size_t nbytes, loff_t * ppos);
static unsigned int dtlk_poll(struct file *, poll_table *);
static int dtlk_open(struct inode *, struct file *);
size_t nbytes, loff_t * ppos);
static unsigned int dtlk_poll(struct file *, poll_table *);
static int dtlk_open(struct inode *, struct file *);