1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_LIST_H
3#define _LINUX_LIST_H
4
5#include <linux/types.h>
6#include <linux/stddef.h>
7#include <linux/poison.h>
8#include <linux/const.h>
9#include <linux/kernel.h>
10
11/*
12 * Simple doubly linked list implementation.
13 *
14 * Some of the internal functions ("__xxx") are useful when
15 * manipulating whole lists rather than single entries, as
16 * sometimes we already know the next/prev entries and we can
17 * generate better code by using them directly rather than
18 * using the generic single-entry routines.
19 */
20
21#define LIST_HEAD_INIT(name) { &(name), &(name) }
22
23#define LIST_HEAD(name) \
24 struct list_head name = LIST_HEAD_INIT(name)
25
26static inline void INIT_LIST_HEAD(struct list_head *list)
27{
28 WRITE_ONCE(list->next, list);
29 list->prev = list;
30}
31
32#ifdef CONFIG_DEBUG_LIST
33extern bool __list_add_valid(struct list_head *new,
34 struct list_head *prev,
35 struct list_head *next);
36extern bool __list_del_entry_valid(struct list_head *entry);
37#else
38static inline bool __list_add_valid(struct list_head *new,
39 struct list_head *prev,
40 struct list_head *next)
41{
42 return true;
43}
44static inline bool __list_del_entry_valid(struct list_head *entry)
45{
46 return true;
47}
48#endif
49
50/*
51 * Insert a new entry between two known consecutive entries.
52 *
53 * This is only for internal list manipulation where we know
54 * the prev/next entries already!
55 */
56static inline void __list_add(struct list_head *new,
57 struct list_head *prev,
58 struct list_head *next)
59{
60 if (!__list_add_valid(new, prev, next))
61 return;
62
63 next->prev = new;
64 new->next = next;
65 new->prev = prev;
66 WRITE_ONCE(prev->next, new);
67}
68
69/**
70 * list_add - add a new entry
71 * @new: new entry to be added
72 * @head: list head to add it after
73 *
74 * Insert a new entry after the specified head.
75 * This is good for implementing stacks.
76 */
77static inline void list_add(struct list_head *new, struct list_head *head)
78{
79 __list_add(new, head, head->next);
80}
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 WRITE_ONCE(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_entry(struct list_head *entry)
116{
117 if (!__list_del_entry_valid(entry))
118 return;
119
120 __list_del(entry->prev, entry->next);
121}
122
123static inline void list_del(struct list_head *entry)
124{
125 __list_del_entry(entry);
126 entry->next = LIST_POISON1;
127 entry->prev = LIST_POISON2;
128}
129
130/**
131 * list_replace - replace old entry by new one
132 * @old : the element to be replaced
133 * @new : the new element to insert
134 *
135 * If @old was empty, it will be overwritten.
136 */
137static inline void list_replace(struct list_head *old,
138 struct list_head *new)
139{
140 new->next = old->next;
141 new->next->prev = new;
142 new->prev = old->prev;
143 new->prev->next = new;
144}
145
146static inline void list_replace_init(struct list_head *old,
147 struct list_head *new)
148{
149 list_replace(old, new);
150 INIT_LIST_HEAD(old);
151}
152
153/**
154 * list_del_init - deletes entry from list and reinitialize it.
155 * @entry: the element to delete from the list.
156 */
157static inline void list_del_init(struct list_head *entry)
158{
159 __list_del_entry(entry);
160 INIT_LIST_HEAD(entry);
161}
162
163/**
164 * list_move - delete from one list and add as another's head
165 * @list: the entry to move
166 * @head: the head that will precede our entry
167 */
168static inline void list_move(struct list_head *list, struct list_head *head)
169{
170 __list_del_entry(list);
171 list_add(list, head);
172}
173
174/**
175 * list_move_tail - delete from one list and add as another's tail
176 * @list: the entry to move
177 * @head: the head that will follow our entry
178 */
179static inline void list_move_tail(struct list_head *list,
180 struct list_head *head)
181{
182 __list_del_entry(list);
183 list_add_tail(list, head);
184}
185
186/**
187 * list_is_last - tests whether @list is the last entry in list @head
188 * @list: the entry to test
189 * @head: the head of the list
190 */
191static inline int list_is_last(const struct list_head *list,
192 const struct list_head *head)
193{
194 return list->next == head;
195}
196
197/**
198 * list_empty - tests whether a list is empty
199 * @head: the list to test.
200 */
201static inline int list_empty(const struct list_head *head)
202{
203 return READ_ONCE(head->next) == head;
204}
205
206/**
207 * list_empty_careful - tests whether a list is empty and not being modified
208 * @head: the list to test
209 *
210 * Description:
211 * tests whether a list is empty _and_ checks that no other CPU might be
212 * in the process of modifying either member (next or prev)
213 *
214 * NOTE: using list_empty_careful() without synchronization
215 * can only be safe if the only activity that can happen
216 * to the list entry is list_del_init(). Eg. it cannot be used
217 * if another CPU could re-list_add() it.
218 */
219static inline int list_empty_careful(const struct list_head *head)
220{
221 struct list_head *next = head->next;
222 return (next == head) && (next == head->prev);
223}
224
225/**
226 * list_rotate_left - rotate the list to the left
227 * @head: the head of the list
228 */
229static inline void list_rotate_left(struct list_head *head)
230{
231 struct list_head *first;
232
233 if (!list_empty(head)) {
234 first = head->next;
235 list_move_tail(first, head);
236 }
237}
238
239/**
240 * list_is_singular - tests whether a list has just one entry.
241 * @head: the list to test.
242 */
243static inline int list_is_singular(const struct list_head *head)
244{
245 return !list_empty(head) && (head->next == head->prev);
246}
247
248static inline void __list_cut_position(struct list_head *list,
249 struct list_head *head, struct list_head *entry)
250{
251 struct list_head *new_first = entry->next;
252 list->next = head->next;
253 list->next->prev = list;
254 list->prev = entry;
255 entry->next = list;
256 head->next = new_first;
257 new_first->prev = head;
258}
259
260/**
261 * list_cut_position - cut a list into two
262 * @list: a new list to add all removed entries
263 * @head: a list with entries
264 * @entry: an entry within head, could be the head itself
265 * and if so we won't cut the list
266 *
267 * This helper moves the initial part of @head, up to and
268 * including @entry, from @head to @list. You should
269 * pass on @entry an element you know is on @head. @list
270 * should be an empty list or a list you do not care about
271 * losing its data.
272 *
273 */
274static inline void list_cut_position(struct list_head *list,
275 struct list_head *head, struct list_head *entry)
276{
277 if (list_empty(head))
278 return;
279 if (list_is_singular(head) &&
280 (head->next != entry && head != entry))
281 return;
282 if (entry == head)
283 INIT_LIST_HEAD(list);
284 else
285 __list_cut_position(list, head, entry);
286}
287
288/**
289 * list_cut_before - cut a list into two, before given entry
290 * @list: a new list to add all removed entries
291 * @head: a list with entries
292 * @entry: an entry within head, could be the head itself
293 *
294 * This helper moves the initial part of @head, up to but
295 * excluding @entry, from @head to @list. You should pass
296 * in @entry an element you know is on @head. @list should
297 * be an empty list or a list you do not care about losing
298 * its data.
299 * If @entry == @head, all entries on @head are moved to
300 * @list.
301 */
302static inline void list_cut_before(struct list_head *list,
303 struct list_head *head,
304 struct list_head *entry)
305{
306 if (head->next == entry) {
307 INIT_LIST_HEAD(list);
308 return;
309 }
310 list->next = head->next;
311 list->next->prev = list;
312 list->prev = entry->prev;
313 list->prev->next = list;
314 head->next = entry;
315 entry->prev = head;
316}
317
318static inline void __list_splice(const struct list_head *list,
319 struct list_head *prev,
320 struct list_head *next)
321{
322 struct list_head *first = list->next;
323 struct list_head *last = list->prev;
324
325 first->prev = prev;
326 prev->next = first;
327
328 last->next = next;
329 next->prev = last;
330}
331
332/**
333 * list_splice - join two lists, this is designed for stacks
334 * @list: the new list to add.
335 * @head: the place to add it in the first list.
336 */
337static inline void list_splice(const struct list_head *list,
338 struct list_head *head)
339{
340 if (!list_empty(list))
341 __list_splice(list, head, head->next);
342}
343
344/**
345 * list_splice_tail - join two lists, each list being a queue
346 * @list: the new list to add.
347 * @head: the place to add it in the first list.
348 */
349static inline void list_splice_tail(struct list_head *list,
350 struct list_head *head)
351{
352 if (!list_empty(list))
353 __list_splice(list, head->prev, head);
354}
355
356/**
357 * list_splice_init - join two lists and reinitialise the emptied list.
358 * @list: the new list to add.
359 * @head: the place to add it in the first list.
360 *
361 * The list at @list is reinitialised
362 */
363static inline void list_splice_init(struct list_head *list,
364 struct list_head *head)
365{
366 if (!list_empty(list)) {
367 __list_splice(list, head, head->next);
368 INIT_LIST_HEAD(list);
369 }
370}
371
372/**
373 * list_splice_tail_init - join two lists and reinitialise the emptied list
374 * @list: the new list to add.
375 * @head: the place to add it in the first list.
376 *
377 * Each of the lists is a queue.
378 * The list at @list is reinitialised
379 */
380static inline void list_splice_tail_init(struct list_head *list,
381 struct list_head *head)
382{
383 if (!list_empty(list)) {
384 __list_splice(list, head->prev, head);
385 INIT_LIST_HEAD(list);
386 }
387}
388
389/**
390 * list_entry - get the struct for this entry
391 * @ptr: the &struct list_head pointer.
392 * @type: the type of the struct this is embedded in.
393 * @member: the name of the list_head within the struct.
394 */
395#define list_entry(ptr, type, member) \
396 container_of(ptr, type, member)
397
398/**
399 * list_first_entry - get the first element from a list
400 * @ptr: the list head to take the element from.
401 * @type: the type of the struct this is embedded in.
402 * @member: the name of the list_head within the struct.
403 *
404 * Note, that list is expected to be not empty.
405 */
406#define list_first_entry(ptr, type, member) \
407 list_entry((ptr)->next, type, member)
408
409/**
410 * list_last_entry - get the last element from a list
411 * @ptr: the list head to take the element from.
412 * @type: the type of the struct this is embedded in.
413 * @member: the name of the list_head within the struct.
414 *
415 * Note, that list is expected to be not empty.
416 */
417#define list_last_entry(ptr, type, member) \
418 list_entry((ptr)->prev, type, member)
419
420/**
421 * list_first_entry_or_null - get the first element from a list
422 * @ptr: the list head to take the element from.
423 * @type: the type of the struct this is embedded in.
424 * @member: the name of the list_head within the struct.
425 *
426 * Note that if the list is empty, it returns NULL.
427 */
428#define list_first_entry_or_null(ptr, type, member) ({ \
429 struct list_head *head__ = (ptr); \
430 struct list_head *pos__ = READ_ONCE(head__->next); \
431 pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
432})
433
434/**
435 * list_next_entry - get the next element in list
436 * @pos: the type * to cursor
437 * @member: the name of the list_head within the struct.
438 */
439#define list_next_entry(pos, member) \
440 list_entry((pos)->member.next, typeof(*(pos)), member)
441
442/**
443 * list_prev_entry - get the prev element in list
444 * @pos: the type * to cursor
445 * @member: the name of the list_head within the struct.
446 */
447#define list_prev_entry(pos, member) \
448 list_entry((pos)->member.prev, typeof(*(pos)), member)
449
450/**
451 * list_for_each - iterate over a list
452 * @pos: the &struct list_head to use as a loop cursor.
453 * @head: the head for your list.
454 */
455#define list_for_each(pos, head) \
456 for (pos = (head)->next; pos != (head); pos = pos->next)
457
458/**
459 * list_for_each_prev - iterate over a list backwards
460 * @pos: the &struct list_head to use as a loop cursor.
461 * @head: the head for your list.
462 */
463#define list_for_each_prev(pos, head) \
464 for (pos = (head)->prev; pos != (head); pos = pos->prev)
465
466/**
467 * list_for_each_safe - iterate over a list safe against removal of list entry
468 * @pos: the &struct list_head to use as a loop cursor.
469 * @n: another &struct list_head to use as temporary storage
470 * @head: the head for your list.
471 */
472#define list_for_each_safe(pos, n, head) \
473 for (pos = (head)->next, n = pos->next; pos != (head); \
474 pos = n, n = pos->next)
475
476/**
477 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
478 * @pos: the &struct list_head to use as a loop cursor.
479 * @n: another &struct list_head to use as temporary storage
480 * @head: the head for your list.
481 */
482#define list_for_each_prev_safe(pos, n, head) \
483 for (pos = (head)->prev, n = pos->prev; \
484 pos != (head); \
485 pos = n, n = pos->prev)
486
487/**
488 * list_for_each_entry - iterate over list of given type
489 * @pos: the type * to use as a loop cursor.
490 * @head: the head for your list.
491 * @member: the name of the list_head within the struct.
492 */
493#define list_for_each_entry(pos, head, member) \
494 for (pos = list_first_entry(head, typeof(*pos), member); \
495 &pos->member != (head); \
496 pos = list_next_entry(pos, member))
497
498/**
499 * list_for_each_entry_reverse - iterate backwards over list of given type.
500 * @pos: the type * to use as a loop cursor.
501 * @head: the head for your list.
502 * @member: the name of the list_head within the struct.
503 */
504#define list_for_each_entry_reverse(pos, head, member) \
505 for (pos = list_last_entry(head, typeof(*pos), member); \
506 &pos->member != (head); \
507 pos = list_prev_entry(pos, member))
508
509/**
510 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
511 * @pos: the type * to use as a start point
512 * @head: the head of the list
513 * @member: the name of the list_head within the struct.
514 *
515 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
516 */
517#define list_prepare_entry(pos, head, member) \
518 ((pos) ? : list_entry(head, typeof(*pos), member))
519
520/**
521 * list_for_each_entry_continue - continue iteration over list of given type
522 * @pos: the type * to use as a loop cursor.
523 * @head: the head for your list.
524 * @member: the name of the list_head within the struct.
525 *
526 * Continue to iterate over list of given type, continuing after
527 * the current position.
528 */
529#define list_for_each_entry_continue(pos, head, member) \
530 for (pos = list_next_entry(pos, member); \
531 &pos->member != (head); \
532 pos = list_next_entry(pos, member))
533
534/**
535 * list_for_each_entry_continue_reverse - iterate backwards from the given point
536 * @pos: the type * to use as a loop cursor.
537 * @head: the head for your list.
538 * @member: the name of the list_head within the struct.
539 *
540 * Start to iterate over list of given type backwards, continuing after
541 * the current position.
542 */
543#define list_for_each_entry_continue_reverse(pos, head, member) \
544 for (pos = list_prev_entry(pos, member); \
545 &pos->member != (head); \
546 pos = list_prev_entry(pos, member))
547
548/**
549 * list_for_each_entry_from - iterate over list of given type from the current point
550 * @pos: the type * to use as a loop cursor.
551 * @head: the head for your list.
552 * @member: the name of the list_head within the struct.
553 *
554 * Iterate over list of given type, continuing from current position.
555 */
556#define list_for_each_entry_from(pos, head, member) \
557 for (; &pos->member != (head); \
558 pos = list_next_entry(pos, member))
559
560/**
561 * list_for_each_entry_from_reverse - iterate backwards over list of given type
562 * from the current point
563 * @pos: the type * to use as a loop cursor.
564 * @head: the head for your list.
565 * @member: the name of the list_head within the struct.
566 *
567 * Iterate backwards over list of given type, continuing from current position.
568 */
569#define list_for_each_entry_from_reverse(pos, head, member) \
570 for (; &pos->member != (head); \
571 pos = list_prev_entry(pos, member))
572
573/**
574 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
575 * @pos: the type * to use as a loop cursor.
576 * @n: another type * to use as temporary storage
577 * @head: the head for your list.
578 * @member: the name of the list_head within the struct.
579 */
580#define list_for_each_entry_safe(pos, n, head, member) \
581 for (pos = list_first_entry(head, typeof(*pos), member), \
582 n = list_next_entry(pos, member); \
583 &pos->member != (head); \
584 pos = n, n = list_next_entry(n, member))
585
586/**
587 * list_for_each_entry_safe_continue - continue list iteration safe against removal
588 * @pos: the type * to use as a loop cursor.
589 * @n: another type * to use as temporary storage
590 * @head: the head for your list.
591 * @member: the name of the list_head within the struct.
592 *
593 * Iterate over list of given type, continuing after current point,
594 * safe against removal of list entry.
595 */
596#define list_for_each_entry_safe_continue(pos, n, head, member) \
597 for (pos = list_next_entry(pos, member), \
598 n = list_next_entry(pos, member); \
599 &pos->member != (head); \
600 pos = n, n = list_next_entry(n, member))
601
602/**
603 * list_for_each_entry_safe_from - iterate over list from current point safe against removal
604 * @pos: the type * to use as a loop cursor.
605 * @n: another type * to use as temporary storage
606 * @head: the head for your list.
607 * @member: the name of the list_head within the struct.
608 *
609 * Iterate over list of given type from current point, safe against
610 * removal of list entry.
611 */
612#define list_for_each_entry_safe_from(pos, n, head, member) \
613 for (n = list_next_entry(pos, member); \
614 &pos->member != (head); \
615 pos = n, n = list_next_entry(n, member))
616
617/**
618 * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
619 * @pos: the type * to use as a loop cursor.
620 * @n: another type * to use as temporary storage
621 * @head: the head for your list.
622 * @member: the name of the list_head within the struct.
623 *
624 * Iterate backwards over list of given type, safe against removal
625 * of list entry.
626 */
627#define list_for_each_entry_safe_reverse(pos, n, head, member) \
628 for (pos = list_last_entry(head, typeof(*pos), member), \
629 n = list_prev_entry(pos, member); \
630 &pos->member != (head); \
631 pos = n, n = list_prev_entry(n, member))
632
633/**
634 * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
635 * @pos: the loop cursor used in the list_for_each_entry_safe loop
636 * @n: temporary storage used in list_for_each_entry_safe
637 * @member: the name of the list_head within the struct.
638 *
639 * list_safe_reset_next is not safe to use in general if the list may be
640 * modified concurrently (eg. the lock is dropped in the loop body). An
641 * exception to this is if the cursor element (pos) is pinned in the list,
642 * and list_safe_reset_next is called after re-taking the lock and before
643 * completing the current iteration of the loop body.
644 */
645#define list_safe_reset_next(pos, n, member) \
646 n = list_next_entry(pos, member)
647
648/*
649 * Double linked lists with a single pointer list head.
650 * Mostly useful for hash tables where the two pointer list head is
651 * too wasteful.
652 * You lose the ability to access the tail in O(1).
653 */
654
655#define HLIST_HEAD_INIT { .first = NULL }
656#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
657#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
658static inline void INIT_HLIST_NODE(struct hlist_node *h)
659{
660 h->next = NULL;
661 h->pprev = NULL;
662}
663
664static inline int hlist_unhashed(const struct hlist_node *h)
665{
666 return !h->pprev;
667}
668
669static inline int hlist_empty(const struct hlist_head *h)
670{
671 return !READ_ONCE(h->first);
672}
673
674static inline void __hlist_del(struct hlist_node *n)
675{
676 struct hlist_node *next = n->next;
677 struct hlist_node **pprev = n->pprev;
678
679 WRITE_ONCE(*pprev, next);
680 if (next)
681 next->pprev = pprev;
682}
683
684static inline void hlist_del(struct hlist_node *n)
685{
686 __hlist_del(n);
687 n->next = LIST_POISON1;
688 n->pprev = LIST_POISON2;
689}
690
691static inline void hlist_del_init(struct hlist_node *n)
692{
693 if (!hlist_unhashed(n)) {
694 __hlist_del(n);
695 INIT_HLIST_NODE(n);
696 }
697}
698
699static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
700{
701 struct hlist_node *first = h->first;
702 n->next = first;
703 if (first)
704 first->pprev = &n->next;
705 WRITE_ONCE(h->first, n);
706 n->pprev = &h->first;
707}
708
709/* next must be != NULL */
710static inline void hlist_add_before(struct hlist_node *n,
711 struct hlist_node *next)
712{
713 n->pprev = next->pprev;
714 n->next = next;
715 next->pprev = &n->next;
716 WRITE_ONCE(*(n->pprev), n);
717}
718
719static inline void hlist_add_behind(struct hlist_node *n,
720 struct hlist_node *prev)
721{
722 n->next = prev->next;
723 WRITE_ONCE(prev->next, n);
724 n->pprev = &prev->next;
725
726 if (n->next)
727 n->next->pprev = &n->next;
728}
729
730/* after that we'll appear to be on some hlist and hlist_del will work */
731static inline void hlist_add_fake(struct hlist_node *n)
732{
733 n->pprev = &n->next;
734}
735
736static inline bool hlist_fake(struct hlist_node *h)
737{
738 return h->pprev == &h->next;
739}
740
741/*
742 * Check whether the node is the only node of the head without
743 * accessing head:
744 */
745static inline bool
746hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h)
747{
748 return !n->next && n->pprev == &h->first;
749}
750
751/*
752 * Move a list from one list head to another. Fixup the pprev
753 * reference of the first entry if it exists.
754 */
755static inline void hlist_move_list(struct hlist_head *old,
756 struct hlist_head *new)
757{
758 new->first = old->first;
759 if (new->first)
760 new->first->pprev = &new->first;
761 old->first = NULL;
762}
763
764#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
765
766#define hlist_for_each(pos, head) \
767 for (pos = (head)->first; pos ; pos = pos->next)
768
769#define hlist_for_each_safe(pos, n, head) \
770 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
771 pos = n)
772
773#define hlist_entry_safe(ptr, type, member) \
774 ({ typeof(ptr) ____ptr = (ptr); \
775 ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
776 })
777
778/**
779 * hlist_for_each_entry - iterate over list of given type
780 * @pos: the type * to use as a loop cursor.
781 * @head: the head for your list.
782 * @member: the name of the hlist_node within the struct.
783 */
784#define hlist_for_each_entry(pos, head, member) \
785 for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
786 pos; \
787 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
788
789/**
790 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
791 * @pos: the type * to use as a loop cursor.
792 * @member: the name of the hlist_node within the struct.
793 */
794#define hlist_for_each_entry_continue(pos, member) \
795 for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
796 pos; \
797 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
798
799/**
800 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
801 * @pos: the type * to use as a loop cursor.
802 * @member: the name of the hlist_node within the struct.
803 */
804#define hlist_for_each_entry_from(pos, member) \
805 for (; pos; \
806 pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
807
808/**
809 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
810 * @pos: the type * to use as a loop cursor.
811 * @n: another &struct hlist_node to use as temporary storage
812 * @head: the head for your list.
813 * @member: the name of the hlist_node within the struct.
814 */
815#define hlist_for_each_entry_safe(pos, n, head, member) \
816 for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
817 pos && ({ n = pos->member.next; 1; }); \
818 pos = hlist_entry_safe(n, typeof(*pos), member))
819
820#endif
821