Linux内核同步机制之completion

最新推荐文章于 2024-04-06 18:03:48 发布

mishuang2017

最新推荐文章于 2024-04-06 18:03:48 发布

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https://blog.youkuaiyun.com/bullbat/article/details/7401688

#include <linux/module.h>
#include <linux/init.h>
 
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/completion.h>
 
MODULE_LICENSE("GPL");
 
static int complete_major=160;
DECLARE_COMPLETION(comp);
 
ssize_t complete_read(struct file *filp,char __user *buf,size_t count,loff_t *pos)
{
	printk(KERN_ERR "process %i (%s) going to sleep\n",current->pid,current->comm);
	wait_for_completion(&comp);
	printk(KERN_ERR "awoken %i (%s)\n",current->pid,current->comm);
	return 0;
}
 
ssize_t complete_write(struct file *filp,const char __user *buf,size_t count,loff_t *pos)
{
	printk(KERN_ERR "process %i (%s) awakening the readers...\n",current->pid,current->comm);
	complete(&comp);
	return count;
}
 
struct file_operations complete_fops={
	.owner=THIS_MODULE,
	.read=complete_read,
	.write=complete_write,
};
 
int complete_init(void)
{
	int result;
	result=register_chrdev(complete_major,"complete",&complete_fops);
	if(result<0)
		return result;
	if(complete_major==0)
		complete_major=result;
	return 0;
}
void complete_cleanup(void)
{
	unregister_chrdev(complete_major,"complete");
}
module_init(complete_init);
module_exit(complete_cleanup);