kernel-list.h revision a6ce1349539f866334ef3d5758bc2ee44a454acd 
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#if (!defined(__GNUC__) && !defined(__WATCOMC__))
28#define __inline__
29#endif
30
31/*
32 * Insert a new entry between two known consecutive entries.
33 *
34 * This is only for internal list manipulation where we know
35 * the prev/next entries already!
36 */
37static __inline__ void __list_add(struct list_head * new,
38	struct list_head * prev,
39	struct list_head * next)
40{
41	next->prev = new;
42	new->next = next;
43	new->prev = prev;
44	prev->next = new;
45}
46
47/*
48 * Insert a new entry after the specified head..
49 */
50static __inline__ void list_add(struct list_head *new, struct list_head *head)
51{
52	__list_add(new, head, head->next);
53}
54
55/*
56 * Insert a new entry at the tail
57 */
58static __inline__ void list_add_tail(struct list_head *new, struct list_head *head)
59{
60	__list_add(new, head->prev, head);
61}
62
63/*
64 * Delete a list entry by making the prev/next entries
65 * point to each other.
66 *
67 * This is only for internal list manipulation where we know
68 * the prev/next entries already!
69 */
70static __inline__ void __list_del(struct list_head * prev,
71				  struct list_head * next)
72{
73	next->prev = prev;
74	prev->next = next;
75}
76
77static __inline__ void list_del(struct list_head *entry)
78{
79	__list_del(entry->prev, entry->next);
80}
81
82static __inline__ int list_empty(struct list_head *head)
83{
84	return head->next == head;
85}
86
87/*
88 * Splice in "list" into "head"
89 */
90static __inline__ void list_splice(struct list_head *list, struct list_head *head)
91{
92	struct list_head *first = list->next;
93
94	if (first != list) {
95		struct list_head *last = list->prev;
96		struct list_head *at = head->next;
97
98		first->prev = head;
99		head->next = first;
100
101		last->next = at;
102		at->prev = last;
103	}
104}
105
106#define list_entry(ptr, type, member) \
107	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
108
109#define list_for_each(pos, head) \
110        for (pos = (head)->next; pos != (head); pos = pos->next)
111
112#endif
113