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