static ssize_t ac_write (struct file *, const char __user *, size_t, loff_t *);
static int ac_ioctl(struct inode *, struct file *, unsigned int,
unsigned long);
static ssize_t ac_write (struct file *, const char __user *, size_t, loff_t *);
static int ac_ioctl(struct inode *, struct file *, unsigned int,
unsigned long);