Horace papa's life

/*
 * =============================================================================
 *
 *       Filename:  list_head_ex.h
 *
 *    Description: Write a doubly linked list by using list_head structure
 *
 *        Version:  1.0
 *        Created:  Fri Oct 19 14:17:58 GMT 2007
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Adrian Huang
 *       Web Site:  http://adrianhuang.blogspot.com/
 *
 * =============================================================================
 */

#ifndef  LIST_HEAD_EX_INC
#define  LIST_HEAD_EX_INC

#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_INFO */
#include <linux/jiffies.h>
#include <linux/list.h>  /* list_head structure */

#define NR_STDS 5 

struct student {
 char    name[16];
 int     id;
 struct list_head list;
};

typedef enum _Boolean { FALSE = 0, TRUE = 1 } LHBOOL; // list head boolean

#endif   /* ----- #ifndef LIST_HEAD_EX_INC  ----- */

/*
 * =============================================================================
 *
 *       Filename:  list_head_ex.c
 *
 *    Description:  Write a doubly linked list by using list_head structure
 *
 *        Version:  1.0
 *        Created:  Fri Oct 19 14:14:57 GMT 2007
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Adrian Huang
 *        Web Site:  http://adrianhuang.blogspot.com/
 *
 * ============================================================================
 */

#include "list_head_ex.h"

int __init list_head_init(void)
{
 struct list_head std_head, *next;
 struct student  sl[NR_STDS];   // student list
 struct student  *studentP;  // student pointer
 int     idx;

 /* init std_head */
 INIT_LIST_HEAD(&std_head);

 /* Check whether the std_head is empty */
 if(list_empty(&std_head) == TRUE) {
  printk(KERN_INFO "[Adrian] std_head is NULL\n");
 }

 /* Add each element to student head (std_head) */
 for(idx=0;idx<sizeof(sl)/sizeof(struct student);idx++) {
  sprintf(sl[idx].name, "Adrian Huang");
  sl[idx].id = idx + 1;
  list_add(&sl[idx].list, &std_head);
 } 
 
 printk(KERN_INFO "======dump all elements of the list by invoking "
     "'list_for_each'=========\n");
 /* Traverse all elements of the list */
 list_for_each(next, &std_head) {
  studentP = (struct student *) list_entry(next, struct student, list);
  printk(KERN_INFO "[Adrian] name: %s, id: %d\n",
        studentP->name, studentP->id);
 }

 printk(KERN_INFO "\n======dump all elements of the list by invoking "
     "'list_entry'=========\n");
 /* Traverse all elements of the list and delete each of it */ 
 for(idx=0;idx<sizeof(sl)/sizeof(struct student);idx++) {
  studentP = (struct student *) list_entry(std_head.next,
          struct student, list);

  printk(KERN_INFO "[Adrian] name: %s, id: %d\n",
        studentP->name, studentP->id);
 
  list_del(std_head.next);
 }
   
 return 0;
}

void __exit list_head_exit(void)
{
 ;
}

module_init(list_head_init);
module_exit(list_head_exit);