高手进阶 Linux系统中内核定时器的应用

[CODE]#include<linux/init.h>#include<linux/sched.h>#include<linux/module.h>#include<linux/jiffies.h>#include<asm/io.h>#include<linux/timer.h>#include<linux/wait.h>MODULE_LICENSE("GPL");static DECLARE_WAIT_QUEUE_HEAD(wq);static int flag = 0;struct timer_list my_timer;void timer_test(unsigned long data){        printk("this is a test/n");        flag = 1;        wake_up_interruptible(&wq);}static int __init hello_init(void){        init_timer(&my_timer);        my_timer.expires = jiffies + 5000;        my_timer.data = 0;        my_timer.function = timer_test;        add_timer(&my_timer);        wait_event_interruptible(wq, flag != 0);        flag = 0;        return 0;}static void __exit hello_exit(void){        del_timer(&my_timer);        printk(KERN_ALERT "Goodbye/n");}module_init(hello_init);module_exit(hello_exit);[/CODE]