upd_marker)
 588                 return -EBADF;
 589
 590         if (len == 0)
 591                 return 0;
 592
 593         return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
 594 }
 595 EXPORT_SYMBOL_GPL(ubi_leb_change);
 596
 597 /**
 598  * ubi_leb_erase - erase logical eraseblock.
 599  * @desc: volume descriptor
 600  * @lnum: logical eraseblock number
 601  *
 602  * This function un-maps logical eraseblock @lnum and synchronously erases the
 603  * correspondent physical eraseblock. Returns zero in case of success and a
 604  * negative error code in case of failure.
 605  *
 606  * If the volume is damaged because of an interrupted update this function just
 607  * returns immediately with %-EBADF code.
 608  */
 609 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 610 {
 611         struct ubi_volume *vol = desc->vol;
 612         struct ubi_device *ubi = vol->ubi;
 613         int err;
 614
 615         dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 616
 617         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 618                 return -EROFS;
 619
 620         if (lnum < 0 || lnum >= vol->reserved_pebs)
 621                 return -EINVAL;
 622
 623         if (vol->upd_marker)
 624                 return -EBADF;
 625
 626         err = ubi_eba_unmap_leb(ubi, vol, lnum);
 627         if (err)
 628                 return err;
 629
 630         return ubi_wl_flush(ubi, vol->vol_id, lnum);
 631 }
 632 EXPORT_SYMBOL_GPL(ubi_leb_erase);
 633
 634 /**
 635  * ubi_leb_unmap - un-map logical eraseblock.
 636  * @desc: volume descriptor
 637  * @lnum: logical eraseblock number
 638  *
 639  * This function un-maps logical eraseblock @lnum and schedules the
 640  * corresponding physical eraseblock for erasure, so that it will eventually be
 641  * physically erased in background. This operation is much faster than the
 642  * erase operation.
 643  *
 644  * Unlike erase, the un-map operation does not guarantee that the logical
 645  * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 646  * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 647  * happens after this, the logical eraseblocks will not necessarily be
 648  * un-mapped again when this MTD device is attached. They may actually be
 649  * mapped to the same physical eraseblocks again. So, this function has to be
 650  * used with care.
 651  *
 652  * In other words, when un-mapping a logical eraseblock, UBI does not store
 653  * any information about this on the flash media, it just marks the logical
 654  * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 655  * eraseblock is physically erased, it will be mapped again to the same logical
 656  * eraseblock when the MTD device is attached again.
 657  *
 658  * The main and obvious use-case of this function is when the contents of a
 659  * logical eraseblock has to be re-written. Then it is much more efficient to
 660  * first un-map it, then write new data, rather than first erase it, then write
 661  * new data. Note, once new data has been written to the logical eraseblock,
 662  * UBI guarantees that the old contents has gone forever. In other words, if an
 663  * unclean reboot happens after the logical eraseblock has been un-mapped and
 664  * then written to, it will contain the last written data.
 665  *
 666  * This function returns zero in case of success and a negative error code in
 667  * case of failure. If the volume is damaged because of an interrupted update
 668  * this function just returns immediately with %-EBADF code.
 669  */
 670 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 671 {
 672         struct ubi_volume *vol = desc->vol;
 673         struct ubi_device *ubi = vol->ubi;
 674
 675         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 676
 677         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 678                 return -EROFS;
 679
 680         if (lnum < 0 || lnum >= vol->reserved_pebs)
 681                 return -EINVAL;
 682
 683         if (vol->upd_marker)
 684                 return -EBADF;
 685
 686         return ubi_eba_unmap_leb(ubi, vol, lnum);
 687 }
 688 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 689
 690 /**
 691  * ubi_leb_map - map logical eraseblock to a physical eraseblock.
 692  * @desc: volume descriptor
 693  * @lnum: logical eraseblock number
 694  *
 695  * This function maps an un-mapped logical eraseblock @lnum to a physical
 696  * eraseblock. This means, that after a successful invocation of this
 697  * function the logical eraseblock @lnum will be empty (contain only %0xFF
 698  * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
 699  * happens.
 700  *
 701  * This function returns zero in case of success, %-EBADF if the volume is
 702  * damaged because of an interrupted update, %-EBADMSG if the logical
 703  * eraseblock is already mapped, and other negative error codes in case of
 704  * other failures.
 705  */
 706 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
 707 {
 708         struct ubi_volume *vol = desc->vol;
 709         struct ubi_device *ubi = vol->ubi;
 710
 711         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 712
 713         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 714                 return -EROFS;
 715
 716         if (lnum < 0 || lnum >= vol->reserved_pebs)
 717                 return -EINVAL;
 718
 719         if (vol->upd_marker)
 720                 return -EBADF;
 721
 722         if (vol->eba_tbl[lnum] >= 0)
 723                 return -EBADMSG;
 724
 725         return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
 726 }
 727 EXPORT_SYMBOL_GPL(ubi_leb_map);
 728
 729 /**
 730  * ubi_is_mapped - check if logical eraseblock is mapped.
 731  * @desc: volume descriptor
 732  * @lnum: logical eraseblock number
 733  *
 734  * This function checks if logical eraseblock @lnum is mapped to a physical
 735  * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 736  * mean it will still be un-mapped after the UBI device is re-attached. The
 737  * logical eraseblock may become mapped to the physical eraseblock it was last
 738  * mapped to.
 739  *
 740  * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 741  * error code in case of failure. If the volume is damaged because of an
 742  * interrupted update this function just returns immediately with %-EBADF error
 743  * code.
 744  */
 745 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 746 {
 747         struct ubi_volume *vol = desc->vol;
 748
 749         dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
 750
 751         if (lnum < 0 || lnum >= vol->reserved_pebs)
 752                 return -EINVAL;
 753
 754         if (vol->upd_marker)
 755                 return -EBADF;
 756
 757         return vol->eba_tbl[lnum] >= 0;
 758 }
 759 EXPORT_SYMBOL_GPL(ubi_is_mapped);
 760
 761 /**
 762  * ubi_sync - synchronize UBI device buffers.
 763  * @ubi_num: UBI device to synchronize
 764  *
 765  * The underlying MTD device may cache data in hardware or in software. This
 766  * function ensures the caches are flushed. Returns zero in case of success and
 767  * a negative error code in case of failure.
 768  */
 769 int ubi_sync(int ubi_num)
 770 {
 771         struct ubi_device *ubi;
 772
 773         ubi = ubi_get_device(ubi_num);
 774         if (!ubi)
 775                 return -ENODEV;
 776
 777         mtd_sync(ubi->mtd);
 778         ubi_put_device(ubi);
 779         return 0;
 780 }
 781 EXPORT_SYMBOL_GPL(ubi_sync);
 782
 783 /**
 784  * ubi_flush - flush UBI work queue.
 785  * @ubi_num: UBI device to flush work queue
 786  * @vol_id: volume id to flush for
 787  * @lnum: logical eraseblock number to flush for
 788  *
 789  * This function executes all pending works for a particular volume id / logical
 790  * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
 791  * a wildcard for all of the corresponding volume numbers or logical
 792  * eraseblock numbers. It returns zero in case of success and a negative error
 793  * code in case of failure.
 794  */
 795 int ubi_flush(int ubi_num, int vol_id, int lnum)
 796 {
 797         struct ubi_device *ubi;
 798         int err = 0;
 799
 800         ubi = ubi_get_device(ubi_num);
 801         if (!ubi)
 802                 return -ENODEV;
 803
 804         err = ubi_wl_flush(ubi, vol_id, lnum);
 805         ubi_put_device(ubi);
 806         return err;
 807 }
 808 EXPORT_SYMBOL_GPL(ubi_flush);
 809
 810 BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
 811
 812 /**
 813  * ubi_register_volume_notifier - register a volume notifier.
 814  * @nb: the notifier description object
 815  * @ignore_existing: if non-zero, do not send "added" notification for all
 816  *                   already existing volumes
 817  *
 818  * This function registers a volume notifier, which means that
 819  * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
 820  * removed, re-sized, re-named, or updated. The first argument of the function
 821  * is the notification type. The second argument is pointer to a
 822  * &struct ubi_notification object which describes the notification event.
 823  * Using UBI API from the volume notifier is prohibited.
 824  *
 825  * This function returns zero in case of success and a negative error code
 826  * in case of failure.
 827  */
 828 int ubi_register_volume_notifier(struct notifier_block *nb,
 829                                  int ignore_existing)
 830 {
 831         int err;
 832
 833         err = blocking_notifier_chain_register(&ubi_notifiers, nb);
 834         if (err != 0)
 835                 return err;
 836         if (ignore_existing)
 837                 return 0;
 838
 839         /*
 840          * We are going to walk all UBI devices and all volumes, and
 841          * notify the user about existing volumes by the %UBI_VOLUME_ADDED
 842          * event. We have to lock the @ubi_devices_mutex to make sure UBI
 843          * devices do not disappear.
 844          */
 845         mutex_lock(&ubi_devices_mutex);
 846         ubi_enumerate_volumes(nb);
 847         mutex_unlock(&ubi_devices_mutex);
 848
 849         return err;
 850 }
 851 EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
 852
 853 /**
 854  * ubi_unregister_volume_notifier - unregister the volume notifier.
 855  * @nb: the notifier description object
 856  *
 857  * This function unregisters volume notifier @nm and returns zero in case of
 858  * success and a negative error code in case of failure.
 859  */
 860 int ubi_unregister_volume_notifier(struct notifier_block *nb)
 861 {
 862         return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
 863 }
 864 EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);