1 #ifndef _LINUX_LIST_H
2 #define _LINUX_LIST_H
3
4 struct list_head {
5 struct list_head *next, *prev;
6 };
7
8 struct hlist_head {
9 struct hlist_node *first;
10 };
11
12 struct hlist_node {
13 struct hlist_node *next, **pprev;
14 };
15
16 #ifndef offsetof
17 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
18 #endif
19
20 #ifndef container_of
21 /**
22 * container_of - cast a member of a structure out to the containing structure
23 * @ptr: the pointer to the member.
24 * @type: the type of the container struct this is embedded in.
25 * @member: the name of the member within the struct.
26 *
27 */
28 #define container_of(ptr, type, member) ({ 29 const typeof(((type *)0)->member) * __mptr = (ptr); 30 (type *)((char *)__mptr - offsetof(type, member)); })
31 #endif
32
33 #define LIST_POISON1 NULL
34 #define LIST_POISON2 NULL
35
36 /*
37 * Simple doubly linked list implementation.
38 *
39 * Some of the internal functions ("__xxx") are useful when
40 * manipulating whole lists rather than single entries, as
41 * sometimes we already know the next/prev entries and we can
42 * generate better code by using them directly rather than
43 * using the generic single-entry routines.
44 */
45
46 #define LIST_HEAD_INIT(name) { &(name), &(name) }
47
48 #define LIST_HEAD(name) 49 struct list_head name = LIST_HEAD_INIT(name)
50
51 static inline void INIT_LIST_HEAD(struct list_head *list)
52 {
53 list->next = list;
54 list->prev = list;
55 }
56
57 /*
58 * Insert a new entry between two known consecutive entries.
59 *
60 * This is only for internal list manipulation where we know
61 * the prev/next entries already!
62 */
63 #ifndef CONFIG_DEBUG_LIST
64 static inline void __list_add(struct list_head *new,
65 struct list_head *prev,
66 struct list_head *next)
67 {
68 next->prev = new;
69 new->next = next;
70 new->prev = prev;
71 prev->next = new;
72 }
73 #else
74 extern void __list_add(struct list_head *new,
75 struct list_head *prev,
76 struct list_head *next);
77 #endif
78
79 /**
80 * list_add - add a new entry
81 * @new: new entry to be added
82 * @head: list head to add it after
83 *
84 * Insert a new entry after the specified head.
85 * This is good for implementing stacks.
86 */
87 static inline void list_add(struct list_head *new, struct list_head *head)
88 {
89 __list_add(new, head, head->next);
90 }
91
92
93 /**
94 * list_add_tail - add a new entry
95 * @new: new entry to be added
96 * @head: list head to add it before
97 *
98 * Insert a new entry before the specified head.
99 * This is useful for implementing queues.
100 */
101 static inline void list_add_tail(struct list_head *new, struct list_head *head)
102 {
103 __list_add(new, head->prev, head);
104 }
105
106 /*
107 * Delete a list entry by making the prev/next entries
108 * point to each other.
109 *
110 * This is only for internal list manipulation where we know
111 * the prev/next entries already!
112 */
113 static inline void __list_del(struct list_head * prev, struct list_head * next)
114 {
115 next->prev = prev;
116 prev->next = next;
117 }
118
119 /**
120 * list_del - deletes entry from list.
121 * @entry: the element to delete from the list.
122 * Note: list_empty() on entry does not return true after this, the entry is
123 * in an undefined state.
124 */
125 #ifndef CONFIG_DEBUG_LIST
126 static inline void __list_del_entry(struct list_head *entry)
127 {
128 __list_del(entry->prev, entry->next);
129 }
130
131 static inline void list_del(struct list_head *entry)
132 {
133 __list_del(entry->prev, entry->next);
134 entry->next = LIST_POISON1;
135 entry->prev = LIST_POISON2;
136 }
137 #else
138 extern void __list_del_entry(struct list_head *entry);
139 extern void list_del(struct list_head *entry);
140 #endif
141
142 /**
143 * list_replace - replace old entry by new one
144 * @old : the element to be replaced
145 * @new : the new element to insert
146 *
147 * If @old was empty, it will be overwritten.
148 */
149 static inline void list_replace(struct list_head *old,
150 struct list_head *new)
151 {
152 new->next = old->next;
153 new->next->prev = new;
154 new->prev = old->prev;
155 new->prev->next = new;
156 }
157
158 static inline void list_replace_init(struct list_head *old,
159 struct list_head *new)
160 {
161 list_replace(old, new);
162 INIT_LIST_HEAD(old);
163 }
164
165 /**
166 * list_del_init - deletes entry from list and reinitialize it.
167 * @entry: the element to delete from the list.
168 */
169 static inline void list_del_init(struct list_head *entry)
170 {
171 __list_del_entry(entry);
172 INIT_LIST_HEAD(entry);
173 }
174
175 /**
176 * list_move - delete from one list and add as another‘s head
177 * @list: the entry to move
178 * @head: the head that will precede our entry
179 */
180 static inline void list_move(struct list_head *list, struct list_head *head)
181 {
182 __list_del_entry(list);
183 list_add(list, head);
184 }
185
186 /**
187 * list_move_tail - delete from one list and add as another‘s tail
188 * @list: the entry to move
189 * @head: the head that will follow our entry
190 */
191 static inline void list_move_tail(struct list_head *list,
192 struct list_head *head)
193 {
194 __list_del_entry(list);
195 list_add_tail(list, head);
196 }
197
198 /**
199 * list_is_last - tests whether @list is the last entry in list @head
200 * @list: the entry to test
201 * @head: the head of the list
202 */
203 static inline int list_is_last(const struct list_head *list,
204 const struct list_head *head)
205 {
206 return list->next == head;
207 }
208
209 /**
210 * list_empty - tests whether a list is empty
211 * @head: the list to test.
212 */
213 static inline int list_empty(const struct list_head *head)
214 {
215 return head->next == head;
216 }
217
218 /**
219 * list_empty_careful - tests whether a list is empty and not being modified
220 * @head: the list to test
221 *
222 * Description:
223 * tests whether a list is empty _and_ checks that no other CPU might be
224 * in the process of modifying either member (next or prev)
225 *
226 * NOTE: using list_empty_careful() without synchronization
227 * can only be safe if the only activity that can happen
228 * to the list entry is list_del_init(). Eg. it cannot be used
229 * if another CPU could re-list_add() it.
230 */
231 static inline int list_empty_careful(const struct list_head *head)
232 {
233 struct list_head *next = head->next;
234 return (next == head) && (next == head->prev);
235 }
236
237 /**
238 * list_rotate_left - rotate the list to the left
239 * @head: the head of the list
240 */
241 static inline void list_rotate_left(struct list_head *head)
242 {
243 struct list_head *first;
244
245 if (!list_empty(head)) {
246 first = head->next;
247 list_move_tail(first, head);
248 }
249 }
250
251 /**
252 * list_is_singular - tests whether a list has just one entry.
253 * @head: the list to test.
254 */
255 static inline int list_is_singular(const struct list_head *head)
256 {
257 return !list_empty(head) && (head->next == head->prev);
258 }
259
260 static inline void __list_cut_position(struct list_head *list,
261 struct list_head *head, struct list_head *entry)
262 {
263 struct list_head *new_first = entry->next;
264 list->next = head->next;
265 list->next->prev = list;
266 list->prev = entry;
267 entry->next = list;
268 head->next = new_first;
269 new_first->prev = head;
270 }
271
272 /**
273 * list_cut_position - cut a list into two
274 * @list: a new list to add all removed entries
275 * @head: a list with entries
276 * @entry: an entry within head, could be the head itself
277 * and if so we won‘t cut the list
278 *
279 * This helper moves the initial part of @head, up to and
280 * including @entry, from @head to @list. You should
281 * pass on @entry an element you know is on @head. @list
282 * should be an empty list or a list you do not care about
283 * losing its data.
284 *
285 */
286 static inline void list_cut_position(struct list_head *list,
287 struct list_head *head, struct list_head *entry)
288 {
289 if (list_empty(head))
290 return;
291 if (list_is_singular(head) &&
292 (head->next != entry && head != entry))
293 return;
294 if (entry == head)
295 INIT_LIST_HEAD(list);
296 else
297 __list_cut_position(list, head, entry);
298 }
299
300 static inline void __list_splice(const struct list_head *list,
301 struct list_head *prev,
302 struct list_head *next)
303 {
304 struct list_head *first = list->next;
305 struct list_head *last = list->prev;
306
307 first->prev = prev;
308 prev->next = first;
309
310 last->next = next;
311 next->prev = last;
312 }
313
314 /**
315 * list_splice - join two lists, this is designed for stacks
316 * @list: the new list to add.
317 * @head: the place to add it in the first list.
318 */
319 static inline void list_splice(const struct list_head *list,
320 struct list_head *head)
321 {
322 if (!list_empty(list))
323 __list_splice(list, head, head->next);
324 }
325
326 /**
327 * list_splice_tail - join two lists, each list being a queue
328 * @list: the new list to add.
329 * @head: the place to add it in the first list.
330 */
331 static inline void list_splice_tail(struct list_head *list,
332 struct list_head *head)
333 {
334 if (!list_empty(list))
335 __list_splice(list, head->prev, head);
336 }
337
338 /**
339 * list_splice_init - join two lists and reinitialise the emptied list.
340 * @list: the new list to add.
341 * @head: the place to add it in the first list.
342 *
343 * The list at @list is reinitialised
344 */
345 static inline void list_splice_init(struct list_head *list,
346 struct list_head *head)
347 {
348 if (!list_empty(list)) {
349 __list_splice(list, head, head->next);
350 INIT_LIST_HEAD(list);
351 }
352 }
353
354 /**
355 * list_splice_tail_init - join two lists and reinitialise the emptied list
356 * @list: the new list to add.
357 * @head: the place to add it in the first list.
358 *
359 * Each of the lists is a queue.
360 * The list at @list is reinitialised
361 */
362 static inline void list_splice_tail_init(struct list_head *list,
363 struct list_head *head)
364 {
365 if (!list_empty(list)) {
366 __list_splice(list, head->prev, head);
367 INIT_LIST_HEAD(list);
368 }
369 }
370
371 /**
372 * list_entry - get the struct for this entry
373 * @ptr: the &struct list_head pointer.
374 * @type: the type of the struct this is embedded in.
375 * @member: the name of the list_struct within the struct.
376 */
377 #define list_entry(ptr, type, member) 378 container_of(ptr, type, member)
379
380 /**
381 * list_first_entry - get the first element from a list
382 * @ptr: the list head to take the element from.
383 * @type: the type of the struct this is embedded in.
384 * @member: the name of the list_struct within the struct.
385 *
386 * Note, that list is expected to be not empty.
387 */
388 #define list_first_entry(ptr, type, member) 389 list_entry((ptr)->next, type, member)
390
391 /**
392 * list_for_each - iterate over a list
393 * @pos: the &struct list_head to use as a loop cursor.
394 * @head: the head for your list.
395 */
396 #define list_for_each(pos, head) 397 for (pos = (head)->next; pos != (head); pos = pos->next)
398
399 /**
400 * __list_for_each - iterate over a list
401 * @pos: the &struct list_head to use as a loop cursor.
402 * @head: the head for your list.
403 *
404 * This variant doesn‘t differ from list_for_each() any more.
405 * We don‘t do prefetching in either case.
406 */
407 #define __list_for_each(pos, head) 408 for (pos = (head)->next; pos != (head); pos = pos->next)
409
410 /**
411 * list_for_each_prev - iterate over a list backwards
412 * @pos: the &struct list_head to use as a loop cursor.
413 * @head: the head for your list.
414 */
415 #define list_for_each_prev(pos, head) 416 for (pos = (head)->prev; pos != (head); pos = pos->prev)
417
418 /**
419 * list_for_each_safe - iterate over a list safe against removal of list entry
420 * @pos: the &struct list_head to use as a loop cursor.
421 * @n: another &struct list_head to use as temporary storage
422 * @head: the head for your list.
423 */
424 #define list_for_each_safe(pos, n, head) 425 for (pos = (head)->next, n = pos->next; pos != (head); 426 pos = n, n = pos->next)
427
428 /**
429 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
430 * @pos: the &struct list_head to use as a loop cursor.
431 * @n: another &struct list_head to use as temporary storage
432 * @head: the head for your list.
433 */
434 #define list_for_each_prev_safe(pos, n, head) 435 for (pos = (head)->prev, n = pos->prev; 436 pos != (head); 437 pos = n, n = pos->prev)
438
439 /**
440 * list_for_each_entry - iterate over list of given type
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 #define list_for_each_entry(pos, head, member) 446 for (pos = list_entry((head)->next, typeof(*pos), member); 447 &pos->member != (head); 448 pos = list_entry(pos->member.next, typeof(*pos), member))
449
450 /**
451 * list_for_each_entry_reverse - iterate backwards over list of given type.
452 * @pos: the type * to use as a loop cursor.
453 * @head: the head for your list.
454 * @member: the name of the list_struct within the struct.
455 */
456 #define list_for_each_entry_reverse(pos, head, member) 457 for (pos = list_entry((head)->prev, typeof(*pos), member); 458 &pos->member != (head); 459 pos = list_entry(pos->member.prev, typeof(*pos), member))
460
461 /**
462 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
463 * @pos: the type * to use as a start point
464 * @head: the head of the list
465 * @member: the name of the list_struct within the struct.
466 *
467 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
468 */
469 #define list_prepare_entry(pos, head, member) 470 ((pos) ? : list_entry(head, typeof(*pos), member))
471
472 /**
473 * list_for_each_entry_continue - continue iteration over list of given type
474 * @pos: the type * to use as a loop cursor.
475 * @head: the head for your list.
476 * @member: the name of the list_struct within the struct.
477 *
478 * Continue to iterate over list of given type, continuing after
479 * the current position.
480 */
481 #define list_for_each_entry_continue(pos, head, member) 482 for (pos = list_entry(pos->member.next, typeof(*pos), member); 483 &pos->member != (head); 484 pos = list_entry(pos->member.next, typeof(*pos), member))
485
486 /**
487 * list_for_each_entry_continue_reverse - iterate backwards from the given point
488 * @pos: the type * to use as a loop cursor.
489 * @head: the head for your list.
490 * @member: the name of the list_struct within the struct.
491 *
492 * Start to iterate over list of given type backwards, continuing after
493 * the current position.
494 */
495 #define list_for_each_entry_continue_reverse(pos, head, member) 496 for (pos = list_entry(pos->member.prev, typeof(*pos), member); 497 &pos->member != (head); 498 pos = list_entry(pos->member.prev, typeof(*pos), member))
499
500 /**
501 * list_for_each_entry_from - iterate over list of given type from the current point
502 * @pos: the type * to use as a loop cursor.
503 * @head: the head for your list.
504 * @member: the name of the list_struct within the struct.
505 *
506 * Iterate over list of given type, continuing from current position.
507 */
508 #define list_for_each_entry_from(pos, head, member) 509 for (; &pos->member != (head); 510 pos = list_entry(pos->member.next, typeof(*pos), member))
511
512 /**
513 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
514 * @pos: the type * to use as a loop cursor.
515 * @n: another type * to use as temporary storage
516 * @head: the head for your list.
517 * @member: the name of the list_struct within the struct.
518 */
519 #define list_for_each_entry_safe(pos, n, head, member) 520 for (pos = list_entry((head)->next, typeof(*pos), member), 521 n = list_entry(pos->member.next, typeof(*pos), member); 522 &pos->member != (head); 523 pos = n, n = list_entry(n->member.next, typeof(*n), member))
524
525 /**
526 * list_for_each_entry_safe_continue - continue list iteration safe against removal
527 * @pos: the type * to use as a loop cursor.
528 * @n: another type * to use as temporary storage
529 * @head: the head for your list.
530 * @member: the name of the list_struct within the struct.
531 *
532 * Iterate over list of given type, continuing after current point,
533 * safe against removal of list entry.
534 */
535 #define list_for_each_entry_safe_continue(pos, n, head, member) 536 for (pos = list_entry(pos->member.next, typeof(*pos), member), 537 n = list_entry(pos->member.next, typeof(*pos), member); 538 &pos->member != (head); 539 pos = n, n = list_entry(n->member.next, typeof(*n), member))
540
541 /**
542 * list_for_each_entry_safe_from - iterate over list from current point safe against removal
543 * @pos: the type * to use as a loop cursor.
544 * @n: another type * to use as temporary storage
545 * @head: the head for your list.
546 * @member: the name of the list_struct within the struct.
547 *
548 * Iterate over list of given type from current point, safe against
549 * removal of list entry.
550 */
551 #define list_for_each_entry_safe_from(pos, n, head, member) 552 for (n = list_entry(pos->member.next, typeof(*pos), member); 553 &pos->member != (head); 554 pos = n, n = list_entry(n->member.next, typeof(*n), member))
555
556 /**
557 * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
558 * @pos: the type * to use as a loop cursor.
559 * @n: another type * to use as temporary storage
560 * @head: the head for your list.
561 * @member: the name of the list_struct within the struct.
562 *
563 * Iterate backwards over list of given type, safe against removal
564 * of list entry.
565 */
566 #define list_for_each_entry_safe_reverse(pos, n, head, member) 567 for (pos = list_entry((head)->prev, typeof(*pos), member), 568 n = list_entry(pos->member.prev, typeof(*pos), member); 569 &pos->member != (head); 570 pos = n, n = list_entry(n->member.prev, typeof(*n), member))
571
572 /**
573 * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
574 * @pos: the loop cursor used in the list_for_each_entry_safe loop
575 * @n: temporary storage used in list_for_each_entry_safe
576 * @member: the name of the list_struct within the struct.
577 *
578 * list_safe_reset_next is not safe to use in general if the list may be
579 * modified concurrently (eg. the lock is dropped in the loop body). An
580 * exception to this is if the cursor element (pos) is pinned in the list,
581 * and list_safe_reset_next is called after re-taking the lock and before
582 * completing the current iteration of the loop body.
583 */
584 #define list_safe_reset_next(pos, n, member) 585 n = list_entry(pos->member.next, typeof(*pos), member)
586
587 /*
588 * Double linked lists with a single pointer list head.
589 * Mostly useful for hash tables where the two pointer list head is
590 * too wasteful.
591 * You lose the ability to access the tail in O(1).
592 */
593
594 #define HLIST_HEAD_INIT { .first = NULL }
595 #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
596 #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
597 static inline void INIT_HLIST_NODE(struct hlist_node *h)
598 {
599 h->next = NULL;
600 h->pprev = NULL;
601 }
602
603 static inline int hlist_unhashed(const struct hlist_node *h)
604 {
605 return !h->pprev;
606 }
607
608 static inline int hlist_empty(const struct hlist_head *h)
609 {
610 return !h->first;
611 }
612
613 static inline void __hlist_del(struct hlist_node *n)
614 {
615 struct hlist_node *next = n->next;
616 struct hlist_node **pprev = n->pprev;
617 *pprev = next;
618 if (next)
619 next->pprev = pprev;
620 }
621
622 static inline void hlist_del(struct hlist_node *n)
623 {
624 __hlist_del(n);
625 n->next = LIST_POISON1;
626 n->pprev = LIST_POISON2;
627 }
628
629 static inline void hlist_del_init(struct hlist_node *n)
630 {
631 if (!hlist_unhashed(n)) {
632 __hlist_del(n);
633 INIT_HLIST_NODE(n);
634 }
635 }
636
637 static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
638 {
639 struct hlist_node *first = h->first;
640 n->next = first;
641 if (first)
642 first->pprev = &n->next;
643 h->first = n;
644 n->pprev = &h->first;
645 }
646
647 /* next must be != NULL */
648 static inline void hlist_add_before(struct hlist_node *n,
649 struct hlist_node *next)
650 {
651 n->pprev = next->pprev;
652 n->next = next;
653 next->pprev = &n->next;
654 *(n->pprev) = n;
655 }
656
657 static inline void hlist_add_after(struct hlist_node *n,
658 struct hlist_node *next)
659 {
660 next->next = n->next;
661 n->next = next;
662 next->pprev = &n->next;
663
664 if(next->next)
665 next->next->pprev = &next->next;
666 }
667
668 /* after that we‘ll appear to be on some hlist and hlist_del will work */
669 static inline void hlist_add_fake(struct hlist_node *n)
670 {
671 n->pprev = &n->next;
672 }
673
674 /*
675 * Move a list from one list head to another. Fixup the pprev
676 * reference of the first entry if it exists.
677 */
678 static inline void hlist_move_list(struct hlist_head *old,
679 struct hlist_head *new)
680 {
681 new->first = old->first;
682 if (new->first)
683 new->first->pprev = &new->first;
684 old->first = NULL;
685 }
686
687 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
688
689 #define hlist_for_each(pos, head) 690 for (pos = (head)->first; pos ; pos = pos->next)
691
692 #define hlist_for_each_safe(pos, n, head) 693 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); 694 pos = n)
695
696 /**
697 * hlist_for_each_entry - iterate over list of given type
698 * @tpos: the type * to use as a loop cursor.
699 * @pos: the &struct hlist_node to use as a loop cursor.
700 * @head: the head for your list.
701 * @member: the name of the hlist_node within the struct.
702 */
703 #define hlist_for_each_entry(tpos, pos, head, member) 704 for (pos = (head)->first; 705 pos && 706 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); 707 pos = pos->next)
708
709 /**
710 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
711 * @tpos: the type * to use as a loop cursor.
712 * @pos: the &struct hlist_node to use as a loop cursor.
713 * @member: the name of the hlist_node within the struct.
714 */
715 #define hlist_for_each_entry_continue(tpos, pos, member) 716 for (pos = (pos)->next; 717 pos && 718 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); 719 pos = pos->next)
720
721 /**
722 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
723 * @tpos: the type * to use as a loop cursor.
724 * @pos: the &struct hlist_node to use as a loop cursor.
725 * @member: the name of the hlist_node within the struct.
726 */
727 #define hlist_for_each_entry_from(tpos, pos, member) 728 for (; pos && 729 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); 730 pos = pos->next)
731
732 /**
733 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
734 * @tpos: the type * to use as a loop cursor.
735 * @pos: the &struct hlist_node to use as a loop cursor.
736 * @n: another &struct hlist_node to use as temporary storage
737 * @head: the head for your list.
738 * @member: the name of the hlist_node within the struct.
739 */
740 #define hlist_for_each_entry_safe(tpos, pos, n, head, member) 741 for (pos = (head)->first; 742 pos && ({ n = pos->next; 1; }) && 743 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); 744 pos = n)
745
746 #endif
时间： 2024-10-10 06:27:48