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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 : :
26 : : /**
27 : : * INIT_LIST_HEAD - Initialize a list_head structure
28 : : * @list: list_head structure to be initialized.
29 : : *
30 : : * Initializes the list_head to point to itself. If it is a list header,
31 : : * the result is an empty list.
32 : : */
33 : 1777172 : static inline void INIT_LIST_HEAD(struct list_head *list)
34 : : {
35 [ + + + + : 1180554 : WRITE_ONCE(list->next, list);
# # # # #
# # # ]
36 [ + + + + : 1251697 : list->prev = list;
# # # # #
# # # ]
37 : 332826 : }
38 : :
39 : : #ifdef CONFIG_DEBUG_LIST
40 : : extern bool __list_add_valid(struct list_head *new,
41 : : struct list_head *prev,
42 : : struct list_head *next);
43 : : extern bool __list_del_entry_valid(struct list_head *entry);
44 : : #else
45 : 1498778 : static inline bool __list_add_valid(struct list_head *new,
46 : : struct list_head *prev,
47 : : struct list_head *next)
48 : : {
49 : 1361595 : return true;
50 : : }
51 : 825347 : static inline bool __list_del_entry_valid(struct list_head *entry)
52 : : {
53 : 825347 : return true;
54 : : }
55 : : #endif
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 : 1497305 : static inline void __list_add(struct list_head *new,
64 : : struct list_head *prev,
65 : : struct list_head *next)
66 : : {
67 : 1497305 : if (!__list_add_valid(new, prev, next))
68 : : return;
69 : :
70 : 1497305 : next->prev = new;
71 : 1497305 : new->next = next;
72 : 1497305 : new->prev = prev;
73 : 1497305 : WRITE_ONCE(prev->next, new);
74 : : }
75 : :
76 : : /**
77 : : * list_add - add a new entry
78 : : * @new: new entry to be added
79 : : * @head: list head to add it after
80 : : *
81 : : * Insert a new entry after the specified head.
82 : : * This is good for implementing stacks.
83 : : */
84 : 1028916 : static inline void list_add(struct list_head *new, struct list_head *head)
85 : : {
86 [ + + - - ]: 966681 : __list_add(new, head, head->next);
87 : 246156 : }
88 : :
89 : :
90 : : /**
91 : : * list_add_tail - add a new entry
92 : : * @new: new entry to be added
93 : : * @head: list head to add it before
94 : : *
95 : : * Insert a new entry before the specified head.
96 : : * This is useful for implementing queues.
97 : : */
98 : 468389 : static inline void list_add_tail(struct list_head *new, struct list_head *head)
99 : : {
100 [ + + + + : 466550 : __list_add(new, head->prev, head);
- + # # ]
101 : 22741 : }
102 : :
103 : : /*
104 : : * Delete a list entry by making the prev/next entries
105 : : * point to each other.
106 : : *
107 : : * This is only for internal list manipulation where we know
108 : : * the prev/next entries already!
109 : : */
110 : 825347 : static inline void __list_del(struct list_head * prev, struct list_head * next)
111 : : {
112 : 825347 : next->prev = prev;
113 : 825347 : WRITE_ONCE(prev->next, next);
114 : : }
115 : :
116 : : /*
117 : : * Delete a list entry and clear the 'prev' pointer.
118 : : *
119 : : * This is a special-purpose list clearing method used in the networking code
120 : : * for lists allocated as per-cpu, where we don't want to incur the extra
121 : : * WRITE_ONCE() overhead of a regular list_del_init(). The code that uses this
122 : : * needs to check the node 'prev' pointer instead of calling list_empty().
123 : : */
124 : : static inline void __list_del_clearprev(struct list_head *entry)
125 : : {
126 : : __list_del(entry->prev, entry->next);
127 : : entry->prev = NULL;
128 : : }
129 : :
130 : 825347 : static inline void __list_del_entry(struct list_head *entry)
131 : : {
132 : 825347 : if (!__list_del_entry_valid(entry))
133 : : return;
134 : :
135 [ - + # # ]: 682100 : __list_del(entry->prev, entry->next);
136 : : }
137 : :
138 : : /**
139 : : * list_del - deletes entry from list.
140 : : * @entry: the element to delete from the list.
141 : : * Note: list_empty() on entry does not return true after this, the entry is
142 : : * in an undefined state.
143 : : */
144 : 641534 : static inline void list_del(struct list_head *entry)
145 : : {
146 [ + + + + : 641534 : __list_del_entry(entry);
# # # # #
# # # #
# ]
147 : 641534 : entry->next = LIST_POISON1;
148 [ + + + + : 641519 : entry->prev = LIST_POISON2;
# # # # #
# # # #
# ]
149 : 78 : }
150 : :
151 : : /**
152 : : * list_replace - replace old entry by new one
153 : : * @old : the element to be replaced
154 : : * @new : the new element to insert
155 : : *
156 : : * If @old was empty, it will be overwritten.
157 : : */
158 : 3821 : static inline void list_replace(struct list_head *old,
159 : : struct list_head *new)
160 : : {
161 : 3821 : new->next = old->next;
162 : 3821 : new->next->prev = new;
163 : 3821 : new->prev = old->prev;
164 [ # # # # ]: 3821 : new->prev->next = new;
165 : 0 : }
166 : :
167 : : /**
168 : : * list_replace_init - replace old entry by new one and initialize the old one
169 : : * @old : the element to be replaced
170 : : * @new : the new element to insert
171 : : *
172 : : * If @old was empty, it will be overwritten.
173 : : */
174 : 3821 : static inline void list_replace_init(struct list_head *old,
175 : : struct list_head *new)
176 : : {
177 : 3821 : list_replace(old, new);
178 [ # # ]: 3821 : INIT_LIST_HEAD(old);
179 : 0 : }
180 : :
181 : : /**
182 : : * list_swap - replace entry1 with entry2 and re-add entry1 at entry2's position
183 : : * @entry1: the location to place entry2
184 : : * @entry2: the location to place entry1
185 : : */
186 : : static inline void list_swap(struct list_head *entry1,
187 : : struct list_head *entry2)
188 : : {
189 : : struct list_head *pos = entry2->prev;
190 : :
191 : : list_del(entry2);
192 : : list_replace(entry1, entry2);
193 : : if (pos == entry1)
194 : : pos = entry2;
195 : : list_add(entry1, pos);
196 : : }
197 : :
198 : : /**
199 : : * list_del_init - deletes entry from list and reinitialize it.
200 : : * @entry: the element to delete from the list.
201 : : */
202 : 114547 : static inline void list_del_init(struct list_head *entry)
203 : : {
204 [ + + - - : 113268 : __list_del_entry(entry);
+ + # # #
# ]
205 [ + + - - : 81867 : INIT_LIST_HEAD(entry);
+ + # # #
# ]
206 : 33652 : }
207 : :
208 : : /**
209 : : * list_move - delete from one list and add as another's head
210 : : * @list: the entry to move
211 : : * @head: the head that will precede our entry
212 : : */
213 : 33342 : static inline void list_move(struct list_head *list, struct list_head *head)
214 : : {
215 [ + + + - ]: 33342 : __list_del_entry(list);
216 [ + + + - ]: 33243 : list_add(list, head);
217 : 106 : }
218 : :
219 : : /**
220 : : * list_move_tail - delete from one list and add as another's tail
221 : : * @list: the entry to move
222 : : * @head: the head that will follow our entry
223 : : */
224 : 1406 : static inline void list_move_tail(struct list_head *list,
225 : : struct list_head *head)
226 : : {
227 [ + + + + : 1377 : __list_del_entry(list);
+ + - + ]
228 [ + + + + : 1295 : list_add_tail(list, head);
+ + - + ]
229 : 118 : }
230 : :
231 : : /**
232 : : * list_bulk_move_tail - move a subsection of a list to its tail
233 : : * @head: the head that will follow our entry
234 : : * @first: first entry to move
235 : : * @last: last entry to move, can be the same as first
236 : : *
237 : : * Move all entries between @first and including @last before @head.
238 : : * All three entries must belong to the same linked list.
239 : : */
240 : : static inline void list_bulk_move_tail(struct list_head *head,
241 : : struct list_head *first,
242 : : struct list_head *last)
243 : : {
244 : : first->prev->next = last->next;
245 : : last->next->prev = first->prev;
246 : :
247 : : head->prev->next = first;
248 : : first->prev = head->prev;
249 : :
250 : : last->next = head;
251 : : head->prev = last;
252 : : }
253 : :
254 : : /**
255 : : * list_is_first -- tests whether @list is the first entry in list @head
256 : : * @list: the entry to test
257 : : * @head: the head of the list
258 : : */
259 : 0 : static inline int list_is_first(const struct list_head *list,
260 : : const struct list_head *head)
261 : : {
262 [ # # ]: 0 : return list->prev == head;
263 : : }
264 : :
265 : : /**
266 : : * list_is_last - tests whether @list is the last entry in list @head
267 : : * @list: the entry to test
268 : : * @head: the head of the list
269 : : */
270 : 0 : static inline int list_is_last(const struct list_head *list,
271 : : const struct list_head *head)
272 : : {
273 [ # # # # : 0 : return list->next == head;
# # # # #
# ]
274 : : }
275 : :
276 : : /**
277 : : * list_empty - tests whether a list is empty
278 : : * @head: the list to test.
279 : : */
280 : 830157 : static inline int list_empty(const struct list_head *head)
281 : : {
282 [ + + + + : 725691 : return READ_ONCE(head->next) == head;
+ + + + +
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+ + + + +
+ + + + ]
283 : : }
284 : :
285 : : /**
286 : : * list_empty_careful - tests whether a list is empty and not being modified
287 : : * @head: the list to test
288 : : *
289 : : * Description:
290 : : * tests whether a list is empty _and_ checks that no other CPU might be
291 : : * in the process of modifying either member (next or prev)
292 : : *
293 : : * NOTE: using list_empty_careful() without synchronization
294 : : * can only be safe if the only activity that can happen
295 : : * to the list entry is list_del_init(). Eg. it cannot be used
296 : : * if another CPU could re-list_add() it.
297 : : */
298 : 122759 : static inline int list_empty_careful(const struct list_head *head)
299 : : {
300 : 122759 : struct list_head *next = head->next;
301 [ + + + + : 78226 : return (next == head) && (next == head->prev);
+ + + + +
+ + + + +
+ - - - -
- ]
302 : : }
303 : :
304 : : /**
305 : : * list_rotate_left - rotate the list to the left
306 : : * @head: the head of the list
307 : : */
308 : : static inline void list_rotate_left(struct list_head *head)
309 : : {
310 : : struct list_head *first;
311 : :
312 : : if (!list_empty(head)) {
313 : : first = head->next;
314 : : list_move_tail(first, head);
315 : : }
316 : : }
317 : :
318 : : /**
319 : : * list_rotate_to_front() - Rotate list to specific item.
320 : : * @list: The desired new front of the list.
321 : : * @head: The head of the list.
322 : : *
323 : : * Rotates list so that @list becomes the new front of the list.
324 : : */
325 : : static inline void list_rotate_to_front(struct list_head *list,
326 : : struct list_head *head)
327 : : {
328 : : /*
329 : : * Deletes the list head from the list denoted by @head and
330 : : * places it as the tail of @list, this effectively rotates the
331 : : * list so that @list is at the front.
332 : : */
333 : : list_move_tail(head, list);
334 : : }
335 : :
336 : : /**
337 : : * list_is_singular - tests whether a list has just one entry.
338 : : * @head: the list to test.
339 : : */
340 : 13186 : static inline int list_is_singular(const struct list_head *head)
341 : : {
342 [ + - + + : 13186 : return !list_empty(head) && (head->next == head->prev);
+ + + + +
+ + + ]
343 : : }
344 : :
345 : 9 : static inline void __list_cut_position(struct list_head *list,
346 : : struct list_head *head, struct list_head *entry)
347 : : {
348 : 9 : struct list_head *new_first = entry->next;
349 : 9 : list->next = head->next;
350 : 9 : list->next->prev = list;
351 : 9 : list->prev = entry;
352 : 9 : entry->next = list;
353 : 9 : head->next = new_first;
354 : 9 : new_first->prev = head;
355 : 9 : }
356 : :
357 : : /**
358 : : * list_cut_position - cut a list into two
359 : : * @list: a new list to add all removed entries
360 : : * @head: a list with entries
361 : : * @entry: an entry within head, could be the head itself
362 : : * and if so we won't cut the list
363 : : *
364 : : * This helper moves the initial part of @head, up to and
365 : : * including @entry, from @head to @list. You should
366 : : * pass on @entry an element you know is on @head. @list
367 : : * should be an empty list or a list you do not care about
368 : : * losing its data.
369 : : *
370 : : */
371 : 9 : static inline void list_cut_position(struct list_head *list,
372 : : struct list_head *head, struct list_head *entry)
373 : : {
374 [ + - ]: 9 : if (list_empty(head))
375 : : return;
376 [ + - - + ]: 18 : if (list_is_singular(head) &&
377 [ # # ]: 0 : (head->next != entry && head != entry))
378 : : return;
379 [ - + ]: 9 : if (entry == head)
380 : 0 : INIT_LIST_HEAD(list);
381 : : else
382 : 9 : __list_cut_position(list, head, entry);
383 : : }
384 : :
385 : : /**
386 : : * list_cut_before - cut a list into two, before given entry
387 : : * @list: a new list to add all removed entries
388 : : * @head: a list with entries
389 : : * @entry: an entry within head, could be the head itself
390 : : *
391 : : * This helper moves the initial part of @head, up to but
392 : : * excluding @entry, from @head to @list. You should pass
393 : : * in @entry an element you know is on @head. @list should
394 : : * be an empty list or a list you do not care about losing
395 : : * its data.
396 : : * If @entry == @head, all entries on @head are moved to
397 : : * @list.
398 : : */
399 : 2500 : static inline void list_cut_before(struct list_head *list,
400 : : struct list_head *head,
401 : : struct list_head *entry)
402 : : {
403 [ - + ]: 2500 : if (head->next == entry) {
404 : 0 : INIT_LIST_HEAD(list);
405 : 0 : return;
406 : : }
407 : 2500 : list->next = head->next;
408 : 2500 : list->next->prev = list;
409 : 2500 : list->prev = entry->prev;
410 : 2500 : list->prev->next = list;
411 : 2500 : head->next = entry;
412 [ # # ]: 2500 : entry->prev = head;
413 : : }
414 : :
415 : 35942 : static inline void __list_splice(const struct list_head *list,
416 : : struct list_head *prev,
417 : : struct list_head *next)
418 : : {
419 : 35942 : struct list_head *first = list->next;
420 : 35942 : struct list_head *last = list->prev;
421 : :
422 : 35942 : first->prev = prev;
423 : 35942 : prev->next = first;
424 : :
425 : 35942 : last->next = next;
426 : 35942 : next->prev = last;
427 : 204 : }
428 : :
429 : : /**
430 : : * list_splice - join two lists, this is designed for stacks
431 : : * @list: the new list to add.
432 : : * @head: the place to add it in the first list.
433 : : */
434 : 32345 : static inline void list_splice(const struct list_head *list,
435 : : struct list_head *head)
436 : : {
437 [ + + # # : 32345 : if (!list_empty(list))
# # # # #
# ]
438 : 201 : __list_splice(list, head, head->next);
439 : : }
440 : :
441 : : /**
442 : : * list_splice_tail - join two lists, each list being a queue
443 : : * @list: the new list to add.
444 : : * @head: the place to add it in the first list.
445 : : */
446 : 18 : static inline void list_splice_tail(struct list_head *list,
447 : : struct list_head *head)
448 : : {
449 [ - + + - ]: 18 : if (!list_empty(list))
450 : 3 : __list_splice(list, head->prev, head);
451 : : }
452 : :
453 : : /**
454 : : * list_splice_init - join two lists and reinitialise the emptied list.
455 : : * @list: the new list to add.
456 : : * @head: the place to add it in the first list.
457 : : *
458 : : * The list at @list is reinitialised
459 : : */
460 : 35584 : static inline void list_splice_init(struct list_head *list,
461 : : struct list_head *head)
462 : : {
463 [ + + + + : 35584 : if (!list_empty(list)) {
+ - # # #
# # # ]
464 : 35068 : __list_splice(list, head, head->next);
465 : 35068 : INIT_LIST_HEAD(list);
466 : : }
467 : : }
468 : :
469 : : /**
470 : : * list_splice_tail_init - join two lists and reinitialise the emptied list
471 : : * @list: the new list to add.
472 : : * @head: the place to add it in the first list.
473 : : *
474 : : * Each of the lists is a queue.
475 : : * The list at @list is reinitialised
476 : : */
477 : 1427 : static inline void list_splice_tail_init(struct list_head *list,
478 : : struct list_head *head)
479 : : {
480 [ + + + + : 1151 : if (!list_empty(list)) {
+ + - - #
# # # #
# ]
481 : 670 : __list_splice(list, head->prev, head);
482 : 670 : INIT_LIST_HEAD(list);
483 : : }
484 : : }
485 : :
486 : : /**
487 : : * list_entry - get the struct for this entry
488 : : * @ptr: the &struct list_head pointer.
489 : : * @type: the type of the struct this is embedded in.
490 : : * @member: the name of the list_head within the struct.
491 : : */
492 : : #define list_entry(ptr, type, member) \
493 : : container_of(ptr, type, member)
494 : :
495 : : /**
496 : : * list_first_entry - get the first element from a list
497 : : * @ptr: the list head to take the element from.
498 : : * @type: the type of the struct this is embedded in.
499 : : * @member: the name of the list_head within the struct.
500 : : *
501 : : * Note, that list is expected to be not empty.
502 : : */
503 : : #define list_first_entry(ptr, type, member) \
504 : : list_entry((ptr)->next, type, member)
505 : :
506 : : /**
507 : : * list_last_entry - get the last element from a list
508 : : * @ptr: the list head to take the element from.
509 : : * @type: the type of the struct this is embedded in.
510 : : * @member: the name of the list_head within the struct.
511 : : *
512 : : * Note, that list is expected to be not empty.
513 : : */
514 : : #define list_last_entry(ptr, type, member) \
515 : : list_entry((ptr)->prev, type, member)
516 : :
517 : : /**
518 : : * list_first_entry_or_null - get the first element from a list
519 : : * @ptr: the list head to take the element from.
520 : : * @type: the type of the struct this is embedded in.
521 : : * @member: the name of the list_head within the struct.
522 : : *
523 : : * Note that if the list is empty, it returns NULL.
524 : : */
525 : : #define list_first_entry_or_null(ptr, type, member) ({ \
526 : : struct list_head *head__ = (ptr); \
527 : : struct list_head *pos__ = READ_ONCE(head__->next); \
528 : : pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
529 : : })
530 : :
531 : : /**
532 : : * list_next_entry - get the next element in list
533 : : * @pos: the type * to cursor
534 : : * @member: the name of the list_head within the struct.
535 : : */
536 : : #define list_next_entry(pos, member) \
537 : : list_entry((pos)->member.next, typeof(*(pos)), member)
538 : :
539 : : /**
540 : : * list_prev_entry - get the prev element in list
541 : : * @pos: the type * to cursor
542 : : * @member: the name of the list_head within the struct.
543 : : */
544 : : #define list_prev_entry(pos, member) \
545 : : list_entry((pos)->member.prev, typeof(*(pos)), member)
546 : :
547 : : /**
548 : : * list_for_each - iterate over a list
549 : : * @pos: the &struct list_head to use as a loop cursor.
550 : : * @head: the head for your list.
551 : : */
552 : : #define list_for_each(pos, head) \
553 : : for (pos = (head)->next; pos != (head); pos = pos->next)
554 : :
555 : : /**
556 : : * list_for_each_continue - continue iteration over a list
557 : : * @pos: the &struct list_head to use as a loop cursor.
558 : : * @head: the head for your list.
559 : : *
560 : : * Continue to iterate over a list, continuing after the current position.
561 : : */
562 : : #define list_for_each_continue(pos, head) \
563 : : for (pos = pos->next; pos != (head); pos = pos->next)
564 : :
565 : : /**
566 : : * list_for_each_prev - iterate over a list backwards
567 : : * @pos: the &struct list_head to use as a loop cursor.
568 : : * @head: the head for your list.
569 : : */
570 : : #define list_for_each_prev(pos, head) \
571 : : for (pos = (head)->prev; pos != (head); pos = pos->prev)
572 : :
573 : : /**
574 : : * list_for_each_safe - iterate over a list safe against removal of list entry
575 : : * @pos: the &struct list_head to use as a loop cursor.
576 : : * @n: another &struct list_head to use as temporary storage
577 : : * @head: the head for your list.
578 : : */
579 : : #define list_for_each_safe(pos, n, head) \
580 : : for (pos = (head)->next, n = pos->next; pos != (head); \
581 : : pos = n, n = pos->next)
582 : :
583 : : /**
584 : : * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
585 : : * @pos: the &struct list_head to use as a loop cursor.
586 : : * @n: another &struct list_head to use as temporary storage
587 : : * @head: the head for your list.
588 : : */
589 : : #define list_for_each_prev_safe(pos, n, head) \
590 : : for (pos = (head)->prev, n = pos->prev; \
591 : : pos != (head); \
592 : : pos = n, n = pos->prev)
593 : :
594 : : /**
595 : : * list_for_each_entry - iterate over list of given type
596 : : * @pos: the type * to use as a loop cursor.
597 : : * @head: the head for your list.
598 : : * @member: the name of the list_head within the struct.
599 : : */
600 : : #define list_for_each_entry(pos, head, member) \
601 : : for (pos = list_first_entry(head, typeof(*pos), member); \
602 : : &pos->member != (head); \
603 : : pos = list_next_entry(pos, member))
604 : :
605 : : /**
606 : : * list_for_each_entry_reverse - iterate backwards over list of given type.
607 : : * @pos: the type * to use as a loop cursor.
608 : : * @head: the head for your list.
609 : : * @member: the name of the list_head within the struct.
610 : : */
611 : : #define list_for_each_entry_reverse(pos, head, member) \
612 : : for (pos = list_last_entry(head, typeof(*pos), member); \
613 : : &pos->member != (head); \
614 : : pos = list_prev_entry(pos, member))
615 : :
616 : : /**
617 : : * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
618 : : * @pos: the type * to use as a start point
619 : : * @head: the head of the list
620 : : * @member: the name of the list_head within the struct.
621 : : *
622 : : * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
623 : : */
624 : : #define list_prepare_entry(pos, head, member) \
625 : : ((pos) ? : list_entry(head, typeof(*pos), member))
626 : :
627 : : /**
628 : : * list_for_each_entry_continue - continue iteration over list of given type
629 : : * @pos: the type * to use as a loop cursor.
630 : : * @head: the head for your list.
631 : : * @member: the name of the list_head within the struct.
632 : : *
633 : : * Continue to iterate over list of given type, continuing after
634 : : * the current position.
635 : : */
636 : : #define list_for_each_entry_continue(pos, head, member) \
637 : : for (pos = list_next_entry(pos, member); \
638 : : &pos->member != (head); \
639 : : pos = list_next_entry(pos, member))
640 : :
641 : : /**
642 : : * list_for_each_entry_continue_reverse - iterate backwards from the given point
643 : : * @pos: the type * to use as a loop cursor.
644 : : * @head: the head for your list.
645 : : * @member: the name of the list_head within the struct.
646 : : *
647 : : * Start to iterate over list of given type backwards, continuing after
648 : : * the current position.
649 : : */
650 : : #define list_for_each_entry_continue_reverse(pos, head, member) \
651 : : for (pos = list_prev_entry(pos, member); \
652 : : &pos->member != (head); \
653 : : pos = list_prev_entry(pos, member))
654 : :
655 : : /**
656 : : * list_for_each_entry_from - iterate over list of given type from the current point
657 : : * @pos: the type * to use as a loop cursor.
658 : : * @head: the head for your list.
659 : : * @member: the name of the list_head within the struct.
660 : : *
661 : : * Iterate over list of given type, continuing from current position.
662 : : */
663 : : #define list_for_each_entry_from(pos, head, member) \
664 : : for (; &pos->member != (head); \
665 : : pos = list_next_entry(pos, member))
666 : :
667 : : /**
668 : : * list_for_each_entry_from_reverse - iterate backwards over list of given type
669 : : * from the current point
670 : : * @pos: the type * to use as a loop cursor.
671 : : * @head: the head for your list.
672 : : * @member: the name of the list_head within the struct.
673 : : *
674 : : * Iterate backwards over list of given type, continuing from current position.
675 : : */
676 : : #define list_for_each_entry_from_reverse(pos, head, member) \
677 : : for (; &pos->member != (head); \
678 : : pos = list_prev_entry(pos, member))
679 : :
680 : : /**
681 : : * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
682 : : * @pos: the type * to use as a loop cursor.
683 : : * @n: another type * to use as temporary storage
684 : : * @head: the head for your list.
685 : : * @member: the name of the list_head within the struct.
686 : : */
687 : : #define list_for_each_entry_safe(pos, n, head, member) \
688 : : for (pos = list_first_entry(head, typeof(*pos), member), \
689 : : n = list_next_entry(pos, member); \
690 : : &pos->member != (head); \
691 : : pos = n, n = list_next_entry(n, member))
692 : :
693 : : /**
694 : : * list_for_each_entry_safe_continue - continue list iteration safe against removal
695 : : * @pos: the type * to use as a loop cursor.
696 : : * @n: another type * to use as temporary storage
697 : : * @head: the head for your list.
698 : : * @member: the name of the list_head within the struct.
699 : : *
700 : : * Iterate over list of given type, continuing after current point,
701 : : * safe against removal of list entry.
702 : : */
703 : : #define list_for_each_entry_safe_continue(pos, n, head, member) \
704 : : for (pos = list_next_entry(pos, member), \
705 : : n = list_next_entry(pos, member); \
706 : : &pos->member != (head); \
707 : : pos = n, n = list_next_entry(n, member))
708 : :
709 : : /**
710 : : * list_for_each_entry_safe_from - iterate over list from current point safe against removal
711 : : * @pos: the type * to use as a loop cursor.
712 : : * @n: another type * to use as temporary storage
713 : : * @head: the head for your list.
714 : : * @member: the name of the list_head within the struct.
715 : : *
716 : : * Iterate over list of given type from current point, safe against
717 : : * removal of list entry.
718 : : */
719 : : #define list_for_each_entry_safe_from(pos, n, head, member) \
720 : : for (n = list_next_entry(pos, member); \
721 : : &pos->member != (head); \
722 : : pos = n, n = list_next_entry(n, member))
723 : :
724 : : /**
725 : : * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
726 : : * @pos: the type * to use as a loop cursor.
727 : : * @n: another type * to use as temporary storage
728 : : * @head: the head for your list.
729 : : * @member: the name of the list_head within the struct.
730 : : *
731 : : * Iterate backwards over list of given type, safe against removal
732 : : * of list entry.
733 : : */
734 : : #define list_for_each_entry_safe_reverse(pos, n, head, member) \
735 : : for (pos = list_last_entry(head, typeof(*pos), member), \
736 : : n = list_prev_entry(pos, member); \
737 : : &pos->member != (head); \
738 : : pos = n, n = list_prev_entry(n, member))
739 : :
740 : : /**
741 : : * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
742 : : * @pos: the loop cursor used in the list_for_each_entry_safe loop
743 : : * @n: temporary storage used in list_for_each_entry_safe
744 : : * @member: the name of the list_head within the struct.
745 : : *
746 : : * list_safe_reset_next is not safe to use in general if the list may be
747 : : * modified concurrently (eg. the lock is dropped in the loop body). An
748 : : * exception to this is if the cursor element (pos) is pinned in the list,
749 : : * and list_safe_reset_next is called after re-taking the lock and before
750 : : * completing the current iteration of the loop body.
751 : : */
752 : : #define list_safe_reset_next(pos, n, member) \
753 : : n = list_next_entry(pos, member)
754 : :
755 : : /*
756 : : * Double linked lists with a single pointer list head.
757 : : * Mostly useful for hash tables where the two pointer list head is
758 : : * too wasteful.
759 : : * You lose the ability to access the tail in O(1).
760 : : */
761 : :
762 : : #define HLIST_HEAD_INIT { .first = NULL }
763 : : #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
764 : : #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
765 : 256350 : static inline void INIT_HLIST_NODE(struct hlist_node *h)
766 : : {
767 : 256350 : h->next = NULL;
768 [ + + + - ]: 159812 : h->pprev = NULL;
769 : 14439 : }
770 : :
771 : : /**
772 : : * hlist_unhashed - Has node been removed from list and reinitialized?
773 : : * @h: Node to be checked
774 : : *
775 : : * Not that not all removal functions will leave a node in unhashed
776 : : * state. For example, hlist_nulls_del_init_rcu() does leave the
777 : : * node in unhashed state, but hlist_nulls_del() does not.
778 : : */
779 : 112554 : static inline int hlist_unhashed(const struct hlist_node *h)
780 : : {
781 [ + + + + : 105248 : return !h->pprev;
+ + + + +
+ + - - -
+ + - - -
- ]
782 : : }
783 : :
784 : : /**
785 : : * hlist_unhashed_lockless - Version of hlist_unhashed for lockless use
786 : : * @h: Node to be checked
787 : : *
788 : : * This variant of hlist_unhashed() must be used in lockless contexts
789 : : * to avoid potential load-tearing. The READ_ONCE() is paired with the
790 : : * various WRITE_ONCE() in hlist helpers that are defined below.
791 : : */
792 : : static inline int hlist_unhashed_lockless(const struct hlist_node *h)
793 : : {
794 : : return !READ_ONCE(h->pprev);
795 : : }
796 : :
797 : : /**
798 : : * hlist_empty - Is the specified hlist_head structure an empty hlist?
799 : : * @h: Structure to check.
800 : : */
801 : 19926 : static inline int hlist_empty(const struct hlist_head *h)
802 : : {
803 [ + + + + : 19926 : return !READ_ONCE(h->first);
+ + - + -
- - - - -
- - - - -
- - - - -
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # ]
804 : : }
805 : :
806 : 28213 : static inline void __hlist_del(struct hlist_node *n)
807 : : {
808 : 28213 : struct hlist_node *next = n->next;
809 : 28213 : struct hlist_node **pprev = n->pprev;
810 : :
811 [ + + + + : 28024 : WRITE_ONCE(*pprev, next);
+ + # # #
# # # #
# ]
812 [ + + + + : 28213 : if (next)
+ + - - -
- + + + +
+ + # # #
# ]
813 : 3178 : WRITE_ONCE(next->pprev, pprev);
814 : : }
815 : :
816 : : /**
817 : : * hlist_del - Delete the specified hlist_node from its list
818 : : * @n: Node to delete.
819 : : *
820 : : * Note that this function leaves the node in hashed state. Use
821 : : * hlist_del_init() or similar instead to unhash @n.
822 : : */
823 : 150 : static inline void hlist_del(struct hlist_node *n)
824 : : {
825 [ - + - - : 150 : __hlist_del(n);
+ + ]
826 : 150 : n->next = LIST_POISON1;
827 [ + - - - ]: 150 : n->pprev = LIST_POISON2;
828 : 0 : }
829 : :
830 : : /**
831 : : * hlist_del_init - Delete the specified hlist_node from its list and initialize
832 : : * @n: Node to delete.
833 : : *
834 : : * Note that this function leaves the node in unhashed state.
835 : : */
836 : 14406 : static inline void hlist_del_init(struct hlist_node *n)
837 : : {
838 [ + + + - : 14406 : if (!hlist_unhashed(n)) {
+ - # # ]
839 [ + + + + : 14394 : __hlist_del(n);
+ + # # ]
840 : 14394 : INIT_HLIST_NODE(n);
841 : : }
842 : : }
843 : :
844 : : /**
845 : : * hlist_add_head - add a new entry at the beginning of the hlist
846 : : * @n: new entry to be added
847 : : * @h: hlist head to add it after
848 : : *
849 : : * Insert a new entry after the specified head.
850 : : * This is good for implementing stacks.
851 : : */
852 : 92140 : static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
853 : : {
854 : 92140 : struct hlist_node *first = h->first;
855 [ + + + + : 92140 : WRITE_ONCE(n->next, first);
+ + - + +
+ + + + +
# # ]
856 [ + + + + : 92140 : if (first)
+ + - + +
+ + + + +
# # ]
857 : 4957 : WRITE_ONCE(first->pprev, &n->next);
858 [ + - - - : 92122 : WRITE_ONCE(h->first, n);
- - ]
859 [ + - - - : 92092 : WRITE_ONCE(n->pprev, &h->first);
- - ]
860 : 1457 : }
861 : :
862 : : /**
863 : : * hlist_add_before - add a new entry before the one specified
864 : : * @n: new entry to be added
865 : : * @next: hlist node to add it before, which must be non-NULL
866 : : */
867 : : static inline void hlist_add_before(struct hlist_node *n,
868 : : struct hlist_node *next)
869 : : {
870 : : WRITE_ONCE(n->pprev, next->pprev);
871 : : WRITE_ONCE(n->next, next);
872 : : WRITE_ONCE(next->pprev, &n->next);
873 : : WRITE_ONCE(*(n->pprev), n);
874 : : }
875 : :
876 : : /**
877 : : * hlist_add_behing - add a new entry after the one specified
878 : : * @n: new entry to be added
879 : : * @prev: hlist node to add it after, which must be non-NULL
880 : : */
881 : : static inline void hlist_add_behind(struct hlist_node *n,
882 : : struct hlist_node *prev)
883 : : {
884 : : WRITE_ONCE(n->next, prev->next);
885 : : WRITE_ONCE(prev->next, n);
886 : : WRITE_ONCE(n->pprev, &prev->next);
887 : :
888 : : if (n->next)
889 : : WRITE_ONCE(n->next->pprev, &n->next);
890 : : }
891 : :
892 : : /**
893 : : * hlist_add_fake - create a fake hlist consisting of a single headless node
894 : : * @n: Node to make a fake list out of
895 : : *
896 : : * This makes @n appear to be its own predecessor on a headless hlist.
897 : : * The point of this is to allow things like hlist_del() to work correctly
898 : : * in cases where there is no list.
899 : : */
900 : : static inline void hlist_add_fake(struct hlist_node *n)
901 : : {
902 : : n->pprev = &n->next;
903 : : }
904 : :
905 : : /**
906 : : * hlist_fake: Is this node a fake hlist?
907 : : * @h: Node to check for being a self-referential fake hlist.
908 : : */
909 : 753 : static inline bool hlist_fake(struct hlist_node *h)
910 : : {
911 [ + - ]: 753 : return h->pprev == &h->next;
912 : : }
913 : :
914 : : /**
915 : : * hlist_is_singular_node - is node the only element of the specified hlist?
916 : : * @n: Node to check for singularity.
917 : : * @h: Header for potentially singular list.
918 : : *
919 : : * Check whether the node is the only node of the head without
920 : : * accessing head, thus avoiding unnecessary cache misses.
921 : : */
922 : : static inline bool
923 : 6643 : hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h)
924 : : {
925 [ + + + + : 6824 : return !n->next && n->pprev == &h->first;
+ + ]
926 : : }
927 : :
928 : : /**
929 : : * hlist_move_list - Move an hlist
930 : : * @old: hlist_head for old list.
931 : : * @new: hlist_head for new list.
932 : : *
933 : : * Move a list from one list head to another. Fixup the pprev
934 : : * reference of the first entry if it exists.
935 : : */
936 : 536 : static inline void hlist_move_list(struct hlist_head *old,
937 : : struct hlist_head *new)
938 : : {
939 : 536 : new->first = old->first;
940 [ + + ]: 536 : if (new->first)
941 : 332 : new->first->pprev = &new->first;
942 [ - + ]: 536 : old->first = NULL;
943 : : }
944 : :
945 : : #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
946 : :
947 : : #define hlist_for_each(pos, head) \
948 : : for (pos = (head)->first; pos ; pos = pos->next)
949 : :
950 : : #define hlist_for_each_safe(pos, n, head) \
951 : : for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
952 : : pos = n)
953 : :
954 : : #define hlist_entry_safe(ptr, type, member) \
955 : : ({ typeof(ptr) ____ptr = (ptr); \
956 : : ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
957 : : })
958 : :
959 : : /**
960 : : * hlist_for_each_entry - iterate over list of given type
961 : : * @pos: the type * to use as a loop cursor.
962 : : * @head: the head for your list.
963 : : * @member: the name of the hlist_node within the struct.
964 : : */
965 : : #define hlist_for_each_entry(pos, head, member) \
966 : : for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
967 : : pos; \
968 : : pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
969 : :
970 : : /**
971 : : * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
972 : : * @pos: the type * to use as a loop cursor.
973 : : * @member: the name of the hlist_node within the struct.
974 : : */
975 : : #define hlist_for_each_entry_continue(pos, member) \
976 : : for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
977 : : pos; \
978 : : pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
979 : :
980 : : /**
981 : : * hlist_for_each_entry_from - iterate over a hlist continuing from current point
982 : : * @pos: the type * to use as a loop cursor.
983 : : * @member: the name of the hlist_node within the struct.
984 : : */
985 : : #define hlist_for_each_entry_from(pos, member) \
986 : : for (; pos; \
987 : : pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
988 : :
989 : : /**
990 : : * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
991 : : * @pos: the type * to use as a loop cursor.
992 : : * @n: another &struct hlist_node to use as temporary storage
993 : : * @head: the head for your list.
994 : : * @member: the name of the hlist_node within the struct.
995 : : */
996 : : #define hlist_for_each_entry_safe(pos, n, head, member) \
997 : : for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
998 : : pos && ({ n = pos->member.next; 1; }); \
999 : : pos = hlist_entry_safe(n, typeof(*pos), member))
1000 : :
1001 : : #endif
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