Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1108 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
new file mode 100644
index 000000000..f43430b9c
--- /dev/null
+++ b/drivers/mtd/ubi/cdev.c
@@ -0,0 +1,1108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file includes implementation of UBI character device operations.
+ *
+ * There are two kinds of character devices in UBI: 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.
+ *
+ * Well, there is the third kind of character devices - the UBI control
+ * character device, which allows to manipulate by UBI devices - create and
+ * delete them. In other words, it is used for attaching and detaching MTD
+ * devices.
+ */
+
+#include <linux/module.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/ioctl.h>
+#include <linux/capability.h>
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <linux/math64.h>
+#include <mtd/ubi-user.h>
+#include "ubi.h"
+
+/**
+ * get_exclusive - get exclusive access to an UBI volume.
+ * @desc: volume descriptor
+ *
+ * This function changes UBI volume open mode to "exclusive". Returns previous
+ * mode value (positive integer) in case of success and a negative error code
+ * in case of failure.
+ */
+static int get_exclusive(struct ubi_volume_desc *desc)
+{
+	int users, err;
+	struct ubi_volume *vol = desc->vol;
+
+	spin_lock(&vol->ubi->volumes_lock);
+	users = vol->readers + vol->writers + vol->exclusive + vol->metaonly;
+	ubi_assert(users > 0);
+	if (users > 1) {
+		ubi_err(vol->ubi, "%d users for volume %d", users, vol->vol_id);
+		err = -EBUSY;
+	} else {
+		vol->readers = vol->writers = vol->metaonly = 0;
+		vol->exclusive = 1;
+		err = desc->mode;
+		desc->mode = UBI_EXCLUSIVE;
+	}
+	spin_unlock(&vol->ubi->volumes_lock);
+
+	return err;
+}
+
+/**
+ * revoke_exclusive - revoke exclusive mode.
+ * @desc: volume descriptor
+ * @mode: new mode to switch to
+ */
+static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
+{
+	struct ubi_volume *vol = desc->vol;
+
+	spin_lock(&vol->ubi->volumes_lock);
+	ubi_assert(vol->readers == 0 && vol->writers == 0 && vol->metaonly == 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 if (mode == UBI_METAONLY)
+		vol->metaonly = 1;
+	else
+		vol->exclusive = 1;
+	spin_unlock(&vol->ubi->volumes_lock);
+
+	desc->mode = mode;
+}
+
+static int vol_cdev_open(struct inode *inode, struct file *file)
+{
+	struct ubi_volume_desc *desc;
+	int vol_id = iminor(inode) - 1, mode, ubi_num;
+
+	ubi_num = ubi_major2num(imajor(inode));
+	if (ubi_num < 0)
+		return ubi_num;
+
+	if (file->f_mode & FMODE_WRITE)
+		mode = UBI_READWRITE;
+	else
+		mode = UBI_READONLY;
+
+	dbg_gen("open device %d, volume %d, mode %d",
+		ubi_num, vol_id, mode);
+
+	desc = ubi_open_volume(ubi_num, vol_id, mode);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	file->private_data = desc;
+	return 0;
+}
+
+static int vol_cdev_release(struct inode *inode, struct file *file)
+{
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_volume *vol = desc->vol;
+
+	dbg_gen("release device %d, volume %d, mode %d",
+		vol->ubi->ubi_num, vol->vol_id, desc->mode);
+
+	if (vol->updating) {
+		ubi_warn(vol->ubi, "update of volume %d not finished, volume is damaged",
+			 vol->vol_id);
+		ubi_assert(!vol->changing_leb);
+		vol->updating = 0;
+		vfree(vol->upd_buf);
+	} else if (vol->changing_leb) {
+		dbg_gen("only %lld of %lld bytes received for atomic LEB change for volume %d:%d, cancel",
+			vol->upd_received, vol->upd_bytes, vol->ubi->ubi_num,
+			vol->vol_id);
+		vol->changing_leb = 0;
+		vfree(vol->upd_buf);
+	}
+
+	ubi_close_volume(desc);
+	return 0;
+}
+
+static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
+{
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_volume *vol = desc->vol;
+
+	if (vol->updating) {
+		/* Update is in progress, seeking is prohibited */
+		ubi_err(vol->ubi, "updating");
+		return -EBUSY;
+	}
+
+	return fixed_size_llseek(file, offset, origin, vol->used_bytes);
+}
+
+static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
+			  int datasync)
+{
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_device *ubi = desc->vol->ubi;
+	struct inode *inode = file_inode(file);
+	int err;
+	inode_lock(inode);
+	err = ubi_sync(ubi->ubi_num);
+	inode_unlock(inode);
+	return err;
+}
+
+
+static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
+			     loff_t *offp)
+{
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	int err, lnum, off, len,  tbuf_size;
+	size_t count_save = count;
+	void *tbuf;
+
+	dbg_gen("read %zd bytes from offset %lld of volume %d",
+		count, *offp, vol->vol_id);
+
+	if (vol->updating) {
+		ubi_err(vol->ubi, "updating");
+		return -EBUSY;
+	}
+	if (vol->upd_marker) {
+		ubi_err(vol->ubi, "damaged volume, update marker is set");
+		return -EBADF;
+	}
+	if (*offp == vol->used_bytes || count == 0)
+		return 0;
+
+	if (vol->corrupted)
+		dbg_gen("read from corrupted volume %d", vol->vol_id);
+
+	if (*offp + count > vol->used_bytes)
+		count_save = count = vol->used_bytes - *offp;
+
+	tbuf_size = vol->usable_leb_size;
+	if (count < tbuf_size)
+		tbuf_size = ALIGN(count, ubi->min_io_size);
+	tbuf = vmalloc(tbuf_size);
+	if (!tbuf)
+		return -ENOMEM;
+
+	len = count > tbuf_size ? tbuf_size : count;
+	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
+
+	do {
+		cond_resched();
+
+		if (off + len >= vol->usable_leb_size)
+			len = vol->usable_leb_size - off;
+
+		err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
+		if (err)
+			break;
+
+		off += len;
+		if (off == vol->usable_leb_size) {
+			lnum += 1;
+			off -= vol->usable_leb_size;
+		}
+
+		count -= len;
+		*offp += len;
+
+		err = copy_to_user(buf, tbuf, len);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		buf += len;
+		len = count > tbuf_size ? tbuf_size : count;
+	} while (count);
+
+	vfree(tbuf);
+	return err ? err : count_save - count;
+}
+
+/*
+ * This function allows to directly write to dynamic UBI volumes, without
+ * issuing the volume update operation.
+ */
+static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
+				     size_t count, loff_t *offp)
+{
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	int lnum, off, len, tbuf_size, err = 0;
+	size_t count_save = count;
+	char *tbuf;
+
+	if (!vol->direct_writes)
+		return -EPERM;
+
+	dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
+		count, *offp, vol->vol_id);
+
+	if (vol->vol_type == UBI_STATIC_VOLUME)
+		return -EROFS;
+
+	lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
+	if (off & (ubi->min_io_size - 1)) {
+		ubi_err(ubi, "unaligned position");
+		return -EINVAL;
+	}
+
+	if (*offp + count > vol->used_bytes)
+		count_save = count = vol->used_bytes - *offp;
+
+	/* We can write only in fractions of the minimum I/O unit */
+	if (count & (ubi->min_io_size - 1)) {
+		ubi_err(ubi, "unaligned write length");
+		return -EINVAL;
+	}
+
+	tbuf_size = vol->usable_leb_size;
+	if (count < tbuf_size)
+		tbuf_size = ALIGN(count, ubi->min_io_size);
+	tbuf = vmalloc(tbuf_size);
+	if (!tbuf)
+		return -ENOMEM;
+
+	len = count > tbuf_size ? tbuf_size : count;
+
+	while (count) {
+		cond_resched();
+
+		if (off + len >= vol->usable_leb_size)
+			len = vol->usable_leb_size - off;
+
+		err = copy_from_user(tbuf, buf, len);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
+		if (err)
+			break;
+
+		off += len;
+		if (off == vol->usable_leb_size) {
+			lnum += 1;
+			off -= vol->usable_leb_size;
+		}
+
+		count -= len;
+		*offp += len;
+		buf += len;
+		len = count > tbuf_size ? tbuf_size : count;
+	}
+
+	vfree(tbuf);
+	return err ? err : count_save - count;
+}
+
+static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
+			      size_t count, loff_t *offp)
+{
+	int err = 0;
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+
+	if (!vol->updating && !vol->changing_leb)
+		return vol_cdev_direct_write(file, buf, count, offp);
+
+	if (vol->updating)
+		err = ubi_more_update_data(ubi, vol, buf, count);
+	else
+		err = ubi_more_leb_change_data(ubi, vol, buf, count);
+
+	if (err < 0) {
+		ubi_err(ubi, "cannot accept more %zd bytes of data, error %d",
+			count, err);
+		return err;
+	}
+
+	if (err) {
+		/*
+		 * The operation is finished, @err contains number of actually
+		 * written bytes.
+		 */
+		count = err;
+
+		if (vol->changing_leb) {
+			revoke_exclusive(desc, UBI_READWRITE);
+			return count;
+		}
+
+		/*
+		 * We voluntarily do not take into account the skip_check flag
+		 * as we want to make sure what we wrote was correctly written.
+		 */
+		err = ubi_check_volume(ubi, vol->vol_id);
+		if (err < 0)
+			return err;
+
+		if (err) {
+			ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
+				 vol->vol_id, ubi->ubi_num);
+			vol->corrupted = 1;
+		}
+		vol->checked = 1;
+		ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
+		revoke_exclusive(desc, UBI_READWRITE);
+	}
+
+	return count;
+}
+
+static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+	int err = 0;
+	struct ubi_volume_desc *desc = file->private_data;
+	struct ubi_volume *vol = desc->vol;
+	struct ubi_device *ubi = vol->ubi;
+	void __user *argp = (void __user *)arg;
+
+	switch (cmd) {
+	/* Volume update command */
+	case UBI_IOCVOLUP:
+	{
+		int64_t bytes, rsvd_bytes;
+
+		if (!capable(CAP_SYS_RESOURCE)) {
+			err = -EPERM;
+			break;
+		}
+
+		err = copy_from_user(&bytes, argp, sizeof(int64_t));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		if (desc->mode == UBI_READONLY) {
+			err = -EROFS;
+			break;
+		}
+
+		rsvd_bytes = (long long)vol->reserved_pebs *
+					vol->usable_leb_size;
+		if (bytes < 0 || bytes > rsvd_bytes) {
+			err = -EINVAL;
+			break;
+		}
+
+		err = get_exclusive(desc);
+		if (err < 0)
+			break;
+
+		err = ubi_start_update(ubi, vol, bytes);
+		if (bytes == 0) {
+			ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
+			revoke_exclusive(desc, UBI_READWRITE);
+		}
+		break;
+	}
+
+	/* Atomic logical eraseblock change command */
+	case UBI_IOCEBCH:
+	{
+		struct ubi_leb_change_req req;
+
+		err = copy_from_user(&req, argp,
+				     sizeof(struct ubi_leb_change_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		if (desc->mode == UBI_READONLY ||
+		    vol->vol_type == UBI_STATIC_VOLUME) {
+			err = -EROFS;
+			break;
+		}
+
+		/* Validate the request */
+		err = -EINVAL;
+		if (!ubi_leb_valid(vol, req.lnum) ||
+		    req.bytes < 0 || req.bytes > vol->usable_leb_size)
+			break;
+
+		err = get_exclusive(desc);
+		if (err < 0)
+			break;
+
+		err = ubi_start_leb_change(ubi, vol, &req);
+		if (req.bytes == 0)
+			revoke_exclusive(desc, UBI_READWRITE);
+		break;
+	}
+
+	/* Logical eraseblock erasure command */
+	case UBI_IOCEBER:
+	{
+		int32_t lnum;
+
+		err = get_user(lnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		if (desc->mode == UBI_READONLY ||
+		    vol->vol_type == UBI_STATIC_VOLUME) {
+			err = -EROFS;
+			break;
+		}
+
+		if (!ubi_leb_valid(vol, lnum)) {
+			err = -EINVAL;
+			break;
+		}
+
+		dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
+		err = ubi_eba_unmap_leb(ubi, vol, lnum);
+		if (err)
+			break;
+
+		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
+		break;
+	}
+
+	/* Logical eraseblock map command */
+	case UBI_IOCEBMAP:
+	{
+		struct ubi_map_req req;
+
+		err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		err = ubi_leb_map(desc, req.lnum);
+		break;
+	}
+
+	/* Logical eraseblock un-map command */
+	case UBI_IOCEBUNMAP:
+	{
+		int32_t lnum;
+
+		err = get_user(lnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		err = ubi_leb_unmap(desc, lnum);
+		break;
+	}
+
+	/* Check if logical eraseblock is mapped command */
+	case UBI_IOCEBISMAP:
+	{
+		int32_t lnum;
+
+		err = get_user(lnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		err = ubi_is_mapped(desc, lnum);
+		break;
+	}
+
+	/* Set volume property command */
+	case UBI_IOCSETVOLPROP:
+	{
+		struct ubi_set_vol_prop_req req;
+
+		err = copy_from_user(&req, argp,
+				     sizeof(struct ubi_set_vol_prop_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+		switch (req.property) {
+		case UBI_VOL_PROP_DIRECT_WRITE:
+			mutex_lock(&ubi->device_mutex);
+			desc->vol->direct_writes = !!req.value;
+			mutex_unlock(&ubi->device_mutex);
+			break;
+		default:
+			err = -EINVAL;
+			break;
+		}
+		break;
+	}
+
+	/* Create a R/O block device on top of the UBI volume */
+	case UBI_IOCVOLCRBLK:
+	{
+		struct ubi_volume_info vi;
+
+		ubi_get_volume_info(desc, &vi);
+		err = ubiblock_create(&vi);
+		break;
+	}
+
+	/* Remove the R/O block device */
+	case UBI_IOCVOLRMBLK:
+	{
+		struct ubi_volume_info vi;
+
+		ubi_get_volume_info(desc, &vi);
+		err = ubiblock_remove(&vi);
+		break;
+	}
+
+	default:
+		err = -ENOTTY;
+		break;
+	}
+	return err;
+}
+
+/**
+ * verify_mkvol_req - verify volume creation request.
+ * @ubi: UBI device description object
+ * @req: the request to check
+ *
+ * This function zero if the request is correct, and %-EINVAL if not.
+ */
+static int verify_mkvol_req(const struct ubi_device *ubi,
+			    const struct ubi_mkvol_req *req)
+{
+	int n, err = -EINVAL;
+
+	if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
+	    req->name_len < 0)
+		goto bad;
+
+	if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
+	    req->vol_id != UBI_VOL_NUM_AUTO)
+		goto bad;
+
+	if (req->alignment == 0)
+		goto bad;
+
+	if (req->bytes == 0)
+		goto bad;
+
+	if (req->vol_type != UBI_DYNAMIC_VOLUME &&
+	    req->vol_type != UBI_STATIC_VOLUME)
+		goto bad;
+
+	if (req->flags & ~UBI_VOL_VALID_FLGS)
+		goto bad;
+
+	if (req->flags & UBI_VOL_SKIP_CRC_CHECK_FLG &&
+	    req->vol_type != UBI_STATIC_VOLUME)
+		goto bad;
+
+	if (req->alignment > ubi->leb_size)
+		goto bad;
+
+	n = req->alignment & (ubi->min_io_size - 1);
+	if (req->alignment != 1 && n)
+		goto bad;
+
+	if (!req->name[0] || !req->name_len)
+		goto bad;
+
+	if (req->name_len > UBI_VOL_NAME_MAX) {
+		err = -ENAMETOOLONG;
+		goto bad;
+	}
+
+	n = strnlen(req->name, req->name_len + 1);
+	if (n != req->name_len)
+		goto bad;
+
+	return 0;
+
+bad:
+	ubi_err(ubi, "bad volume creation request");
+	ubi_dump_mkvol_req(req);
+	return err;
+}
+
+/**
+ * verify_rsvol_req - verify volume re-size request.
+ * @ubi: UBI device description object
+ * @req: the request to check
+ *
+ * This function returns zero if the request is correct, and %-EINVAL if not.
+ */
+static int verify_rsvol_req(const struct ubi_device *ubi,
+			    const struct ubi_rsvol_req *req)
+{
+	if (req->bytes <= 0)
+		return -EINVAL;
+
+	if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
+		return -EINVAL;
+
+	return 0;
+}
+
+/**
+ * rename_volumes - rename UBI volumes.
+ * @ubi: UBI device description object
+ * @req: volumes re-name request
+ *
+ * This is a helper function for the volume re-name IOCTL which validates the
+ * request, opens the volume and calls corresponding volumes management
+ * function. Returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+static int rename_volumes(struct ubi_device *ubi,
+			  struct ubi_rnvol_req *req)
+{
+	int i, n, err;
+	struct list_head rename_list;
+	struct ubi_rename_entry *re, *re1;
+
+	if (req->count < 0 || req->count > UBI_MAX_RNVOL)
+		return -EINVAL;
+
+	if (req->count == 0)
+		return 0;
+
+	/* Validate volume IDs and names in the request */
+	for (i = 0; i < req->count; i++) {
+		if (req->ents[i].vol_id < 0 ||
+		    req->ents[i].vol_id >= ubi->vtbl_slots)
+			return -EINVAL;
+		if (req->ents[i].name_len < 0)
+			return -EINVAL;
+		if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
+			return -ENAMETOOLONG;
+		req->ents[i].name[req->ents[i].name_len] = '\0';
+		n = strlen(req->ents[i].name);
+		if (n != req->ents[i].name_len)
+			return -EINVAL;
+	}
+
+	/* Make sure volume IDs and names are unique */
+	for (i = 0; i < req->count - 1; i++) {
+		for (n = i + 1; n < req->count; n++) {
+			if (req->ents[i].vol_id == req->ents[n].vol_id) {
+				ubi_err(ubi, "duplicated volume id %d",
+					req->ents[i].vol_id);
+				return -EINVAL;
+			}
+			if (!strcmp(req->ents[i].name, req->ents[n].name)) {
+				ubi_err(ubi, "duplicated volume name \"%s\"",
+					req->ents[i].name);
+				return -EINVAL;
+			}
+		}
+	}
+
+	/* Create the re-name list */
+	INIT_LIST_HEAD(&rename_list);
+	for (i = 0; i < req->count; i++) {
+		int vol_id = req->ents[i].vol_id;
+		int name_len = req->ents[i].name_len;
+		const char *name = req->ents[i].name;
+
+		re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
+		if (!re) {
+			err = -ENOMEM;
+			goto out_free;
+		}
+
+		re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_METAONLY);
+		if (IS_ERR(re->desc)) {
+			err = PTR_ERR(re->desc);
+			ubi_err(ubi, "cannot open volume %d, error %d",
+				vol_id, err);
+			kfree(re);
+			goto out_free;
+		}
+
+		/* Skip this re-naming if the name does not really change */
+		if (re->desc->vol->name_len == name_len &&
+		    !memcmp(re->desc->vol->name, name, name_len)) {
+			ubi_close_volume(re->desc);
+			kfree(re);
+			continue;
+		}
+
+		re->new_name_len = name_len;
+		memcpy(re->new_name, name, name_len);
+		list_add_tail(&re->list, &rename_list);
+		dbg_gen("will rename volume %d from \"%s\" to \"%s\"",
+			vol_id, re->desc->vol->name, name);
+	}
+
+	if (list_empty(&rename_list))
+		return 0;
+
+	/* Find out the volumes which have to be removed */
+	list_for_each_entry(re, &rename_list, list) {
+		struct ubi_volume_desc *desc;
+		int no_remove_needed = 0;
+
+		/*
+		 * Volume @re->vol_id is going to be re-named to
+		 * @re->new_name, while its current name is @name. If a volume
+		 * with name @re->new_name currently exists, it has to be
+		 * removed, unless it is also re-named in the request (@req).
+		 */
+		list_for_each_entry(re1, &rename_list, list) {
+			if (re->new_name_len == re1->desc->vol->name_len &&
+			    !memcmp(re->new_name, re1->desc->vol->name,
+				    re1->desc->vol->name_len)) {
+				no_remove_needed = 1;
+				break;
+			}
+		}
+
+		if (no_remove_needed)
+			continue;
+
+		/*
+		 * It seems we need to remove volume with name @re->new_name,
+		 * if it exists.
+		 */
+		desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
+					  UBI_EXCLUSIVE);
+		if (IS_ERR(desc)) {
+			err = PTR_ERR(desc);
+			if (err == -ENODEV)
+				/* Re-naming into a non-existing volume name */
+				continue;
+
+			/* The volume exists but busy, or an error occurred */
+			ubi_err(ubi, "cannot open volume \"%s\", error %d",
+				re->new_name, err);
+			goto out_free;
+		}
+
+		re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
+		if (!re1) {
+			err = -ENOMEM;
+			ubi_close_volume(desc);
+			goto out_free;
+		}
+
+		re1->remove = 1;
+		re1->desc = desc;
+		list_add(&re1->list, &rename_list);
+		dbg_gen("will remove volume %d, name \"%s\"",
+			re1->desc->vol->vol_id, re1->desc->vol->name);
+	}
+
+	mutex_lock(&ubi->device_mutex);
+	err = ubi_rename_volumes(ubi, &rename_list);
+	mutex_unlock(&ubi->device_mutex);
+
+out_free:
+	list_for_each_entry_safe(re, re1, &rename_list, list) {
+		ubi_close_volume(re->desc);
+		list_del(&re->list);
+		kfree(re);
+	}
+	return err;
+}
+
+static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+	int err = 0;
+	struct ubi_device *ubi;
+	struct ubi_volume_desc *desc;
+	void __user *argp = (void __user *)arg;
+
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	ubi = ubi_get_by_major(imajor(file->f_mapping->host));
+	if (!ubi)
+		return -ENODEV;
+
+	switch (cmd) {
+	/* Create volume command */
+	case UBI_IOCMKVOL:
+	{
+		struct ubi_mkvol_req req;
+
+		dbg_gen("create volume");
+		err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		err = verify_mkvol_req(ubi, &req);
+		if (err)
+			break;
+
+		mutex_lock(&ubi->device_mutex);
+		err = ubi_create_volume(ubi, &req);
+		mutex_unlock(&ubi->device_mutex);
+		if (err)
+			break;
+
+		err = put_user(req.vol_id, (__user int32_t *)argp);
+		if (err)
+			err = -EFAULT;
+
+		break;
+	}
+
+	/* Remove volume command */
+	case UBI_IOCRMVOL:
+	{
+		int vol_id;
+
+		dbg_gen("remove volume");
+		err = get_user(vol_id, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
+		if (IS_ERR(desc)) {
+			err = PTR_ERR(desc);
+			break;
+		}
+
+		mutex_lock(&ubi->device_mutex);
+		err = ubi_remove_volume(desc, 0);
+		mutex_unlock(&ubi->device_mutex);
+
+		/*
+		 * The volume is deleted (unless an error occurred), and the
+		 * 'struct ubi_volume' object will be freed when
+		 * 'ubi_close_volume()' will call 'put_device()'.
+		 */
+		ubi_close_volume(desc);
+		break;
+	}
+
+	/* Re-size volume command */
+	case UBI_IOCRSVOL:
+	{
+		int pebs;
+		struct ubi_rsvol_req req;
+
+		dbg_gen("re-size volume");
+		err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		err = verify_rsvol_req(ubi, &req);
+		if (err)
+			break;
+
+		desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
+		if (IS_ERR(desc)) {
+			err = PTR_ERR(desc);
+			break;
+		}
+
+		pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
+			       desc->vol->usable_leb_size);
+
+		mutex_lock(&ubi->device_mutex);
+		err = ubi_resize_volume(desc, pebs);
+		mutex_unlock(&ubi->device_mutex);
+		ubi_close_volume(desc);
+		break;
+	}
+
+	/* Re-name volumes command */
+	case UBI_IOCRNVOL:
+	{
+		struct ubi_rnvol_req *req;
+
+		dbg_gen("re-name volumes");
+		req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
+		if (!req) {
+			err = -ENOMEM;
+			break;
+		}
+
+		err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
+		if (err) {
+			err = -EFAULT;
+			kfree(req);
+			break;
+		}
+
+		err = rename_volumes(ubi, req);
+		kfree(req);
+		break;
+	}
+
+	/* Check a specific PEB for bitflips and scrub it if needed */
+	case UBI_IOCRPEB:
+	{
+		int pnum;
+
+		err = get_user(pnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		err = ubi_bitflip_check(ubi, pnum, 0);
+		break;
+	}
+
+	/* Force scrubbing for a specific PEB */
+	case UBI_IOCSPEB:
+	{
+		int pnum;
+
+		err = get_user(pnum, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		err = ubi_bitflip_check(ubi, pnum, 1);
+		break;
+	}
+
+	default:
+		err = -ENOTTY;
+		break;
+	}
+
+	ubi_put_device(ubi);
+	return err;
+}
+
+static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	int err = 0;
+	void __user *argp = (void __user *)arg;
+
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+
+	switch (cmd) {
+	/* Attach an MTD device command */
+	case UBI_IOCATT:
+	{
+		struct ubi_attach_req req;
+		struct mtd_info *mtd;
+
+		dbg_gen("attach MTD device");
+		err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		if (req.mtd_num < 0 ||
+		    (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
+			err = -EINVAL;
+			break;
+		}
+
+		mtd = get_mtd_device(NULL, req.mtd_num);
+		if (IS_ERR(mtd)) {
+			err = PTR_ERR(mtd);
+			break;
+		}
+
+		/*
+		 * Note, further request verification is done by
+		 * 'ubi_attach_mtd_dev()'.
+		 */
+		mutex_lock(&ubi_devices_mutex);
+		err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
+					 req.max_beb_per1024, !!req.disable_fm);
+		mutex_unlock(&ubi_devices_mutex);
+		if (err < 0)
+			put_mtd_device(mtd);
+		else
+			/* @err contains UBI device number */
+			err = put_user(err, (__user int32_t *)argp);
+
+		break;
+	}
+
+	/* Detach an MTD device command */
+	case UBI_IOCDET:
+	{
+		int ubi_num;
+
+		dbg_gen("detach MTD device");
+		err = get_user(ubi_num, (__user int32_t *)argp);
+		if (err) {
+			err = -EFAULT;
+			break;
+		}
+
+		mutex_lock(&ubi_devices_mutex);
+		err = ubi_detach_mtd_dev(ubi_num, 0);
+		mutex_unlock(&ubi_devices_mutex);
+		break;
+	}
+
+	default:
+		err = -ENOTTY;
+		break;
+	}
+
+	return err;
+}
+
+/* UBI volume character device operations */
+const struct file_operations ubi_vol_cdev_operations = {
+	.owner          = THIS_MODULE,
+	.open           = vol_cdev_open,
+	.release        = vol_cdev_release,
+	.llseek         = vol_cdev_llseek,
+	.read           = vol_cdev_read,
+	.write          = vol_cdev_write,
+	.fsync		= vol_cdev_fsync,
+	.unlocked_ioctl = vol_cdev_ioctl,
+	.compat_ioctl   = compat_ptr_ioctl,
+};
+
+/* UBI character device operations */
+const struct file_operations ubi_cdev_operations = {
+	.owner          = THIS_MODULE,
+	.llseek         = no_llseek,
+	.unlocked_ioctl = ubi_cdev_ioctl,
+	.compat_ioctl   = compat_ptr_ioctl,
+};
+
+/* UBI control character device operations */
+const struct file_operations ubi_ctrl_cdev_operations = {
+	.owner          = THIS_MODULE,
+	.unlocked_ioctl = ctrl_cdev_ioctl,
+	.compat_ioctl   = compat_ptr_ioctl,
+	.llseek		= no_llseek,
+};