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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_LIST_H
2#define _LINUX_LIST_H
3
Chris Metcalfde5d9bf2010-07-02 13:41:14 -04004#include <linux/types.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005#include <linux/stddef.h>
Randy Dunlapc9cf5522006-06-27 02:53:52 -07006#include <linux/poison.h>
Linus Torvaldse66eed62011-05-19 14:15:29 -07007#include <linux/const.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008
9/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 * Simple doubly linked list implementation.
11 *
12 * Some of the internal functions ("__xxx") are useful when
13 * manipulating whole lists rather than single entries, as
14 * sometimes we already know the next/prev entries and we can
15 * generate better code by using them directly rather than
16 * using the generic single-entry routines.
17 */
18
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#define LIST_HEAD_INIT(name) { &(name), &(name) }
20
21#define LIST_HEAD(name) \
22 struct list_head name = LIST_HEAD_INIT(name)
23
Zach Brown490d6ab2006-02-03 03:03:56 -080024static inline void INIT_LIST_HEAD(struct list_head *list)
25{
26 list->next = list;
27 list->prev = list;
28}
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30/*
31 * Insert a new entry between two known consecutive entries.
32 *
33 * This is only for internal list manipulation where we know
34 * the prev/next entries already!
35 */
Dave Jones199a9af2006-09-29 01:59:00 -070036#ifndef CONFIG_DEBUG_LIST
Linus Torvalds1da177e2005-04-16 15:20:36 -070037static 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}
Dave Jones199a9af2006-09-29 01:59:00 -070046#else
47extern void __list_add(struct list_head *new,
48 struct list_head *prev,
49 struct list_head *next);
50#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
52/**
53 * list_add - add a new entry
54 * @new: new entry to be added
55 * @head: list head to add it after
56 *
57 * Insert a new entry after the specified head.
58 * This is good for implementing stacks.
59 */
60static inline void list_add(struct list_head *new, struct list_head *head)
61{
62 __list_add(new, head, head->next);
63}
Dave Jones199a9af2006-09-29 01:59:00 -070064
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66/**
67 * list_add_tail - add a new entry
68 * @new: new entry to be added
69 * @head: list head to add it before
70 *
71 * Insert a new entry before the specified head.
72 * This is useful for implementing queues.
73 */
74static inline void list_add_tail(struct list_head *new, struct list_head *head)
75{
76 __list_add(new, head->prev, head);
77}
78
79/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 * Delete a list entry by making the prev/next entries
81 * point to each other.
82 *
83 * This is only for internal list manipulation where we know
84 * the prev/next entries already!
85 */
86static inline void __list_del(struct list_head * prev, struct list_head * next)
87{
88 next->prev = prev;
89 prev->next = next;
90}
91
92/**
93 * list_del - deletes entry from list.
94 * @entry: the element to delete from the list.
Robert P. J. Day72fd4a32007-02-10 01:45:59 -080095 * Note: list_empty() on entry does not return true after this, the entry is
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 * in an undefined state.
97 */
Dave Jones199a9af2006-09-29 01:59:00 -070098#ifndef CONFIG_DEBUG_LIST
Linus Torvalds3c18d4d2011-02-18 11:32:28 -080099static inline void __list_del_entry(struct list_head *entry)
100{
101 __list_del(entry->prev, entry->next);
102}
103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104static inline void list_del(struct list_head *entry)
105{
106 __list_del(entry->prev, entry->next);
107 entry->next = LIST_POISON1;
108 entry->prev = LIST_POISON2;
109}
Dave Jones199a9af2006-09-29 01:59:00 -0700110#else
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800111extern void __list_del_entry(struct list_head *entry);
Dave Jones199a9af2006-09-29 01:59:00 -0700112extern void list_del(struct list_head *entry);
113#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
115/**
Oleg Nesterov54e73772006-06-23 02:05:54 -0700116 * list_replace - replace old entry by new one
117 * @old : the element to be replaced
118 * @new : the new element to insert
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800119 *
120 * If @old was empty, it will be overwritten.
Oleg Nesterov54e73772006-06-23 02:05:54 -0700121 */
122static inline void list_replace(struct list_head *old,
123 struct list_head *new)
124{
125 new->next = old->next;
126 new->next->prev = new;
127 new->prev = old->prev;
128 new->prev->next = new;
129}
130
131static inline void list_replace_init(struct list_head *old,
132 struct list_head *new)
133{
134 list_replace(old, new);
135 INIT_LIST_HEAD(old);
136}
137
Robert P. J. Day45f8bde2007-01-26 00:57:09 -0800138/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 * list_del_init - deletes entry from list and reinitialize it.
140 * @entry: the element to delete from the list.
141 */
142static inline void list_del_init(struct list_head *entry)
143{
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800144 __list_del_entry(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 INIT_LIST_HEAD(entry);
146}
147
148/**
149 * list_move - delete from one list and add as another's head
150 * @list: the entry to move
151 * @head: the head that will precede our entry
152 */
153static inline void list_move(struct list_head *list, struct list_head *head)
154{
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800155 __list_del_entry(list);
Daniel Walker78db2ad2007-05-12 16:28:35 -0700156 list_add(list, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157}
158
159/**
160 * list_move_tail - delete from one list and add as another's tail
161 * @list: the entry to move
162 * @head: the head that will follow our entry
163 */
164static inline void list_move_tail(struct list_head *list,
165 struct list_head *head)
166{
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800167 __list_del_entry(list);
Daniel Walker78db2ad2007-05-12 16:28:35 -0700168 list_add_tail(list, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169}
170
171/**
Shailabh Nagare8f4d972006-07-14 00:24:35 -0700172 * list_is_last - tests whether @list is the last entry in list @head
173 * @list: the entry to test
174 * @head: the head of the list
175 */
176static inline int list_is_last(const struct list_head *list,
177 const struct list_head *head)
178{
179 return list->next == head;
180}
181
182/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 * list_empty - tests whether a list is empty
184 * @head: the list to test.
185 */
186static inline int list_empty(const struct list_head *head)
187{
188 return head->next == head;
189}
190
191/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700192 * list_empty_careful - tests whether a list is empty and not being modified
193 * @head: the list to test
194 *
195 * Description:
196 * tests whether a list is empty _and_ checks that no other CPU might be
197 * in the process of modifying either member (next or prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 *
199 * NOTE: using list_empty_careful() without synchronization
200 * can only be safe if the only activity that can happen
201 * to the list entry is list_del_init(). Eg. it cannot be used
202 * if another CPU could re-list_add() it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 */
204static inline int list_empty_careful(const struct list_head *head)
205{
206 struct list_head *next = head->next;
207 return (next == head) && (next == head->prev);
208}
209
Masami Hiramatsu99602572008-04-28 02:14:27 -0700210/**
Frederic Weisbecker5908cdc2010-01-09 20:53:14 +0100211 * list_rotate_left - rotate the list to the left
212 * @head: the head of the list
213 */
214static inline void list_rotate_left(struct list_head *head)
215{
216 struct list_head *first;
217
218 if (!list_empty(head)) {
219 first = head->next;
220 list_move_tail(first, head);
221 }
222}
223
224/**
Masami Hiramatsu99602572008-04-28 02:14:27 -0700225 * list_is_singular - tests whether a list has just one entry.
226 * @head: the list to test.
227 */
228static inline int list_is_singular(const struct list_head *head)
229{
230 return !list_empty(head) && (head->next == head->prev);
231}
232
Luis R. Rodriguez00e8a4d2008-08-06 13:28:54 -0700233static inline void __list_cut_position(struct list_head *list,
234 struct list_head *head, struct list_head *entry)
235{
236 struct list_head *new_first = entry->next;
237 list->next = head->next;
238 list->next->prev = list;
239 list->prev = entry;
240 entry->next = list;
241 head->next = new_first;
242 new_first->prev = head;
243}
244
245/**
246 * list_cut_position - cut a list into two
247 * @list: a new list to add all removed entries
248 * @head: a list with entries
249 * @entry: an entry within head, could be the head itself
250 * and if so we won't cut the list
251 *
252 * This helper moves the initial part of @head, up to and
253 * including @entry, from @head to @list. You should
254 * pass on @entry an element you know is on @head. @list
255 * should be an empty list or a list you do not care about
256 * losing its data.
257 *
258 */
259static inline void list_cut_position(struct list_head *list,
260 struct list_head *head, struct list_head *entry)
261{
262 if (list_empty(head))
263 return;
264 if (list_is_singular(head) &&
265 (head->next != entry && head != entry))
266 return;
267 if (entry == head)
268 INIT_LIST_HEAD(list);
269 else
270 __list_cut_position(list, head, entry);
271}
272
Robert P. J. Day95d8c362008-04-29 00:59:29 -0700273static inline void __list_splice(const struct list_head *list,
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700274 struct list_head *prev,
275 struct list_head *next)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276{
277 struct list_head *first = list->next;
278 struct list_head *last = list->prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700280 first->prev = prev;
281 prev->next = first;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700283 last->next = next;
284 next->prev = last;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285}
286
287/**
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700288 * list_splice - join two lists, this is designed for stacks
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 * @list: the new list to add.
290 * @head: the place to add it in the first list.
291 */
Robert P. J. Day95d8c362008-04-29 00:59:29 -0700292static inline void list_splice(const struct list_head *list,
293 struct list_head *head)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294{
295 if (!list_empty(list))
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700296 __list_splice(list, head, head->next);
297}
298
299/**
300 * list_splice_tail - join two lists, each list being a queue
301 * @list: the new list to add.
302 * @head: the place to add it in the first list.
303 */
304static inline void list_splice_tail(struct list_head *list,
305 struct list_head *head)
306{
307 if (!list_empty(list))
308 __list_splice(list, head->prev, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309}
310
311/**
312 * list_splice_init - join two lists and reinitialise the emptied list.
313 * @list: the new list to add.
314 * @head: the place to add it in the first list.
315 *
316 * The list at @list is reinitialised
317 */
318static inline void list_splice_init(struct list_head *list,
319 struct list_head *head)
320{
321 if (!list_empty(list)) {
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700322 __list_splice(list, head, head->next);
323 INIT_LIST_HEAD(list);
324 }
325}
326
327/**
Randy Dunlap6724cce2008-08-08 13:56:20 -0700328 * list_splice_tail_init - join two lists and reinitialise the emptied list
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700329 * @list: the new list to add.
330 * @head: the place to add it in the first list.
331 *
Randy Dunlap6724cce2008-08-08 13:56:20 -0700332 * Each of the lists is a queue.
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700333 * The list at @list is reinitialised
334 */
335static inline void list_splice_tail_init(struct list_head *list,
336 struct list_head *head)
337{
338 if (!list_empty(list)) {
339 __list_splice(list, head->prev, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 INIT_LIST_HEAD(list);
341 }
342}
343
344/**
345 * list_entry - get the struct for this entry
346 * @ptr: the &struct list_head pointer.
347 * @type: the type of the struct this is embedded in.
348 * @member: the name of the list_struct within the struct.
349 */
350#define list_entry(ptr, type, member) \
351 container_of(ptr, type, member)
352
353/**
Pavel Emelianovb5e61812007-05-08 00:30:19 -0700354 * list_first_entry - get the first element from a list
355 * @ptr: the list head to take the element from.
356 * @type: the type of the struct this is embedded in.
357 * @member: the name of the list_struct within the struct.
358 *
359 * Note, that list is expected to be not empty.
360 */
361#define list_first_entry(ptr, type, member) \
362 list_entry((ptr)->next, type, member)
363
364/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 * list_for_each - iterate over a list
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700366 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 * @head: the head for your list.
368 */
369#define list_for_each(pos, head) \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700370 for (pos = (head)->next; pos != (head); pos = pos->next)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371
372/**
373 * __list_for_each - iterate over a list
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700374 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 * @head: the head for your list.
376 *
Linus Torvaldse66eed62011-05-19 14:15:29 -0700377 * This variant doesn't differ from list_for_each() any more.
378 * We don't do prefetching in either case.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 */
380#define __list_for_each(pos, head) \
381 for (pos = (head)->next; pos != (head); pos = pos->next)
382
383/**
384 * list_for_each_prev - iterate over a list backwards
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700385 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 * @head: the head for your list.
387 */
388#define list_for_each_prev(pos, head) \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700389 for (pos = (head)->prev; pos != (head); pos = pos->prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390
391/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700392 * list_for_each_safe - iterate over a list safe against removal of list entry
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700393 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 * @n: another &struct list_head to use as temporary storage
395 * @head: the head for your list.
396 */
397#define list_for_each_safe(pos, n, head) \
398 for (pos = (head)->next, n = pos->next; pos != (head); \
399 pos = n, n = pos->next)
400
401/**
Randy Dunlap8f731f72007-10-18 23:39:28 -0700402 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
Denis V. Lunev37c42522007-10-16 23:29:53 -0700403 * @pos: the &struct list_head to use as a loop cursor.
404 * @n: another &struct list_head to use as temporary storage
405 * @head: the head for your list.
406 */
407#define list_for_each_prev_safe(pos, n, head) \
408 for (pos = (head)->prev, n = pos->prev; \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700409 pos != (head); \
Denis V. Lunev37c42522007-10-16 23:29:53 -0700410 pos = n, n = pos->prev)
411
412/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 * list_for_each_entry - iterate over list of given type
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700414 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 * @head: the head for your list.
416 * @member: the name of the list_struct within the struct.
417 */
418#define list_for_each_entry(pos, head, member) \
419 for (pos = list_entry((head)->next, typeof(*pos), member); \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700420 &pos->member != (head); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 pos = list_entry(pos->member.next, typeof(*pos), member))
422
423/**
424 * list_for_each_entry_reverse - iterate backwards over list of given type.
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700425 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 * @head: the head for your list.
427 * @member: the name of the list_struct within the struct.
428 */
429#define list_for_each_entry_reverse(pos, head, member) \
430 for (pos = list_entry((head)->prev, typeof(*pos), member); \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700431 &pos->member != (head); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 pos = list_entry(pos->member.prev, typeof(*pos), member))
433
434/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800435 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 * @pos: the type * to use as a start point
437 * @head: the head of the list
438 * @member: the name of the list_struct within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700439 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800440 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 */
442#define list_prepare_entry(pos, head, member) \
443 ((pos) ? : list_entry(head, typeof(*pos), member))
444
445/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700446 * list_for_each_entry_continue - continue iteration over list of given type
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700447 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 * @head: the head for your list.
449 * @member: the name of the list_struct within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700450 *
451 * Continue to iterate over list of given type, continuing after
452 * the current position.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 */
454#define list_for_each_entry_continue(pos, head, member) \
455 for (pos = list_entry(pos->member.next, typeof(*pos), member); \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700456 &pos->member != (head); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 pos = list_entry(pos->member.next, typeof(*pos), member))
458
459/**
Pavel Emelyanov768f35912007-09-18 13:20:41 -0700460 * list_for_each_entry_continue_reverse - iterate backwards from the given point
461 * @pos: the type * to use as a loop cursor.
462 * @head: the head for your list.
463 * @member: the name of the list_struct within the struct.
464 *
465 * Start to iterate over list of given type backwards, continuing after
466 * the current position.
467 */
468#define list_for_each_entry_continue_reverse(pos, head, member) \
469 for (pos = list_entry(pos->member.prev, typeof(*pos), member); \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700470 &pos->member != (head); \
Pavel Emelyanov768f35912007-09-18 13:20:41 -0700471 pos = list_entry(pos->member.prev, typeof(*pos), member))
472
473/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700474 * list_for_each_entry_from - iterate over list of given type from the current point
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700475 * @pos: the type * to use as a loop cursor.
Arnaldo Carvalho de Meloe229c2f2006-03-20 17:19:17 -0800476 * @head: the head for your list.
477 * @member: the name of the list_struct within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700478 *
479 * Iterate over list of given type, continuing from current position.
Arnaldo Carvalho de Meloe229c2f2006-03-20 17:19:17 -0800480 */
481#define list_for_each_entry_from(pos, head, member) \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700482 for (; &pos->member != (head); \
Arnaldo Carvalho de Meloe229c2f2006-03-20 17:19:17 -0800483 pos = list_entry(pos->member.next, typeof(*pos), member))
484
485/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700487 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 * @n: another type * to use as temporary storage
489 * @head: the head for your list.
490 * @member: the name of the list_struct within the struct.
491 */
492#define list_for_each_entry_safe(pos, n, head, member) \
493 for (pos = list_entry((head)->next, typeof(*pos), member), \
494 n = list_entry(pos->member.next, typeof(*pos), member); \
495 &pos->member != (head); \
496 pos = n, n = list_entry(n->member.next, typeof(*n), member))
497
498/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800499 * list_for_each_entry_safe_continue - continue list iteration safe against removal
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700500 * @pos: the type * to use as a loop cursor.
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700501 * @n: another type * to use as temporary storage
502 * @head: the head for your list.
503 * @member: the name of the list_struct within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700504 *
505 * Iterate over list of given type, continuing after current point,
506 * safe against removal of list entry.
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700507 */
508#define list_for_each_entry_safe_continue(pos, n, head, member) \
Arnaldo Carvalho de Melo8c60f3f2005-08-10 12:59:38 -0300509 for (pos = list_entry(pos->member.next, typeof(*pos), member), \
510 n = list_entry(pos->member.next, typeof(*pos), member); \
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700511 &pos->member != (head); \
512 pos = n, n = list_entry(n->member.next, typeof(*n), member))
513
514/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800515 * list_for_each_entry_safe_from - iterate over list from current point safe against removal
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700516 * @pos: the type * to use as a loop cursor.
Arnaldo Carvalho de Melod8dcffe2006-03-20 17:18:05 -0800517 * @n: another type * to use as temporary storage
518 * @head: the head for your list.
519 * @member: the name of the list_struct within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700520 *
521 * Iterate over list of given type from current point, safe against
522 * removal of list entry.
Arnaldo Carvalho de Melod8dcffe2006-03-20 17:18:05 -0800523 */
524#define list_for_each_entry_safe_from(pos, n, head, member) \
525 for (n = list_entry(pos->member.next, typeof(*pos), member); \
526 &pos->member != (head); \
527 pos = n, n = list_entry(n->member.next, typeof(*n), member))
528
529/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800530 * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700531 * @pos: the type * to use as a loop cursor.
David Howells0ad42352006-01-09 20:51:31 -0800532 * @n: another type * to use as temporary storage
533 * @head: the head for your list.
534 * @member: the name of the list_struct within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700535 *
536 * Iterate backwards over list of given type, safe against removal
537 * of list entry.
David Howells0ad42352006-01-09 20:51:31 -0800538 */
539#define list_for_each_entry_safe_reverse(pos, n, head, member) \
540 for (pos = list_entry((head)->prev, typeof(*pos), member), \
541 n = list_entry(pos->member.prev, typeof(*pos), member); \
542 &pos->member != (head); \
543 pos = n, n = list_entry(n->member.prev, typeof(*n), member))
544
npiggin@suse.de57439f82010-06-24 13:02:14 +1000545/**
546 * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
547 * @pos: the loop cursor used in the list_for_each_entry_safe loop
548 * @n: temporary storage used in list_for_each_entry_safe
549 * @member: the name of the list_struct within the struct.
550 *
551 * list_safe_reset_next is not safe to use in general if the list may be
552 * modified concurrently (eg. the lock is dropped in the loop body). An
553 * exception to this is if the cursor element (pos) is pinned in the list,
554 * and list_safe_reset_next is called after re-taking the lock and before
555 * completing the current iteration of the loop body.
556 */
557#define list_safe_reset_next(pos, n, member) \
558 n = list_entry(pos->member.next, typeof(*pos), member)
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560/*
561 * Double linked lists with a single pointer list head.
562 * Mostly useful for hash tables where the two pointer list head is
563 * too wasteful.
564 * You lose the ability to access the tail in O(1).
565 */
566
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567#define HLIST_HEAD_INIT { .first = NULL }
568#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
569#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
Zach Brown490d6ab2006-02-03 03:03:56 -0800570static inline void INIT_HLIST_NODE(struct hlist_node *h)
571{
572 h->next = NULL;
573 h->pprev = NULL;
574}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575
576static inline int hlist_unhashed(const struct hlist_node *h)
577{
578 return !h->pprev;
579}
580
581static inline int hlist_empty(const struct hlist_head *h)
582{
583 return !h->first;
584}
585
586static inline void __hlist_del(struct hlist_node *n)
587{
588 struct hlist_node *next = n->next;
589 struct hlist_node **pprev = n->pprev;
590 *pprev = next;
591 if (next)
592 next->pprev = pprev;
593}
594
595static inline void hlist_del(struct hlist_node *n)
596{
597 __hlist_del(n);
598 n->next = LIST_POISON1;
599 n->pprev = LIST_POISON2;
600}
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602static inline void hlist_del_init(struct hlist_node *n)
603{
Akinobu Mitada753be2006-04-28 15:21:23 -0700604 if (!hlist_unhashed(n)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 __hlist_del(n);
606 INIT_HLIST_NODE(n);
607 }
608}
609
610static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
611{
612 struct hlist_node *first = h->first;
613 n->next = first;
614 if (first)
615 first->pprev = &n->next;
616 h->first = n;
617 n->pprev = &h->first;
618}
619
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620/* next must be != NULL */
621static inline void hlist_add_before(struct hlist_node *n,
622 struct hlist_node *next)
623{
624 n->pprev = next->pprev;
625 n->next = next;
626 next->pprev = &n->next;
627 *(n->pprev) = n;
628}
629
630static inline void hlist_add_after(struct hlist_node *n,
631 struct hlist_node *next)
632{
633 next->next = n->next;
634 n->next = next;
635 next->pprev = &n->next;
636
637 if(next->next)
638 next->next->pprev = &next->next;
639}
640
Al Viro756acc22010-10-23 15:23:40 -0400641/* after that we'll appear to be on some hlist and hlist_del will work */
642static inline void hlist_add_fake(struct hlist_node *n)
643{
644 n->pprev = &n->next;
645}
646
Vegard Nossum673d62cc2008-08-31 23:39:21 +0200647/*
648 * Move a list from one list head to another. Fixup the pprev
649 * reference of the first entry if it exists.
650 */
651static inline void hlist_move_list(struct hlist_head *old,
652 struct hlist_head *new)
653{
654 new->first = old->first;
655 if (new->first)
656 new->first->pprev = &new->first;
657 old->first = NULL;
658}
659
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
661
662#define hlist_for_each(pos, head) \
Linus Torvalds75d65a42011-05-19 13:50:07 -0700663 for (pos = (head)->first; pos ; pos = pos->next)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664
665#define hlist_for_each_safe(pos, n, head) \
666 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
667 pos = n)
668
Sasha Levinb67bfe02013-02-27 17:06:00 -0800669#define hlist_entry_safe(ptr, type, member) \
670 (ptr) ? hlist_entry(ptr, type, member) : NULL
671
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672/**
673 * hlist_for_each_entry - iterate over list of given type
Sasha Levinb67bfe02013-02-27 17:06:00 -0800674 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 * @head: the head for your list.
676 * @member: the name of the hlist_node within the struct.
677 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800678#define hlist_for_each_entry(pos, head, member) \
679 for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
680 pos; \
681 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682
683/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700684 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
Sasha Levinb67bfe02013-02-27 17:06:00 -0800685 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 * @member: the name of the hlist_node within the struct.
687 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800688#define hlist_for_each_entry_continue(pos, member) \
689 for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
690 pos; \
691 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692
693/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700694 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
Sasha Levinb67bfe02013-02-27 17:06:00 -0800695 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 * @member: the name of the hlist_node within the struct.
697 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800698#define hlist_for_each_entry_from(pos, member) \
699 for (; pos; \
700 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
702/**
703 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
Sasha Levinb67bfe02013-02-27 17:06:00 -0800704 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 * @n: another &struct hlist_node to use as temporary storage
706 * @head: the head for your list.
707 * @member: the name of the hlist_node within the struct.
708 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800709#define hlist_for_each_entry_safe(pos, n, head, member) \
710 for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
711 pos && ({ n = pos->member.next; 1; }); \
712 pos = hlist_entry_safe(n, typeof(*pos), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714#endif