第一个代码

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>

static unsigned int hello_major;

static int hello_open (struct inode *inode, struct file *file)
{

 return 0;
}
static ssize_t hello_read (struct file *file, char __user *buf, size_t count, loff_t *opps)
{

 return 0;
}
static ssize_t hello_write (struct file *file, const char __user *buf, size_t count, loff_t *opps)
{

 return 0;
}

struct file_operations hello_fops{
 .owner  = THIS_MODULE,
 .open  = hello_open,
 .write  = hello_write,
 .read  = hello_read,

};

static int __init hello_init(void)
{
 hello_major=register_chrdev(0, "hello", &hello_fops);
 return 0;
}

static void __exit hello_exit(void)
{

 unregister_chrdev(hello_major, "hello");
}

module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");