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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/mtd/ubi/kapi.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/mtd/ubi/kapi.c')
-rw-r--r--kernel/drivers/mtd/ubi/kapi.c864
1 files changed, 864 insertions, 0 deletions
diff --git a/kernel/drivers/mtd/ubi/kapi.c b/kernel/drivers/mtd/ubi/kapi.c
new file mode 100644
index 000000000..e84488773
--- /dev/null
+++ b/kernel/drivers/mtd/ubi/kapi.c
@@ -0,0 +1,864 @@
+/*
+ * 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 Bityutskiy (Битюцкий Артём)
+ */
+
+/* This file mostly implements UBI kernel API functions */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/namei.h>
+#include <linux/fs.h>
+#include <asm/div64.h>
+#include "ubi.h"
+
+/**
+ * ubi_do_get_device_info - get information about UBI device.
+ * @ubi: UBI device description object
+ * @di: the information is stored here
+ *
+ * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
+ * device is locked and cannot disappear.
+ */
+void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
+{
+ di->ubi_num = ubi->ubi_num;
+ di->leb_size = ubi->leb_size;
+ di->leb_start = ubi->leb_start;
+ di->min_io_size = ubi->min_io_size;
+ di->max_write_size = ubi->max_write_size;
+ di->ro_mode = ubi->ro_mode;
+ di->cdev = ubi->cdev.dev;
+}
+EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
+
+/**
+ * ubi_get_device_info - get information about UBI device.
+ * @ubi_num: UBI device number
+ * @di: the information is stored here
+ *
+ * This function returns %0 in case of success, %-EINVAL if the UBI device
+ * number is invalid, and %-ENODEV if there is no such UBI device.
+ */
+int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
+{
+ struct ubi_device *ubi;
+
+ if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
+ return -EINVAL;
+ ubi = ubi_get_device(ubi_num);
+ if (!ubi)
+ return -ENODEV;
+ ubi_do_get_device_info(ubi, di);
+ ubi_put_device(ubi);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ubi_get_device_info);
+
+/**
+ * ubi_do_get_volume_info - get information about UBI volume.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @vi: the information is stored here
+ */
+void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
+ struct ubi_volume_info *vi)
+{
+ vi->vol_id = vol->vol_id;
+ vi->ubi_num = ubi->ubi_num;
+ vi->size = vol->reserved_pebs;
+ vi->used_bytes = vol->used_bytes;
+ vi->vol_type = vol->vol_type;
+ vi->corrupted = vol->corrupted;
+ vi->upd_marker = vol->upd_marker;
+ vi->alignment = vol->alignment;
+ vi->usable_leb_size = vol->usable_leb_size;
+ vi->name_len = vol->name_len;
+ vi->name = vol->name;
+ vi->cdev = vol->cdev.dev;
+}
+
+/**
+ * ubi_get_volume_info - get information about UBI volume.
+ * @desc: volume descriptor
+ * @vi: the information is stored here
+ */
+void ubi_get_volume_info(struct ubi_volume_desc *desc,
+ struct ubi_volume_info *vi)
+{
+ ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
+}
+EXPORT_SYMBOL_GPL(ubi_get_volume_info);
+
+/**
+ * ubi_open_volume - open UBI volume.
+ * @ubi_num: UBI device number
+ * @vol_id: volume ID
+ * @mode: open mode
+ *
+ * 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, it 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 volume descriptor in case of success and a negative
+ * error code in case of failure.
+ */
+struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
+{
+ int err;
+ struct ubi_volume_desc *desc;
+ struct ubi_device *ubi;
+ struct ubi_volume *vol;
+
+ dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
+
+ if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
+ return ERR_PTR(-EINVAL);
+
+ if (mode != UBI_READONLY && mode != UBI_READWRITE &&
+ mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
+ return ERR_PTR(-EINVAL);
+
+ /*
+ * First of all, we have to get the UBI device to prevent its removal.
+ */
+ ubi = ubi_get_device(ubi_num);
+ if (!ubi)
+ return ERR_PTR(-ENODEV);
+
+ if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
+ err = -EINVAL;
+ goto out_put_ubi;
+ }
+
+ desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
+ if (!desc) {
+ err = -ENOMEM;
+ goto out_put_ubi;
+ }
+
+ err = -ENODEV;
+ if (!try_module_get(THIS_MODULE))
+ goto out_free;
+
+ spin_lock(&ubi->volumes_lock);
+ vol = ubi->volumes[vol_id];
+ if (!vol)
+ goto out_unlock;
+
+ err = -EBUSY;
+ switch (mode) {
+ case UBI_READONLY:
+ if (vol->exclusive)
+ goto out_unlock;
+ vol->readers += 1;
+ break;
+
+ case UBI_READWRITE:
+ if (vol->exclusive || vol->writers > 0)
+ goto out_unlock;
+ vol->writers += 1;
+ break;
+
+ case UBI_EXCLUSIVE:
+ if (vol->exclusive || vol->writers || vol->readers ||
+ vol->metaonly)
+ goto out_unlock;
+ vol->exclusive = 1;
+ break;
+
+ case UBI_METAONLY:
+ if (vol->metaonly || vol->exclusive)
+ goto out_unlock;
+ vol->metaonly = 1;
+ break;
+ }
+ get_device(&vol->dev);
+ vol->ref_count += 1;
+ spin_unlock(&ubi->volumes_lock);
+
+ desc->vol = vol;
+ desc->mode = mode;
+
+ mutex_lock(&ubi->ckvol_mutex);
+ if (!vol->checked) {
+ /* This is the first open - check the volume */
+ err = ubi_check_volume(ubi, vol_id);
+ if (err < 0) {
+ mutex_unlock(&ubi->ckvol_mutex);
+ ubi_close_volume(desc);
+ return ERR_PTR(err);
+ }
+ if (err == 1) {
+ ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
+ vol_id, ubi->ubi_num);
+ vol->corrupted = 1;
+ }
+ vol->checked = 1;
+ }
+ mutex_unlock(&ubi->ckvol_mutex);
+
+ return desc;
+
+out_unlock:
+ spin_unlock(&ubi->volumes_lock);
+ module_put(THIS_MODULE);
+out_free:
+ kfree(desc);
+out_put_ubi:
+ ubi_put_device(ubi);
+ ubi_err(ubi, "cannot open device %d, volume %d, error %d",
+ ubi_num, vol_id, err);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(ubi_open_volume);
+
+/**
+ * ubi_open_volume_nm - open UBI volume by name.
+ * @ubi_num: UBI device number
+ * @name: volume name
+ * @mode: open mode
+ *
+ * This function is similar to 'ubi_open_volume()', but opens a volume by name.
+ */
+struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
+ int mode)
+{
+ int i, vol_id = -1, len;
+ struct ubi_device *ubi;
+ struct ubi_volume_desc *ret;
+
+ dbg_gen("open device %d, volume %s, mode %d", ubi_num, 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);
+
+ if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
+ return ERR_PTR(-EINVAL);
+
+ ubi = ubi_get_device(ubi_num);
+ if (!ubi)
+ return ERR_PTR(-ENODEV);
+
+ spin_lock(&ubi->volumes_lock);
+ /* Walk all volumes of this UBI device */
+ for (i = 0; i < ubi->vtbl_slots; i++) {
+ struct ubi_volume *vol = ubi->volumes[i];
+
+ if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
+ vol_id = i;
+ break;
+ }
+ }
+ spin_unlock(&ubi->volumes_lock);
+
+ if (vol_id >= 0)
+ ret = ubi_open_volume(ubi_num, vol_id, mode);
+ else
+ ret = ERR_PTR(-ENODEV);
+
+ /*
+ * We should put the UBI device even in case of success, because
+ * 'ubi_open_volume()' took a reference as well.
+ */
+ ubi_put_device(ubi);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
+
+/**
+ * ubi_open_volume_path - open UBI volume by its character device node path.
+ * @pathname: volume character device node path
+ * @mode: open mode
+ *
+ * This function is similar to 'ubi_open_volume()', but opens a volume the path
+ * to its character device node.
+ */
+struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
+{
+ int error, ubi_num, vol_id, mod;
+ struct inode *inode;
+ struct path path;
+
+ dbg_gen("open volume %s, mode %d", pathname, mode);
+
+ if (!pathname || !*pathname)
+ return ERR_PTR(-EINVAL);
+
+ error = kern_path(pathname, LOOKUP_FOLLOW, &path);
+ if (error)
+ return ERR_PTR(error);
+
+ inode = d_backing_inode(path.dentry);
+ mod = inode->i_mode;
+ ubi_num = ubi_major2num(imajor(inode));
+ vol_id = iminor(inode) - 1;
+ path_put(&path);
+
+ if (!S_ISCHR(mod))
+ return ERR_PTR(-EINVAL);
+ if (vol_id >= 0 && ubi_num >= 0)
+ return ubi_open_volume(ubi_num, vol_id, mode);
+ return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL_GPL(ubi_open_volume_path);
+
+/**
+ * ubi_close_volume - close UBI volume.
+ * @desc: volume descriptor
+ */
+void ubi_close_volume(struct ubi_volume_desc *desc)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+
+ dbg_gen("close device %d, volume %d, mode %d",
+ ubi->ubi_num, vol->vol_id, desc->mode);
+
+ spin_lock(&ubi->volumes_lock);
+ switch (desc->mode) {
+ case UBI_READONLY:
+ vol->readers -= 1;
+ break;
+ case UBI_READWRITE:
+ vol->writers -= 1;
+ break;
+ case UBI_EXCLUSIVE:
+ vol->exclusive = 0;
+ break;
+ case UBI_METAONLY:
+ vol->metaonly = 0;
+ break;
+ }
+ vol->ref_count -= 1;
+ spin_unlock(&ubi->volumes_lock);
+
+ kfree(desc);
+ put_device(&vol->dev);
+ ubi_put_device(ubi);
+ module_put(THIS_MODULE);
+}
+EXPORT_SYMBOL_GPL(ubi_close_volume);
+
+/**
+ * leb_read_sanity_check - does sanity checks on read requests.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to read from
+ * @offset: offset within the logical eraseblock to read from
+ * @len: how many bytes to read
+ *
+ * This function is used by ubi_leb_read() and ubi_leb_read_sg()
+ * to perform sanity checks.
+ */
+static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
+ int offset, int len)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int vol_id = vol->vol_id;
+
+ if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
+ lnum >= vol->used_ebs || offset < 0 || len < 0 ||
+ offset + len > vol->usable_leb_size)
+ return -EINVAL;
+
+ if (vol->vol_type == UBI_STATIC_VOLUME) {
+ if (vol->used_ebs == 0)
+ /* Empty static UBI volume */
+ return 0;
+ if (lnum == vol->used_ebs - 1 &&
+ offset + len > vol->last_eb_bytes)
+ return -EINVAL;
+ }
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ return 0;
+}
+
+/**
+ * ubi_leb_read - read data.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to read from
+ * @buf: buffer where to store the read data
+ * @offset: offset within the logical eraseblock to read from
+ * @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 logical eraseblock @lnum and
+ * stores the data at @buf. When reading from static volumes, @check specifies
+ * whether the data has to be checked or not. If yes, 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.
+ *
+ * %-EBADMSG error code is returned:
+ * o for both static and dynamic volumes if MTD driver has detected a data
+ * integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
+ * o for static volumes in case of data CRC mismatch.
+ *
+ * If the volume is damaged because of an interrupted update this function just
+ * returns immediately with %-EBADF error code.
+ */
+int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
+ int len, int check)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int err, vol_id = vol->vol_id;
+
+ dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
+
+ err = leb_read_sanity_check(desc, lnum, offset, len);
+ if (err < 0)
+ return err;
+
+ if (len == 0)
+ return 0;
+
+ err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
+ if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
+ ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
+ vol->corrupted = 1;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(ubi_leb_read);
+
+
+/**
+ * ubi_leb_read_sg - read data into a scatter gather list.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to read from
+ * @buf: buffer where to store the read data
+ * @offset: offset within the logical eraseblock to read from
+ * @len: how many bytes to read
+ * @check: whether UBI has to check the read data's CRC or not.
+ *
+ * This function works exactly like ubi_leb_read_sg(). But instead of
+ * storing the read data into a buffer it writes to an UBI scatter gather
+ * list.
+ */
+int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
+ int offset, int len, int check)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int err, vol_id = vol->vol_id;
+
+ dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
+
+ err = leb_read_sanity_check(desc, lnum, offset, len);
+ if (err < 0)
+ return err;
+
+ if (len == 0)
+ return 0;
+
+ err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
+ if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
+ ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
+ vol->corrupted = 1;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
+
+/**
+ * ubi_leb_write - write data.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to write to
+ * @buf: data to write
+ * @offset: offset within the logical eraseblock where to write
+ * @len: how many bytes to write
+ *
+ * This function writes @len bytes of data from @buf to offset @offset of
+ * logical eraseblock @lnum.
+ *
+ * This function takes care of physical eraseblock write failures. If 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 code.
+ */
+int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
+ int offset, int len)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int vol_id = vol->vol_id;
+
+ dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
+
+ if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
+ return -EINVAL;
+
+ if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
+ offset + len > vol->usable_leb_size ||
+ offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ if (len == 0)
+ return 0;
+
+ return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_write);
+
+/*
+ * ubi_leb_change - change logical eraseblock atomically.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number to change
+ * @buf: data to write
+ * @len: how many bytes to write
+ *
+ * This function changes the contents of a logical eraseblock atomically. @buf
+ * has to contain new logical eraseblock data, and @len - the length of the
+ * data, which has to be aligned. The length may be shorter than the logical
+ * eraseblock size, ant the logical eraseblock may be appended to more times
+ * later on. This function guarantees that in case of an unclean reboot the old
+ * contents is preserved. Returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
+ int len)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int vol_id = vol->vol_id;
+
+ dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
+
+ if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
+ return -EINVAL;
+
+ if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
+ len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ if (len == 0)
+ return 0;
+
+ return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_change);
+
+/**
+ * ubi_leb_erase - erase logical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * 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 code.
+ */
+int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+ int err;
+
+ dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
+
+ if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs)
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ err = ubi_eba_unmap_leb(ubi, vol, lnum);
+ if (err)
+ return err;
+
+ return ubi_wl_flush(ubi, vol->vol_id, lnum);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_erase);
+
+/**
+ * ubi_leb_unmap - un-map logical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * 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. This operation is much faster than 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, it 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 than 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 code.
+ */
+int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+
+ dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
+
+ if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs)
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ return ubi_eba_unmap_leb(ubi, vol, lnum);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_unmap);
+
+/**
+ * ubi_leb_map - map logical eraseblock to a physical eraseblock.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * This function maps an un-mapped logical eraseblock @lnum to a physical
+ * eraseblock. This means, that after a successful invocation of this
+ * function the logical eraseblock @lnum will be empty (contain only %0xFF
+ * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
+ * happens.
+ *
+ * This function returns zero in case of success, %-EBADF if the volume is
+ * damaged because of an interrupted update, %-EBADMSG if the logical
+ * eraseblock is already mapped, and other negative error codes in case of
+ * other failures.
+ */
+int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
+{
+ struct ubi_volume *vol = desc->vol;
+ struct ubi_device *ubi = vol->ubi;
+
+ dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
+
+ if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
+ return -EROFS;
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs)
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ if (vol->eba_tbl[lnum] >= 0)
+ return -EBADMSG;
+
+ return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
+}
+EXPORT_SYMBOL_GPL(ubi_leb_map);
+
+/**
+ * ubi_is_mapped - check if logical eraseblock is mapped.
+ * @desc: volume descriptor
+ * @lnum: logical eraseblock number
+ *
+ * This function checks if logical eraseblock @lnum is mapped to a physical
+ * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
+ * mean it will still be un-mapped after the UBI device is re-attached. The
+ * logical eraseblock may become mapped to the physical eraseblock it was last
+ * mapped to.
+ *
+ * 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_is_mapped(struct ubi_volume_desc *desc, int lnum)
+{
+ struct ubi_volume *vol = desc->vol;
+
+ dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
+
+ if (lnum < 0 || lnum >= vol->reserved_pebs)
+ return -EINVAL;
+
+ if (vol->upd_marker)
+ return -EBADF;
+
+ return vol->eba_tbl[lnum] >= 0;
+}
+EXPORT_SYMBOL_GPL(ubi_is_mapped);
+
+/**
+ * ubi_sync - synchronize UBI device buffers.
+ * @ubi_num: UBI device to synchronize
+ *
+ * The underlying MTD device may cache data in hardware or in software. This
+ * function ensures the caches are flushed. Returns zero in case of success and
+ * a negative error code in case of failure.
+ */
+int ubi_sync(int ubi_num)
+{
+ struct ubi_device *ubi;
+
+ ubi = ubi_get_device(ubi_num);
+ if (!ubi)
+ return -ENODEV;
+
+ mtd_sync(ubi->mtd);
+ ubi_put_device(ubi);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ubi_sync);
+
+/**
+ * ubi_flush - flush UBI work queue.
+ * @ubi_num: UBI device to flush work queue
+ * @vol_id: volume id to flush for
+ * @lnum: logical eraseblock number to flush for
+ *
+ * This function executes all pending works for a particular volume id / logical
+ * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
+ * a wildcard for all of the corresponding volume numbers or logical
+ * eraseblock numbers. It returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubi_flush(int ubi_num, int vol_id, int lnum)
+{
+ struct ubi_device *ubi;
+ int err = 0;
+
+ ubi = ubi_get_device(ubi_num);
+ if (!ubi)
+ return -ENODEV;
+
+ err = ubi_wl_flush(ubi, vol_id, lnum);
+ ubi_put_device(ubi);
+ return err;
+}
+EXPORT_SYMBOL_GPL(ubi_flush);
+
+BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
+
+/**
+ * ubi_register_volume_notifier - register a volume notifier.
+ * @nb: the notifier description object
+ * @ignore_existing: if non-zero, do not send "added" notification for all
+ * already existing volumes
+ *
+ * This function registers a volume notifier, which means that
+ * 'nb->notifier_call()' will be invoked when an UBI volume is created,
+ * removed, re-sized, re-named, or updated. The first argument of the function
+ * is the notification type. The second argument is pointer to a
+ * &struct ubi_notification object which describes the notification event.
+ * Using UBI API from the volume notifier is prohibited.
+ *
+ * This function returns zero in case of success and a negative error code
+ * in case of failure.
+ */
+int ubi_register_volume_notifier(struct notifier_block *nb,
+ int ignore_existing)
+{
+ int err;
+
+ err = blocking_notifier_chain_register(&ubi_notifiers, nb);
+ if (err != 0)
+ return err;
+ if (ignore_existing)
+ return 0;
+
+ /*
+ * We are going to walk all UBI devices and all volumes, and
+ * notify the user about existing volumes by the %UBI_VOLUME_ADDED
+ * event. We have to lock the @ubi_devices_mutex to make sure UBI
+ * devices do not disappear.
+ */
+ mutex_lock(&ubi_devices_mutex);
+ ubi_enumerate_volumes(nb);
+ mutex_unlock(&ubi_devices_mutex);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
+
+/**
+ * ubi_unregister_volume_notifier - unregister the volume notifier.
+ * @nb: the notifier description object
+ *
+ * This function unregisters volume notifier @nm and returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubi_unregister_volume_notifier(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
+}
+EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);