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    Subject[PATCH 11/22 take 3] UBI: user-interfaces unit
    diff -auNrp tmp-from/drivers/mtd/ubi/uif.c tmp-to/drivers/mtd/ubi/uif.c
    --- tmp-from/drivers/mtd/ubi/uif.c 1970-01-01 02:00:00.000000000 +0200
    +++ tmp-to/drivers/mtd/ubi/uif.c 2007-03-14 17:15:50.000000000 +0200
    @@ -0,0 +1,842 @@
    +/*
    + * Copyright (c) International Business Machines Corp., 2006
    + *
    + * 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 B. Bityutskiy
    + */
    +
    +/*
    + * UBI user interfaces unit.
    + *
    + * This unit implements all the UBI user interfaces: kernel interfaces,
    + * character device interfaces, and sysfs interfaces.
    + *
    + * This file mostly implements kernel-API functions, character device
    + * operations are implemented in cdev.c, update functionality is implemented in
    + * upd.c, volume chane functionality - in vmt.c, and sysfs interfaces are
    + * implemented in sysfs.c.
    + *
    + * There are two kinds of character devices: UBI character devices and UBI
    + * volume character devices. UBI character devices allow users to manipulate
    + * whole volumes: create, remove, and re-size them. Volume character devices
    + * provide volume I/O capabilities.
    + *
    + * Major and minor numbers are assigned dynamically to both UBI and volume
    + * character devices.
    + */
    +
    +#include <linux/module.h>
    +#include <linux/err.h>
    +#include <asm/div64.h>
    +#include "ubi.h"
    +
    +/**
    + * ubi_get_device_info - get information about an UBI device.
    + *
    + * @ubi_num: UBI device number
    + * @di: the volume information is returned here
    + *
    + * This function fills the provided @di object with the information about the
    + * UBI device number @ubi_num. Returns %0 in case of success and a %-ENODEV if
    + * there is no such UBI device.
    + */
    +int ubi_get_device_info(int ubi_num, struct ubi_dev_info *di)
    +{
    + const struct ubi_info *ubi;
    + int err = -ENODEV;
    +
    + if (!try_module_get(THIS_MODULE))
    + return err;
    +
    + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
    + goto out_put;
    +
    + if (!ubis[ubi_num])
    + goto out_put;
    +
    + ubi = ubis[ubi_num];
    +
    + di->ubi_num = ubi->ubi_num;
    + di->leb_size = ubi->io.leb_size;
    + di->min_io_size = ubi->io.min_io_size;
    + di->ro_mode = ubi->io.ro_mode;
    + di->cdev = MKDEV(ubi->uif.major, 0);
    + err = 0;
    +
    +out_put:
    + module_put(THIS_MODULE);
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(ubi_get_device_info);
    +
    +/**
    + * ubi_get_volume_info - get information about an UBI volume.
    + *
    + * @desc: volume descriptor
    + * @vi: the volume information is returned here
    + */
    +void ubi_get_volume_info(struct ubi_vol_desc *desc, struct ubi_vol_info *vi)
    +{
    + int vol_id = desc->vol->vol_id;
    + const struct ubi_info *ubi = desc->vol->ubi;
    + const struct ubi_vtbl_vtr *vtr;
    +
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    +
    + vi->vol_id = vol_id;
    + vi->ubi_num = ubi->ubi_num;
    + vi->size = vtr->reserved_pebs;
    + vi->used_bytes = vtr->used_bytes;
    + vi->vol_type = vtr->vol_type;
    + vi->corrupted = vtr->corrupted;
    + vi->upd_marker = vtr->upd_marker;
    + vi->alignment = vtr->alignment;
    + vi->usable_leb_size = vtr->usable_leb_size;
    + vi->name_len = vtr->name_len;
    + vi->name = vtr->name;
    + vi->cdev = MKDEV(ubi->uif.major, vi->vol_id + 1);
    +}
    +EXPORT_SYMBOL_GPL(ubi_get_volume_info);
    +
    +/*
    + * ubi_open_volume - open an UBI volume.
    + *
    + * @ubi_num: the UBI device number
    + * @vol_id: ID of the volume to open
    + * @mode: volume open mode
    + *
    + * This function opens an UBI volume. The @mode parameter specifies if the
    + * volume should be opened in read-only mode, read-write mode, or exclusive
    + * mode. The exclusive mode guarantees that nobody else will be able to open
    + * this volume. UBI allows to have many volume readers and one writer at a
    + * time.
    + *
    + * If a static volume is being opened for the first time since boot, the volume
    + * will be checked by this function, which means it will be fully read and the
    + * CRC checksum of each logical eraseblock will be checked.
    + *
    + * This function returns an UBI volume descriptor in case of success. In case
    + * of failure, the following error codes may be returned:
    + *
    + * o %-EBUSY if the volume is busy (it is being updated, or it is already
    + * opened in exclusive or read-write mode by somebody else);
    + * o %-EINVAL if the input arguments are invalid;
    + * o %-ENODEV if this volume does not exist or the UBI device does not exist;
    + * o other negative error codes in case of other errors.
    + */
    +struct ubi_vol_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
    +{
    + int err, found = 0;
    + struct ubi_vol_desc *desc;
    + struct ubi_info *ubi;
    + struct ubi_uif_volume *vol;
    +
    + dbg_uif("open device %d volume %d, mode %d", ubi_num, vol_id, mode);
    +
    + err = -ENODEV;
    + if (!try_module_get(THIS_MODULE))
    + return ERR_PTR(err);
    +
    + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
    + goto out_put;
    +
    + if (!ubis[ubi_num])
    + goto out_put;
    +
    + ubi = ubis[ubi_num];
    + ubi_assert(ubi->ubi_num == ubi_num);
    +
    + desc = kmalloc(sizeof(struct ubi_vol_desc), GFP_KERNEL);
    + if (!desc) {
    + err = -ENOMEM;
    + goto out_put;
    + }
    +
    + err = -EINVAL;
    + if (vol_id < 0 || vol_id >= ubi->vtbl.vt_slots)
    + goto out_free;
    +
    + if (mode != UBI_READONLY && mode != UBI_READWRITE &&
    + mode != UBI_EXCLUSIVE)
    + goto out_free;
    +
    + spin_lock(&ubi->uif.volumes_list_lock);
    + list_for_each_entry(vol, &ubi->uif.volumes, list) {
    + if (vol->vol_id == vol_id) {
    + found = 1;
    + break;
    + }
    + }
    +
    + if (!found) {
    + err = -ENODEV;
    + goto out_unlock;
    + }
    +
    + err = -EBUSY;
    + spin_lock(&vol->vol_lock);
    + switch (mode) {
    + case UBI_READONLY:
    + if (vol->exclusive)
    + goto out_unlock_vol;
    + vol->readers += 1;
    + break;
    +
    + case UBI_READWRITE:
    + if (vol->exclusive || vol->writers > 0)
    + goto out_unlock_vol;
    + vol->writers += 1;
    + break;
    +
    + case UBI_EXCLUSIVE:
    + if (vol->exclusive || vol->writers || vol->readers)
    + goto out_unlock_vol;
    + vol->exclusive = 1;
    + break;
    + }
    + spin_unlock(&vol->vol_lock);
    + spin_unlock(&ubi->uif.volumes_list_lock);
    +
    + desc->vol = vol;
    + desc->mode = mode;
    +
    + mutex_lock(&ubi->uif.vol_check_lock);
    + if (!vol->checked) {
    + /*
    + * This is the first time this volume is being opened, we have
    + * to check it. If the volume is corrupted, we still return
    + * success, but mark it as corrupted and return %-EUCLEAN on
    + * any further read.
    + */
    + err = ubi_check_volume(ubi, vol_id);
    + if (err < 0)
    + goto unlock_close;
    +
    + if (err == 1) {
    + ubi_warn("volume %d on UBI device %d is corrupted",
    + vol_id, ubi->ubi_num);
    + err = ubi_vtbl_set_corrupted(ubi, vol_id);
    + if (err)
    + goto unlock_close;
    + }
    + vol->checked = 1;
    + }
    + mutex_unlock(&ubi->uif.vol_check_lock);
    +
    + return desc;
    +
    +out_unlock_vol:
    + spin_unlock(&vol->vol_lock);
    +out_unlock:
    + spin_unlock(&ubi->uif.volumes_list_lock);
    +out_free:
    + kfree(desc);
    +out_put:
    + module_put(THIS_MODULE);
    + return ERR_PTR(err);
    +
    +unlock_close:
    + mutex_unlock(&ubi->uif.vol_check_lock);
    + ubi_close_volume(desc);
    + return ERR_PTR(err);
    +}
    +EXPORT_SYMBOL_GPL(ubi_open_volume);
    +
    +/*
    + * ubi_open_volume_nm - open an UBI volume by volume name.
    + *
    + * @ubi_num: the UBI device number
    + * @name: volume name
    + * @mode: volume open mode
    + *
    + * This function is similar to the 'ubi_open_volume()' function, but opens UBI
    + * volumes by name.
    + */
    +struct ubi_vol_desc *ubi_open_volume_nm(int ubi_num, const char *name, int mode)
    +{
    + int vol_id = -1, len;
    + struct ubi_vol_desc *ret;
    + struct ubi_info *ubi;
    + struct ubi_uif_volume *vol;
    +
    + dbg_uif("open volume by name %s, mode %d", name, mode);
    +
    + if (!name)
    + return ERR_PTR(-EINVAL);
    +
    + len = strnlen(name, UBI_VOL_NAME_MAX + 1);
    + if (len > UBI_VOL_NAME_MAX)
    + return ERR_PTR(-EINVAL);
    +
    + ret = ERR_PTR(-ENODEV);
    + if (!try_module_get(THIS_MODULE))
    + return ret;
    +
    + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
    + goto out_put;
    +
    + if (!ubis[ubi_num])
    + goto out_put;
    +
    + ubi = ubis[ubi_num];
    + ubi_assert(ubi->ubi_num == ubi_num);
    +
    + /* Walk all volumes of this UBI device */
    + spin_lock(&ubi->uif.volumes_list_lock);
    + list_for_each_entry(vol, &ubi->uif.volumes, list) {
    + const struct ubi_vtbl_vtr *vtr;
    +
    + vtr = ubi_vtbl_get_vtr(vol->ubi, vol->vol_id);
    + if (len == vtr->name_len && !strcmp(name, vtr->name)) {
    + vol_id = vol->vol_id;
    + spin_unlock(&vol->vol_lock);
    + break;
    + }
    + }
    + spin_unlock(&ubi->uif.volumes_list_lock);
    +
    + if (vol_id < 0)
    + goto out_put;
    +
    + ret = ubi_open_volume(ubi_num, vol_id, mode);
    +
    +out_put:
    + module_put(THIS_MODULE);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
    +
    +/**
    + * ubi_close_volume - close an UBI volume.
    + *
    + * @desc: UBI volume descriptor
    + */
    +void ubi_close_volume(struct ubi_vol_desc *desc)
    +{
    + struct ubi_uif_volume *vol = desc->vol;
    +
    + dbg_uif("close volume %d, mode %d", vol->vol_id, desc->mode);
    +
    + spin_lock(&vol->vol_lock);
    + switch (desc->mode) {
    + case UBI_READONLY:
    + ubi_assert(vol->readers > 0 && vol->writers >= 0);
    + ubi_assert(vol->exclusive == 0);
    + vol->readers -= 1;
    + break;
    +
    + case UBI_READWRITE:
    + ubi_assert(vol->readers >= 0 && vol->writers == 1);
    + ubi_assert(vol->exclusive == 0);
    + vol->writers -= 1;
    + break;
    +
    + case UBI_EXCLUSIVE:
    + ubi_assert(vol->readers == 0 && vol->writers == 0);
    + ubi_assert(vol->exclusive == 1);
    + vol->exclusive = 0;
    + }
    + spin_unlock(&vol->vol_lock);
    +
    + kfree(desc);
    + module_put(THIS_MODULE);
    +}
    +EXPORT_SYMBOL_GPL(ubi_close_volume);
    +
    +/**
    + * ubi_eraseblock_read - read data from a logical eraseblock.
    + *
    + * @desc: volume descriptor
    + * @lnum: the logical eraseblock number to read from
    + * @buf: a buffer where to store the read data
    + * @offset: the offset within the logical eraseblock from where to read
    + * @len: how many bytes to read
    + * @check: whether UBI has to check the read data's CRC or not.
    + *
    + * This function reads data from offset @offset of the logical eraseblock @lnum
    + * and stores the read data at @buf. When reading from static volumes, @check
    + * may be used to specify whether the read data has to be checked or not. If
    + * checking is requested, the whole logical eraseblock will be read and its CRC
    + * checksum will be checked (i.e., the CRC checksum is per-eraseblock). So
    + * checking may substantially slow down the read speed. The @check argument is
    + * ignored for dynamic volumes.
    + *
    + * In case of success, this function returns zero. In case of failure, this
    + * function returns a negative error code.
    + *
    + * A special %-EBADMSG error code is returned:
    + * o for both static and dynamic volumes if the MTD driver has detected a data
    + * integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
    + * o for static volumes if the data CRC mismatches.
    + *
    + * In case of reading a corrupted UBI volume, this function never returns zero,
    + * but %-EUCLEAN is returned instead, even though the data was read without
    + * errors because the corruption did not affect this particular piece of data,
    + * otherwise %-EBADMSG would have been returned. Thus, %-EUCLEAN just means
    + * that the read static volume is corrupted, but the read data is actually OK.
    + *
    + * %-EUCLEAN is not returned for dynamic volumes, because UBI does not protect
    + * their contents.
    + *
    + * If the volume is damaged because of an interrupted update this function just
    + * returns immediately with %-EBADF error code.
    + */
    +int ubi_eraseblock_read(struct ubi_vol_desc *desc, int lnum, char *buf,
    + int offset, int len, int check)
    +{
    + const struct ubi_vtbl_vtr *vtr;
    + struct ubi_info *ubi = desc->vol->ubi;
    + int err, vol_id = desc->vol->vol_id;
    +
    + dbg_uif("read %d bytes from LEB %d:%d:%d",
    + len, vol_id, lnum, offset);
    +
    + if (unlikely(vol_id < 0 || vol_id >= ubi->vtbl.vt_slots))
    + return -EINVAL;
    +
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    +
    + if (unlikely(lnum < 0 || lnum >= vtr->used_ebs))
    + return -EINVAL;
    +
    + if (unlikely(offset < 0 || len < 0 ||
    + offset + len > vtr->usable_leb_size))
    + return -EINVAL;
    +
    + if (unlikely(vtr->vol_type == UBI_STATIC_VOLUME &&
    + lnum == vtr->used_ebs - 1 &&
    + offset + len > vtr->last_eb_bytes))
    + return -EINVAL;
    +
    + if (unlikely(vtr->upd_marker))
    + return -EBADF;
    +
    + if (unlikely(len == 0))
    + return 0;
    +
    +reread:
    + err = ubi_eba_read_leb(ubi, vol_id, lnum, buf, offset, len, check);
    + if (unlikely(err)) {
    + if (err == -EBADMSG && vtr->vol_type == UBI_STATIC_VOLUME &&
    + !vtr->corrupted) {
    + int err1;
    +
    + /*
    + * We have read a static volume and result in data
    + * integrity error. If we did not do checking, re-read
    + * with checking enabled. Otherwise mark this static
    + * eraseblock as corrupted.
    + */
    + if (!check) {
    + check = 1;
    + goto reread;
    + }
    +
    + ubi_warn("mark volume %d as corrupted", vol_id);
    + err1 = ubi_vtbl_set_corrupted(ubi, vol_id);
    + if (err1)
    + err = err1;
    + }
    + return err;
    + }
    +
    + if (unlikely(vtr->corrupted)) {
    + ubi_assert(vtr->vol_type == UBI_STATIC_VOLUME);
    + err = -EUCLEAN;
    + }
    +
    + return err;
    +}
    +EXPORT_SYMBOL_GPL(ubi_eraseblock_read);
    +
    +/**
    + * ubi_eraseblock_write - write data to a logical eraseblock.
    + *
    + * @desc: volume descriptor
    + * @lnum: the logical eraseblock number to write to
    + * @buf: the data to write
    + * @offset: offset within the logical eraseblock where to write
    + * @len: how many bytes from @buf to write
    + * @dtype: expected data type
    + *
    + * This function writes @len bytes of data from buffer @buf to offset @offset
    + * of logical eraseblock @lnum. The @dtype argument describes the expected
    + * lifetime of the data that is being written.
    + *
    + * Note, this function takes care of physical eraseblock write failures. If a
    + * write to the physical eraseblock write operation fails, the logical
    + * eraseblock is re-mapped to another physical eraseblock, the data is
    + * recovered, and the write finishes. UBI has a pool of reserved physical
    + * eraseblocks for this.
    + *
    + * If all the data were successfully written, zero is returned. If an error
    + * occurred and UBI has not been able to recover from it, this function returns
    + * a negative error code. Note, in case of an error, it is possible that
    + * something was still written to the flash media, but that may be some
    + * garbage.
    + *
    + * If the volume is damaged because of an interrupted update this function just
    + * returns immediately with %-EBADF error code.
    + */
    +int ubi_eraseblock_write(struct ubi_vol_desc *desc, int lnum, const void *buf,
    + int offset, int len, int dtype)
    +{
    + const struct ubi_vtbl_vtr *vtr;
    + struct ubi_info *ubi = desc->vol->ubi;
    + int vol_id = desc->vol->vol_id;
    +
    + dbg_uif("write %zd bytes to LEB %d:%d:%d",
    + len, vol_id, lnum, offset);
    +
    + if (unlikely(vol_id < 0 || vol_id >= ubi->vtbl.vt_slots))
    + return -EINVAL;
    +
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    +
    + if (unlikely(desc->mode == UBI_READONLY ||
    + vtr->vol_type == UBI_STATIC_VOLUME))
    + return -EROFS;
    +
    + if (unlikely(lnum < 0 || lnum >= vtr->reserved_pebs))
    + return -EINVAL;
    +
    + if (unlikely(offset < 0 || len < 0 ||
    + offset + len > vtr->usable_leb_size))
    + return -EINVAL;
    +
    + if (unlikely(offset % ubi->io.min_io_size ||
    + len % ubi->io.min_io_size))
    + return -EINVAL;
    +
    + if (unlikely(dtype != UBI_DATA_LONGTERM &&
    + dtype != UBI_DATA_SHORTTERM &&
    + dtype != UBI_DATA_UNKNOWN))
    + return -EINVAL;
    +
    + if (unlikely(vtr->upd_marker))
    + return -EBADF;
    +
    + if (unlikely(len == 0))
    + return 0;
    +
    + return ubi_eba_write_leb(ubi, vol_id, lnum, buf, offset, len, dtype);
    +}
    +EXPORT_SYMBOL_GPL(ubi_eraseblock_write);
    +
    +/**
    + * ubi_eraseblock_erase - erase a logical eraseblock.
    + *
    + * @desc: volume descriptor
    + * @lnum: the logical eraseblock number to erase
    + *
    + * This function un-maps logical eraseblock @lnum and synchronously erases the
    + * correspondent physical eraseblock. Returns zero in case of success and a
    + * negative error code in case of failure.
    + *
    + * If the volume is damaged because of an interrupted update this function just
    + * returns immediately with %-EBADF error code.
    + */
    +int ubi_eraseblock_erase(struct ubi_vol_desc *desc, int lnum)
    +{
    + const struct ubi_vtbl_vtr *vtr;
    + struct ubi_info *ubi = desc->vol->ubi;
    + int err, vol_id = desc->vol->vol_id;
    +
    + dbg_uif("erase LEB %d:%d", vol_id, lnum);
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    +
    + if (unlikely(desc->mode == UBI_READONLY ||
    + vtr->vol_type == UBI_STATIC_VOLUME))
    + return -EROFS;
    +
    + if (unlikely(lnum < 0 || lnum >= vtr->reserved_pebs))
    + return -EINVAL;
    +
    + if (unlikely(vtr->upd_marker))
    + return -EBADF;
    +
    + err = ubi_eba_unmap_leb(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + return ubi_wl_flush(ubi);
    +}
    +EXPORT_SYMBOL_GPL(ubi_eraseblock_erase);
    +
    +/**
    + * ubi_eraseblock_unmap - un-map a logical eraseblock.
    + *
    + * @desc: volume descriptor
    + * @lnum: the logical eraseblock number to un-map
    + *
    + * This function un-maps logical eraseblock @lnum and schedules the
    + * corresponding physical eraseblock for erasure, so that it will eventually be
    + * physically erased in background. So this operation is much faster then the
    + * erase operation.
    + *
    + * Unlike erase, the un-map operation does not guarantee that the logical
    + * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
    + * example, if several logical eraseblocks are un-mapped, and an unclean reboot
    + * happens after this, the logical eraseblocks will not necessarily be
    + * un-mapped again when this MTD device is attached. They may actually be
    + * mapped to the same physical eraseblocks again. So, this function has to be
    + * used with care.
    + *
    + * In other words, when un-mapping a logical eraseblock, UBI does not store
    + * any information about this on the flash media, it just marks the logical
    + * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
    + * eraseblock is physically erased, the physical eraseblock will be mapped
    + * again to the same logical eraseblock when the MTD device is attached again.
    + *
    + * The main and obvious use-case of this function is when the contents of a
    + * logical eraseblock has to be re-written. Then it is much more efficient to
    + * first un-map it, then write new data, rather then first erase it, then write
    + * new data. Note, once new data has been written to the logical eraseblock,
    + * UBI guarantees that the old contents has gone forever. In other words, if an
    + * unclean reboot happens after the logical eraseblock has been un-mapped and
    + * then written to, it will contain the last written data.
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure. If the volume is damaged because of an interrupted update
    + * this function just returns immediately with %-EBADF error code.
    + */
    +int ubi_eraseblock_unmap(struct ubi_vol_desc *desc, int lnum)
    +{
    + const struct ubi_vtbl_vtr *vtr;
    + struct ubi_info *ubi = desc->vol->ubi;
    + int vol_id = desc->vol->vol_id;
    +
    + dbg_uif("unmap LEB %d:%d", vol_id, lnum);
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    +
    + if (unlikely(desc->mode == UBI_READONLY ||
    + vtr->vol_type == UBI_STATIC_VOLUME))
    + return -EROFS;
    +
    + if (unlikely(lnum < 0 || lnum >= vtr->reserved_pebs))
    + return -EINVAL;
    +
    + if (unlikely(vtr->upd_marker))
    + return -EBADF;
    +
    + return ubi_eba_unmap_leb(ubi, vol_id, lnum);
    +}
    +EXPORT_SYMBOL_GPL(ubi_eraseblock_unmap);
    +
    +/**
    + * ubi_eraseblock_is_mapped - check if a logical eraseblock is mapped to a
    + * physical eraseblock
    + *
    + * @desc: volume descriptor
    + * @lnum: the logical eraseblock number to erase
    + *
    + * This function checks if a logical eraseblock is mapped to a physical
    + * eraseblock. Unmapped logical eraseblocks are equivalent to erased logical
    + * eraseblocks and contain only 0xFF bytes. Mapped logical eraseblocks are
    + * those that were explicitly written to. They may also contain only 0xFF
    + * bytes if these were written there.
    + *
    + * Note, if a logical eraseblock is unmapped, this does not necessarily mean
    + * it will still be un-mapped after the corresponding UBI device is detached
    + * and attached again. After the UBI device is re-attached, the logical
    + * eraseblock may become mapped to the physical eraseblock it was last mapped
    + * to. Se the 'ubi_eraseblock_unmap()' function for more explanation.
    + *
    + * This function returns %1 if the LEB is mapped, %0 if not, and a negative
    + * error code in case of failure. If the volume is damaged because of an
    + * interrupted update this function just returns immediately with %-EBADF error
    + * code.
    + */
    +int ubi_eraseblock_is_mapped(struct ubi_vol_desc *desc, int lnum)
    +{
    + const struct ubi_vtbl_vtr *vtr;
    + struct ubi_info *ubi = desc->vol->ubi;
    + int vol_id = desc->vol->vol_id;
    +
    + dbg_uif("check LEB %d:%d", vol_id, lnum);
    + vtr = ubi_vtbl_get_vtr(ubi, vol_id);
    + ubi_assert(!IS_ERR(vtr));
    +
    + if (unlikely(lnum < 0 || lnum >= vtr->reserved_pebs))
    + return -EINVAL;
    +
    + if (unlikely(vtr->upd_marker))
    + return -EBADF;
    +
    + return ubi_eba_leb_is_mapped(ubi, vol_id, lnum);
    +}
    +EXPORT_SYMBOL_GPL(ubi_eraseblock_is_mapped);
    +
    +/**
    + * kill_volumes - close user interfaces for all volumes.
    + *
    + * @ubi: the UBI device description object
    + *
    + * This function is called when the UBI device is detached so no locking is
    + * needed.
    + */
    +static void kill_volumes(struct ubi_info *ubi)
    +{
    + struct ubi_uif_volume *vol, *vol_tmp;
    +
    + list_for_each_entry_safe(vol, vol_tmp, &ubi->uif.volumes, list) {
    + int err;
    +
    + list_del(&vol->list);
    + err = ubi_gluebi_vol_close(vol);
    + BUG_ON(err);
    + cdev_del(&vol->cdev);
    + ubi_sysfs_vol_close(vol);
    + }
    +}
    +
    +/**
    + * ubi_uif_init - initialize user interfaces for an UBI device.
    + *
    + * @ubi: the UBI device description object
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +int ubi_uif_init(struct ubi_info *ubi)
    +{
    + int i, err;
    +
    + dbg_uif("initialize the user interfaces unit");
    +
    + spin_lock_init(&ubi->uif.volumes_list_lock);
    + mutex_init(&ubi->uif.vol_check_lock);
    + mutex_init(&ubi->uif.vol_change_lock);
    + INIT_LIST_HEAD(&ubi->uif.volumes);
    +
    + sprintf(ubi->uif.ubi_name, UBI_STRING_NAME "%d", ubi->ubi_num);
    +
    + err = ubi_cdev_init(ubi);
    + if (err)
    + return 0;
    +
    + err = ubi_sysfs_init(ubi);
    + if (err)
    + goto out_cdev;
    +
    + for (i = 0; i < ubi->vtbl.vt_slots; i++) {
    + const struct ubi_vtbl_vtr *vtr;
    +
    + cond_resched();
    +
    + vtr = ubi_vtbl_get_vtr(ubi, i);
    + if (IS_ERR(vtr))
    + continue;
    +
    + err = ubi_vmt_mkvol(ubi, i, NULL);
    + if (err < 0)
    + goto out_volumes;
    + }
    +
    + dbg_uif("the user interfaces unit is initialized");
    + return 0;
    +
    +out_volumes:
    + kill_volumes(ubi);
    + ubi_sysfs_close(ubi);
    +out_cdev:
    + ubi_cdev_close(ubi);
    + return err;
    +}
    +
    +/**
    + * ubi_uif_close - close the UBI user interface unit for an UBI device.
    + *
    + * @ubi: the UBI device description object
    + */
    +void ubi_uif_close(struct ubi_info *ubi)
    +{
    + dbg_uif("close the user interface unit for %s", ubi->uif.ubi_name);
    +
    + kill_volumes(ubi);
    + ubi_sysfs_close(ubi);
    + ubi_cdev_close(ubi);
    +}
    +
    +/**
    + * ubi_uif_get_exclusive - get exclusive access to an UBI volume.
    + *
    + * @desc: volume descriptor
    + *
    + * This function changes UBI volume mode to "exclusive". Obviously, the caller
    + * has to be the only holder of the volume to make this function succeed.
    + * Returns previous mode value (positive integer) in case of success and a
    + * negative error code in case of failure.
    + */
    +int ubi_uif_get_exclusive(struct ubi_vol_desc *desc)
    +{
    + int users, ret;
    + struct ubi_uif_volume *vol = desc->vol;
    +
    + spin_lock(&vol->vol_lock);
    + users = vol->readers + vol->writers + vol->exclusive;
    + ubi_assert(users > 0);
    + if (users > 1) {
    + dbg_err("%d users for volume %d", users, vol->vol_id);
    + ret = -EBUSY;
    + } else {
    + dbg_uif("changed volume %d mode %d to exclusive",
    + vol->vol_id, desc->mode);
    + vol->readers = vol->writers = 0;
    + vol->exclusive = 1;
    + }
    + spin_unlock(&vol->vol_lock);
    +
    + ret = desc->mode;
    + desc->mode = UBI_EXCLUSIVE;
    + return ret;
    +}
    +
    +/**
    + * ubi_uif_revoke_exclusive - switch to a non-exclusive open mode.
    + *
    + * @desc: volume descriptor
    + * @mode: the new mode to switch to
    + *
    + * This function revokes the "exclusive" mode and switches to the @mode mode.
    + */
    +void ubi_uif_revoke_exclusive(struct ubi_vol_desc *desc, int mode)
    +{
    + struct ubi_uif_volume *vol = desc->vol;
    +
    + spin_lock(&vol->vol_lock);
    + ubi_assert(vol->readers == 0 && vol->writers == 0);
    + ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
    +
    + vol->exclusive = 0;
    + if (mode == UBI_READONLY)
    + vol->readers = 1;
    + else if (mode == UBI_READWRITE)
    + vol->writers = 1;
    + else
    + vol->exclusive = 1;
    +
    + spin_unlock(&vol->vol_lock);
    +
    + desc->mode = mode;
    + dbg_uif("revoke exclusive mode for volume %d, new mode is %d",
    + vol->vol_id, mode);
    +}
    -
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      Last update: 2007-03-14 16:27    [W:4.860 / U:0.044 seconds]
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