static int odev_open(struct inode *inode, struct file *file);
static int odev_release(struct inode *inode, struct file *file);
static ssize_t odev_read(struct file *file, char __user *buf, size_t count, loff_t *offset);
static ssize_t odev_write(struct file *file, const char __user *buf, size_t count, loff_t *offset);
static int odev_open(struct inode *inode, struct file *file);
static int odev_release(struct inode *inode, struct file *file);
static ssize_t odev_read(struct file *file, char __user *buf, size_t count, loff_t *offset);
static ssize_t odev_write(struct file *file, const char __user *buf, size_t count, loff_t *offset);