linux驱动14---linux内核链表list的使用

1.链表的基本操作
   初始化链表-->插入链表-->遍历链表-->删除链表中的某一项
下面两个代码一个不用entry,一个用entry,还是用entry的比较简单明了
2.代码->testlist1.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>

#define LIST_LEN 10
typedef struct __num_node_{
    int num;
    struct list_head list;
}num_node;

num_node head;
static int __init hello_init(void)
{
    int i;
    -->不用entry时，既需要定义struct list_head也需要定义num_node
    struct list_head* pos;
    struct list_head* n;
    num_node* listnode;
    num_node* p;
    //1.初始化链表
    INIT_LIST_HEAD(&head.list);             -->初始化双向链表
    //2.向链表中添加项
    printk(KERN_ALERT "add node 1-10:\n");
    for(i=0; i<LIST_LEN; i++)
    {
        listnode = (num_node*)kmalloc(sizeof(num_node), GFP_KERNEL);
        listnode->num = i;
        list_add_tail(&listnode->list, &head.list);  -->只是把list插入到链表中，而数据本身不会插入到链表中
        printk(KERN_ALERT "add node=%d\n", i);
    }
    printk(KERN_ALERT "\n");
    //3.遍历链表
    printk(KERN_ALERT "node traversal 1111:\n");
    list_for_each(pos, &head.list)
    {
        p = list_entry(pos, num_node, list);
        printk(KERN_ALERT "node data=%d\n", p->num);
    }
    printk(KERN_ALERT "\n");
    //4.删除链表中的某一项
    printk(KERN_ALERT "node delete 3:\n");
    list_for_each_safe(pos, n, &head.list)
    {
        p = list_entry(pos, num_node, list);
        if(3 == p->num)
        {
            printk(KERN_ALERT "find node -> 3\n");
            list_del(&p->list);
            kfree(p);
        }
        //printk(KERN_ALERT "node data=%d\n", p->num);
    }
    printk(KERN_ALERT "\n");
    //5.再次遍历链表
    printk(KERN_ALERT "node traversal 2222:\n");
    list_for_each(pos, &head.list)
    {
        p = list_entry(pos, num_node, list);
        printk(KERN_ALERT "node data=%d\n", p->num);
    }
    printk(KERN_ALERT "\n");

    return 0;
}

static void __exit hello_exit(void)
{
    printk(KERN_ALERT "goodbye my first dirver\n");
    return ;
}

module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("wangcong");

3. 代码->testlist2.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>

#define LIST_LEN 10
typedef struct __num_node_{
    int num;
    struct list_head list;
}num_node;

num_node head;
static int __init hello_init(void)
{
    int i;
    num_node* listnode;
    num_node* p;      -->这个地方就不需要struct list_head了
    num_node* n;      -->这个地方就不需要struct list_head了
    //1.初始化链表
    INIT_LIST_HEAD(&head.list);
    //2.向链表中添加项
    printk(KERN_ALERT "add node 1-10:\n");
    for(i=0; i<LIST_LEN; i++)
    {
        listnode = (num_node*)kmalloc(sizeof(num_node), GFP_KERNEL);
        listnode->num = i;
        list_add_tail(&listnode->list, &head.list);
        printk(KERN_ALERT "add node=%d\n", i);
    }
    printk(KERN_ALERT "\n");
    //3.遍历链表
    printk(KERN_ALERT "node traversal 1111:\n");
    list_for_each_entry(p, &head.list, list)
    {
        printk(KERN_ALERT "node data=%d\n", p->num);
    }
    printk(KERN_ALERT "\n");
    //4.删除链表中的某一项
    printk(KERN_ALERT "node delete 4:\n");
    list_for_each_entry_safe(p, n, &head.list, list)
    {
        if(4 == p->num)
        {
            printk(KERN_ALERT "find node -> 4\n");
            list_del(&p->list);
            kfree(p);
        }
        //printk(KERN_ALERT "node data=%d\n", p->num);
    }
    printk(KERN_ALERT "\n");
    //5.再次遍历链表
    printk(KERN_ALERT "node traversal 2222:\n");
    list_for_each_entry(p, &head.list, list)
    {
        printk(KERN_ALERT "node data=%d\n", p->num);
    }
    printk(KERN_ALERT "\n");

    return 0;
}

static void __exit hello_exit(void)
{
    printk(KERN_ALERT "goodbye my first dirver\n");
    return ;
}

module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("wangcong");

注：判断链表为空
 printk(KERN_ALERT "list_empty=%d\n", list_empty(&head.list));
为空时会打印1, 不为空时会打印0

4.代码打包
testlist.rar（下载后改名为testlist.tar.gz）