linux內核鏈表操作

與linux鏈表有關的操作定義在linux/list.h

鏈表頭：

struct list_head {
	struct list_head *next, *prev;
};

該結構體爲鏈接結構中的成員，這樣將鏈表的指針域與鏈表的數據域分開

鏈表頭的初始化

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

#define LIST_HEAD(name) \
	struct list_head name = LIST_HEAD_INIT(name)

2 static inline void INIT_LIST_HEAD(struct list_head *list)
{
	list->next = list;
	list->prev = list;
}

鏈表的插入

1. static inline void list_add(struct list_head *new, struct list_head *head)
{
	__list_add(new, head, head->next);
}

2. static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
	__list_add(new, head->prev, head);
}

#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);

鏈表的刪除

1. #ifndef CONFIG_DEBUG_LIST
static inline void list_del(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	entry->next = LIST_POISON1;
	entry->prev = LIST_POISON2;
}
#else
extern void list_del(struct list_head *entry);
#endif

2. static inline void list_del_init(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	INIT_LIST_HEAD(entry);
}

static inline void __list_del(struct list_head * prev, struct list_head * next)
{
	next->prev = prev;
	prev->next = next;
}

鏈表的替換

static inline void list_replace(struct list_head *old,
				struct list_head *new)
{
	new->next = old->next;
	new->next->prev = new;
	new->prev = old->prev;
	new->prev->next = new;
}

static inline void list_replace_init(struct list_head *old,
					struct list_head *new)
{
	list_replace(old, new);
	INIT_LIST_HEAD(old);
}

鏈表的移動，從一個鏈表刪除移動到另一個鏈表

static inline void list_move(struct list_head *list, struct list_head *head)
{
	__list_del(list->prev, list->next);
	list_add(list, head);
}

鏈表的遍歷

1. #define __list_for_each(pos, head) \
	for (pos = (head)->next; pos != (head); pos = pos->next)

2.#define list_for_each_prev(pos, head) \
	for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
        	pos = pos->prev)

鏈表與用戶結構鏈接list_entry

linux/list.h

#define list_entry(ptr, type, member) \
	container_of(ptr, type, member)

linux/kernel.h

#define container_of(ptr, type, member) ({          \
/*將鏈表中的元素prt轉換成結構type中成員member類型*/
	const typeof(((type *)0)->member)*__mptr = (ptr);    \
/*__mptr減去member成員偏移地址正好是type的結構地址*/
		     (type *)((char *)__mptr - offsetof(type, member)); })

hjk