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]