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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>
Masahiro Yamada8b21d9c2014-10-13 15:51:30 -07008#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009
10/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Simple doubly linked list implementation.
12 *
13 * Some of the internal functions ("__xxx") are useful when
14 * manipulating whole lists rather than single entries, as
15 * sometimes we already know the next/prev entries and we can
16 * generate better code by using them directly rather than
17 * using the generic single-entry routines.
18 */
19
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#define LIST_HEAD_INIT(name) { &(name), &(name) }
21
22#define LIST_HEAD(name) \
23 struct list_head name = LIST_HEAD_INIT(name)
24
Zach Brown490d6ab2006-02-03 03:03:56 -080025static inline void INIT_LIST_HEAD(struct list_head *list)
26{
27 list->next = list;
28 list->prev = list;
29}
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
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 */
Dave Jones199a9af2006-09-29 01:59:00 -070037#ifndef CONFIG_DEBUG_LIST
Linus Torvalds1da177e2005-04-16 15:20:36 -070038static inline void __list_add(struct list_head *new,
39 struct list_head *prev,
40 struct list_head *next)
41{
42 next->prev = new;
43 new->next = next;
44 new->prev = prev;
45 prev->next = new;
46}
Dave Jones199a9af2006-09-29 01:59:00 -070047#else
48extern void __list_add(struct list_head *new,
49 struct list_head *prev,
50 struct list_head *next);
51#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53/**
54 * list_add - add a new entry
55 * @new: new entry to be added
56 * @head: list head to add it after
57 *
58 * Insert a new entry after the specified head.
59 * This is good for implementing stacks.
60 */
61static inline void list_add(struct list_head *new, struct list_head *head)
62{
63 __list_add(new, head, head->next);
64}
Dave Jones199a9af2006-09-29 01:59:00 -070065
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67/**
68 * list_add_tail - add a new entry
69 * @new: new entry to be added
70 * @head: list head to add it before
71 *
72 * Insert a new entry before the specified head.
73 * This is useful for implementing queues.
74 */
75static inline void list_add_tail(struct list_head *new, struct list_head *head)
76{
77 __list_add(new, head->prev, head);
78}
79
80/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 * Delete a list entry by making the prev/next entries
82 * point to each other.
83 *
84 * This is only for internal list manipulation where we know
85 * the prev/next entries already!
86 */
87static inline void __list_del(struct list_head * prev, struct list_head * next)
88{
89 next->prev = prev;
90 prev->next = next;
91}
92
93/**
94 * list_del - deletes entry from list.
95 * @entry: the element to delete from the list.
Robert P. J. Day72fd4a32007-02-10 01:45:59 -080096 * Note: list_empty() on entry does not return true after this, the entry is
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 * in an undefined state.
98 */
Dave Jones199a9af2006-09-29 01:59:00 -070099#ifndef CONFIG_DEBUG_LIST
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800100static inline void __list_del_entry(struct list_head *entry)
101{
102 __list_del(entry->prev, entry->next);
103}
104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105static inline void list_del(struct list_head *entry)
106{
107 __list_del(entry->prev, entry->next);
108 entry->next = LIST_POISON1;
109 entry->prev = LIST_POISON2;
110}
Dave Jones199a9af2006-09-29 01:59:00 -0700111#else
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800112extern void __list_del_entry(struct list_head *entry);
Dave Jones199a9af2006-09-29 01:59:00 -0700113extern void list_del(struct list_head *entry);
114#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
116/**
Oleg Nesterov54e73772006-06-23 02:05:54 -0700117 * list_replace - replace old entry by new one
118 * @old : the element to be replaced
119 * @new : the new element to insert
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800120 *
121 * If @old was empty, it will be overwritten.
Oleg Nesterov54e73772006-06-23 02:05:54 -0700122 */
123static inline void list_replace(struct list_head *old,
124 struct list_head *new)
125{
126 new->next = old->next;
127 new->next->prev = new;
128 new->prev = old->prev;
129 new->prev->next = new;
130}
131
132static inline void list_replace_init(struct list_head *old,
133 struct list_head *new)
134{
135 list_replace(old, new);
136 INIT_LIST_HEAD(old);
137}
138
Robert P. J. Day45f8bde2007-01-26 00:57:09 -0800139/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 * list_del_init - deletes entry from list and reinitialize it.
141 * @entry: the element to delete from the list.
142 */
143static inline void list_del_init(struct list_head *entry)
144{
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800145 __list_del_entry(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 INIT_LIST_HEAD(entry);
147}
148
149/**
150 * list_move - delete from one list and add as another's head
151 * @list: the entry to move
152 * @head: the head that will precede our entry
153 */
154static inline void list_move(struct list_head *list, struct list_head *head)
155{
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800156 __list_del_entry(list);
Daniel Walker78db2ad2007-05-12 16:28:35 -0700157 list_add(list, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158}
159
160/**
161 * list_move_tail - delete from one list and add as another's tail
162 * @list: the entry to move
163 * @head: the head that will follow our entry
164 */
165static inline void list_move_tail(struct list_head *list,
166 struct list_head *head)
167{
Linus Torvalds3c18d4d2011-02-18 11:32:28 -0800168 __list_del_entry(list);
Daniel Walker78db2ad2007-05-12 16:28:35 -0700169 list_add_tail(list, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
172/**
Shailabh Nagare8f4d972006-07-14 00:24:35 -0700173 * list_is_last - tests whether @list is the last entry in list @head
174 * @list: the entry to test
175 * @head: the head of the list
176 */
177static inline int list_is_last(const struct list_head *list,
178 const struct list_head *head)
179{
180 return list->next == head;
181}
182
183/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 * list_empty - tests whether a list is empty
185 * @head: the list to test.
186 */
187static inline int list_empty(const struct list_head *head)
188{
189 return head->next == head;
190}
191
192/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700193 * list_empty_careful - tests whether a list is empty and not being modified
194 * @head: the list to test
195 *
196 * Description:
197 * tests whether a list is empty _and_ checks that no other CPU might be
198 * in the process of modifying either member (next or prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 *
200 * NOTE: using list_empty_careful() without synchronization
201 * can only be safe if the only activity that can happen
202 * to the list entry is list_del_init(). Eg. it cannot be used
203 * if another CPU could re-list_add() it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 */
205static inline int list_empty_careful(const struct list_head *head)
206{
207 struct list_head *next = head->next;
208 return (next == head) && (next == head->prev);
209}
210
Masami Hiramatsu99602572008-04-28 02:14:27 -0700211/**
Frederic Weisbecker5908cdc2010-01-09 20:53:14 +0100212 * list_rotate_left - rotate the list to the left
213 * @head: the head of the list
214 */
215static inline void list_rotate_left(struct list_head *head)
216{
217 struct list_head *first;
218
219 if (!list_empty(head)) {
220 first = head->next;
221 list_move_tail(first, head);
222 }
223}
224
225/**
Masami Hiramatsu99602572008-04-28 02:14:27 -0700226 * list_is_singular - tests whether a list has just one entry.
227 * @head: the list to test.
228 */
229static inline int list_is_singular(const struct list_head *head)
230{
231 return !list_empty(head) && (head->next == head->prev);
232}
233
Luis R. Rodriguez00e8a4d2008-08-06 13:28:54 -0700234static inline void __list_cut_position(struct list_head *list,
235 struct list_head *head, struct list_head *entry)
236{
237 struct list_head *new_first = entry->next;
238 list->next = head->next;
239 list->next->prev = list;
240 list->prev = entry;
241 entry->next = list;
242 head->next = new_first;
243 new_first->prev = head;
244}
245
246/**
247 * list_cut_position - cut a list into two
248 * @list: a new list to add all removed entries
249 * @head: a list with entries
250 * @entry: an entry within head, could be the head itself
251 * and if so we won't cut the list
252 *
253 * This helper moves the initial part of @head, up to and
254 * including @entry, from @head to @list. You should
255 * pass on @entry an element you know is on @head. @list
256 * should be an empty list or a list you do not care about
257 * losing its data.
258 *
259 */
260static inline void list_cut_position(struct list_head *list,
261 struct list_head *head, struct list_head *entry)
262{
263 if (list_empty(head))
264 return;
265 if (list_is_singular(head) &&
266 (head->next != entry && head != entry))
267 return;
268 if (entry == head)
269 INIT_LIST_HEAD(list);
270 else
271 __list_cut_position(list, head, entry);
272}
273
Robert P. J. Day95d8c362008-04-29 00:59:29 -0700274static inline void __list_splice(const struct list_head *list,
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700275 struct list_head *prev,
276 struct list_head *next)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277{
278 struct list_head *first = list->next;
279 struct list_head *last = list->prev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700281 first->prev = prev;
282 prev->next = first;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700284 last->next = next;
285 next->prev = last;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286}
287
288/**
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700289 * list_splice - join two lists, this is designed for stacks
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 * @list: the new list to add.
291 * @head: the place to add it in the first list.
292 */
Robert P. J. Day95d8c362008-04-29 00:59:29 -0700293static inline void list_splice(const struct list_head *list,
294 struct list_head *head)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295{
296 if (!list_empty(list))
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700297 __list_splice(list, head, head->next);
298}
299
300/**
301 * list_splice_tail - join two lists, each list being a queue
302 * @list: the new list to add.
303 * @head: the place to add it in the first list.
304 */
305static inline void list_splice_tail(struct list_head *list,
306 struct list_head *head)
307{
308 if (!list_empty(list))
309 __list_splice(list, head->prev, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310}
311
312/**
313 * list_splice_init - join two lists and reinitialise the emptied list.
314 * @list: the new list to add.
315 * @head: the place to add it in the first list.
316 *
317 * The list at @list is reinitialised
318 */
319static inline void list_splice_init(struct list_head *list,
320 struct list_head *head)
321{
322 if (!list_empty(list)) {
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700323 __list_splice(list, head, head->next);
324 INIT_LIST_HEAD(list);
325 }
326}
327
328/**
Randy Dunlap6724cce2008-08-08 13:56:20 -0700329 * list_splice_tail_init - join two lists and reinitialise the emptied list
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700330 * @list: the new list to add.
331 * @head: the place to add it in the first list.
332 *
Randy Dunlap6724cce2008-08-08 13:56:20 -0700333 * Each of the lists is a queue.
Luis R. Rodriguez7d283ae2008-08-06 15:21:26 -0700334 * The list at @list is reinitialised
335 */
336static inline void list_splice_tail_init(struct list_head *list,
337 struct list_head *head)
338{
339 if (!list_empty(list)) {
340 __list_splice(list, head->prev, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 INIT_LIST_HEAD(list);
342 }
343}
344
345/**
346 * list_entry - get the struct for this entry
347 * @ptr: the &struct list_head pointer.
348 * @type: the type of the struct this is embedded in.
Andrey Utkin3943f422014-11-14 05:09:55 +0400349 * @member: the name of the list_head within the struct.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 */
351#define list_entry(ptr, type, member) \
352 container_of(ptr, type, member)
353
354/**
Pavel Emelianovb5e61812007-05-08 00:30:19 -0700355 * list_first_entry - get the first element from a list
356 * @ptr: the list head to take the element from.
357 * @type: the type of the struct this is embedded in.
Andrey Utkin3943f422014-11-14 05:09:55 +0400358 * @member: the name of the list_head within the struct.
Pavel Emelianovb5e61812007-05-08 00:30:19 -0700359 *
360 * Note, that list is expected to be not empty.
361 */
362#define list_first_entry(ptr, type, member) \
363 list_entry((ptr)->next, type, member)
364
365/**
Oleg Nesterov93be3c22013-11-12 15:10:03 -0800366 * list_last_entry - get the last element from a list
367 * @ptr: the list head to take the element from.
368 * @type: the type of the struct this is embedded in.
Andrey Utkin3943f422014-11-14 05:09:55 +0400369 * @member: the name of the list_head within the struct.
Oleg Nesterov93be3c22013-11-12 15:10:03 -0800370 *
371 * Note, that list is expected to be not empty.
372 */
373#define list_last_entry(ptr, type, member) \
374 list_entry((ptr)->prev, type, member)
375
376/**
Jiri Pirko6d7581e2013-05-29 05:02:56 +0000377 * list_first_entry_or_null - get the first element from a list
378 * @ptr: the list head to take the element from.
379 * @type: the type of the struct this is embedded in.
Andrey Utkin3943f422014-11-14 05:09:55 +0400380 * @member: the name of the list_head within the struct.
Jiri Pirko6d7581e2013-05-29 05:02:56 +0000381 *
382 * Note that if the list is empty, it returns NULL.
383 */
384#define list_first_entry_or_null(ptr, type, member) \
385 (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
386
387/**
Oleg Nesterov008208c2013-11-12 15:10:01 -0800388 * list_next_entry - get the next element in list
389 * @pos: the type * to cursor
Andrey Utkin3943f422014-11-14 05:09:55 +0400390 * @member: the name of the list_head within the struct.
Oleg Nesterov008208c2013-11-12 15:10:01 -0800391 */
392#define list_next_entry(pos, member) \
393 list_entry((pos)->member.next, typeof(*(pos)), member)
394
395/**
396 * list_prev_entry - get the prev element in list
397 * @pos: the type * to cursor
Andrey Utkin3943f422014-11-14 05:09:55 +0400398 * @member: the name of the list_head within the struct.
Oleg Nesterov008208c2013-11-12 15:10:01 -0800399 */
400#define list_prev_entry(pos, member) \
401 list_entry((pos)->member.prev, typeof(*(pos)), member)
402
403/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 * list_for_each - iterate over a list
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700405 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 * @head: the head for your list.
407 */
408#define list_for_each(pos, head) \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700409 for (pos = (head)->next; pos != (head); pos = pos->next)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410
411/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 * list_for_each_prev - iterate over a list backwards
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700413 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 * @head: the head for your list.
415 */
416#define list_for_each_prev(pos, head) \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700417 for (pos = (head)->prev; pos != (head); pos = pos->prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418
419/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700420 * list_for_each_safe - iterate over a list safe against removal of list entry
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700421 * @pos: the &struct list_head to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 * @n: another &struct list_head to use as temporary storage
423 * @head: the head for your list.
424 */
425#define list_for_each_safe(pos, n, head) \
426 for (pos = (head)->next, n = pos->next; pos != (head); \
427 pos = n, n = pos->next)
428
429/**
Randy Dunlap8f731f72007-10-18 23:39:28 -0700430 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
Denis V. Lunev37c42522007-10-16 23:29:53 -0700431 * @pos: the &struct list_head to use as a loop cursor.
432 * @n: another &struct list_head to use as temporary storage
433 * @head: the head for your list.
434 */
435#define list_for_each_prev_safe(pos, n, head) \
436 for (pos = (head)->prev, n = pos->prev; \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700437 pos != (head); \
Denis V. Lunev37c42522007-10-16 23:29:53 -0700438 pos = n, n = pos->prev)
439
440/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 * list_for_each_entry - iterate over list of given type
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700442 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400444 * @member: the name of the list_head within the struct.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 */
446#define list_for_each_entry(pos, head, member) \
Oleg Nesterov93be3c22013-11-12 15:10:03 -0800447 for (pos = list_first_entry(head, typeof(*pos), member); \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800448 &pos->member != (head); \
449 pos = list_next_entry(pos, member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450
451/**
452 * list_for_each_entry_reverse - iterate backwards over list of given type.
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700453 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400455 * @member: the name of the list_head within the struct.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 */
457#define list_for_each_entry_reverse(pos, head, member) \
Oleg Nesterov93be3c22013-11-12 15:10:03 -0800458 for (pos = list_last_entry(head, typeof(*pos), member); \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800459 &pos->member != (head); \
460 pos = list_prev_entry(pos, member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
462/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800463 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 * @pos: the type * to use as a start point
465 * @head: the head of the list
Andrey Utkin3943f422014-11-14 05:09:55 +0400466 * @member: the name of the list_head within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700467 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800468 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 */
470#define list_prepare_entry(pos, head, member) \
471 ((pos) ? : list_entry(head, typeof(*pos), member))
472
473/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700474 * list_for_each_entry_continue - continue iteration over list of given type
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700475 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400477 * @member: the name of the list_head within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700478 *
479 * Continue to iterate over list of given type, continuing after
480 * the current position.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 */
482#define list_for_each_entry_continue(pos, head, member) \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800483 for (pos = list_next_entry(pos, member); \
484 &pos->member != (head); \
485 pos = list_next_entry(pos, member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486
487/**
Pavel Emelyanov768f35912007-09-18 13:20:41 -0700488 * list_for_each_entry_continue_reverse - iterate backwards from the given point
489 * @pos: the type * to use as a loop cursor.
490 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400491 * @member: the name of the list_head within the struct.
Pavel Emelyanov768f35912007-09-18 13:20:41 -0700492 *
493 * Start to iterate over list of given type backwards, continuing after
494 * the current position.
495 */
496#define list_for_each_entry_continue_reverse(pos, head, member) \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800497 for (pos = list_prev_entry(pos, member); \
498 &pos->member != (head); \
499 pos = list_prev_entry(pos, member))
Pavel Emelyanov768f35912007-09-18 13:20:41 -0700500
501/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700502 * list_for_each_entry_from - iterate over list of given type from the current point
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700503 * @pos: the type * to use as a loop cursor.
Arnaldo Carvalho de Meloe229c2f2006-03-20 17:19:17 -0800504 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400505 * @member: the name of the list_head within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700506 *
507 * Iterate over list of given type, continuing from current position.
Arnaldo Carvalho de Meloe229c2f2006-03-20 17:19:17 -0800508 */
509#define list_for_each_entry_from(pos, head, member) \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800510 for (; &pos->member != (head); \
511 pos = list_next_entry(pos, member))
Arnaldo Carvalho de Meloe229c2f2006-03-20 17:19:17 -0800512
513/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700515 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 * @n: another type * to use as temporary storage
517 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400518 * @member: the name of the list_head within the struct.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 */
520#define list_for_each_entry_safe(pos, n, head, member) \
Oleg Nesterov93be3c22013-11-12 15:10:03 -0800521 for (pos = list_first_entry(head, typeof(*pos), member), \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800522 n = list_next_entry(pos, member); \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 &pos->member != (head); \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800524 pos = n, n = list_next_entry(n, member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525
526/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800527 * list_for_each_entry_safe_continue - continue list iteration safe against removal
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700528 * @pos: the type * to use as a loop cursor.
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700529 * @n: another type * to use as temporary storage
530 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400531 * @member: the name of the list_head within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700532 *
533 * Iterate over list of given type, continuing after current point,
534 * safe against removal of list entry.
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700535 */
536#define list_for_each_entry_safe_continue(pos, n, head, member) \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800537 for (pos = list_next_entry(pos, member), \
538 n = list_next_entry(pos, member); \
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700539 &pos->member != (head); \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800540 pos = n, n = list_next_entry(n, member))
Arnaldo Carvalho de Melo74459dc2005-08-09 20:15:51 -0700541
542/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800543 * list_for_each_entry_safe_from - iterate over list from current point safe against removal
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700544 * @pos: the type * to use as a loop cursor.
Arnaldo Carvalho de Melod8dcffe2006-03-20 17:18:05 -0800545 * @n: another type * to use as temporary storage
546 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400547 * @member: the name of the list_head within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700548 *
549 * Iterate over list of given type from current point, safe against
550 * removal of list entry.
Arnaldo Carvalho de Melod8dcffe2006-03-20 17:18:05 -0800551 */
552#define list_for_each_entry_safe_from(pos, n, head, member) \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800553 for (n = list_next_entry(pos, member); \
Arnaldo Carvalho de Melod8dcffe2006-03-20 17:18:05 -0800554 &pos->member != (head); \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800555 pos = n, n = list_next_entry(n, member))
Arnaldo Carvalho de Melod8dcffe2006-03-20 17:18:05 -0800556
557/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800558 * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
Randy Dunlap8e3a67a2006-06-25 05:47:43 -0700559 * @pos: the type * to use as a loop cursor.
David Howells0ad42352006-01-09 20:51:31 -0800560 * @n: another type * to use as temporary storage
561 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400562 * @member: the name of the list_head within the struct.
Randy Dunlapfe96e572006-06-25 05:47:42 -0700563 *
564 * Iterate backwards over list of given type, safe against removal
565 * of list entry.
David Howells0ad42352006-01-09 20:51:31 -0800566 */
567#define list_for_each_entry_safe_reverse(pos, n, head, member) \
Oleg Nesterov93be3c22013-11-12 15:10:03 -0800568 for (pos = list_last_entry(head, typeof(*pos), member), \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800569 n = list_prev_entry(pos, member); \
David Howells0ad42352006-01-09 20:51:31 -0800570 &pos->member != (head); \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800571 pos = n, n = list_prev_entry(n, member))
David Howells0ad42352006-01-09 20:51:31 -0800572
npiggin@suse.de57439f82010-06-24 13:02:14 +1000573/**
574 * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
575 * @pos: the loop cursor used in the list_for_each_entry_safe loop
576 * @n: temporary storage used in list_for_each_entry_safe
Andrey Utkin3943f422014-11-14 05:09:55 +0400577 * @member: the name of the list_head within the struct.
npiggin@suse.de57439f82010-06-24 13:02:14 +1000578 *
579 * list_safe_reset_next is not safe to use in general if the list may be
580 * modified concurrently (eg. the lock is dropped in the loop body). An
581 * exception to this is if the cursor element (pos) is pinned in the list,
582 * and list_safe_reset_next is called after re-taking the lock and before
583 * completing the current iteration of the loop body.
584 */
585#define list_safe_reset_next(pos, n, member) \
Oleg Nesterov8120e2e2013-11-12 15:10:02 -0800586 n = list_next_entry(pos, member)
npiggin@suse.de57439f82010-06-24 13:02:14 +1000587
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588/*
589 * Double linked lists with a single pointer list head.
590 * Mostly useful for hash tables where the two pointer list head is
591 * too wasteful.
592 * You lose the ability to access the tail in O(1).
593 */
594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595#define HLIST_HEAD_INIT { .first = NULL }
596#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
597#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
Zach Brown490d6ab2006-02-03 03:03:56 -0800598static inline void INIT_HLIST_NODE(struct hlist_node *h)
599{
600 h->next = NULL;
601 h->pprev = NULL;
602}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603
604static inline int hlist_unhashed(const struct hlist_node *h)
605{
606 return !h->pprev;
607}
608
609static inline int hlist_empty(const struct hlist_head *h)
610{
611 return !h->first;
612}
613
614static inline void __hlist_del(struct hlist_node *n)
615{
616 struct hlist_node *next = n->next;
617 struct hlist_node **pprev = n->pprev;
618 *pprev = next;
619 if (next)
620 next->pprev = pprev;
621}
622
623static inline void hlist_del(struct hlist_node *n)
624{
625 __hlist_del(n);
626 n->next = LIST_POISON1;
627 n->pprev = LIST_POISON2;
628}
629
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630static inline void hlist_del_init(struct hlist_node *n)
631{
Akinobu Mitada753be2006-04-28 15:21:23 -0700632 if (!hlist_unhashed(n)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 __hlist_del(n);
634 INIT_HLIST_NODE(n);
635 }
636}
637
638static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
639{
640 struct hlist_node *first = h->first;
641 n->next = first;
642 if (first)
643 first->pprev = &n->next;
644 h->first = n;
645 n->pprev = &h->first;
646}
647
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648/* next must be != NULL */
649static inline void hlist_add_before(struct hlist_node *n,
650 struct hlist_node *next)
651{
652 n->pprev = next->pprev;
653 n->next = next;
654 next->pprev = &n->next;
655 *(n->pprev) = n;
656}
657
Ken Helias1d023282014-08-06 16:09:16 -0700658static inline void hlist_add_behind(struct hlist_node *n,
659 struct hlist_node *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660{
Ken Heliasbc18dd32014-08-06 16:09:14 -0700661 n->next = prev->next;
662 prev->next = n;
663 n->pprev = &prev->next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664
Ken Heliasbc18dd32014-08-06 16:09:14 -0700665 if (n->next)
666 n->next->pprev = &n->next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667}
668
Al Viro756acc22010-10-23 15:23:40 -0400669/* after that we'll appear to be on some hlist and hlist_del will work */
670static inline void hlist_add_fake(struct hlist_node *n)
671{
672 n->pprev = &n->next;
673}
674
Vegard Nossum673d62cc2008-08-31 23:39:21 +0200675/*
676 * Move a list from one list head to another. Fixup the pprev
677 * reference of the first entry if it exists.
678 */
679static inline void hlist_move_list(struct hlist_head *old,
680 struct hlist_head *new)
681{
682 new->first = old->first;
683 if (new->first)
684 new->first->pprev = &new->first;
685 old->first = NULL;
686}
687
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
689
690#define hlist_for_each(pos, head) \
Linus Torvalds75d65a42011-05-19 13:50:07 -0700691 for (pos = (head)->first; pos ; pos = pos->next)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692
693#define hlist_for_each_safe(pos, n, head) \
694 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
695 pos = n)
696
Sasha Levinb67bfe02013-02-27 17:06:00 -0800697#define hlist_entry_safe(ptr, type, member) \
Paul E. McKenneyf65846a2013-03-09 07:38:41 -0800698 ({ typeof(ptr) ____ptr = (ptr); \
699 ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
700 })
Sasha Levinb67bfe02013-02-27 17:06:00 -0800701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702/**
703 * hlist_for_each_entry - iterate over list of given type
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 * @head: the head for your list.
706 * @member: the name of the hlist_node within the struct.
707 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800708#define hlist_for_each_entry(pos, head, member) \
709 for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
710 pos; \
711 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
713/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700714 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
Sasha Levinb67bfe02013-02-27 17:06:00 -0800715 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 * @member: the name of the hlist_node within the struct.
717 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800718#define hlist_for_each_entry_continue(pos, member) \
719 for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
720 pos; \
721 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722
723/**
Randy Dunlapfe96e572006-06-25 05:47:42 -0700724 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
Sasha Levinb67bfe02013-02-27 17:06:00 -0800725 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 * @member: the name of the hlist_node within the struct.
727 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800728#define hlist_for_each_entry_from(pos, member) \
729 for (; pos; \
730 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
732/**
733 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
Sasha Levinb67bfe02013-02-27 17:06:00 -0800734 * @pos: the type * to use as a loop cursor.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 * @n: another &struct hlist_node to use as temporary storage
736 * @head: the head for your list.
737 * @member: the name of the hlist_node within the struct.
738 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800739#define hlist_for_each_entry_safe(pos, n, head, member) \
740 for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
741 pos && ({ n = pos->member.next; 1; }); \
742 pos = hlist_entry_safe(n, typeof(*pos), member))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744#endif