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 INIT_LIST_HEAD(ptr) do { \
21 (ptr)->next = (ptr); (ptr)->prev = (ptr); \
22 } while (0)
23
24 #if (!defined(__GNUC__) && !defined(__WATCOMC__))
25 #define __inline__
26 #endif
27
28 /*
29 * Insert a new entry between two known consecutive entries.
30 *
31 * This is only for internal list manipulation where we know
32 * the prev/next entries already!
33 */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)34 static __inline__ void __list_add(struct list_head * new,
35 struct list_head * prev,
36 struct list_head * next)
37 {
38 next->prev = new;
39 new->next = next;
40 new->prev = prev;
41 prev->next = new;
42 }
43
44 /*
45 * Insert a new entry after the specified head..
46 */
list_add(struct list_head * new,struct list_head * head)47 static __inline__ void list_add(struct list_head *new, struct list_head *head)
48 {
49 __list_add(new, head, head->next);
50 }
51
52 /*
53 * Insert a new entry at the tail
54 */
list_add_tail(struct list_head * new,struct list_head * head)55 static __inline__ void list_add_tail(struct list_head *new, struct list_head *head)
56 {
57 __list_add(new, head->prev, head);
58 }
59
60 /*
61 * Delete a list entry by making the prev/next entries
62 * point to each other.
63 *
64 * This is only for internal list manipulation where we know
65 * the prev/next entries already!
66 */
__list_del(struct list_head * prev,struct list_head * next)67 static __inline__ void __list_del(struct list_head * prev,
68 struct list_head * next)
69 {
70 next->prev = prev;
71 prev->next = next;
72 }
73
list_del(struct list_head * entry)74 static __inline__ void list_del(struct list_head *entry)
75 {
76 __list_del(entry->prev, entry->next);
77 }
78
list_empty(struct list_head * head)79 static __inline__ int list_empty(struct list_head *head)
80 {
81 return head->next == head;
82 }
83
84 /*
85 * Splice in "list" into "head"
86 */
list_splice(struct list_head * list,struct list_head * head)87 static __inline__ void list_splice(struct list_head *list, struct list_head *head)
88 {
89 struct list_head *first = list->next;
90
91 if (first != list) {
92 struct list_head *last = list->prev;
93 struct list_head *at = head->next;
94
95 first->prev = head;
96 head->next = first;
97
98 last->next = at;
99 at->prev = last;
100 }
101 }
102
103 #define list_entry(ptr, type, member) \
104 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
105
106 #define list_for_each(pos, head) \
107 for (pos = (head)->next; pos != (head); pos = pos->next)
108
109 #endif
110