1 files changed, 722 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
new file mode 100644
index 000000000000..6612eb79bf17
--- /dev/null
+++ b/drivers/mtd/ubi/cdev.c
@@ -0,0 +1,722 @@
+/*
+ * 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 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.
+ */
+
+#include <linux/module.h>
+#include <linux/stat.h>
+#include <linux/ioctl.h>
+#include <linux/capability.h>
+#include <mtd/ubi-user.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+#include "ubi.h"
+
+/*
+ * Maximum sequence numbers of UBI and volume character device IOCTLs (direct
+ * logical eraseblock erase is a debug-only feature).
+ */
+#define UBI_CDEV_IOC_MAX_SEQ 2
+#ifndef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
+#define VOL_CDEV_IOC_MAX_SEQ 1
+#else
+#define VOL_CDEV_IOC_MAX_SEQ 2
+#endif
+
+/**
+ * major_to_device - get UBI device object by character device major number.
+ * @major: major number
+ *
+ * This function returns a pointer to the UBI device object.
+ */
+static struct ubi_device *major_to_device(int major)
+{
+        int i;
+
+        for (i = 0; i < ubi_devices_cnt; i++)
+                if (ubi_devices[i] && ubi_devices[i]->major == major)
+                        return ubi_devices[i];
+        BUG();
+}
+
+/**
+ * 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;
+        ubi_assert(users > 0);
+        if (users > 1) {
+                dbg_err("%d users for volume %d", users, vol->vol_id);
+                err = -EBUSY;
+        } else {
+                vol->readers = vol->writers = 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);
+        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->ubi->volumes_lock);
+
+        desc->mode = mode;
+}
+
+static int vol_cdev_open(struct inode *inode, struct file *file)
+{
+        struct ubi_volume_desc *desc;
+        const struct ubi_device *ubi = major_to_device(imajor(inode));
+        int vol_id = iminor(inode) - 1;
+        int mode;
+
+        if (file->f_mode & FMODE_WRITE)
+                mode = UBI_READWRITE;
+        else
+                mode = UBI_READONLY;
+
+        dbg_msg("open volume %d, mode %d", vol_id, mode);
+
+        desc = ubi_open_volume(ubi->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_msg("release volume %d, mode %d", vol->vol_id, desc->mode);
+
+        if (vol->updating) {
+                ubi_warn("update of volume %d not finished, volume is damaged",
+                         vol->vol_id);
+                vol->updating = 0;
+                kfree(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;
+        loff_t new_offset;
+
+        if (vol->updating) {
+                 /* Update is in progress, seeking is prohibited */
+                dbg_err("updating");
+                return -EBUSY;
+        }
+
+        switch (origin) {
+        case 0: /* SEEK_SET */
+                new_offset = offset;
+                break;
+        case 1: /* SEEK_CUR */
+                new_offset = file->f_pos + offset;
+                break;
+        case 2: /* SEEK_END */
+                new_offset = vol->used_bytes + offset;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        if (new_offset < 0 || new_offset > vol->used_bytes) {
+                dbg_err("bad seek %lld", new_offset);
+                return -EINVAL;
+        }
+
+        dbg_msg("seek volume %d, offset %lld, origin %d, new offset %lld",
+                vol->vol_id, offset, origin, new_offset);
+
+        file->f_pos = new_offset;
+        return new_offset;
+}
+
+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,  vol_id = desc->vol->vol_id, tbuf_size;
+        size_t count_save = count;
+        void *tbuf;
+        uint64_t tmp;
+
+        dbg_msg("read %zd bytes from offset %lld of volume %d",
+                count, *offp, vol_id);
+
+        if (vol->updating) {
+                dbg_err("updating");
+                return -EBUSY;
+        }
+        if (vol->upd_marker) {
+                dbg_err("damaged volume, update marker is set");
+                return -EBADF;
+        }
+        if (*offp == vol->used_bytes || count == 0)
+                return 0;
+
+        if (vol->corrupted)
+                dbg_msg("read from corrupted volume %d", 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 = kmalloc(tbuf_size, GFP_KERNEL);
+        if (!tbuf)
+                return -ENOMEM;
+
+        len = count > tbuf_size ? tbuf_size : count;
+
+        tmp = *offp;
+        off = do_div(tmp, vol->usable_leb_size);
+        lnum = tmp;
+
+        do {
+                cond_resched();
+
+                if (off + len >= vol->usable_leb_size)
+                        len = vol->usable_leb_size - off;
+
+                err = ubi_eba_read_leb(ubi, vol_id, 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);
+
+        kfree(tbuf);
+        return err ? err : count_save - count;
+}
+
+#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
+
+/*
+ * This function allows to directly write to dynamic UBI volumes, without
+ * issuing the volume update operation. Available only as a debugging feature.
+ * Very useful for testing UBI.
+ */
+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, vol_id = vol->vol_id, err = 0;
+        size_t count_save = count;
+        char *tbuf;
+        uint64_t tmp;
+
+        dbg_msg("requested: write %zd bytes to offset %lld of volume %u",
+                count, *offp, desc->vol->vol_id);
+
+        if (vol->vol_type == UBI_STATIC_VOLUME)
+                return -EROFS;
+
+        tmp = *offp;
+        off = do_div(tmp, vol->usable_leb_size);
+        lnum = tmp;
+
+        if (off % ubi->min_io_size) {
+                dbg_err("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) {
+                dbg_err("unaligned write length");
+                return -EINVAL;
+        }
+
+        tbuf_size = vol->usable_leb_size;
+        if (count < tbuf_size)
+                tbuf_size = ALIGN(count, ubi->min_io_size);
+        tbuf = kmalloc(tbuf_size, GFP_KERNEL);
+        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_id, lnum, tbuf, off, len,
+                                        UBI_UNKNOWN);
+                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;
+        }
+
+        kfree(tbuf);
+        return err ? err : count_save - count;
+}
+
+#else
+#define vol_cdev_direct_write(file, buf, count, offp) -EPERM
+#endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */
+
+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)
+                return vol_cdev_direct_write(file, buf, count, offp);
+
+        err = ubi_more_update_data(ubi, vol->vol_id, buf, count);
+        if (err < 0) {
+                ubi_err("cannot write %zd bytes of update data", count);
+                return err;
+        }
+
+        if (err) {
+                /*
+                 * Update is finished, @err contains number of actually written
+                 * bytes now.
+                 */
+                count = err;
+
+                err = ubi_check_volume(ubi, vol->vol_id);
+                if (err < 0)
+                        return err;
+
+                if (err) {
+                        ubi_warn("volume %d on UBI device %d is corrupted",
+                                 vol->vol_id, ubi->ubi_num);
+                        vol->corrupted = 1;
+                }
+                vol->checked = 1;
+                revoke_exclusive(desc, UBI_READWRITE);
+        }
+
+        *offp += count;
+        return count;
+}
+
+static int vol_cdev_ioctl(struct inode *inode, 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;
+
+        if (_IOC_NR(cmd) > VOL_CDEV_IOC_MAX_SEQ ||
+            _IOC_TYPE(cmd) != UBI_VOL_IOC_MAGIC)
+                return -ENOTTY;
+
+        if (_IOC_DIR(cmd) && _IOC_READ)
+                err = !access_ok(VERIFY_WRITE, argp, _IOC_SIZE(cmd));
+        else if (_IOC_DIR(cmd) && _IOC_WRITE)
+                err = !access_ok(VERIFY_READ, argp, _IOC_SIZE(cmd));
+        if (err)
+                return -EFAULT;
+
+        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 = vol->reserved_pebs * (ubi->leb_size-vol->data_pad);
+                if (bytes < 0 || bytes > rsvd_bytes) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                err = get_exclusive(desc);
+                if (err < 0)
+                        break;
+
+                err = ubi_start_update(ubi, vol->vol_id, bytes);
+                if (bytes == 0)
+                        revoke_exclusive(desc, UBI_READWRITE);
+
+                file->f_pos = 0;
+                break;
+        }
+
+#ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
+        /* 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) {
+                        err = -EROFS;
+                        break;
+                }
+
+                if (lnum < 0 || lnum >= vol->reserved_pebs) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                if (vol->vol_type != UBI_DYNAMIC_VOLUME) {
+                        err = -EROFS;
+                        break;
+                }
+
+                dbg_msg("erase LEB %d:%d", vol->vol_id, lnum);
+                err = ubi_eba_unmap_leb(ubi, vol->vol_id, lnum);
+                if (err)
+                        break;
+
+                err = ubi_wl_flush(ubi);
+                break;
+        }
+#endif
+
+        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->alignment > ubi->leb_size)
+                goto bad;
+
+        n = req->alignment % ubi->min_io_size;
+        if (req->alignment != 1 && n)
+                goto bad;
+
+        if (req->name_len > UBI_VOL_NAME_MAX) {
+                err = -ENAMETOOLONG;
+                goto bad;
+        }
+
+        return 0;
+
+bad:
+        dbg_err("bad volume creation request");
+        ubi_dbg_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;
+}
+
+static int ubi_cdev_ioctl(struct inode *inode, 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 (_IOC_NR(cmd) > UBI_CDEV_IOC_MAX_SEQ ||
+            _IOC_TYPE(cmd) != UBI_IOC_MAGIC)
+                return -ENOTTY;
+
+        if (_IOC_DIR(cmd) && _IOC_READ)
+                err = !access_ok(VERIFY_WRITE, argp, _IOC_SIZE(cmd));
+        else if (_IOC_DIR(cmd) && _IOC_WRITE)
+                err = !access_ok(VERIFY_READ, argp, _IOC_SIZE(cmd));
+        if (err)
+                return -EFAULT;
+
+        if (!capable(CAP_SYS_RESOURCE))
+                return -EPERM;
+
+        ubi = major_to_device(imajor(inode));
+        if (IS_ERR(ubi))
+                return PTR_ERR(ubi);
+
+        switch (cmd) {
+        /* Create volume command */
+        case UBI_IOCMKVOL:
+        {
+                struct ubi_mkvol_req req;
+
+                dbg_msg("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;
+
+                req.name[req.name_len] = '\0';
+
+                err = ubi_create_volume(ubi, &req);
+                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_msg("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;
+                }
+
+                err = ubi_remove_volume(desc);
+                if (err)
+                        ubi_close_volume(desc);
+
+                break;
+        }
+
+        /* Re-size volume command */
+        case UBI_IOCRSVOL:
+        {
+                int pebs;
+                uint64_t tmp;
+                struct ubi_rsvol_req req;
+
+                dbg_msg("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;
+                }
+
+                tmp = req.bytes;
+                pebs = !!do_div(tmp, desc->vol->usable_leb_size);
+                pebs += tmp;
+
+                err = ubi_resize_volume(desc, pebs);
+                ubi_close_volume(desc);
+                break;
+        }
+
+        default:
+                err = -ENOTTY;
+                break;
+        }
+
+        return err;
+}
+
+/* UBI character device operations */
+struct file_operations ubi_cdev_operations = {
+        .owner = THIS_MODULE,
+        .ioctl = ubi_cdev_ioctl,
+        .llseek = no_llseek
+};
+
+/* UBI volume character device operations */
+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,
+        .ioctl   = vol_cdev_ioctl
+};