linux自旋锁
#include<linux/sched.h>
#include<linux/kthread.h>
#include<linux/module.h>
#include<linux/delay.h>
static int i=0,j=100;
struct task_struct *MyThread1=NULL;
struct task_struct *MyThread2=NULL;
static int myVar = 0;
static int count = 0;
spinlock_t lock;
static void setMyVar(int input)
{
spin_lock(&lock);
if(count)
{
printk("busy setMyVar\n");
}
count++;
myVar = input;
printk("setMyVar is %d\n",myVar);
spin_unlock(&lock);
count--;
}
static int getMyVar(void)
{
int res = 0 ;
spin_lock(&lock);
if(count)
{
printk("busy setMyVar\n");
}
count++;
res = myVar;
printk("getMyVar is %d\n",res);
spin_unlock(&lock);
count--;
return 0;
}
static int print1(void *data)
{
while(!kthread_should_stop())
{
printk("this is thread1......\n");
getMyVar();
setMyVar(i);
ssleep(1);
i++;
}
return 0;
}
static int print2(void *data)
{
while(!kthread_should_stop())
{
printk("this is thread2......\n");
getMyVar();
setMyVar(j);
ssleep(1);
j++;
}
return 0;
}
static int __init hello_init(void){
spin_lock_init(&lock);
MyThread1 = kthread_run(print1,NULL,"mythread1");
MyThread2 = kthread_run(print2,NULL,"mythread2");
return 0;
}
static void __exit
hello_exit(void){
if(MyThread1)
{
printk("kthread1 stop....\n");
kthread_stop(MyThread1);
MyThread1=NULL;
}
if(MyThread2)
{
printk("kthread2 stop....\n");
kthread_stop(MyThread2);
MyThread2=NULL;
}
}
module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Valerie Henson [email protected]");
MODULE_DESCRIPTION("\"Hello, world!\" minimal module");
MODULE_VERSION("printk");
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