kernel-list.h revision 19007e51a548d1e0eff01025dde9f147a0beb26d 
1#ifndef _LINUX_LIST_H
2#define _LINUX_LIST_H
3
4/*
5 * Simple doubly linked list implementation.
6 *
7 * Some of the internal functions ("__xxx") are useful when
8 * manipulating whole lists rather than single entries, as
9 * sometimes we already know the next/prev entries and we can
10 * generate better code by using them directly rather than
11 * using the generic single-entry routines.
12 */
13
14struct list_head {
15	struct list_head *next, *prev;
16};
17
18#define LIST_HEAD_INIT(name) { &(name), &(name) }
19
20#define LIST_HEAD(name) \
21	struct list_head name = { &name, &name }
22
23#define INIT_LIST_HEAD(ptr) do { \
24	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
25} while (0)
26
27/*
28 * Insert a new entry between two known consecutive entries.
29 *
30 * This is only for internal list manipulation where we know
31 * the prev/next entries already!
32 */
33static __inline__ void __list_add(struct list_head * new,
34	struct list_head * prev,
35	struct list_head * next)
36{
37	next->prev = new;
38	new->next = next;
39	new->prev = prev;
40	prev->next = new;
41}
42
43/*
44 * Insert a new entry after the specified head..
45 */
46static __inline__ void list_add(struct list_head *new, struct list_head *head)
47{
48	__list_add(new, head, head->next);
49}
50
51/*
52 * Insert a new entry at the tail
53 */
54static __inline__ void list_add_tail(struct list_head *new, struct list_head *head)
55{
56	__list_add(new, head->prev, head);
57}
58
59/*
60 * Delete a list entry by making the prev/next entries
61 * point to each other.
62 *
63 * This is only for internal list manipulation where we know
64 * the prev/next entries already!
65 */
66static __inline__ void __list_del(struct list_head * prev,
67				  struct list_head * next)
68{
69	next->prev = prev;
70	prev->next = next;
71}
72
73static __inline__ void list_del(struct list_head *entry)
74{
75	__list_del(entry->prev, entry->next);
76}
77
78static __inline__ int list_empty(struct list_head *head)
79{
80	return head->next == head;
81}
82
83/*
84 * Splice in "list" into "head"
85 */
86static __inline__ void list_splice(struct list_head *list, struct list_head *head)
87{
88	struct list_head *first = list->next;
89
90	if (first != list) {
91		struct list_head *last = list->prev;
92		struct list_head *at = head->next;
93
94		first->prev = head;
95		head->next = first;
96
97		last->next = at;
98		at->prev = last;
99	}
100}
101
102#define list_entry(ptr, type, member) \
103	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
104
105#define list_for_each(pos, head) \
106        for (pos = (head)->next; pos != (head); pos = pos->next)
107
108#endif
109