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
14 struct 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 */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)37 static __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 */
list_add(struct list_head * new,struct list_head * head)50 static __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 */
list_add_tail(struct list_head * new,struct list_head * head)58 static __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 */
__list_del(struct list_head * prev,struct list_head * next)70 static __inline__ void __list_del(struct list_head * prev,
71 struct list_head * next)
72 {
73 next->prev = prev;
74 prev->next = next;
75 }
76
list_del(struct list_head * entry)77 static __inline__ void list_del(struct list_head *entry)
78 {
79 __list_del(entry->prev, entry->next);
80 }
81
list_empty(struct list_head * head)82 static __inline__ int list_empty(struct list_head *head)
83 {
84 return head->next == head;
85 }
86
87 /*
88 * Splice in "list" into "head"
89 */
list_splice(struct list_head * list,struct list_head * head)90 static __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