1 /* SPDX-License-Identifier: GPL-2.0 */
20  * using the generic single-entry routines.
23 #define LIST_HEAD_INIT(name) { &(name), &(name) }  argument
25 #define LIST_HEAD(name) \  argument
26 	struct list_head name = LIST_HEAD_INIT(name)
29  * INIT_LIST_HEAD - Initialize a list_head structure
37 	WRITE_ONCE(list->next, list);  in INIT_LIST_HEAD()
38 	WRITE_ONCE(list->prev, list);  in INIT_LIST_HEAD()
45 extern bool __list_del_entry_valid(struct list_head *entry);
53 static inline bool __list_del_entry_valid(struct list_head *entry)  in __list_del_entry_valid()  argument
60  * Insert a new entry between two known consecutive entries.
72 	next->prev = new;  in __list_add()
73 	new->next = next;  in __list_add()
74 	new->prev = prev;  in __list_add()
75 	WRITE_ONCE(prev->next, new);  in __list_add()
79  * list_add - add a new entry
80  * @new: new entry to be added
83  * Insert a new entry after the specified head.
88 	__list_add(new, head, head->next);  in list_add()
93  * list_add_tail - add a new entry
94  * @new: new entry to be added
97  * Insert a new entry before the specified head.
102 	__list_add(new, head->prev, head);  in list_add_tail()
106  * Delete a list entry by making the prev/next entries
114 	next->prev = prev;  in __list_del()
115 	WRITE_ONCE(prev->next, next);  in __list_del()
119  * Delete a list entry and clear the 'prev' pointer.
121  * This is a special-purpose list clearing method used in the networking code
122  * for lists allocated as per-cpu, where we don't want to incur the extra
126 static inline void __list_del_clearprev(struct list_head *entry)  in __list_del_clearprev()  argument
128 	__list_del(entry->prev, entry->next);  in __list_del_clearprev()
129 	entry->prev = NULL;  in __list_del_clearprev()
132 static inline void __list_del_entry(struct list_head *entry)  in __list_del_entry()  argument
134 	if (!__list_del_entry_valid(entry))  in __list_del_entry()
137 	__list_del(entry->prev, entry->next);  in __list_del_entry()
141  * list_del - deletes entry from list.
142  * @entry: the element to delete from the list.
143  * Note: list_empty() on entry does not return true after this, the entry is
146 static inline void list_del(struct list_head *entry)  in list_del()  argument
148 	__list_del_entry(entry);  in list_del()
149 	entry->next = LIST_POISON1;  in list_del()
150 	entry->prev = LIST_POISON2;  in list_del()
154  * list_replace - replace old entry by new one
163 	new->next = old->next;  in list_replace()
164 	new->next->prev = new;  in list_replace()
165 	new->prev = old->prev;  in list_replace()
166 	new->prev->next = new;  in list_replace()
170  * list_replace_init - replace old entry by new one and initialize the old one
184  * list_swap - replace entry1 with entry2 and re-add entry1 at entry2's position
191 	struct list_head *pos = entry2->prev;  in list_swap()
201  * list_del_init - deletes entry from list and reinitialize it.
202  * @entry: the element to delete from the list.
204 static inline void list_del_init(struct list_head *entry)  in list_del_init()  argument
206 	__list_del_entry(entry);  in list_del_init()
207 	INIT_LIST_HEAD(entry);  in list_del_init()
211  * list_move - delete from one list and add as another's head
212  * @list: the entry to move
213  * @head: the head that will precede our entry
222  * list_move_tail - delete from one list and add as another's tail
223  * @list: the entry to move
224  * @head: the head that will follow our entry
234  * list_bulk_move_tail - move a subsection of a list to its tail
235  * @head: the head that will follow our entry
236  * @first: first entry to move
237  * @last: last entry to move, can be the same as first
246 	first->prev->next = last->next;  in list_bulk_move_tail()
247 	last->next->prev = first->prev;  in list_bulk_move_tail()
249 	head->prev->next = first;  in list_bulk_move_tail()
250 	first->prev = head->prev;  in list_bulk_move_tail()
252 	last->next = head;  in list_bulk_move_tail()
253 	head->prev = last;  in list_bulk_move_tail()
257  * list_is_first -- tests whether @list is the first entry in list @head
258  * @list: the entry to test
263 	return list->prev == head;  in list_is_first()
267  * list_is_last - tests whether @list is the last entry in list @head
268  * @list: the entry to test
273 	return list->next == head;  in list_is_last()
277  * list_is_head - tests whether @list is the list @head
278  * @list: the entry to test
287  * list_empty - tests whether a list is empty
292 	return READ_ONCE(head->next) == head;  in list_empty()
296  * list_del_init_careful - deletes entry from list and reinitialize it.
297  * @entry: the element to delete from the list.
306 static inline void list_del_init_careful(struct list_head *entry)  in list_del_init_careful()  argument
308 	__list_del_entry(entry);  in list_del_init_careful()
309 	WRITE_ONCE(entry->prev, entry);  in list_del_init_careful()
310 	smp_store_release(&entry->next, entry);  in list_del_init_careful()
314  * list_empty_careful - tests whether a list is empty and not being modified
323  * to the list entry is list_del_init(). Eg. it cannot be used
324  * if another CPU could re-list_add() it.
328 	struct list_head *next = smp_load_acquire(&head->next);  in list_empty_careful()
329 	return list_is_head(next, head) && (next == READ_ONCE(head->prev));  in list_empty_careful()
333  * list_rotate_left - rotate the list to the left
341 		first = head->next;  in list_rotate_left()
347  * list_rotate_to_front() - Rotate list to specific item.
365  * list_is_singular - tests whether a list has just one entry.
370 	return !list_empty(head) && (head->next == head->prev);  in list_is_singular()
374 		struct list_head *head, struct list_head *entry)  in __list_cut_position()  argument
376 	struct list_head *new_first = entry->next;  in __list_cut_position()
377 	list->next = head->next;  in __list_cut_position()
378 	list->next->prev = list;  in __list_cut_position()
379 	list->prev = entry;  in __list_cut_position()
380 	entry->next = list;  in __list_cut_position()
381 	head->next = new_first;  in __list_cut_position()
382 	new_first->prev = head;  in __list_cut_position()
386  * list_cut_position - cut a list into two
389  * @entry: an entry within head, could be the head itself
393  * including @entry, from @head to @list. You should
394  * pass on @entry an element you know is on @head. @list
400 		struct list_head *head, struct list_head *entry)  in list_cut_position()  argument
404 	if (list_is_singular(head) && !list_is_head(entry, head) && (entry != head->next))  in list_cut_position()
406 	if (list_is_head(entry, head))  in list_cut_position()
409 		__list_cut_position(list, head, entry);  in list_cut_position()
413  * list_cut_before - cut a list into two, before given entry
416  * @entry: an entry within head, could be the head itself
419  * excluding @entry, from @head to @list.  You should pass
420  * in @entry an element you know is on @head.  @list should
423  * If @entry == @head, all entries on @head are moved to
428 				   struct list_head *entry)  in list_cut_before()  argument
430 	if (head->next == entry) {  in list_cut_before()
434 	list->next = head->next;  in list_cut_before()
435 	list->next->prev = list;  in list_cut_before()
436 	list->prev = entry->prev;  in list_cut_before()
437 	list->prev->next = list;  in list_cut_before()
438 	head->next = entry;  in list_cut_before()
439 	entry->prev = head;  in list_cut_before()
446 	struct list_head *first = list->next;  in __list_splice()
447 	struct list_head *last = list->prev;  in __list_splice()
449 	first->prev = prev;  in __list_splice()
450 	prev->next = first;  in __list_splice()
452 	last->next = next;  in __list_splice()
453 	next->prev = last;  in __list_splice()
457  * list_splice - join two lists, this is designed for stacks
465 		__list_splice(list, head, head->next);  in list_splice()
469  * list_splice_tail - join two lists, each list being a queue
477 		__list_splice(list, head->prev, head);  in list_splice_tail()
481  * list_splice_init - join two lists and reinitialise the emptied list.
491 		__list_splice(list, head, head->next);  in list_splice_init()
497  * list_splice_tail_init - join two lists and reinitialise the emptied list
508 		__list_splice(list, head->prev, head);  in list_splice_tail_init()
514  * list_entry - get the struct for this entry
517  * @member:	the name of the list_head within the struct.
523  * list_first_entry - get the first element from a list
526  * @member:	the name of the list_head within the struct.
531 	list_entry((ptr)->next, type, member)
534  * list_last_entry - get the last element from a list
537  * @member:	the name of the list_head within the struct.
542 	list_entry((ptr)->prev, type, member)
545  * list_first_entry_or_null - get the first element from a list
548  * @member:	the name of the list_head within the struct.
554 	struct list_head *pos__ = READ_ONCE(head__->next); \
559  * list_next_entry - get the next element in list
561  * @member:	the name of the list_head within the struct.
564 	list_entry((pos)->member.next, typeof(*(pos)), member)
567  * list_next_entry_circular - get the next element in list
570  * @member:	the name of the list_head within the struct.
576 	(list_is_last(&(pos)->member, head) ? \
580  * list_prev_entry - get the prev element in list
582  * @member:	the name of the list_head within the struct.
585 	list_entry((pos)->member.prev, typeof(*(pos)), member)
588  * list_prev_entry_circular - get the prev element in list
591  * @member:	the name of the list_head within the struct.
597 	(list_is_first(&(pos)->member, head) ? \
601  * list_for_each	-	iterate over a list
606 	for (pos = (head)->next; !list_is_head(pos, (head)); pos = pos->next)
609  * list_for_each_rcu - Iterate over a list in an RCU-safe fashion
614 	for (pos = rcu_dereference((head)->next); \
616 	     pos = rcu_dereference(pos->next))
619  * list_for_each_continue - continue iteration over a list
626 	for (pos = pos->next; !list_is_head(pos, (head)); pos = pos->next)
629  * list_for_each_prev	-	iterate over a list backwards
634 	for (pos = (head)->prev; !list_is_head(pos, (head)); pos = pos->prev)
637  * list_for_each_safe - iterate over a list safe against removal of list entry
643 	for (pos = (head)->next, n = pos->next; \
645 	     pos = n, n = pos->next)
648  * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
654 	for (pos = (head)->prev, n = pos->prev; \
656 	     pos = n, n = pos->prev)
659  * list_entry_is_head - test if the entry points to the head of the list
662  * @member:	the name of the list_head within the struct.
665 	(&pos->member == (head))
668  * list_for_each_entry	-	iterate over list of given type
671  * @member:	the name of the list_head within the struct.
679  * list_for_each_entry_reverse - iterate backwards over list of given type.
682  * @member:	the name of the list_head within the struct.
690  * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
693  * @member:	the name of the list_head within the struct.
695  * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
701  * list_for_each_entry_continue - continue iteration over list of given type
704  * @member:	the name of the list_head within the struct.
715  * list_for_each_entry_continue_reverse - iterate backwards from the given point
718  * @member:	the name of the list_head within the struct.
729  * list_for_each_entry_from - iterate over list of given type from the current point
732  * @member:	the name of the list_head within the struct.
741  * list_for_each_entry_from_reverse - iterate backwards over list of given type
745  * @member:	the name of the list_head within the struct.
754  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
758  * @member:	the name of the list_head within the struct.
767  * list_for_each_entry_safe_continue - continue list iteration safe against removal
771  * @member:	the name of the list_head within the struct.
774  * safe against removal of list entry.
783  * list_for_each_entry_safe_from - iterate over list from current point safe against removal
787  * @member:	the name of the list_head within the struct.
790  * removal of list entry.
798  * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
802  * @member:	the name of the list_head within the struct.
805  * of list entry.
814  * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
817  * @member:	the name of the list_head within the struct.
822  * and list_safe_reset_next is called after re-taking the lock and before
836 #define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }  argument
837 #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
840 	h->next = NULL;  in INIT_HLIST_NODE()
841 	h->pprev = NULL;  in INIT_HLIST_NODE()
845  * hlist_unhashed - Has node been removed from list and reinitialized?
854 	return !h->pprev;  in hlist_unhashed()
858  * hlist_unhashed_lockless - Version of hlist_unhashed for lockless use
862  * to avoid potential load-tearing.  The READ_ONCE() is paired with the
867 	return !READ_ONCE(h->pprev);  in hlist_unhashed_lockless()
871  * hlist_empty - Is the specified hlist_head structure an empty hlist?
876 	return !READ_ONCE(h->first);  in hlist_empty()
881 	struct hlist_node *next = n->next;  in __hlist_del()
882 	struct hlist_node **pprev = n->pprev;  in __hlist_del()
886 		WRITE_ONCE(next->pprev, pprev);  in __hlist_del()
890  * hlist_del - Delete the specified hlist_node from its list
899 	n->next = LIST_POISON1;  in hlist_del()
900 	n->pprev = LIST_POISON2;  in hlist_del()
904  * hlist_del_init - Delete the specified hlist_node from its list and initialize
918  * hlist_add_head - add a new entry at the beginning of the hlist
919  * @n: new entry to be added
922  * Insert a new entry after the specified head.
927 	struct hlist_node *first = h->first;  in hlist_add_head()
928 	WRITE_ONCE(n->next, first);  in hlist_add_head()
930 		WRITE_ONCE(first->pprev, &n->next);  in hlist_add_head()
931 	WRITE_ONCE(h->first, n);  in hlist_add_head()
932 	WRITE_ONCE(n->pprev, &h->first);  in hlist_add_head()
936  * hlist_add_before - add a new entry before the one specified
937  * @n: new entry to be added
938  * @next: hlist node to add it before, which must be non-NULL
943 	WRITE_ONCE(n->pprev, next->pprev);  in hlist_add_before()
944 	WRITE_ONCE(n->next, next);  in hlist_add_before()
945 	WRITE_ONCE(next->pprev, &n->next);  in hlist_add_before()
946 	WRITE_ONCE(*(n->pprev), n);  in hlist_add_before()
950  * hlist_add_behind - add a new entry after the one specified
951  * @n: new entry to be added
952  * @prev: hlist node to add it after, which must be non-NULL
957 	WRITE_ONCE(n->next, prev->next);  in hlist_add_behind()
958 	WRITE_ONCE(prev->next, n);  in hlist_add_behind()
959 	WRITE_ONCE(n->pprev, &prev->next);  in hlist_add_behind()
961 	if (n->next)  in hlist_add_behind()
962 		WRITE_ONCE(n->next->pprev, &n->next);  in hlist_add_behind()
966  * hlist_add_fake - create a fake hlist consisting of a single headless node
975 	n->pprev = &n->next;  in hlist_add_fake()
980  * @h: Node to check for being a self-referential fake hlist.
984 	return h->pprev == &h->next;  in hlist_fake()
988  * hlist_is_singular_node - is node the only element of the specified hlist?
998 	return !n->next && n->pprev == &h->first;  in hlist_is_singular_node()
1002  * hlist_move_list - Move an hlist
1007  * reference of the first entry if it exists.
1012 	new->first = old->first;  in hlist_move_list()
1013 	if (new->first)  in hlist_move_list()
1014 		new->first->pprev = &new->first;  in hlist_move_list()
1015 	old->first = NULL;  in hlist_move_list()
1021 	for (pos = (head)->first; pos ; pos = pos->next)
1024 	for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
1033  * hlist_for_each_entry	- iterate over list of given type
1036  * @member:	the name of the hlist_node within the struct.
1039 	for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
1041 	     pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
1044  * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
1046  * @member:	the name of the hlist_node within the struct.
1049 	for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
1051 	     pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
1054  * hlist_for_each_entry_from - iterate over a hlist continuing from current point
1056  * @member:	the name of the hlist_node within the struct.
1060 	     pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
1063  * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
1067  * @member:	the name of the hlist_node within the struct.
1070 	for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
1071 	     pos && ({ n = pos->member.next; 1; });			\