kernel中的list_head接口

内核中的list_head连接件使用备忘。

从链表头、链表尾插入节点，从头到尾遍历结点，从尾到头遍历结点，删除节点，遍历并立即删除节点，判断节点是否空。

 

系统环境：ubuntu-10.04/linux-2.6.32-38-generic/gcc version 4.3.4(Ubuntu 4.3.4 10ubuntu1)

代码：

myklist.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/list.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("zl");
MODULE_DESCRIPTION("klist test");

struct list_head klisthead;

struct mytype {
    char *keystring;
    struct list_head knode;
};

typedef int (*cmp_t)(void *arg1, void *arg2);

char *array[] = {
    "aaaaa",
    "bbb",
    "333",
    "c",
    "dddd",
    "111",
    "eeeeeeeee",
    "ffffghi",
    "222",
    "gggabcd",
    "13579"
    "abcdefg"
};

#define TAB_SIZE(array) (sizeof(array)/sizeof(array[0]))

static int __init klist_init(void)
{
    int i;
    struct mytype *node;
    struct list_head *tmp;
    struct list_head *pos;
    INIT_LIST_HEAD(&klisthead);

/** first time list_add/list_del/list_for_each/list_for_each_safe **/
    printk("\n********list_add*************************************\n");
    if(list_empty(&klisthead))
    {
        printk("[%s-%d]: The list have no node !\n", __func__, __LINE__);
    }
    printk("----------list_for_each------------------------------\n");
    for(i = 0; i < TAB_SIZE(array); i++)
    {
        node = kzalloc(sizeof(struct mytype), GFP_KERNEL);
        if(node == NULL)
        {
            printk("[%s-%d]kzalloc failed !\n", __func__, __LINE__);
            goto err1;
        }
        node->keystring = array[i];

        list_add(&(node->knode), &klisthead);
    }

    if(!list_empty(&klisthead))
    {
        printk("[%s-%d]: The list have some node !\n", __func__, __LINE__);
    }

    i = 0;
    list_for_each(pos, &klisthead)
    {
        node = list_entry(pos, struct mytype, knode);
        printk("i = %d, keystring = %s \n", i, node->keystring);
        i++;
    }

    printk("\n----------list_for_each_safe/list_del----------------\n");
    i = 0;
    list_for_each_safe(pos, tmp, &klisthead)
    {
        node = list_entry(pos, struct mytype, knode);
        printk("i = %d, keystring = %s \n", i, node->keystring);
        i++;
        list_del(&(node->knode));
        kfree(node);
    }

    if(list_empty(&klisthead))
    {
        printk("[%s-%d]: The list have no node !\n", __func__, __LINE__);
    }
/** second time list_add_tail/list_del_init/list_for_each_prev/list_for_each_prev_safe **/
    printk("\n********list_add_tail********************************\n");
    printk("----------list_for_each------------------------------\n");
    for(i = 0; i < TAB_SIZE(array); i++)
    {
        node = kzalloc(sizeof(struct mytype), GFP_KERNEL);
        if(node == NULL)
        {
            printk("[%s-%d]kzalloc failed !\n", __func__, __LINE__);
            goto err1;
        }
        node->keystring = array[i];

        //list_add(&(node->knode), &klisthead);
        list_add_tail(&(node->knode), &klisthead);
    }
    if(!list_empty(&klisthead))
    {
        printk("[%s-%d]: The list have some node !\n", __func__, __LINE__);
    }

    i = 0;
    list_for_each(pos, &klisthead)
    {
        node = list_entry(pos, struct mytype, knode);
        printk("i = %d, keystring = %s \n", i, node->keystring);
        i++;
    }

    printk("----------list_for_each_prev-------------------------\n");
    i = 0;
    list_for_each_prev(pos, &klisthead)
    {
        node = list_entry(pos, struct mytype, knode);
        printk("i = %d, keystring = %s \n", i, node->keystring);
        i++;
    }

    printk("----------list_for_each_prev_safe/list_del_init------\n");
    i = 0;
    list_for_each_prev_safe(pos, tmp, &klisthead)
    {
        node = list_entry(pos, struct mytype, knode);
        printk("i = %d, keystring = %s \n", i, node->keystring);
        i++;
        list_del_init(&(node->knode));
        kfree(node);
    }
    if(list_empty(&klisthead))
    {
        printk("[%s-%d]: The list have no node !\n", __func__, __LINE__);
    }
    return 0;
err1:
    return -1;
}

static void __exit klist_exit(void)
{
    printk("exit !\n");
}

module_init(klist_init);
module_exit(klist_exit);

makefile文件

obj-m = myklist.o

#KERNELS = /home/zl/linux-2.6.30.4
#KERNELS = /media/STUDY/linux/kernel/my2440-2.6.36
KERNELS = /lib/modules/$(shell uname -r)/build/

default:
make -C $(KERNELS) M=$(shell pwd) modules

.PHONY:clean
clean:
make -C $(KERNELS) M=$(shell pwd) clean

编译，运行，及查看运行结果：符合预期

make clean;make;sudo insmod myklist.ko;sudo rmmod myklist;tail -n200 /var/log/messages