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/**
12 * container_of - cast a member of a structure out to the containing structure
13 *
14 * @ptr:	the pointer to the member.
15 * @type:	the type of the container struct this is embedded in.
16 * @member:	the name of the member within the struct.
17 *
18 */
19#define container_of(ptr, type, member) ({			\
20	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
21	(type *)( (char *)__mptr - offsetof(type,member) );})
22
23/*
24 * These are non-NULL pointers that will result in page faults
25 * under normal circumstances, used to verify that nobody uses
26 * non-initialized list entries.
27 */
28#define LIST_POISON1  ((void *) 0x00100100)
29#define LIST_POISON2  ((void *) 0x00200200)
30
31/*
32 * Simple doubly linked list implementation.
33 *
34 * Some of the internal functions ("__xxx") are useful when
35 * manipulating whole lists rather than single entries, as
36 * sometimes we already know the next/prev entries and we can
37 * generate better code by using them directly rather than
38 * using the generic single-entry routines.
39 */
40
41struct list_head {
42	struct list_head *next, *prev;
43};
44
45#define LIST_HEAD_INIT(name) { &(name), &(name) }
46
47#define LIST_HEAD(name) \
48	struct list_head name = LIST_HEAD_INIT(name)
49
50#define INIT_LIST_HEAD(ptr) do { \
51	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
52} while (0)
53
54/*
55 * Insert a new entry between two known consecutive entries.
56 *
57 * This is only for internal list manipulation where we know
58 * the prev/next entries already!
59 */
60static inline void __list_add(struct list_head *new,
61			      struct list_head *prev,
62			      struct list_head *next)
63{
64	next->prev = new;
65	new->next = next;
66	new->prev = prev;
67	prev->next = new;
68}
69
70/**
71 * list_add - add a new entry
72 * @new: new entry to be added
73 * @head: list head to add it after
74 *
75 * Insert a new entry after the specified head.
76 * This is good for implementing stacks.
77 */
78static inline void list_add(struct list_head *new, struct list_head *head)
79{
80	__list_add(new, head, head->next);
81}
82
83/**
84 * list_add_tail - add a new entry
85 * @new: new entry to be added
86 * @head: list head to add it before
87 *
88 * Insert a new entry before the specified head.
89 * This is useful for implementing queues.
90 */
91static inline void list_add_tail(struct list_head *new, struct list_head *head)
92{
93	__list_add(new, head->prev, head);
94}
95
96/*
97 * Delete a list entry by making the prev/next entries
98 * point to each other.
99 *
100 * This is only for internal list manipulation where we know
101 * the prev/next entries already!
102 */
103static inline void __list_del(struct list_head * prev, struct list_head * next)
104{
105	next->prev = prev;
106	prev->next = next;
107}
108
109/**
110 * list_del - deletes entry from list.
111 * @entry: the element to delete from the list.
112 * Note: list_empty on entry does not return true after this, the entry is
113 * in an undefined state.
114 */
115static inline void list_del(struct list_head *entry)
116{
117	__list_del(entry->prev, entry->next);
118	entry->next = LIST_POISON1;
119	entry->prev = LIST_POISON2;
120}
121
122/**
123 * list_del_init - deletes entry from list and reinitialize it.
124 * @entry: the element to delete from the list.
125 */
126static inline void list_del_init(struct list_head *entry)
127{
128	__list_del(entry->prev, entry->next);
129	INIT_LIST_HEAD(entry);
130}
131
132/**
133 * list_move - delete from one list and add as another's head
134 * @list: the entry to move
135 * @head: the head that will precede our entry
136 */
137static inline void list_move(struct list_head *list, struct list_head *head)
138{
139	__list_del(list->prev, list->next);
140	list_add(list, head);
141}
142
143/**
144 * list_move_tail - delete from one list and add as another's tail
145 * @list: the entry to move
146 * @head: the head that will follow our entry
147 */
148static inline void list_move_tail(struct list_head *list,
149				  struct list_head *head)
150{
151	__list_del(list->prev, list->next);
152	list_add_tail(list, head);
153}
154
155/**
156 * list_empty - tests whether a list is empty
157 * @head: the list to test.
158 */
159static inline int list_empty(struct list_head *head)
160{
161	return head->next == head;
162}
163
164static inline void __list_splice(struct list_head *list,
165				 struct list_head *head)
166{
167	struct list_head *first = list->next;
168	struct list_head *last = list->prev;
169	struct list_head *at = head->next;
170
171	first->prev = head;
172	head->next = first;
173
174	last->next = at;
175	at->prev = last;
176}
177
178/**
179 * list_splice - join two lists
180 * @list: the new list to add.
181 * @head: the place to add it in the first list.
182 */
183static inline void list_splice(struct list_head *list, struct list_head *head)
184{
185	if (!list_empty(list))
186		__list_splice(list, head);
187}
188
189/**
190 * list_splice_init - join two lists and reinitialise the emptied list.
191 * @list: the new list to add.
192 * @head: the place to add it in the first list.
193 *
194 * The list at @list is reinitialised
195 */
196static inline void list_splice_init(struct list_head *list,
197				    struct list_head *head)
198{
199	if (!list_empty(list)) {
200		__list_splice(list, head);
201		INIT_LIST_HEAD(list);
202	}
203}
204
205/**
206 * list_entry - get the struct for this entry
207 * @ptr:	the &struct list_head pointer.
208 * @type:	the type of the struct this is embedded in.
209 * @member:	the name of the list_struct within the struct.
210 */
211#define list_entry(ptr, type, member) \
212	container_of(ptr, type, member)
213
214/**
215 * list_for_each	-	iterate over a list
216 * @pos:	the &struct list_head to use as a loop counter.
217 * @head:	the head for your list.
218 */
219#define list_for_each(pos, head) \
220	for (pos = (head)->next; pos != (head); \
221		pos = pos->next)
222
223/**
224 * __list_for_each	-	iterate over a list
225 * @pos:	the &struct list_head to use as a loop counter.
226 * @head:	the head for your list.
227 *
228 * This variant differs from list_for_each() in that it's the
229 * simplest possible list iteration code.
230 * Use this for code that knows the list to be very short (empty
231 * or 1 entry) most of the time.
232 */
233#define __list_for_each(pos, head) \
234	for (pos = (head)->next; pos != (head); pos = pos->next)
235
236/**
237 * list_for_each_prev	-	iterate over a list backwards
238 * @pos:	the &struct list_head to use as a loop counter.
239 * @head:	the head for your list.
240 */
241#define list_for_each_prev(pos, head) \
242	for (pos = (head)->prev; pos != (head); pos = pos->prev)
243
244/**
245 * list_for_each_safe	-	iterate over a list safe against removal of list entry
246 * @pos:	the &struct list_head to use as a loop counter.
247 * @n:		another &struct list_head to use as temporary storage
248 * @head:	the head for your list.
249 */
250#define list_for_each_safe(pos, n, head) \
251	for (pos = (head)->next, n = pos->next; pos != (head); \
252		pos = n, n = pos->next)
253
254/**
255 * list_for_each_entry	-	iterate over list of given type
256 * @pos:	the type * to use as a loop counter.
257 * @head:	the head for your list.
258 * @member:	the name of the list_struct within the struct.
259 */
260#define list_for_each_entry(pos, head, member)				\
261	for (pos = list_entry((head)->next, typeof(*pos), member);	\
262	     &pos->member != (head); 					\
263	     pos = list_entry(pos->member.next, typeof(*pos), member))
264
265/**
266 * list_for_each_entry_reverse - iterate backwards over list of given type.
267 * @pos:	the type * to use as a loop counter.
268 * @head:	the head for your list.
269 * @member:	the name of the list_struct within the struct.
270 */
271#define list_for_each_entry_reverse(pos, head, member)			\
272	for (pos = list_entry((head)->prev, typeof(*pos), member);	\
273	     &pos->member != (head); 					\
274	     pos = list_entry(pos->member.prev, typeof(*pos), member))
275
276/**
277 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
278 * @pos:	the type * to use as a loop counter.
279 * @n:		another type * to use as temporary storage
280 * @head:	the head for your list.
281 * @member:	the name of the list_struct within the struct.
282 */
283#define list_for_each_entry_safe(pos, n, head, member)			\
284	for (pos = list_entry((head)->next, typeof(*pos), member),	\
285		n = list_entry(pos->member.next, typeof(*pos), member);	\
286	     &pos->member != (head); 					\
287	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
288
289#endif /* _LIST_H */
290