build.c

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/*
 * Copyright (c) International Business Machines Corp., 2006
 * Copyright (c) Nokia Corporation, 2007
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём),
 *         Frank Haverkamp
 */

/*
 * This file includes UBI initialization and building of UBI devices.
 *
 * When UBI is initialized, it attaches all the MTD devices specified as the
 * module load parameters or the kernel boot parameters. If MTD devices were
 * specified, UBI does not attach any MTD device, but it is possible to do
 * later using the "UBI control device".
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/stringify.h>
#include <linux/namei.h>
#include <linux/stat.h>
#include <linux/miscdevice.h>
#include <linux/mtd/partitions.h>
#include <linux/log2.h>
#include <linux/kthread.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include "ubi.h"

/* Maximum length of the 'mtd=' parameter */
#define MTD_PARAM_LEN_MAX 64

/* Maximum number of comma-separated items in the 'mtd=' parameter */
#define MTD_PARAM_MAX_COUNT 3

/* Maximum value for the number of bad PEBs per 1024 PEBs */
#define MAX_MTD_UBI_BEB_LIMIT 768

#ifdef CONFIG_MTD_UBI_MODULE
#define ubi_is_module() 1
#else
#define ubi_is_module() 0
#endif

struct mtd_dev_param {
    char name[MTD_PARAM_LEN_MAX];
    int vid_hdr_offs;
    int max_beb_per1024;
};

/* Numbers of elements set in the @mtd_dev_param array */
static int __initdata mtd_devs;

/* MTD devices specification parameters */
static struct mtd_dev_param __initdata mtd_dev_param[UBI_MAX_DEVICES];
#ifdef CONFIG_MTD_UBI_FASTMAP
/* UBI module parameter to enable fastmap automatically on non-fastmap images */
static bool fm_autoconvert;
#endif
/* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
struct class *ubi_class;

/* Slab cache for wear-leveling entries */
struct kmem_cache *ubi_wl_entry_slab;

/* UBI control character device */
static struct miscdevice ubi_ctrl_cdev = {
    .minor = MISC_DYNAMIC_MINOR,
    .name = "ubi_ctrl",
    .fops = &ubi_ctrl_cdev_operations,
};

/* All UBI devices in system */
static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];

/* Serializes UBI devices creations and removals */
DEFINE_MUTEX(ubi_devices_mutex);

/* Protects @ubi_devices and @ubi->ref_count */
static DEFINE_SPINLOCK(ubi_devices_lock);

/* "Show" method for files in '/<sysfs>/class/ubi/' */
static ssize_t ubi_version_show(struct class *class,
                struct class_attribute *attr, char *buf)
{
    return sprintf(buf, "%d\n", UBI_VERSION);
}

/* UBI version attribute ('/<sysfs>/class/ubi/version') */
static struct class_attribute ubi_version =
    __ATTR(version, S_IRUGO, ubi_version_show, NULL);

static ssize_t dev_attribute_show(struct device *dev,
                  struct device_attribute *attr, char *buf);

/* UBI device attributes (correspond to files in '/<sysfs>/class/ubi/ubiX') */
static struct device_attribute dev_eraseblock_size =
    __ATTR(eraseblock_size, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_avail_eraseblocks =
    __ATTR(avail_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_total_eraseblocks =
    __ATTR(total_eraseblocks, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_volumes_count =
    __ATTR(volumes_count, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_max_ec =
    __ATTR(max_ec, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_reserved_for_bad =
    __ATTR(reserved_for_bad, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_bad_peb_count =
    __ATTR(bad_peb_count, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_max_vol_count =
    __ATTR(max_vol_count, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_min_io_size =
    __ATTR(min_io_size, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_bgt_enabled =
    __ATTR(bgt_enabled, S_IRUGO, dev_attribute_show, NULL);
static struct device_attribute dev_mtd_num =
    __ATTR(mtd_num, S_IRUGO, dev_attribute_show, NULL);

int ubi_volume_notify(struct ubi_device *ubi, struct ubi_volume *vol, int ntype)
{
    struct ubi_notification nt;

    ubi_do_get_device_info(ubi, &nt.di);
    ubi_do_get_volume_info(ubi, vol, &nt.vi);

#ifdef CONFIG_MTD_UBI_FASTMAP
    switch (ntype) {
    case UBI_VOLUME_ADDED:
    case UBI_VOLUME_REMOVED:
    case UBI_VOLUME_RESIZED:
    case UBI_VOLUME_RENAMED:
        if (ubi_update_fastmap(ubi)) {
            ubi_err("Unable to update fastmap!");
            ubi_ro_mode(ubi);
        }
    }
#endif
    return blocking_notifier_call_chain(&ubi_notifiers, ntype, &nt);
}

int ubi_notify_all(struct ubi_device *ubi, int ntype, struct notifier_block *nb)
{
    struct ubi_notification nt;
    int i, count = 0;

    ubi_do_get_device_info(ubi, &nt.di);

    mutex_lock(&ubi->device_mutex);
    for (i = 0; i < ubi->vtbl_slots; i++) {
        /*
         * Since the @ubi->device is locked, and we are not going to
         * change @ubi->volumes, we do not have to lock
         * @ubi->volumes_lock.
         */
        if (!ubi->volumes[i])
            continue;

        ubi_do_get_volume_info(ubi, ubi->volumes[i], &nt.vi);
        if (nb)
            nb->notifier_call(nb, ntype, &nt);
        else
            blocking_notifier_call_chain(&ubi_notifiers, ntype,
                             &nt);
        count += 1;
    }
    mutex_unlock(&ubi->device_mutex);

    return count;
}

int ubi_enumerate_volumes(struct notifier_block *nb)
{
    int i, count = 0;

    /*
     * Since the @ubi_devices_mutex is locked, and we are not going to
     * change @ubi_devices, we do not have to lock @ubi_devices_lock.
     */
    for (i = 0; i < UBI_MAX_DEVICES; i++) {
        struct ubi_device *ubi = ubi_devices[i];

        if (!ubi)
            continue;
        count += ubi_notify_all(ubi, UBI_VOLUME_ADDED, nb);
    }

    return count;
}

struct ubi_device *ubi_get_device(int ubi_num)
{
    struct ubi_device *ubi;

    spin_lock(&ubi_devices_lock);
    ubi = ubi_devices[ubi_num];
    if (ubi) {
        ubi_assert(ubi->ref_count >= 0);
        ubi->ref_count += 1;
        get_device(&ubi->dev);
    }
    spin_unlock(&ubi_devices_lock);

    return ubi;
}

void ubi_put_device(struct ubi_device *ubi)
{
    spin_lock(&ubi_devices_lock);
    ubi->ref_count -= 1;
    put_device(&ubi->dev);
    spin_unlock(&ubi_devices_lock);
}

struct ubi_device *ubi_get_by_major(int major)
{
    int i;
    struct ubi_device *ubi;

    spin_lock(&ubi_devices_lock);
    for (i = 0; i < UBI_MAX_DEVICES; i++) {
        ubi = ubi_devices[i];
        if (ubi && MAJOR(ubi->cdev.dev) == major) {
            ubi_assert(ubi->ref_count >= 0);
            ubi->ref_count += 1;
            get_device(&ubi->dev);
            spin_unlock(&ubi_devices_lock);
            return ubi;
        }
    }
    spin_unlock(&ubi_devices_lock);

    return NULL;
}

int ubi_major2num(int major)
{
    int i, ubi_num = -ENODEV;

    spin_lock(&ubi_devices_lock);
    for (i = 0; i < UBI_MAX_DEVICES; i++) {
        struct ubi_device *ubi = ubi_devices[i];

        if (ubi && MAJOR(ubi->cdev.dev) == major) {
            ubi_num = ubi->ubi_num;
            break;
        }
    }
    spin_unlock(&ubi_devices_lock);

    return ubi_num;
}

/* "Show" method for files in '/<sysfs>/class/ubi/ubiX/' */
static ssize_t dev_attribute_show(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    ssize_t ret;
    struct ubi_device *ubi;

    /*
     * The below code looks weird, but it actually makes sense. We get the
     * UBI device reference from the contained 'struct ubi_device'. But it
     * is unclear if the device was removed or not yet. Indeed, if the
     * device was removed before we increased its reference count,
     * 'ubi_get_device()' will return -ENODEV and we fail.
     *
     * Remember, 'struct ubi_device' is freed in the release function, so
     * we still can use 'ubi->ubi_num'.
     */
    ubi = container_of(dev, struct ubi_device, dev);
    ubi = ubi_get_device(ubi->ubi_num);
    if (!ubi)
        return -ENODEV;

    if (attr == &dev_eraseblock_size)
        ret = sprintf(buf, "%d\n", ubi->leb_size);
    else if (attr == &dev_avail_eraseblocks)
        ret = sprintf(buf, "%d\n", ubi->avail_pebs);
    else if (attr == &dev_total_eraseblocks)
        ret = sprintf(buf, "%d\n", ubi->good_peb_count);
    else if (attr == &dev_volumes_count)
        ret = sprintf(buf, "%d\n", ubi->vol_count - UBI_INT_VOL_COUNT);
    else if (attr == &dev_max_ec)
        ret = sprintf(buf, "%d\n", ubi->max_ec);
    else if (attr == &dev_reserved_for_bad)
        ret = sprintf(buf, "%d\n", ubi->beb_rsvd_pebs);
    else if (attr == &dev_bad_peb_count)
        ret = sprintf(buf, "%d\n", ubi->bad_peb_count);
    else if (attr == &dev_max_vol_count)
        ret = sprintf(buf, "%d\n", ubi->vtbl_slots);
    else if (attr == &dev_min_io_size)
        ret = sprintf(buf, "%d\n", ubi->min_io_size);
    else if (attr == &dev_bgt_enabled)
        ret = sprintf(buf, "%d\n", ubi->thread_enabled);
    else if (attr == &dev_mtd_num)
        ret = sprintf(buf, "%d\n", ubi->mtd->index);
    else
        ret = -EINVAL;

    ubi_put_device(ubi);
    return ret;
}

static void dev_release(struct device *dev)
{
    struct ubi_device *ubi = container_of(dev, struct ubi_device, dev);

    kfree(ubi);
}

static int ubi_sysfs_init(struct ubi_device *ubi, int *ref)
{
    int err;

    ubi->dev.release = dev_release;
    ubi->dev.devt = ubi->cdev.dev;
    ubi->dev.class = ubi_class;
    dev_set_name(&ubi->dev, UBI_NAME_STR"%d", ubi->ubi_num);
    err = device_register(&ubi->dev);
    if (err)
        return err;

    *ref = 1;
    err = device_create_file(&ubi->dev, &dev_eraseblock_size);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_avail_eraseblocks);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_total_eraseblocks);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_volumes_count);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_max_ec);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_reserved_for_bad);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_bad_peb_count);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_max_vol_count);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_min_io_size);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_bgt_enabled);
    if (err)
        return err;
    err = device_create_file(&ubi->dev, &dev_mtd_num);
    return err;
}

static void ubi_sysfs_close(struct ubi_device *ubi)
{
    device_remove_file(&ubi->dev, &dev_mtd_num);
    device_remove_file(&ubi->dev, &dev_bgt_enabled);
    device_remove_file(&ubi->dev, &dev_min_io_size);
    device_remove_file(&ubi->dev, &dev_max_vol_count);
    device_remove_file(&ubi->dev, &dev_bad_peb_count);
    device_remove_file(&ubi->dev, &dev_reserved_for_bad);
    device_remove_file(&ubi->dev, &dev_max_ec);
    device_remove_file(&ubi->dev, &dev_volumes_count);
    device_remove_file(&ubi->dev, &dev_total_eraseblocks);
    device_remove_file(&ubi->dev, &dev_avail_eraseblocks);
    device_remove_file(&ubi->dev, &dev_eraseblock_size);
    device_unregister(&ubi->dev);
}

static void kill_volumes(struct ubi_device *ubi)
{
    int i;

    for (i = 0; i < ubi->vtbl_slots; i++)
        if (ubi->volumes[i])
            ubi_free_volume(ubi, ubi->volumes[i]);
}

static int uif_init(struct ubi_device *ubi, int *ref)
{
    int i, err;
    dev_t dev;

    *ref = 0;
    sprintf(ubi->ubi_name, UBI_NAME_STR "%d", ubi->ubi_num);

    /*
     * Major numbers for the UBI character devices are allocated
     * dynamically. Major numbers of volume character devices are
     * equivalent to ones of the corresponding UBI character device. Minor
     * numbers of UBI character devices are 0, while minor numbers of
     * volume character devices start from 1. Thus, we allocate one major
     * number and ubi->vtbl_slots + 1 minor numbers.
     */
    err = alloc_chrdev_region(&dev, 0, ubi->vtbl_slots + 1, ubi->ubi_name);
    if (err) {
        ubi_err("cannot register UBI character devices");
        return err;
    }

    ubi_assert(MINOR(dev) == 0);
    cdev_init(&ubi->cdev, &ubi_cdev_operations);
    dbg_gen("%s major is %u", ubi->ubi_name, MAJOR(dev));
    ubi->cdev.owner = THIS_MODULE;

    err = cdev_add(&ubi->cdev, dev, 1);
    if (err) {
        ubi_err("cannot add character device");
        goto out_unreg;
    }

    err = ubi_sysfs_init(ubi, ref);
    if (err)
        goto out_sysfs;

    for (i = 0; i < ubi->vtbl_slots; i++)
        if (ubi->volumes[i]) {
            err = ubi_add_volume(ubi, ubi->volumes[i]);
            if (err) {
                ubi_err("cannot add volume %d", i);
                goto out_volumes;
            }
        }

    return 0;

out_volumes:
    kill_volumes(ubi);
out_sysfs:
    if (*ref)
        get_device(&ubi->dev);
    ubi_sysfs_close(ubi);
    cdev_del(&ubi->cdev);
out_unreg:
    unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
    ubi_err("cannot initialize UBI %s, error %d", ubi->ubi_name, err);
    return err;
}

static void uif_close(struct ubi_device *ubi)
{
    kill_volumes(ubi);
    ubi_sysfs_close(ubi);
    cdev_del(&ubi->cdev);
    unregister_chrdev_region(ubi->cdev.dev, ubi->vtbl_slots + 1);
}

void ubi_free_internal_volumes(struct ubi_device *ubi)
{
    int i;

    for (i = ubi->vtbl_slots;
         i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
        kfree(ubi->volumes[i]->eba_tbl);
        kfree(ubi->volumes[i]);
    }
}

static int get_bad_peb_limit(const struct ubi_device *ubi, int max_beb_per1024)
{
    int limit, device_pebs;
    uint64_t device_size;

    if (!max_beb_per1024)
        return 0;

    /*
     * Here we are using size of the entire flash chip and
     * not just the MTD partition size because the maximum
     * number of bad eraseblocks is a percentage of the
     * whole device and bad eraseblocks are not fairly
     * distributed over the flash chip. So the worst case
     * is that all the bad eraseblocks of the chip are in
     * the MTD partition we are attaching (ubi->mtd).
     */
    device_size = mtd_get_device_size(ubi->mtd);
    device_pebs = mtd_div_by_eb(device_size, ubi->mtd);
    limit = mult_frac(device_pebs, max_beb_per1024, 1024);

    /* Round it up */
    if (mult_frac(limit, 1024, max_beb_per1024) < device_pebs)
        limit += 1;

    return limit;
}

static int io_init(struct ubi_device *ubi, int max_beb_per1024)
{
    dbg_gen("sizeof(struct ubi_ainf_peb) %zu", sizeof(struct ubi_ainf_peb));
    dbg_gen("sizeof(struct ubi_wl_entry) %zu", sizeof(struct ubi_wl_entry));

    if (ubi->mtd->numeraseregions != 0) {
        /*
         * Some flashes have several erase regions. Different regions
         * may have different eraseblock size and other
         * characteristics. It looks like mostly multi-region flashes
         * have one "main" region and one or more small regions to
         * store boot loader code or boot parameters or whatever. I
         * guess we should just pick the largest region. But this is
         * not implemented.
         */
        ubi_err("multiple regions, not implemented");
        return -EINVAL;
    }

    if (ubi->vid_hdr_offset < 0)
        return -EINVAL;

    /*
     * Note, in this implementation we support MTD devices with 0x7FFFFFFF
     * physical eraseblocks maximum.
     */

    ubi->peb_size   = ubi->mtd->erasesize;
    ubi->peb_count  = mtd_div_by_eb(ubi->mtd->size, ubi->mtd);
    ubi->flash_size = ubi->mtd->size;

    if (mtd_can_have_bb(ubi->mtd)) {
        ubi->bad_allowed = 1;
        ubi->bad_peb_limit = get_bad_peb_limit(ubi, max_beb_per1024);
    }

    if (ubi->mtd->type == MTD_NORFLASH) {
        ubi_assert(ubi->mtd->writesize == 1);
        ubi->nor_flash = 1;
    }

    ubi->min_io_size = ubi->mtd->writesize;
    ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;

    /*
     * Make sure minimal I/O unit is power of 2. Note, there is no
     * fundamental reason for this assumption. It is just an optimization
     * which allows us to avoid costly division operations.
     */
    if (!is_power_of_2(ubi->min_io_size)) {
        ubi_err("min. I/O unit (%d) is not power of 2",
            ubi->min_io_size);
        return -EINVAL;
    }

    ubi_assert(ubi->hdrs_min_io_size > 0);
    ubi_assert(ubi->hdrs_min_io_size <= ubi->min_io_size);
    ubi_assert(ubi->min_io_size % ubi->hdrs_min_io_size == 0);

    ubi->max_write_size = ubi->mtd->writebufsize;
    /*
     * Maximum write size has to be greater or equivalent to min. I/O
     * size, and be multiple of min. I/O size.
     */
    if (ubi->max_write_size < ubi->min_io_size ||
        ubi->max_write_size % ubi->min_io_size ||
        !is_power_of_2(ubi->max_write_size)) {
        ubi_err("bad write buffer size %d for %d min. I/O unit",
            ubi->max_write_size, ubi->min_io_size);
        return -EINVAL;
    }

    /* Calculate default aligned sizes of EC and VID headers */
    ubi->ec_hdr_alsize = ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size);
    ubi->vid_hdr_alsize = ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size);

    dbg_gen("min_io_size      %d", ubi->min_io_size);
    dbg_gen("max_write_size   %d", ubi->max_write_size);
    dbg_gen("hdrs_min_io_size %d", ubi->hdrs_min_io_size);
    dbg_gen("ec_hdr_alsize    %d", ubi->ec_hdr_alsize);
    dbg_gen("vid_hdr_alsize   %d", ubi->vid_hdr_alsize);

    if (ubi->vid_hdr_offset == 0)
        /* Default offset */
        ubi->vid_hdr_offset = ubi->vid_hdr_aloffset =
                      ubi->ec_hdr_alsize;
    else {
        ubi->vid_hdr_aloffset = ubi->vid_hdr_offset &
                        ~(ubi->hdrs_min_io_size - 1);
        ubi->vid_hdr_shift = ubi->vid_hdr_offset -
                        ubi->vid_hdr_aloffset;
    }

    /* Similar for the data offset */
    ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
    ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);

    dbg_gen("vid_hdr_offset   %d", ubi->vid_hdr_offset);
    dbg_gen("vid_hdr_aloffset %d", ubi->vid_hdr_aloffset);
    dbg_gen("vid_hdr_shift    %d", ubi->vid_hdr_shift);
    dbg_gen("leb_start        %d", ubi->leb_start);

    /* The shift must be aligned to 32-bit boundary */
    if (ubi->vid_hdr_shift % 4) {
        ubi_err("unaligned VID header shift %d",
            ubi->vid_hdr_shift);
        return -EINVAL;
    }

    /* Check sanity */
    if (ubi->vid_hdr_offset < UBI_EC_HDR_SIZE ||
        ubi->leb_start < ubi->vid_hdr_offset + UBI_VID_HDR_SIZE ||
        ubi->leb_start > ubi->peb_size - UBI_VID_HDR_SIZE ||
        ubi->leb_start & (ubi->min_io_size - 1)) {
        ubi_err("bad VID header (%d) or data offsets (%d)",
            ubi->vid_hdr_offset, ubi->leb_start);
        return -EINVAL;
    }

    /*
     * Set maximum amount of physical erroneous eraseblocks to be 10%.
     * Erroneous PEB are those which have read errors.
     */
    ubi->max_erroneous = ubi->peb_count / 10;
    if (ubi->max_erroneous < 16)
        ubi->max_erroneous = 16;
    dbg_gen("max_erroneous    %d", ubi->max_erroneous);

    /*
     * It may happen that EC and VID headers are situated in one minimal
     * I/O unit. In this case we can only accept this UBI image in
     * read-only mode.
     */
    if (ubi->vid_hdr_offset + UBI_VID_HDR_SIZE <= ubi->hdrs_min_io_size) {
        ubi_warn("EC and VID headers are in the same minimal I/O unit, switch to read-only mode");
        ubi->ro_mode = 1;
    }

    ubi->leb_size = ubi->peb_size - ubi->leb_start;

    if (!(ubi->mtd->flags & MTD_WRITEABLE)) {
        ubi_msg("MTD device %d is write-protected, attach in read-only mode",
            ubi->mtd->index);
        ubi->ro_mode = 1;
    }

    /*
     * Note, ideally, we have to initialize @ubi->bad_peb_count here. But
     * unfortunately, MTD does not provide this information. We should loop
     * over all physical eraseblocks and invoke mtd->block_is_bad() for
     * each physical eraseblock. So, we leave @ubi->bad_peb_count
     * uninitialized so far.
     */

    return 0;
}

static int autoresize(struct ubi_device *ubi, int vol_id)
{
    struct ubi_volume_desc desc;
    struct ubi_volume *vol = ubi->volumes[vol_id];
    int err, old_reserved_pebs = vol->reserved_pebs;

    if (ubi->ro_mode) {
        ubi_warn("skip auto-resize because of R/O mode");
        return 0;
    }

    /*
     * Clear the auto-resize flag in the volume in-memory copy of the
     * volume table, and 'ubi_resize_volume()' will propagate this change
     * to the flash.
     */
    ubi->vtbl[vol_id].flags &= ~UBI_VTBL_AUTORESIZE_FLG;

    if (ubi->avail_pebs == 0) {
        struct ubi_vtbl_record vtbl_rec;

        /*
         * No available PEBs to re-size the volume, clear the flag on
         * flash and exit.
         */
        memcpy(&vtbl_rec, &ubi->vtbl[vol_id],
               sizeof(struct ubi_vtbl_record));
        err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
        if (err)
            ubi_err("cannot clean auto-resize flag for volume %d",
                vol_id);
    } else {
        desc.vol = vol;
        err = ubi_resize_volume(&desc,
                    old_reserved_pebs + ubi->avail_pebs);
        if (err)
            ubi_err("cannot auto-resize volume %d", vol_id);
    }

    if (err)
        return err;

    ubi_msg("volume %d (\"%s\") re-sized from %d to %d LEBs", vol_id,
        vol->name, old_reserved_pebs, vol->reserved_pebs);
    return 0;
}

int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
               int vid_hdr_offset, int max_beb_per1024)
{
    struct ubi_device *ubi;
    int i, err, ref = 0;

    if (max_beb_per1024 < 0 || max_beb_per1024 > MAX_MTD_UBI_BEB_LIMIT)
        return -EINVAL;

    if (!max_beb_per1024)
        max_beb_per1024 = CONFIG_MTD_UBI_BEB_LIMIT;

    /*
     * Check if we already have the same MTD device attached.
     *
     * Note, this function assumes that UBI devices creations and deletions
     * are serialized, so it does not take the &ubi_devices_lock.
     */
    for (i = 0; i < UBI_MAX_DEVICES; i++) {
        ubi = ubi_devices[i];
        if (ubi && mtd->index == ubi->mtd->index) {
            ubi_err("mtd%d is already attached to ubi%d",
                mtd->index, i);
            return -EEXIST;
        }
    }

    /*
     * Make sure this MTD device is not emulated on top of an UBI volume
     * already. Well, generally this recursion works fine, but there are
     * different problems like the UBI module takes a reference to itself
     * by attaching (and thus, opening) the emulated MTD device. This
     * results in inability to unload the module. And in general it makes
     * no sense to attach emulated MTD devices, so we prohibit this.
     */
    if (mtd->type == MTD_UBIVOLUME) {
        ubi_err("refuse attaching mtd%d - it is already emulated on top of UBI",
            mtd->index);
        return -EINVAL;
    }

    if (ubi_num == UBI_DEV_NUM_AUTO) {
        /* Search for an empty slot in the @ubi_devices array */
        for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
            if (!ubi_devices[ubi_num])
                break;
        if (ubi_num == UBI_MAX_DEVICES) {
            ubi_err("only %d UBI devices may be created",
                UBI_MAX_DEVICES);
            return -ENFILE;
        }
    } else {
        if (ubi_num >= UBI_MAX_DEVICES)
            return -EINVAL;

        /* Make sure ubi_num is not busy */
        if (ubi_devices[ubi_num]) {
            ubi_err("ubi%d already exists", ubi_num);
            return -EEXIST;
        }
    }

    ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
    if (!ubi)
        return -ENOMEM;

    ubi->mtd = mtd;
    ubi->ubi_num = ubi_num;
    ubi->vid_hdr_offset = vid_hdr_offset;
    ubi->autoresize_vol_id = -1;

#ifdef CONFIG_MTD_UBI_FASTMAP
    ubi->fm_pool.used = ubi->fm_pool.size = 0;
    ubi->fm_wl_pool.used = ubi->fm_wl_pool.size = 0;

    /*
     * fm_pool.max_size is 5% of the total number of PEBs but it's also
     * between UBI_FM_MAX_POOL_SIZE and UBI_FM_MIN_POOL_SIZE.
     */
    ubi->fm_pool.max_size = min(((int)mtd_div_by_eb(ubi->mtd->size,
        ubi->mtd) / 100) * 5, UBI_FM_MAX_POOL_SIZE);
    if (ubi->fm_pool.max_size < UBI_FM_MIN_POOL_SIZE)
        ubi->fm_pool.max_size = UBI_FM_MIN_POOL_SIZE;

    ubi->fm_wl_pool.max_size = UBI_FM_WL_POOL_SIZE;
    ubi->fm_disabled = !fm_autoconvert;

    if (!ubi->fm_disabled && (int)mtd_div_by_eb(ubi->mtd->size, ubi->mtd)
        <= UBI_FM_MAX_START) {
        ubi_err("More than %i PEBs are needed for fastmap, sorry.",
            UBI_FM_MAX_START);
        ubi->fm_disabled = 1;
    }

    ubi_msg("default fastmap pool size: %d", ubi->fm_pool.max_size);
    ubi_msg("default fastmap WL pool size: %d", ubi->fm_wl_pool.max_size);
#else
    ubi->fm_disabled = 1;
#endif
    mutex_init(&ubi->buf_mutex);
    mutex_init(&ubi->ckvol_mutex);
    mutex_init(&ubi->device_mutex);
    spin_lock_init(&ubi->volumes_lock);
    mutex_init(&ubi->fm_mutex);
    init_rwsem(&ubi->fm_sem);

    ubi_msg("attaching mtd%d to ubi%d", mtd->index, ubi_num);

    err = io_init(ubi, max_beb_per1024);
    if (err)
        goto out_free;

    err = -ENOMEM;
    ubi->peb_buf = vmalloc(ubi->peb_size);
    if (!ubi->peb_buf)
        goto out_free;

#ifdef CONFIG_MTD_UBI_FASTMAP
    ubi->fm_size = ubi_calc_fm_size(ubi);
    ubi->fm_buf = vzalloc(ubi->fm_size);
    if (!ubi->fm_buf)
        goto out_free;
#endif
    err = ubi_debugging_init_dev(ubi);
    if (err)
        goto out_free;

    err = ubi_attach(ubi, 0);
    if (err) {
        ubi_err("failed to attach mtd%d, error %d", mtd->index, err);
        goto out_debugging;
    }

    if (ubi->autoresize_vol_id != -1) {
        err = autoresize(ubi, ubi->autoresize_vol_id);
        if (err)
            goto out_detach;
    }

    err = uif_init(ubi, &ref);
    if (err)
        goto out_detach;

    err = ubi_debugfs_init_dev(ubi);
    if (err)
        goto out_uif;

    ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name);
    if (IS_ERR(ubi->bgt_thread)) {
        err = PTR_ERR(ubi->bgt_thread);
        ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name,
            err);
        goto out_debugfs;
    }

    ubi_msg("attached mtd%d (name \"%s\", size %llu MiB) to ubi%d",
        mtd->index, mtd->name, ubi->flash_size >> 20, ubi_num);
    ubi_msg("PEB size: %d bytes (%d KiB), LEB size: %d bytes",
        ubi->peb_size, ubi->peb_size >> 10, ubi->leb_size);
    ubi_msg("min./max. I/O unit sizes: %d/%d, sub-page size %d",
        ubi->min_io_size, ubi->max_write_size, ubi->hdrs_min_io_size);
    ubi_msg("VID header offset: %d (aligned %d), data offset: %d",
        ubi->vid_hdr_offset, ubi->vid_hdr_aloffset, ubi->leb_start);
    ubi_msg("good PEBs: %d, bad PEBs: %d, corrupted PEBs: %d",
        ubi->good_peb_count, ubi->bad_peb_count, ubi->corr_peb_count);
    ubi_msg("user volume: %d, internal volumes: %d, max. volumes count: %d",
        ubi->vol_count - UBI_INT_VOL_COUNT, UBI_INT_VOL_COUNT,
        ubi->vtbl_slots);
    ubi_msg("max/mean erase counter: %d/%d, WL threshold: %d, image sequence number: %u",
        ubi->max_ec, ubi->mean_ec, CONFIG_MTD_UBI_WL_THRESHOLD,
        ubi->image_seq);
    ubi_msg("available PEBs: %d, total reserved PEBs: %d, PEBs reserved for bad PEB handling: %d",
        ubi->avail_pebs, ubi->rsvd_pebs, ubi->beb_rsvd_pebs);

    /*
     * The below lock makes sure we do not race with 'ubi_thread()' which
     * checks @ubi->thread_enabled. Otherwise we may fail to wake it up.
     */
    spin_lock(&ubi->wl_lock);
    ubi->thread_enabled = 1;
    wake_up_process(ubi->bgt_thread);
    spin_unlock(&ubi->wl_lock);

    ubi_devices[ubi_num] = ubi;
    ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
    return ubi_num;

out_debugfs:
    ubi_debugfs_exit_dev(ubi);
out_uif:
    get_device(&ubi->dev);
    ubi_assert(ref);
    uif_close(ubi);
out_detach:
    ubi_wl_close(ubi);
    ubi_free_internal_volumes(ubi);
    vfree(ubi->vtbl);
out_debugging:
    ubi_debugging_exit_dev(ubi);
out_free:
    vfree(ubi->peb_buf);
    vfree(ubi->fm_buf);
    if (ref)
        put_device(&ubi->dev);
    else
        kfree(ubi);
    return err;
}

int ubi_detach_mtd_dev(int ubi_num, int anyway)
{
    struct ubi_device *ubi;

    if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
        return -EINVAL;

    ubi = ubi_get_device(ubi_num);
    if (!ubi)
        return -EINVAL;

    spin_lock(&ubi_devices_lock);
    put_device(&ubi->dev);
    ubi->ref_count -= 1;
    if (ubi->ref_count) {
        if (!anyway) {
            spin_unlock(&ubi_devices_lock);
            return -EBUSY;
        }
        /* This may only happen if there is a bug */
        ubi_err("%s reference count %d, destroy anyway",
            ubi->ubi_name, ubi->ref_count);
    }
    ubi_devices[ubi_num] = NULL;
    spin_unlock(&ubi_devices_lock);

    ubi_assert(ubi_num == ubi->ubi_num);
    ubi_notify_all(ubi, UBI_VOLUME_REMOVED, NULL);
    ubi_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
#ifdef CONFIG_MTD_UBI_FASTMAP
    /* If we don't write a new fastmap at detach time we lose all
     * EC updates that have been made since the last written fastmap. */
    ubi_update_fastmap(ubi);
#endif
    /*
     * Before freeing anything, we have to stop the background thread to
     * prevent it from doing anything on this device while we are freeing.
     */
    if (ubi->bgt_thread)
        kthread_stop(ubi->bgt_thread);

    /*
     * Get a reference to the device in order to prevent 'dev_release()'
     * from freeing the @ubi object.
     */
    get_device(&ubi->dev);

    ubi_debugfs_exit_dev(ubi);
    uif_close(ubi);

    ubi_wl_close(ubi);
    ubi_free_internal_volumes(ubi);
    vfree(ubi->vtbl);
    put_mtd_device(ubi->mtd);
    ubi_debugging_exit_dev(ubi);
    vfree(ubi->peb_buf);
    vfree(ubi->fm_buf);
    ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
    put_device(&ubi->dev);
    return 0;
}

static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
{
    int err, major, minor, mode;
    struct path path;

    /* Probably this is an MTD character device node path */
    err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
    if (err)
        return ERR_PTR(err);

    /* MTD device number is defined by the major / minor numbers */
    major = imajor(path.dentry->d_inode);
    minor = iminor(path.dentry->d_inode);
    mode = path.dentry->d_inode->i_mode;
    path_put(&path);
    if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode))
        return ERR_PTR(-EINVAL);

    if (minor & 1)
        /*
         * Just do not think the "/dev/mtdrX" devices support is need,
         * so do not support them to avoid doing extra work.
         */
        return ERR_PTR(-EINVAL);

    return get_mtd_device(NULL, minor / 2);
}

static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
{
    struct mtd_info *mtd;
    int mtd_num;
    char *endp;

    mtd_num = simple_strtoul(mtd_dev, &endp, 0);
    if (*endp != '\0' || mtd_dev == endp) {
        /*
         * This does not look like an ASCII integer, probably this is
         * MTD device name.
         */
        mtd = get_mtd_device_nm(mtd_dev);
        if (IS_ERR(mtd) && PTR_ERR(mtd) == -ENODEV)
            /* Probably this is an MTD character device node path */
            mtd = open_mtd_by_chdev(mtd_dev);
    } else
        mtd = get_mtd_device(NULL, mtd_num);

    return mtd;
}

static int __init ubi_init(void)
{
    int err, i, k;

    /* Ensure that EC and VID headers have correct size */
    BUILD_BUG_ON(sizeof(struct ubi_ec_hdr) != 64);
    BUILD_BUG_ON(sizeof(struct ubi_vid_hdr) != 64);

    if (mtd_devs > UBI_MAX_DEVICES) {
        ubi_err("too many MTD devices, maximum is %d", UBI_MAX_DEVICES);
        return -EINVAL;
    }

    /* Create base sysfs directory and sysfs files */
    ubi_class = class_create(THIS_MODULE, UBI_NAME_STR);
    if (IS_ERR(ubi_class)) {
        err = PTR_ERR(ubi_class);
        ubi_err("cannot create UBI class");
        goto out;
    }

    err = class_create_file(ubi_class, &ubi_version);
    if (err) {
        ubi_err("cannot create sysfs file");
        goto out_class;
    }

    err = misc_register(&ubi_ctrl_cdev);
    if (err) {
        ubi_err("cannot register device");
        goto out_version;
    }

    ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",
                          sizeof(struct ubi_wl_entry),
                          0, 0, NULL);
    if (!ubi_wl_entry_slab)
        goto out_dev_unreg;

    err = ubi_debugfs_init();
    if (err)
        goto out_slab;


    /* Attach MTD devices */
    for (i = 0; i < mtd_devs; i++) {
        struct mtd_dev_param *p = &mtd_dev_param[i];
        struct mtd_info *mtd;

        cond_resched();

        mtd = open_mtd_device(p->name);
        if (IS_ERR(mtd)) {
            err = PTR_ERR(mtd);
            goto out_detach;
        }

        mutex_lock(&ubi_devices_mutex);
        err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO,
                     p->vid_hdr_offs, p->max_beb_per1024);
        mutex_unlock(&ubi_devices_mutex);
        if (err < 0) {
            ubi_err("cannot attach mtd%d", mtd->index);
            put_mtd_device(mtd);

            /*
             * Originally UBI stopped initializing on any error.
             * However, later on it was found out that this
             * behavior is not very good when UBI is compiled into
             * the kernel and the MTD devices to attach are passed
             * through the command line. Indeed, UBI failure
             * stopped whole boot sequence.
             *
             * To fix this, we changed the behavior for the
             * non-module case, but preserved the old behavior for
             * the module case, just for compatibility. This is a
             * little inconsistent, though.
             */
            if (ubi_is_module())
                goto out_detach;
        }
    }

    return 0;

out_detach:
    for (k = 0; k < i; k++)
        if (ubi_devices[k]) {
            mutex_lock(&ubi_devices_mutex);
            ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
            mutex_unlock(&ubi_devices_mutex);
        }
    ubi_debugfs_exit();
out_slab:
    kmem_cache_destroy(ubi_wl_entry_slab);
out_dev_unreg:
    misc_deregister(&ubi_ctrl_cdev);
out_version:
    class_remove_file(ubi_class, &ubi_version);
out_class:
    class_destroy(ubi_class);
out:
    ubi_err("UBI error: cannot initialize UBI, error %d", err);
    return err;
}
late_initcall(ubi_init);

static void __exit ubi_exit(void)
{
    int i;

    for (i = 0; i < UBI_MAX_DEVICES; i++)
        if (ubi_devices[i]) {
            mutex_lock(&ubi_devices_mutex);
            ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
            mutex_unlock(&ubi_devices_mutex);
        }
    ubi_debugfs_exit();
    kmem_cache_destroy(ubi_wl_entry_slab);
    misc_deregister(&ubi_ctrl_cdev);
    class_remove_file(ubi_class, &ubi_version);
    class_destroy(ubi_class);
}
module_exit(ubi_exit);

static int __init bytes_str_to_int(const char *str)
{
    char *endp;
    unsigned long result;

    result = simple_strtoul(str, &endp, 0);
    if (str == endp || result >= INT_MAX) {
        ubi_err("UBI error: incorrect bytes count: \"%s\"\n", str);
        return -EINVAL;
    }

    switch (*endp) {
    case 'G':
        result *= 1024;
    case 'M':
        result *= 1024;
    case 'K':
        result *= 1024;
        if (endp[1] == 'i' && endp[2] == 'B')
            endp += 2;
    case '\0':
        break;
    default:
        ubi_err("UBI error: incorrect bytes count: \"%s\"\n", str);
        return -EINVAL;
    }

    return result;
}

static int __init ubi_mtd_param_parse(const char *val, struct kernel_param *kp)
{
    int i, len;
    struct mtd_dev_param *p;
    char buf[MTD_PARAM_LEN_MAX];
    char *pbuf = &buf[0];
    char *tokens[MTD_PARAM_MAX_COUNT];

    if (!val)
        return -EINVAL;

    if (mtd_devs == UBI_MAX_DEVICES) {
        ubi_err("UBI error: too many parameters, max. is %d\n",
            UBI_MAX_DEVICES);
        return -EINVAL;
    }

    len = strnlen(val, MTD_PARAM_LEN_MAX);
    if (len == MTD_PARAM_LEN_MAX) {
        ubi_err("UBI error: parameter \"%s\" is too long, max. is %d\n",
            val, MTD_PARAM_LEN_MAX);
        return -EINVAL;
    }

    if (len == 0) {
        pr_warn("UBI warning: empty 'mtd=' parameter - ignored\n");
        return 0;
    }

    strcpy(buf, val);

    /* Get rid of the final newline */
    if (buf[len - 1] == '\n')
        buf[len - 1] = '\0';

    for (i = 0; i < MTD_PARAM_MAX_COUNT; i++)
        tokens[i] = strsep(&pbuf, ",");

    if (pbuf) {
        ubi_err("UBI error: too many arguments at \"%s\"\n", val);
        return -EINVAL;
    }

    p = &mtd_dev_param[mtd_devs];
    strcpy(&p->name[0], tokens[0]);

    if (tokens[1])
        p->vid_hdr_offs = bytes_str_to_int(tokens[1]);

    if (p->vid_hdr_offs < 0)
        return p->vid_hdr_offs;

    if (tokens[2]) {
        int err = kstrtoint(tokens[2], 10, &p->max_beb_per1024);

        if (err) {
            ubi_err("UBI error: bad value for max_beb_per1024 parameter: %s",
                tokens[2]);
            return -EINVAL;
        }
    }

    mtd_devs += 1;
    return 0;
}

module_param_call(mtd, ubi_mtd_param_parse, NULL, NULL, 000);
MODULE_PARM_DESC(mtd, "MTD devices to attach. Parameter format: mtd=<name|num|path>[,<vid_hdr_offs>[,max_beb_per1024]].\n"
              "Multiple \"mtd\" parameters may be specified.\n"
              "MTD devices may be specified by their number, name, or path to the MTD character device node.\n"
              "Optional \"vid_hdr_offs\" parameter specifies UBI VID header position to be used by UBI. (default value if 0)\n"
              "Optional \"max_beb_per1024\" parameter specifies the maximum expected bad eraseblock per 1024 eraseblocks. (default value ("
              __stringify(CONFIG_MTD_UBI_BEB_LIMIT) ") if 0)\n"
              "\n"
              "Example 1: mtd=/dev/mtd0 - attach MTD device /dev/mtd0.\n"
              "Example 2: mtd=content,1984 mtd=4 - attach MTD device with name \"content\" using VID header offset 1984, and MTD device number 4 with default VID header offset.\n"
              "Example 3: mtd=/dev/mtd1,0,25 - attach MTD device /dev/mtd1 using default VID header offset and reserve 25*nand_size_in_blocks/1024 erase blocks for bad block handling.\n"
              "\t(e.g. if the NAND *chipset* has 4096 PEB, 100 will be reserved for this UBI device).");
#ifdef CONFIG_MTD_UBI_FASTMAP
module_param(fm_autoconvert, bool, 0644);
MODULE_PARM_DESC(fm_autoconvert, "Set this parameter to enable fastmap automatically on images without a fastmap.");
#endif
MODULE_VERSION(__stringify(UBI_VERSION));
MODULE_DESCRIPTION("UBI - Unsorted Block Images");
MODULE_AUTHOR("Artem Bityutskiy");
MODULE_LICENSE("GPL");