uboot/drivers/mtd/ubi/kapi.c
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   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#ifndef __UBOOT__
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/namei.h>
  15#include <linux/fs.h>
  16#include <asm/div64.h>
  17#else
  18#include <ubi_uboot.h>
  19#endif
  20#include <linux/err.h>
  21
  22#include "ubi.h"
  23
  24/**
  25 * ubi_do_get_device_info - get information about UBI device.
  26 * @ubi: UBI device description object
  27 * @di: the information is stored here
  28 *
  29 * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
  30 * device is locked and cannot disappear.
  31 */
  32void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
  33{
  34        di->ubi_num = ubi->ubi_num;
  35        di->leb_size = ubi->leb_size;
  36        di->leb_start = ubi->leb_start;
  37        di->min_io_size = ubi->min_io_size;
  38        di->max_write_size = ubi->max_write_size;
  39        di->ro_mode = ubi->ro_mode;
  40#ifndef __UBOOT__
  41        di->cdev = ubi->cdev.dev;
  42#endif
  43}
  44EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
  45
  46/**
  47 * ubi_get_device_info - get information about UBI device.
  48 * @ubi_num: UBI device number
  49 * @di: the information is stored here
  50 *
  51 * This function returns %0 in case of success, %-EINVAL if the UBI device
  52 * number is invalid, and %-ENODEV if there is no such UBI device.
  53 */
  54int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
  55{
  56        struct ubi_device *ubi;
  57
  58        if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
  59                return -EINVAL;
  60        ubi = ubi_get_device(ubi_num);
  61        if (!ubi)
  62                return -ENODEV;
  63        ubi_do_get_device_info(ubi, di);
  64        ubi_put_device(ubi);
  65        return 0;
  66}
  67EXPORT_SYMBOL_GPL(ubi_get_device_info);
  68
  69/**
  70 * ubi_do_get_volume_info - get information about UBI volume.
  71 * @ubi: UBI device description object
  72 * @vol: volume description object
  73 * @vi: the information is stored here
  74 */
  75void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
  76                            struct ubi_volume_info *vi)
  77{
  78        vi->vol_id = vol->vol_id;
  79        vi->ubi_num = ubi->ubi_num;
  80        vi->size = vol->reserved_pebs;
  81        vi->used_bytes = vol->used_bytes;
  82        vi->vol_type = vol->vol_type;
  83        vi->corrupted = vol->corrupted;
  84        vi->upd_marker = vol->upd_marker;
  85        vi->alignment = vol->alignment;
  86        vi->usable_leb_size = vol->usable_leb_size;
  87        vi->name_len = vol->name_len;
  88        vi->name = vol->name;
  89        vi->cdev = vol->cdev.dev;
  90}
  91
  92/**
  93 * ubi_get_volume_info - get information about UBI volume.
  94 * @desc: volume descriptor
  95 * @vi: the information is stored here
  96 */
  97void ubi_get_volume_info(struct ubi_volume_desc *desc,
  98                         struct ubi_volume_info *vi)
  99{
 100        ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
 101}
 102EXPORT_SYMBOL_GPL(ubi_get_volume_info);
 103
 104/**
 105 * ubi_open_volume - open UBI volume.
 106 * @ubi_num: UBI device number
 107 * @vol_id: volume ID
 108 * @mode: open mode
 109 *
 110 * The @mode parameter specifies if the volume should be opened in read-only
 111 * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
 112 * nobody else will be able to open this volume. UBI allows to have many volume
 113 * readers and one writer at a time.
 114 *
 115 * If a static volume is being opened for the first time since boot, it will be
 116 * checked by this function, which means it will be fully read and the CRC
 117 * checksum of each logical eraseblock will be checked.
 118 *
 119 * This function returns volume descriptor in case of success and a negative
 120 * error code in case of failure.
 121 */
 122struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
 123{
 124        int err;
 125        struct ubi_volume_desc *desc;
 126        struct ubi_device *ubi;
 127        struct ubi_volume *vol;
 128
 129        dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
 130
 131        if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 132                return ERR_PTR(-EINVAL);
 133
 134        if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 135            mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
 136                return ERR_PTR(-EINVAL);
 137
 138        /*
 139         * First of all, we have to get the UBI device to prevent its removal.
 140         */
 141        ubi = ubi_get_device(ubi_num);
 142        if (!ubi)
 143                return ERR_PTR(-ENODEV);
 144
 145        if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
 146                err = -EINVAL;
 147                goto out_put_ubi;
 148        }
 149
 150        desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 151        if (!desc) {
 152                err = -ENOMEM;
 153                goto out_put_ubi;
 154        }
 155
 156        err = -ENODEV;
 157        if (!try_module_get(THIS_MODULE))
 158                goto out_free;
 159
 160        spin_lock(&ubi->volumes_lock);
 161        vol = ubi->volumes[vol_id];
 162        if (!vol)
 163                goto out_unlock;
 164
 165        err = -EBUSY;
 166        switch (mode) {
 167        case UBI_READONLY:
 168                if (vol->exclusive)
 169                        goto out_unlock;
 170                vol->readers += 1;
 171                break;
 172
 173        case UBI_READWRITE:
 174                if (vol->exclusive || vol->writers > 0)
 175                        goto out_unlock;
 176                vol->writers += 1;
 177                break;
 178
 179        case UBI_EXCLUSIVE:
 180                if (vol->exclusive || vol->writers || vol->readers ||
 181                    vol->metaonly)
 182                        goto out_unlock;
 183                vol->exclusive = 1;
 184                break;
 185
 186        case UBI_METAONLY:
 187                if (vol->metaonly || vol->exclusive)
 188                        goto out_unlock;
 189                vol->metaonly = 1;
 190                break;
 191        }
 192        get_device(&vol->dev);
 193        vol->ref_count += 1;
 194        spin_unlock(&ubi->volumes_lock);
 195
 196        desc->vol = vol;
 197        desc->mode = mode;
 198
 199        mutex_lock(&ubi->ckvol_mutex);
 200        if (!vol->checked) {
 201                /* This is the first open - check the volume */
 202                err = ubi_check_volume(ubi, vol_id);
 203                if (err < 0) {
 204                        mutex_unlock(&ubi->ckvol_mutex);
 205                        ubi_close_volume(desc);
 206                        return ERR_PTR(err);
 207                }
 208                if (err == 1) {
 209                        ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
 210                                 vol_id, ubi->ubi_num);
 211                        vol->corrupted = 1;
 212                }
 213                vol->checked = 1;
 214        }
 215        mutex_unlock(&ubi->ckvol_mutex);
 216
 217        return desc;
 218
 219out_unlock:
 220        spin_unlock(&ubi->volumes_lock);
 221        module_put(THIS_MODULE);
 222out_free:
 223        kfree(desc);
 224out_put_ubi:
 225        ubi_put_device(ubi);
 226        ubi_err(ubi, "cannot open device %d, volume %d, error %d",
 227                ubi_num, vol_id, err);
 228        return ERR_PTR(err);
 229}
 230EXPORT_SYMBOL_GPL(ubi_open_volume);
 231
 232/**
 233 * ubi_open_volume_nm - open UBI volume by name.
 234 * @ubi_num: UBI device number
 235 * @name: volume name
 236 * @mode: open mode
 237 *
 238 * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 239 */
 240struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 241                                           int mode)
 242{
 243        int i, vol_id = -1, len;
 244        struct ubi_device *ubi;
 245        struct ubi_volume_desc *ret;
 246
 247        dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
 248
 249        if (!name)
 250                return ERR_PTR(-EINVAL);
 251
 252        len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 253        if (len > UBI_VOL_NAME_MAX)
 254                return ERR_PTR(-EINVAL);
 255
 256        if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 257                return ERR_PTR(-EINVAL);
 258
 259        ubi = ubi_get_device(ubi_num);
 260        if (!ubi)
 261                return ERR_PTR(-ENODEV);
 262
 263        spin_lock(&ubi->volumes_lock);
 264        /* Walk all volumes of this UBI device */
 265        for (i = 0; i < ubi->vtbl_slots; i++) {
 266                struct ubi_volume *vol = ubi->volumes[i];
 267
 268                if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 269                        vol_id = i;
 270                        break;
 271                }
 272        }
 273        spin_unlock(&ubi->volumes_lock);
 274
 275        if (vol_id >= 0)
 276                ret = ubi_open_volume(ubi_num, vol_id, mode);
 277        else
 278                ret = ERR_PTR(-ENODEV);
 279
 280        /*
 281         * We should put the UBI device even in case of success, because
 282         * 'ubi_open_volume()' took a reference as well.
 283         */
 284        ubi_put_device(ubi);
 285        return ret;
 286}
 287EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 288
 289#ifndef __UBOOT__
 290/**
 291 * ubi_open_volume_path - open UBI volume by its character device node path.
 292 * @pathname: volume character device node path
 293 * @mode: open mode
 294 *
 295 * This function is similar to 'ubi_open_volume()', but opens a volume the path
 296 * to its character device node.
 297 */
 298struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
 299{
 300        int error, ubi_num, vol_id, mod;
 301        struct inode *inode;
 302        struct path path;
 303
 304        dbg_gen("open volume %s, mode %d", pathname, mode);
 305
 306        if (!pathname || !*pathname)
 307                return ERR_PTR(-EINVAL);
 308
 309        error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 310        if (error)
 311                return ERR_PTR(error);
 312
 313        inode = d_backing_inode(path.dentry);
 314        mod = inode->i_mode;
 315        ubi_num = ubi_major2num(imajor(inode));
 316        vol_id = iminor(inode) - 1;
 317        path_put(&path);
 318
 319        if (!S_ISCHR(mod))
 320                return ERR_PTR(-EINVAL);
 321        if (vol_id >= 0 && ubi_num >= 0)
 322                return ubi_open_volume(ubi_num, vol_id, mode);
 323        return ERR_PTR(-ENODEV);
 324}
 325EXPORT_SYMBOL_GPL(ubi_open_volume_path);
 326#endif
 327
 328/**
 329 * ubi_close_volume - close UBI volume.
 330 * @desc: volume descriptor
 331 */
 332void ubi_close_volume(struct ubi_volume_desc *desc)
 333{
 334        struct ubi_volume *vol = desc->vol;
 335        struct ubi_device *ubi = vol->ubi;
 336
 337        dbg_gen("close device %d, volume %d, mode %d",
 338                ubi->ubi_num, vol->vol_id, desc->mode);
 339
 340        spin_lock(&ubi->volumes_lock);
 341        switch (desc->mode) {
 342        case UBI_READONLY:
 343                vol->readers -= 1;
 344                break;
 345        case UBI_READWRITE:
 346                vol->writers -= 1;
 347                break;
 348        case UBI_EXCLUSIVE:
 349                vol->exclusive = 0;
 350                break;
 351        case UBI_METAONLY:
 352                vol->metaonly = 0;
 353                break;
 354        }
 355        vol->ref_count -= 1;
 356        spin_unlock(&ubi->volumes_lock);
 357
 358        kfree(desc);
 359        put_device(&vol->dev);
 360        ubi_put_device(ubi);
 361        module_put(THIS_MODULE);
 362}
 363EXPORT_SYMBOL_GPL(ubi_close_volume);
 364
 365/**
 366 * leb_read_sanity_check - does sanity checks on read requests.
 367 * @desc: volume descriptor
 368 * @lnum: logical eraseblock number to read from
 369 * @offset: offset within the logical eraseblock to read from
 370 * @len: how many bytes to read
 371 *
 372 * This function is used by ubi_leb_read() and ubi_leb_read_sg()
 373 * to perform sanity checks.
 374 */
 375static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
 376                                 int offset, int len)
 377{
 378        struct ubi_volume *vol = desc->vol;
 379        struct ubi_device *ubi = vol->ubi;
 380        int vol_id = vol->vol_id;
 381
 382        if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 383            lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 384            offset + len > vol->usable_leb_size)
 385                return -EINVAL;
 386
 387        if (vol->vol_type == UBI_STATIC_VOLUME) {
 388                if (vol->used_ebs == 0)
 389                        /* Empty static UBI volume */
 390                        return 0;
 391                if (lnum == vol->used_ebs - 1 &&
 392                    offset + len > vol->last_eb_bytes)
 393                        return -EINVAL;
 394        }
 395
 396        if (vol->upd_marker)
 397                return -EBADF;
 398
 399        return 0;
 400}
 401
 402/**
 403 * ubi_leb_read - read data.
 404 * @desc: volume descriptor
 405 * @lnum: logical eraseblock number to read from
 406 * @buf: buffer where to store the read data
 407 * @offset: offset within the logical eraseblock to read from
 408 * @len: how many bytes to read
 409 * @check: whether UBI has to check the read data's CRC or not.
 410 *
 411 * This function reads data from offset @offset of logical eraseblock @lnum and
 412 * stores the data at @buf. When reading from static volumes, @check specifies
 413 * whether the data has to be checked or not. If yes, the whole logical
 414 * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 415 * checksum is per-eraseblock). So checking may substantially slow down the
 416 * read speed. The @check argument is ignored for dynamic volumes.
 417 *
 418 * In case of success, this function returns zero. In case of failure, this
 419 * function returns a negative error code.
 420 *
 421 * %-EBADMSG error code is returned:
 422 * o for both static and dynamic volumes if MTD driver has detected a data
 423 *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 424 * o for static volumes in case of data CRC mismatch.
 425 *
 426 * If the volume is damaged because of an interrupted update this function just
 427 * returns immediately with %-EBADF error code.
 428 */
 429int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 430                 int len, int check)
 431{
 432        struct ubi_volume *vol = desc->vol;
 433        struct ubi_device *ubi = vol->ubi;
 434        int err, vol_id = vol->vol_id;
 435
 436        dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 437
 438        err = leb_read_sanity_check(desc, lnum, offset, len);
 439        if (err < 0)
 440                return err;
 441
 442        if (len == 0)
 443                return 0;
 444
 445        err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
 446        if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 447                ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
 448                vol->corrupted = 1;
 449        }
 450
 451        return err;
 452}
 453EXPORT_SYMBOL_GPL(ubi_leb_read);
 454
 455#ifndef __UBOOT__
 456/**
 457 * ubi_leb_read_sg - read data into a scatter gather list.
 458 * @desc: volume descriptor
 459 * @lnum: logical eraseblock number to read from
 460 * @buf: buffer where to store the read data
 461 * @offset: offset within the logical eraseblock to read from
 462 * @len: how many bytes to read
 463 * @check: whether UBI has to check the read data's CRC or not.
 464 *
 465 * This function works exactly like ubi_leb_read_sg(). But instead of
 466 * storing the read data into a buffer it writes to an UBI scatter gather
 467 * list.
 468 */
 469int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
 470                    int offset, int len, int check)
 471{
 472        struct ubi_volume *vol = desc->vol;
 473        struct ubi_device *ubi = vol->ubi;
 474        int err, vol_id = vol->vol_id;
 475
 476        dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 477
 478        err = leb_read_sanity_check(desc, lnum, offset, len);
 479        if (err < 0)
 480                return err;
 481
 482        if (len == 0)
 483                return 0;
 484
 485        err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
 486        if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 487                ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
 488                vol->corrupted = 1;
 489        }
 490
 491        return err;
 492}
 493EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
 494#endif
 495
 496/**
 497 * ubi_leb_write - write data.
 498 * @desc: volume descriptor
 499 * @lnum: logical eraseblock number to write to
 500 * @buf: data to write
 501 * @offset: offset within the logical eraseblock where to write
 502 * @len: how many bytes to write
 503 *
 504 * This function writes @len bytes of data from @buf to offset @offset of
 505 * logical eraseblock @lnum.
 506 *
 507 * This function takes care of physical eraseblock write failures. If write to
 508 * the physical eraseblock write operation fails, the logical eraseblock is
 509 * re-mapped to another physical eraseblock, the data is recovered, and the
 510 * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 511 *
 512 * If all the data were successfully written, zero is returned. If an error
 513 * occurred and UBI has not been able to recover from it, this function returns
 514 * a negative error code. Note, in case of an error, it is possible that
 515 * something was still written to the flash media, but that may be some
 516 * garbage.
 517 *
 518 * If the volume is damaged because of an interrupted update this function just
 519 * returns immediately with %-EBADF code.
 520 */
 521int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 522                  int offset, int len)
 523{
 524        struct ubi_volume *vol = desc->vol;
 525        struct ubi_device *ubi = vol->ubi;
 526        int vol_id = vol->vol_id;
 527
 528        dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 529
 530        if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 531                return -EINVAL;
 532
 533        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 534                return -EROFS;
 535
 536        if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 537            offset + len > vol->usable_leb_size ||
 538            offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
 539                return -EINVAL;
 540
 541        if (vol->upd_marker)
 542                return -EBADF;
 543
 544        if (len == 0)
 545                return 0;
 546
 547        return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
 548}
 549EXPORT_SYMBOL_GPL(ubi_leb_write);
 550
 551/*
 552 * ubi_leb_change - change logical eraseblock atomically.
 553 * @desc: volume descriptor
 554 * @lnum: logical eraseblock number to change
 555 * @buf: data to write
 556 * @len: how many bytes to write
 557 *
 558 * This function changes the contents of a logical eraseblock atomically. @buf
 559 * has to contain new logical eraseblock data, and @len - the length of the
 560 * data, which has to be aligned. The length may be shorter than the logical
 561 * eraseblock size, ant the logical eraseblock may be appended to more times
 562 * later on. This function guarantees that in case of an unclean reboot the old
 563 * contents is preserved. Returns zero in case of success and a negative error
 564 * code in case of failure.
 565 */
 566int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 567                   int len)
 568{
 569        struct ubi_volume *vol = desc->vol;
 570        struct ubi_device *ubi = vol->ubi;
 571        int vol_id = vol->vol_id;
 572
 573        dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 574
 575        if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 576                return -EINVAL;
 577
 578        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 579                return -EROFS;
 580
 581        if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 582            len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
 583                return -EINVAL;
 584
 585        if (vol->upd_marker)
 586                return -EBADF;
 587
 588        if (len == 0)
 589                return 0;
 590
 591        return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
 592}
 593EXPORT_SYMBOL_GPL(ubi_leb_change);
 594
 595/**
 596 * ubi_leb_erase - erase logical eraseblock.
 597 * @desc: volume descriptor
 598 * @lnum: logical eraseblock number
 599 *
 600 * This function un-maps logical eraseblock @lnum and synchronously erases the
 601 * correspondent physical eraseblock. Returns zero in case of success and a
 602 * negative error code in case of failure.
 603 *
 604 * If the volume is damaged because of an interrupted update this function just
 605 * returns immediately with %-EBADF code.
 606 */
 607int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 608{
 609        struct ubi_volume *vol = desc->vol;
 610        struct ubi_device *ubi = vol->ubi;
 611        int err;
 612
 613        dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 614
 615        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 616                return -EROFS;
 617
 618        if (lnum < 0 || lnum >= vol->reserved_pebs)
 619                return -EINVAL;
 620
 621        if (vol->upd_marker)
 622                return -EBADF;
 623
 624        err = ubi_eba_unmap_leb(ubi, vol, lnum);
 625        if (err)
 626                return err;
 627
 628        return ubi_wl_flush(ubi, vol->vol_id, lnum);
 629}
 630EXPORT_SYMBOL_GPL(ubi_leb_erase);
 631
 632/**
 633 * ubi_leb_unmap - un-map logical eraseblock.
 634 * @desc: volume descriptor
 635 * @lnum: logical eraseblock number
 636 *
 637 * This function un-maps logical eraseblock @lnum and schedules the
 638 * corresponding physical eraseblock for erasure, so that it will eventually be
 639 * physically erased in background. This operation is much faster than the
 640 * erase operation.
 641 *
 642 * Unlike erase, the un-map operation does not guarantee that the logical
 643 * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 644 * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 645 * happens after this, the logical eraseblocks will not necessarily be
 646 * un-mapped again when this MTD device is attached. They may actually be
 647 * mapped to the same physical eraseblocks again. So, this function has to be
 648 * used with care.
 649 *
 650 * In other words, when un-mapping a logical eraseblock, UBI does not store
 651 * any information about this on the flash media, it just marks the logical
 652 * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 653 * eraseblock is physically erased, it will be mapped again to the same logical
 654 * eraseblock when the MTD device is attached again.
 655 *
 656 * The main and obvious use-case of this function is when the contents of a
 657 * logical eraseblock has to be re-written. Then it is much more efficient to
 658 * first un-map it, then write new data, rather than first erase it, then write
 659 * new data. Note, once new data has been written to the logical eraseblock,
 660 * UBI guarantees that the old contents has gone forever. In other words, if an
 661 * unclean reboot happens after the logical eraseblock has been un-mapped and
 662 * then written to, it will contain the last written data.
 663 *
 664 * This function returns zero in case of success and a negative error code in
 665 * case of failure. If the volume is damaged because of an interrupted update
 666 * this function just returns immediately with %-EBADF code.
 667 */
 668int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 669{
 670        struct ubi_volume *vol = desc->vol;
 671        struct ubi_device *ubi = vol->ubi;
 672
 673        dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 674
 675        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 676                return -EROFS;
 677
 678        if (lnum < 0 || lnum >= vol->reserved_pebs)
 679                return -EINVAL;
 680
 681        if (vol->upd_marker)
 682                return -EBADF;
 683
 684        return ubi_eba_unmap_leb(ubi, vol, lnum);
 685}
 686EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 687
 688/**
 689 * ubi_leb_map - map logical eraseblock to a physical eraseblock.
 690 * @desc: volume descriptor
 691 * @lnum: logical eraseblock number
 692 *
 693 * This function maps an un-mapped logical eraseblock @lnum to a physical
 694 * eraseblock. This means, that after a successful invocation of this
 695 * function the logical eraseblock @lnum will be empty (contain only %0xFF
 696 * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
 697 * happens.
 698 *
 699 * This function returns zero in case of success, %-EBADF if the volume is
 700 * damaged because of an interrupted update, %-EBADMSG if the logical
 701 * eraseblock is already mapped, and other negative error codes in case of
 702 * other failures.
 703 */
 704int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
 705{
 706        struct ubi_volume *vol = desc->vol;
 707        struct ubi_device *ubi = vol->ubi;
 708
 709        dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 710
 711        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 712                return -EROFS;
 713
 714        if (lnum < 0 || lnum >= vol->reserved_pebs)
 715                return -EINVAL;
 716
 717        if (vol->upd_marker)
 718                return -EBADF;
 719
 720        if (vol->eba_tbl[lnum] >= 0)
 721                return -EBADMSG;
 722
 723        return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
 724}
 725EXPORT_SYMBOL_GPL(ubi_leb_map);
 726
 727/**
 728 * ubi_is_mapped - check if logical eraseblock is mapped.
 729 * @desc: volume descriptor
 730 * @lnum: logical eraseblock number
 731 *
 732 * This function checks if logical eraseblock @lnum is mapped to a physical
 733 * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 734 * mean it will still be un-mapped after the UBI device is re-attached. The
 735 * logical eraseblock may become mapped to the physical eraseblock it was last
 736 * mapped to.
 737 *
 738 * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 739 * error code in case of failure. If the volume is damaged because of an
 740 * interrupted update this function just returns immediately with %-EBADF error
 741 * code.
 742 */
 743int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 744{
 745        struct ubi_volume *vol = desc->vol;
 746
 747        dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
 748
 749        if (lnum < 0 || lnum >= vol->reserved_pebs)
 750                return -EINVAL;
 751
 752        if (vol->upd_marker)
 753                return -EBADF;
 754
 755        return vol->eba_tbl[lnum] >= 0;
 756}
 757EXPORT_SYMBOL_GPL(ubi_is_mapped);
 758
 759/**
 760 * ubi_sync - synchronize UBI device buffers.
 761 * @ubi_num: UBI device to synchronize
 762 *
 763 * The underlying MTD device may cache data in hardware or in software. This
 764 * function ensures the caches are flushed. Returns zero in case of success and
 765 * a negative error code in case of failure.
 766 */
 767int ubi_sync(int ubi_num)
 768{
 769        struct ubi_device *ubi;
 770
 771        ubi = ubi_get_device(ubi_num);
 772        if (!ubi)
 773                return -ENODEV;
 774
 775        mtd_sync(ubi->mtd);
 776        ubi_put_device(ubi);
 777        return 0;
 778}
 779EXPORT_SYMBOL_GPL(ubi_sync);
 780
 781/**
 782 * ubi_flush - flush UBI work queue.
 783 * @ubi_num: UBI device to flush work queue
 784 * @vol_id: volume id to flush for
 785 * @lnum: logical eraseblock number to flush for
 786 *
 787 * This function executes all pending works for a particular volume id / logical
 788 * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
 789 * a wildcard for all of the corresponding volume numbers or logical
 790 * eraseblock numbers. It returns zero in case of success and a negative error
 791 * code in case of failure.
 792 */
 793int ubi_flush(int ubi_num, int vol_id, int lnum)
 794{
 795        struct ubi_device *ubi;
 796        int err = 0;
 797
 798        ubi = ubi_get_device(ubi_num);
 799        if (!ubi)
 800                return -ENODEV;
 801
 802        err = ubi_wl_flush(ubi, vol_id, lnum);
 803        ubi_put_device(ubi);
 804        return err;
 805}
 806EXPORT_SYMBOL_GPL(ubi_flush);
 807
 808#ifndef __UBOOT__
 809BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
 810
 811/**
 812 * ubi_register_volume_notifier - register a volume notifier.
 813 * @nb: the notifier description object
 814 * @ignore_existing: if non-zero, do not send "added" notification for all
 815 *                   already existing volumes
 816 *
 817 * This function registers a volume notifier, which means that
 818 * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
 819 * removed, re-sized, re-named, or updated. The first argument of the function
 820 * is the notification type. The second argument is pointer to a
 821 * &struct ubi_notification object which describes the notification event.
 822 * Using UBI API from the volume notifier is prohibited.
 823 *
 824 * This function returns zero in case of success and a negative error code
 825 * in case of failure.
 826 */
 827int ubi_register_volume_notifier(struct notifier_block *nb,
 828                                 int ignore_existing)
 829{
 830        int err;
 831
 832        err = blocking_notifier_chain_register(&ubi_notifiers, nb);
 833        if (err != 0)
 834                return err;
 835        if (ignore_existing)
 836                return 0;
 837
 838        /*
 839         * We are going to walk all UBI devices and all volumes, and
 840         * notify the user about existing volumes by the %UBI_VOLUME_ADDED
 841         * event. We have to lock the @ubi_devices_mutex to make sure UBI
 842         * devices do not disappear.
 843         */
 844        mutex_lock(&ubi_devices_mutex);
 845        ubi_enumerate_volumes(nb);
 846        mutex_unlock(&ubi_devices_mutex);
 847
 848        return err;
 849}
 850EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
 851
 852/**
 853 * ubi_unregister_volume_notifier - unregister the volume notifier.
 854 * @nb: the notifier description object
 855 *
 856 * This function unregisters volume notifier @nm and returns zero in case of
 857 * success and a negative error code in case of failure.
 858 */
 859int ubi_unregister_volume_notifier(struct notifier_block *nb)
 860{
 861        return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
 862}
 863EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
 864#endif
 865