struct list_head {

         struct list_head *next, *prev;

 };

 struct my_list

 {

         void * mydata;   //void * 可以指向任何类型的数据

         struct list_head list;  //隐藏了链表指针

 } 

 #define LIST_HEAD_INIT(name) { &(name), &(name) }

 #define LIST_HEAD(name) \

         struct list_head name = LIST_HEAD_INIT(name)

 /*

  * Insert a new entry between two known consecutive entries.

  *

  * This is only for internal list manipulation where we know

  * the prev/next entries already!

  */

 #ifndef CONFIG_DEBUG_LIST

 static inline void __list_add(struct list_head *new,

                               struct list_head *prev,

                               struct list_head *next)

 {

         next->prev = new;

         new->next = next;

         new->prev = prev;

         prev->next = new;

 }

 #else

 extern void __list_add(struct list_head *new,

                               struct list_head *prev,

                               struct list_head *next);

 #endif

 /**

  * list_add - add a new entry

  * @new: new entry to be added

  * @head: list head to add it after

  *

  * Insert a new entry after the specified head.

  * This is good for implementing stacks.

  */

 static inline void list_add(struct list_head *new, struct list_head *head)　//在head节点后插入new节点，循环链表没有首尾，head可以是任意节点

 {

         __list_add(new, head, head->next);

 }

 /**

  * list_add_tail - add a new entry

  * @new: new entry to be added

  * @head: list head to add it before

  *

  * Insert a new entry before the specified head.

  * This is useful for implementing queues.

  */

 static inline void list_add_tail(struct list_head *new, struct list_head *head)　//在head节点前插入new节点

 {

         __list_add(new, head->prev, head);

 }

 /**

  * list_for_each        -       iterate over a list

  * @pos:        the &struct list_head to use as a loop cursor.

  * @head:       the head for your list.

  */

 #define list_for_each(pos, head) \

         for (pos = (head)->next; pos != (head); pos = pos->next)

 /**

  * list_entry - get the struct for this entry

  * @ptr:        the &struct list_head pointer.

  * @type:       the type of the struct this is embedded in.

  * @member:     the name of the list_struct within the struct.

  */

 #define list_entry(ptr, type, member) \

         container_of(ptr, type, member)