1/*
2 * @TAG(OTHER_GPL)
3 */
4
5#pragma once
6
7#include <stddef.h>
8
9#define LIST_POISON1  ((void *) 0x0)
10#define LIST_POISON2  ((void *) 0x0)
11
12#ifndef ARCH_HAS_PREFETCH
13#define ARCH_HAS_PREFETCH
14static inline void prefetch(const void *x) {;}
15#endif
16
17/*
18 * Simple doubly linked list implementation.
19 *
20 * Some of the internal functions ("__xxx") are useful when
21 * manipulating whole lists rather than single entries, as
22 * sometimes we already know the next/prev entries and we can
23 * generate better code by using them directly rather than
24 * using the generic single-entry routines.
25 */
26
27struct list_head {
28	struct list_head *next, *prev;
29};
30
31static inline void INIT_LIST_HEAD(struct list_head *list)
32{
33	list->next = list;
34	list->prev = list;
35}
36
37/*
38 * Insert a new entry between two known consecutive entries.
39 *
40 * This is only for internal list manipulation where we know
41 * the prev/next entries already!
42 */
43static inline void __list_add(struct list_head *new,
44			      struct list_head *prev,
45			      struct list_head *next)
46{
47	next->prev = new;
48	new->next = next;
49	new->prev = prev;
50	prev->next = new;
51}
52
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}
65
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/*
80 * 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.
95 * Note: list_empty() on entry does not return true after this, the entry is
96 * in an undefined state.
97 */
98static inline void list_del(struct list_head *entry)
99{
100	__list_del(entry->prev, entry->next);
101	entry->next = LIST_POISON1;
102	entry->prev = LIST_POISON2;
103}
104
105/**
106 * list_replace - replace old entry by new one
107 * @old : the element to be replaced
108 * @new : the new element to insert
109 *
110 * If @old was empty, it will be overwritten.
111 */
112static inline void list_replace(struct list_head *old,
113				struct list_head *new)
114{
115	new->next = old->next;
116	new->next->prev = new;
117	new->prev = old->prev;
118	new->prev->next = new;
119}
120
121static inline void list_replace_init(struct list_head *old,
122					struct list_head *new)
123{
124	list_replace(old, new);
125	INIT_LIST_HEAD(old);
126}
127
128/**
129 * list_del_init - deletes entry from list and reinitialize it.
130 * @entry: the element to delete from the list.
131 */
132static inline void list_del_init(struct list_head *entry)
133{
134	__list_del(entry->prev, entry->next);
135	INIT_LIST_HEAD(entry);
136}
137
138/**
139 * list_move - delete from one list and add as another's head
140 * @list: the entry to move
141 * @head: the head that will precede our entry
142 */
143static inline void list_move(struct list_head *list, struct list_head *head)
144{
145	__list_del(list->prev, list->next);
146	list_add(list, head);
147}
148
149/**
150 * list_move_tail - delete from one list and add as another's tail
151 * @list: the entry to move
152 * @head: the head that will follow our entry
153 */
154static inline void list_move_tail(struct list_head *list,
155				  struct list_head *head)
156{
157	__list_del(list->prev, list->next);
158	list_add_tail(list, head);
159}
160
161/**
162 * list_is_last - tests whether @list is the last entry in list @head
163 * @list: the entry to test
164 * @head: the head of the list
165 */
166static inline int list_is_last(const struct list_head *list,
167				const struct list_head *head)
168{
169	return list->next == head;
170}
171
172/**
173 * list_empty - tests whether a list is empty
174 * @head: the list to test.
175 */
176static inline int list_empty(const struct list_head *head)
177{
178	return head->next == head;
179}
180
181/**
182 * list_empty_careful - tests whether a list is empty and not being modified
183 * @head: the list to test
184 *
185 * Description:
186 * tests whether a list is empty _and_ checks that no other CPU might be
187 * in the process of modifying either member (next or prev)
188 *
189 * NOTE: using list_empty_careful() without synchronization
190 * can only be safe if the only activity that can happen
191 * to the list entry is list_del_init(). Eg. it cannot be used
192 * if another CPU could re-list_add() it.
193 */
194static inline int list_empty_careful(const struct list_head *head)
195{
196	struct list_head *next = head->next;
197	return (next == head) && (next == head->prev);
198}
199
200/**
201 * list_is_singular - tests whether a list has just one entry.
202 * @head: the list to test.
203 */
204static inline int list_is_singular(const struct list_head *head)
205{
206	return !list_empty(head) && (head->next == head->prev);
207}
208
209static inline void __list_cut_position(struct list_head *list,
210		struct list_head *head, struct list_head *entry)
211{
212	struct list_head *new_first = entry->next;
213	list->next = head->next;
214	list->next->prev = list;
215	list->prev = entry;
216	entry->next = list;
217	head->next = new_first;
218	new_first->prev = head;
219}
220
221/**
222 * list_cut_position - cut a list into two
223 * @list: a new list to add all removed entries
224 * @head: a list with entries
225 * @entry: an entry within head, could be the head itself
226 *	and if so we won't cut the list
227 *
228 * This helper moves the initial part of @head, up to and
229 * including @entry, from @head to @list. You should
230 * pass on @entry an element you know is on @head. @list
231 * should be an empty list or a list you do not care about
232 * losing its data.
233 *
234 */
235static inline void list_cut_position(struct list_head *list,
236		struct list_head *head, struct list_head *entry)
237{
238	if (list_empty(head))
239		return;
240	if (list_is_singular(head) &&
241		(head->next != entry && head != entry))
242		return;
243	if (entry == head)
244		INIT_LIST_HEAD(list);
245	else
246		__list_cut_position(list, head, entry);
247}
248
249static inline void __list_splice(const struct list_head *list,
250				 struct list_head *prev,
251				 struct list_head *next)
252{
253	struct list_head *first = list->next;
254	struct list_head *last = list->prev;
255
256	first->prev = prev;
257	prev->next = first;
258
259	last->next = next;
260	next->prev = last;
261}
262
263/**
264 * list_splice - join two lists, this is designed for stacks
265 * @list: the new list to add.
266 * @head: the place to add it in the first list.
267 */
268static inline void list_splice(const struct list_head *list,
269				struct list_head *head)
270{
271	if (!list_empty(list))
272		__list_splice(list, head, head->next);
273}
274
275/**
276 * list_splice_tail - join two lists, each list being a queue
277 * @list: the new list to add.
278 * @head: the place to add it in the first list.
279 */
280static inline void list_splice_tail(struct list_head *list,
281				struct list_head *head)
282{
283	if (!list_empty(list))
284		__list_splice(list, head->prev, head);
285}
286
287/**
288 * list_splice_init - join two lists and reinitialise the emptied list.
289 * @list: the new list to add.
290 * @head: the place to add it in the first list.
291 *
292 * The list at @list is reinitialised
293 */
294static inline void list_splice_init(struct list_head *list,
295				    struct list_head *head)
296{
297	if (!list_empty(list)) {
298		__list_splice(list, head, head->next);
299		INIT_LIST_HEAD(list);
300	}
301}
302
303/**
304 * list_splice_tail_init - join two lists and reinitialise the emptied list
305 * @list: the new list to add.
306 * @head: the place to add it in the first list.
307 *
308 * Each of the lists is a queue.
309 * The list at @list is reinitialised
310 */
311static inline void list_splice_tail_init(struct list_head *list,
312					 struct list_head *head)
313{
314	if (!list_empty(list)) {
315		__list_splice(list, head->prev, head);
316		INIT_LIST_HEAD(list);
317	}
318}
319
320/**
321 * list_entry - get the struct for this entry
322 * @ptr:	the &struct list_head pointer.
323 * @type:	the type of the struct this is embedded in.
324 * @member:	the name of the list_struct within the struct.
325 */
326#define list_entry(ptr, type, member) \
327	container_of(ptr, type, member)
328
329/**
330 * list_first_entry - get the first element from a list
331 * @ptr:	the list head to take the element from.
332 * @type:	the type of the struct this is embedded in.
333 * @member:	the name of the list_struct within the struct.
334 *
335 * Note, that list is expected to be not empty.
336 */
337#define list_first_entry(ptr, type, member) \
338	list_entry((ptr)->next, type, member)
339
340/**
341 * list_for_each	-	iterate over a list
342 * @pos:	the &struct list_head to use as a loop cursor.
343 * @head:	the head for your list.
344 */
345#define list_for_each(pos, head) \
346	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
347		pos = pos->next)
348
349/**
350 * __list_for_each	-	iterate over a list
351 * @pos:	the &struct list_head to use as a loop cursor.
352 * @head:	the head for your list.
353 *
354 * This variant differs from list_for_each() in that it's the
355 * simplest possible list iteration code, no prefetching is done.
356 * Use this for code that knows the list to be very short (empty
357 * or 1 entry) most of the time.
358 */
359#define __list_for_each(pos, head) \
360	for (pos = (head)->next; pos != (head); pos = pos->next)
361
362/**
363 * list_for_each_prev	-	iterate over a list backwards
364 * @pos:	the &struct list_head to use as a loop cursor.
365 * @head:	the head for your list.
366 */
367#define list_for_each_prev(pos, head) \
368	for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
369		pos = pos->prev)
370
371/**
372 * list_for_each_safe - iterate over a list safe against removal of list entry
373 * @pos:	the &struct list_head to use as a loop cursor.
374 * @n:		another &struct list_head to use as temporary storage
375 * @head:	the head for your list.
376 */
377#define list_for_each_safe(pos, n, head) \
378	for (pos = (head)->next, n = pos->next; pos != (head); \
379		pos = n, n = pos->next)
380
381/**
382 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
383 * @pos:	the &struct list_head to use as a loop cursor.
384 * @n:		another &struct list_head to use as temporary storage
385 * @head:	the head for your list.
386 */
387#define list_for_each_prev_safe(pos, n, head) \
388	for (pos = (head)->prev, n = pos->prev; \
389	     prefetch(pos->prev), pos != (head); \
390	     pos = n, n = pos->prev)
391
392/**
393 * list_for_each_entry	-	iterate over list of given type
394 * @pos:	the type * to use as a loop cursor.
395 * @head:	the head for your list.
396 * @member:	the name of the list_struct within the struct.
397 */
398#define list_for_each_entry(pos, head, member)				\
399	for (pos = list_entry((head)->next, typeof(*pos), member);	\
400	     prefetch(pos->member.next), &pos->member != (head);	\
401	     pos = list_entry(pos->member.next, typeof(*pos), member))
402
403/**
404 * list_for_each_entry_reverse - iterate backwards over list of given type.
405 * @pos:	the type * to use as a loop cursor.
406 * @head:	the head for your list.
407 * @member:	the name of the list_struct within the struct.
408 */
409#define list_for_each_entry_reverse(pos, head, member)			\
410	for (pos = list_entry((head)->prev, typeof(*pos), member);	\
411	     prefetch(pos->member.prev), &pos->member != (head);	\
412	     pos = list_entry(pos->member.prev, typeof(*pos), member))
413
414/**
415 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
416 * @pos:	the type * to use as a start point
417 * @head:	the head of the list
418 * @member:	the name of the list_struct within the struct.
419 *
420 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
421 */
422#define list_prepare_entry(pos, head, member) \
423	((pos) ? : list_entry(head, typeof(*pos), member))
424
425/**
426 * list_for_each_entry_continue - continue iteration over list of given type
427 * @pos:	the type * to use as a loop cursor.
428 * @head:	the head for your list.
429 * @member:	the name of the list_struct within the struct.
430 *
431 * Continue to iterate over list of given type, continuing after
432 * the current position.
433 */
434#define list_for_each_entry_continue(pos, head, member) 		\
435	for (pos = list_entry(pos->member.next, typeof(*pos), member);	\
436	     prefetch(pos->member.next), &pos->member != (head);	\
437	     pos = list_entry(pos->member.next, typeof(*pos), member))
438
439/**
440 * list_for_each_entry_continue_reverse - iterate backwards from the given point
441 * @pos:	the type * to use as a loop cursor.
442 * @head:	the head for your list.
443 * @member:	the name of the list_struct within the struct.
444 *
445 * Start to iterate over list of given type backwards, continuing after
446 * the current position.
447 */
448#define list_for_each_entry_continue_reverse(pos, head, member)		\
449	for (pos = list_entry(pos->member.prev, typeof(*pos), member);	\
450	     prefetch(pos->member.prev), &pos->member != (head);	\
451	     pos = list_entry(pos->member.prev, typeof(*pos), member))
452
453/**
454 * list_for_each_entry_from - iterate over list of given type from the current point
455 * @pos:	the type * to use as a loop cursor.
456 * @head:	the head for your list.
457 * @member:	the name of the list_struct within the struct.
458 *
459 * Iterate over list of given type, continuing from current position.
460 */
461#define list_for_each_entry_from(pos, head, member)			\
462	for (; prefetch(pos->member.next), &pos->member != (head);	\
463	     pos = list_entry(pos->member.next, typeof(*pos), member))
464
465/**
466 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
467 * @pos:	the type * to use as a loop cursor.
468 * @n:		another type * to use as temporary storage
469 * @head:	the head for your list.
470 * @member:	the name of the list_struct within the struct.
471 */
472#define list_for_each_entry_safe(pos, n, head, member)			\
473	for (pos = list_entry((head)->next, typeof(*pos), member),	\
474		n = list_entry(pos->member.next, typeof(*pos), member);	\
475	     &pos->member != (head);					\
476	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
477
478/**
479 * list_for_each_entry_safe_continue
480 * @pos:	the type * to use as a loop cursor.
481 * @n:		another type * to use as temporary storage
482 * @head:	the head for your list.
483 * @member:	the name of the list_struct within the struct.
484 *
485 * Iterate over list of given type, continuing after current point,
486 * safe against removal of list entry.
487 */
488#define list_for_each_entry_safe_continue(pos, n, head, member) 		\
489	for (pos = list_entry(pos->member.next, typeof(*pos), member),		\
490		n = list_entry(pos->member.next, typeof(*pos), member);		\
491	     &pos->member != (head);						\
492	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
493
494/**
495 * list_for_each_entry_safe_from
496 * @pos:	the type * to use as a loop cursor.
497 * @n:		another type * to use as temporary storage
498 * @head:	the head for your list.
499 * @member:	the name of the list_struct within the struct.
500 *
501 * Iterate over list of given type from current point, safe against
502 * removal of list entry.
503 */
504#define list_for_each_entry_safe_from(pos, n, head, member)			\
505	for (n = list_entry(pos->member.next, typeof(*pos), member);		\
506	     &pos->member != (head);						\
507	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
508
509/**
510 * list_for_each_entry_safe_reverse
511 * @pos:	the type * to use as a loop cursor.
512 * @n:		another type * to use as temporary storage
513 * @head:	the head for your list.
514 * @member:	the name of the list_struct within the struct.
515 *
516 * Iterate backwards over list of given type, safe against removal
517 * of list entry.
518 */
519#define list_for_each_entry_safe_reverse(pos, n, head, member)		\
520	for (pos = list_entry((head)->prev, typeof(*pos), member),	\
521		n = list_entry(pos->member.prev, typeof(*pos), member);	\
522	     &pos->member != (head);					\
523	     pos = n, n = list_entry(n->member.prev, typeof(*n), member))
524
525/*
526 * Double linked lists with a single pointer list head.
527 * Mostly useful for hash tables where the two pointer list head is
528 * too wasteful.
529 * You lose the ability to access the tail in O(1).
530 */
531
532struct hlist_head {
533	struct hlist_node *first;
534};
535
536struct hlist_node {
537	struct hlist_node *next, **pprev;
538};
539
540#define HLIST_HEAD_INIT { .first = NULL }
541#define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
542#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
543static inline void INIT_HLIST_NODE(struct hlist_node *h)
544{
545	h->next = NULL;
546	h->pprev = NULL;
547}
548
549static inline int hlist_unhashed(const struct hlist_node *h)
550{
551	return !h->pprev;
552}
553
554static inline int hlist_empty(const struct hlist_head *h)
555{
556	return !h->first;
557}
558
559static inline void __hlist_del(struct hlist_node *n)
560{
561	struct hlist_node *next = n->next;
562	struct hlist_node **pprev = n->pprev;
563	*pprev = next;
564	if (next)
565		next->pprev = pprev;
566}
567
568static inline void hlist_del(struct hlist_node *n)
569{
570	__hlist_del(n);
571	n->next = LIST_POISON1;
572	n->pprev = LIST_POISON2;
573}
574
575static inline void hlist_del_init(struct hlist_node *n)
576{
577	if (!hlist_unhashed(n)) {
578		__hlist_del(n);
579		INIT_HLIST_NODE(n);
580	}
581}
582
583static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
584{
585	struct hlist_node *first = h->first;
586	n->next = first;
587	if (first)
588		first->pprev = &n->next;
589	h->first = n;
590	n->pprev = &h->first;
591}
592
593/* next must be != NULL */
594static inline void hlist_add_before(struct hlist_node *n,
595					struct hlist_node *next)
596{
597	n->pprev = next->pprev;
598	n->next = next;
599	next->pprev = &n->next;
600	*(n->pprev) = n;
601}
602
603static inline void hlist_add_after(struct hlist_node *n,
604					struct hlist_node *next)
605{
606	next->next = n->next;
607	n->next = next;
608	next->pprev = &n->next;
609
610	if(next->next)
611		next->next->pprev  = &next->next;
612}
613
614#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
615
616#define hlist_for_each(pos, head) \
617	for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
618	     pos = pos->next)
619
620#define hlist_for_each_safe(pos, n, head) \
621	for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
622	     pos = n)
623
624/**
625 * hlist_for_each_entry	- iterate over list of given type
626 * @tpos:	the type * to use as a loop cursor.
627 * @pos:	the &struct hlist_node to use as a loop cursor.
628 * @head:	the head for your list.
629 * @member:	the name of the hlist_node within the struct.
630 */
631#define hlist_for_each_entry(tpos, pos, head, member)			 \
632	for (pos = (head)->first;					 \
633	     pos && ({ prefetch(pos->next); 1;}) &&			 \
634		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
635	     pos = pos->next)
636
637/**
638 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
639 * @tpos:	the type * to use as a loop cursor.
640 * @pos:	the &struct hlist_node to use as a loop cursor.
641 * @member:	the name of the hlist_node within the struct.
642 */
643#define hlist_for_each_entry_continue(tpos, pos, member)		 \
644	for (pos = (pos)->next;						 \
645	     pos && ({ prefetch(pos->next); 1;}) &&			 \
646		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
647	     pos = pos->next)
648
649/**
650 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
651 * @tpos:	the type * to use as a loop cursor.
652 * @pos:	the &struct hlist_node to use as a loop cursor.
653 * @member:	the name of the hlist_node within the struct.
654 */
655#define hlist_for_each_entry_from(tpos, pos, member)			 \
656	for (; pos && ({ prefetch(pos->next); 1;}) &&			 \
657		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
658	     pos = pos->next)
659
660/**
661 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
662 * @tpos:	the type * to use as a loop cursor.
663 * @pos:	the &struct hlist_node to use as a loop cursor.
664 * @n:		another &struct hlist_node to use as temporary storage
665 * @head:	the head for your list.
666 * @member:	the name of the hlist_node within the struct.
667 */
668#define hlist_for_each_entry_safe(tpos, pos, n, head, member)		 \
669	for (pos = (head)->first;					 \
670	     pos && ({ n = pos->next; 1; }) &&				 \
671		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
672	     pos = n)
673
674