1/*
2 * Copied from the Linux kernel source tree, version 2.6.0-test1.
3 *
4 * Licensed under the GPL v2 as per the whole kernel source tree.
5 *
6 */
7
8#ifndef _LIST_H
9#define _LIST_H
10
11#undef offsetof
12#define offsetof(TYPE, MEMBER)	((size_t) &((TYPE *)0)->MEMBER)
13
14/**
15 * container_of - cast a member of a structure out to the containing structure
16 *
17 * @ptr:	the pointer to the member.
18 * @type:	the type of the container struct this is embedded in.
19 * @member:	the name of the member within the struct.
20 *
21 */
22#define container_of(ptr, type, member) ({			\
23	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
24	(type *)( (char *)__mptr - offsetof(type,member) );})
25
26/*
27 * Simple doubly linked list implementation.
28 *
29 * Some of the internal functions ("__xxx") are useful when
30 * manipulating whole lists rather than single entries, as
31 * sometimes we already know the next/prev entries and we can
32 * generate better code by using them directly rather than
33 * using the generic single-entry routines.
34 */
35
36struct list_head {
37	struct list_head *next, *prev;
38};
39
40#define LIST_HEAD_INIT(name) { &(name), &(name) }
41
42#define LIST_HEAD(name) \
43	struct list_head name = LIST_HEAD_INIT(name)
44
45#define INIT_LIST_HEAD(ptr) do { \
46	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
47} while (0)
48
49/*
50 * Insert a new entry between two known consecutive entries.
51 *
52 * This is only for internal list manipulation where we know
53 * the prev/next entries already!
54 */
55static inline void __list_add(struct list_head *new,
56			struct list_head *prev,
57			struct list_head *next)
58{
59	next->prev = new;
60	new->next = next;
61	new->prev = prev;
62	prev->next = new;
63}
64
65/**
66 * list_add - add a new entry
67 * @new: new entry to be added
68 * @head: list head to add it after
69 *
70 * Insert a new entry after the specified head.
71 * This is good for implementing stacks.
72 */
73static inline void list_add(struct list_head *new, struct list_head *head)
74{
75	__list_add(new, head, head->next);
76}
77
78/**
79 * list_add_tail - add a new entry
80 * @new: new entry to be added
81 * @head: list head to add it before
82 *
83 * Insert a new entry before the specified head.
84 * This is useful for implementing queues.
85 */
86static inline void list_add_tail(struct list_head *new, struct list_head *head)
87{
88	__list_add(new, head->prev, head);
89}
90
91/*
92 * Delete a list entry by making the prev/next entries
93 * point to each other.
94 *
95 * This is only for internal list manipulation where we know
96 * the prev/next entries already!
97 */
98static inline void __list_del(struct list_head *prev, struct list_head *next)
99{
100	next->prev = prev;
101	prev->next = next;
102}
103
104/**
105 * list_del - deletes entry from list.
106 * @entry: the element to delete from the list.
107 * Note: list_empty on entry does not return true after this, the entry is
108 * in an undefined state.
109 */
110static inline void list_del(struct list_head *entry)
111{
112	__list_del(entry->prev, entry->next);
113}
114
115/**
116 * list_empty - tests whether a list is empty
117 * @head: the list to test.
118 */
119static inline int list_empty(struct list_head *head)
120{
121	return head->next == head;
122}
123
124/**
125 * list_entry - get the struct for this entry
126 * @ptr:	the &struct list_head pointer.
127 * @type:	the type of the struct this is embedded in.
128 * @member:	the name of the list_struct within the struct.
129 */
130#define list_entry(ptr, type, member) \
131	container_of(ptr, type, member)
132
133/**
134 * list_for_each	-	iterate over a list
135 * @pos:	the &struct list_head to use as a loop counter.
136 * @head:	the head for your list.
137 */
138#define list_for_each(pos, head) \
139	for (pos = (head)->next; pos != (head); pos = pos->next)
140
141/**
142 * list_for_each_safe	-	iterate over a list safe against removal of list entry
143 * @pos:	the &struct list_head to use as a loop counter.
144 * @n:		another &struct list_head to use as temporary storage
145 * @head:	the head for your list.
146 */
147#define list_for_each_safe(pos, n, head) \
148	for (pos = (head)->next, n = pos->next; pos != (head); \
149		pos = n, n = pos->next)
150
151#endif /* _LIST_H */
152
153