Using the list:

#include <stdio.h>
#include <stdlib.h>

#include "list.h"

struct kool_list{
    int to;
    struct list_head list;
    int from;
    };

int main(int argc, char **argv){
    struct kool_list *tmp;
    struct list_head *pos, *q;
    unsigned int i;

    struct kool_list mylist;
    INIT_LIST_HEAD(&mylist.list);

    for(i=5; i!=0; --i){
        tmp=(struct kool_list*)malloc(sizeof(struct kool_list));
        printf("enter to and from:");
        scanf("%d %d", &tmp->to, &tmp->from);
        list_add(&(tmp->list), &(mylist.list));
    }
    printf("\n");

    printf("traversing the list using list_for_each_entry()\n");
    list_for_each_entry(tmp, &mylist.list, list)
        printf("to=%d from=%d\n", tmp->to, tmp->from);
    printf("\n");

    printf("deleting the list using list_for_each_safe()\n");
    list_for_each_safe(pos, q, &mylist.list){
        tmp=list_entry(pos, struct kool_list, list);
        printf("freeing item to=%d from=%d\n", tmp->to, tmp->from);
        list_del(pos);
        free(tmp);
    }

    return 0;
}

Testing, as below:

[dennis@localhost test]$ ./main
enter to and from:19 9
enter to and from:18 8
enter to and from:17 7
enter to and from:16 6
enter to and from:15 5

traversing the list using list_for_each_entry()
to=15 from=5
to=16 from=6
to=17 from=7
to=18 from=8
to=19 from=9

deleting the list using list_for_each_safe()
freeing item to=15 from=5
freeing item to=16 from=6
freeing item to=17 from=7
freeing item to=18 from=8
freeing item to=19 from=9
[dennis@localhost test]$

How it work? go to the reference website for detail.

Reference:

• Linux Kernel Linked List Explained