linux 内核线程，信号量，链表实现算法

下面是一个内核模块多线程的例子，不过这个模块执行的时候你卸载不了

#include
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#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define DEBUG
#ifdef DEBUG
#define DBG(x...)       printk(x)
#else
#define DBG(x...)
#endif

typedef struct kbuff_list        
{
        char buff_node[20];  
        int flag;
        struct  kbuff_list *next;
}KBUFF;
KBUFF *pread_kbuff,*pirq__kbuff;
unsigned long list_cnt;
static struct task_struct *ret;
struct semaphore sem;

static void readThread(void){
        KBUFF *p1;
        while(1){
                down(&sem);
                if(pread_kbuff !=NULL){
                        p1=pread_kbuff;
                        DBG("the pread_kbuff->buff_node is %s,flag is %d\n",pread_kbuff->buff_node,pread_kbuff->flag);
                        pread_kbuff=pread_kbuff->next;

                        kfree(p1);
                }
        }
//      DBG("the  %s is end\n",__FUNCTION__);

}

static void  init_kbuff_list(void){
        list_cnt=0;
        pread_kbuff=pirq__kbuff=NULL;
        sema_init(&sem, 0);
}

static void __init init_funct(void)
{
        KBUFF *p1,*p2;
        char kbuffer[20]="zhangfei is best";

        init_kbuff_list();
        ret = kthread_run(readThread, NULL, "thread_func2"); 
        if (!IS_ERR(ret)) 
        { 
                printk("kthread_create done\n"); 
        } 
        else 
        { 
                printk("kthread_create error\n"); 
        } 
        list_cnt++;
        while(1){
                p2=p1=(KBUFF *)kmalloc(sizeof(KBUFF),GFP_KERNEL);
                strcpy(p1->buff_node,kbuffer);
                p1->flag=list_cnt;
                if(list_cnt==1 || pread_kbuff == NULL){
                        pirq__kbuff=pread_kbuff=p1;
                        printk("the code get %ldth here\n",list_cnt);
                }
                else
                        pirq__kbuff->next=p1;
                p1->next=NULL;
                pirq__kbuff=p1;
                up(&sem);
                list_cnt++;
                if(list_cnt==65536)
                        list_cnt=2;
                DBG("this is the %s-> %d.the flag is %ld\n",__FUNCTION__,__LINE__,list_cnt);

#if 0
                ret = pthread_create(&id1, NULL, (void*)readThread, NULL);
                if(ret != 0) {
                        printf("\n the readThread_create is failed!\n");
                }
                ret=pthread_join(id1,NULL);
                if(ret!=0){
                      perror("Thread join failed");
                      exit(EXIT_FAILURE);
                }
#endif
        }
}

static void __init clean_funct(void){
        KBUFF *p1;
        while(pread_kbuff !=NULL){
                p1=pread_kbuff;
                DBG("the pread_kbuff->buff_node is %s,flag is %d\n",pread_kbuff->buff_node,pread_kbuff->flag);
                pread_kbuff=pread_kbuff->next;

                kfree(p1);
        }
        kthread_stop(ret);
}

module_init(init_funct);
module_exit(clean_funct);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Bob Wang");
MODULE_DESCRIPTION("Dpram Driver Module for NCM Board");

 

上面这个程序中使用了内核线程和内核的信号量机制，还有内核的kmalloc等。。。