]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - include/linux/list.h
4 #include <linux/stddef.h>
5 #include <linux/poison.h>
6 #include <linux/prefetch.h>
7 #include <asm/system.h>
10 * Simple doubly linked list implementation.
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.
20 struct list_head
*next
, *prev
;
23 #define LIST_HEAD_INIT(name) { &(name), &(name) }
25 #define LIST_HEAD(name) \
26 struct list_head name = LIST_HEAD_INIT(name)
28 static inline void INIT_LIST_HEAD(struct list_head
*list
)
35 * Insert a new entry between two known consecutive entries.
37 * This is only for internal list manipulation where we know
38 * the prev/next entries already!
40 #ifndef CONFIG_DEBUG_LIST
41 static inline void __list_add(struct list_head
*new,
42 struct list_head
*prev
,
43 struct list_head
*next
)
51 extern void __list_add(struct list_head
*new,
52 struct list_head
*prev
,
53 struct list_head
*next
);
57 * list_add - add a new entry
58 * @new: new entry to be added
59 * @head: list head to add it after
61 * Insert a new entry after the specified head.
62 * This is good for implementing stacks.
64 static inline void list_add(struct list_head
*new, struct list_head
*head
)
66 __list_add(new, head
, head
->next
);
71 * list_add_tail - add a new entry
72 * @new: new entry to be added
73 * @head: list head to add it before
75 * Insert a new entry before the specified head.
76 * This is useful for implementing queues.
78 static inline void list_add_tail(struct list_head
*new, struct list_head
*head
)
80 __list_add(new, head
->prev
, head
);
84 * Delete a list entry by making the prev/next entries
85 * point to each other.
87 * This is only for internal list manipulation where we know
88 * the prev/next entries already!
90 static inline void __list_del(struct list_head
* prev
, struct list_head
* next
)
97 * list_del - deletes entry from list.
98 * @entry: the element to delete from the list.
99 * Note: list_empty() on entry does not return true after this, the entry is
100 * in an undefined state.
102 #ifndef CONFIG_DEBUG_LIST
103 static inline void list_del(struct list_head
*entry
)
105 __list_del(entry
->prev
, entry
->next
);
106 entry
->next
= LIST_POISON1
;
107 entry
->prev
= LIST_POISON2
;
110 extern void list_del(struct list_head
*entry
);
114 * list_replace - replace old entry by new one
115 * @old : the element to be replaced
116 * @new : the new element to insert
118 * If @old was empty, it will be overwritten.
120 static inline void list_replace(struct list_head
*old
,
121 struct list_head
*new)
123 new->next
= old
->next
;
124 new->next
->prev
= new;
125 new->prev
= old
->prev
;
126 new->prev
->next
= new;
129 static inline void list_replace_init(struct list_head
*old
,
130 struct list_head
*new)
132 list_replace(old
, new);
137 * list_del_init - deletes entry from list and reinitialize it.
138 * @entry: the element to delete from the list.
140 static inline void list_del_init(struct list_head
*entry
)
142 __list_del(entry
->prev
, entry
->next
);
143 INIT_LIST_HEAD(entry
);
147 * list_move - delete from one list and add as another's head
148 * @list: the entry to move
149 * @head: the head that will precede our entry
151 static inline void list_move(struct list_head
*list
, struct list_head
*head
)
153 __list_del(list
->prev
, list
->next
);
154 list_add(list
, head
);
158 * list_move_tail - delete from one list and add as another's tail
159 * @list: the entry to move
160 * @head: the head that will follow our entry
162 static inline void list_move_tail(struct list_head
*list
,
163 struct list_head
*head
)
165 __list_del(list
->prev
, list
->next
);
166 list_add_tail(list
, head
);
170 * list_is_last - tests whether @list is the last entry in list @head
171 * @list: the entry to test
172 * @head: the head of the list
174 static inline int list_is_last(const struct list_head
*list
,
175 const struct list_head
*head
)
177 return list
->next
== head
;
181 * list_empty - tests whether a list is empty
182 * @head: the list to test.
184 static inline int list_empty(const struct list_head
*head
)
186 return head
->next
== head
;
190 * list_empty_careful - tests whether a list is empty and not being modified
191 * @head: the list to test
194 * tests whether a list is empty _and_ checks that no other CPU might be
195 * in the process of modifying either member (next or prev)
197 * NOTE: using list_empty_careful() without synchronization
198 * can only be safe if the only activity that can happen
199 * to the list entry is list_del_init(). Eg. it cannot be used
200 * if another CPU could re-list_add() it.
202 static inline int list_empty_careful(const struct list_head
*head
)
204 struct list_head
*next
= head
->next
;
205 return (next
== head
) && (next
== head
->prev
);
209 * list_is_singular - tests whether a list has just one entry.
210 * @head: the list to test.
212 static inline int list_is_singular(const struct list_head
*head
)
214 return !list_empty(head
) && (head
->next
== head
->prev
);
217 static inline void __list_cut_position(struct list_head
*list
,
218 struct list_head
*head
, struct list_head
*entry
)
220 struct list_head
*new_first
= entry
->next
;
221 list
->next
= head
->next
;
222 list
->next
->prev
= list
;
225 head
->next
= new_first
;
226 new_first
->prev
= head
;
230 * list_cut_position - cut a list into two
231 * @list: a new list to add all removed entries
232 * @head: a list with entries
233 * @entry: an entry within head, could be the head itself
234 * and if so we won't cut the list
236 * This helper moves the initial part of @head, up to and
237 * including @entry, from @head to @list. You should
238 * pass on @entry an element you know is on @head. @list
239 * should be an empty list or a list you do not care about
243 static inline void list_cut_position(struct list_head
*list
,
244 struct list_head
*head
, struct list_head
*entry
)
246 if (list_empty(head
))
248 if (list_is_singular(head
) &&
249 (head
->next
!= entry
&& head
!= entry
))
252 INIT_LIST_HEAD(list
);
254 __list_cut_position(list
, head
, entry
);
257 static inline void __list_splice(const struct list_head
*list
,
258 struct list_head
*prev
,
259 struct list_head
*next
)
261 struct list_head
*first
= list
->next
;
262 struct list_head
*last
= list
->prev
;
272 * list_splice - join two lists, this is designed for stacks
273 * @list: the new list to add.
274 * @head: the place to add it in the first list.
276 static inline void list_splice(const struct list_head
*list
,
277 struct list_head
*head
)
279 if (!list_empty(list
))
280 __list_splice(list
, head
, head
->next
);
284 * list_splice_tail - join two lists, each list being a queue
285 * @list: the new list to add.
286 * @head: the place to add it in the first list.
288 static inline void list_splice_tail(struct list_head
*list
,
289 struct list_head
*head
)
291 if (!list_empty(list
))
292 __list_splice(list
, head
->prev
, head
);
296 * list_splice_init - join two lists and reinitialise the emptied list.
297 * @list: the new list to add.
298 * @head: the place to add it in the first list.
300 * The list at @list is reinitialised
302 static inline void list_splice_init(struct list_head
*list
,
303 struct list_head
*head
)
305 if (!list_empty(list
)) {
306 __list_splice(list
, head
, head
->next
);
307 INIT_LIST_HEAD(list
);
312 * list_splice_tail_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.
316 * Each of the lists is a queue.
317 * The list at @list is reinitialised
319 static inline void list_splice_tail_init(struct list_head
*list
,
320 struct list_head
*head
)
322 if (!list_empty(list
)) {
323 __list_splice(list
, head
->prev
, head
);
324 INIT_LIST_HEAD(list
);
329 * list_entry - get the struct for this entry
330 * @ptr: the &struct list_head pointer.
331 * @type: the type of the struct this is embedded in.
332 * @member: the name of the list_struct within the struct.
334 #define list_entry(ptr, type, member) \
335 container_of(ptr, type, member)
338 * list_first_entry - get the first element from a list
339 * @ptr: the list head to take the element from.
340 * @type: the type of the struct this is embedded in.
341 * @member: the name of the list_struct within the struct.
343 * Note, that list is expected to be not empty.
345 #define list_first_entry(ptr, type, member) \
346 list_entry((ptr)->next, type, member)
349 * list_for_each - iterate over a list
350 * @pos: the &struct list_head to use as a loop cursor.
351 * @head: the head for your list.
353 #define list_for_each(pos, head) \
354 for (pos = (head)->next; prefetch(pos->next), pos != (head); \
358 * __list_for_each - iterate over a list
359 * @pos: the &struct list_head to use as a loop cursor.
360 * @head: the head for your list.
362 * This variant differs from list_for_each() in that it's the
363 * simplest possible list iteration code, no prefetching is done.
364 * Use this for code that knows the list to be very short (empty
365 * or 1 entry) most of the time.
367 #define __list_for_each(pos, head) \
368 for (pos = (head)->next; pos != (head); pos = pos->next)
371 * list_for_each_prev - iterate over a list backwards
372 * @pos: the &struct list_head to use as a loop cursor.
373 * @head: the head for your list.
375 #define list_for_each_prev(pos, head) \
376 for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
380 * list_for_each_safe - iterate over a list safe against removal of list entry
381 * @pos: the &struct list_head to use as a loop cursor.
382 * @n: another &struct list_head to use as temporary storage
383 * @head: the head for your list.
385 #define list_for_each_safe(pos, n, head) \
386 for (pos = (head)->next, n = pos->next; pos != (head); \
387 pos = n, n = pos->next)
390 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
391 * @pos: the &struct list_head to use as a loop cursor.
392 * @n: another &struct list_head to use as temporary storage
393 * @head: the head for your list.
395 #define list_for_each_prev_safe(pos, n, head) \
396 for (pos = (head)->prev, n = pos->prev; \
397 prefetch(pos->prev), pos != (head); \
398 pos = n, n = pos->prev)
401 * list_for_each_entry - iterate over list of given type
402 * @pos: the type * to use as a loop cursor.
403 * @head: the head for your list.
404 * @member: the name of the list_struct within the struct.
406 #define list_for_each_entry(pos, head, member) \
407 for (pos = list_entry((head)->next, typeof(*pos), member); \
408 prefetch(pos->member.next), &pos->member != (head); \
409 pos = list_entry(pos->member.next, typeof(*pos), member))
412 * list_for_each_entry_reverse - iterate backwards over list of given type.
413 * @pos: the type * to use as a loop cursor.
414 * @head: the head for your list.
415 * @member: the name of the list_struct within the struct.
417 #define list_for_each_entry_reverse(pos, head, member) \
418 for (pos = list_entry((head)->prev, typeof(*pos), member); \
419 prefetch(pos->member.prev), &pos->member != (head); \
420 pos = list_entry(pos->member.prev, typeof(*pos), member))
423 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
424 * @pos: the type * to use as a start point
425 * @head: the head of the list
426 * @member: the name of the list_struct within the struct.
428 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
430 #define list_prepare_entry(pos, head, member) \
431 ((pos) ? : list_entry(head, typeof(*pos), member))
434 * list_for_each_entry_continue - continue iteration over list of given type
435 * @pos: the type * to use as a loop cursor.
436 * @head: the head for your list.
437 * @member: the name of the list_struct within the struct.
439 * Continue to iterate over list of given type, continuing after
440 * the current position.
442 #define list_for_each_entry_continue(pos, head, member) \
443 for (pos = list_entry(pos->member.next, typeof(*pos), member); \
444 prefetch(pos->member.next), &pos->member != (head); \
445 pos = list_entry(pos->member.next, typeof(*pos), member))
448 * list_for_each_entry_continue_reverse - iterate backwards from the given point
449 * @pos: the type * to use as a loop cursor.
450 * @head: the head for your list.
451 * @member: the name of the list_struct within the struct.
453 * Start to iterate over list of given type backwards, continuing after
454 * the current position.
456 #define list_for_each_entry_continue_reverse(pos, head, member) \
457 for (pos = list_entry(pos->member.prev, typeof(*pos), member); \
458 prefetch(pos->member.prev), &pos->member != (head); \
459 pos = list_entry(pos->member.prev, typeof(*pos), member))
462 * list_for_each_entry_from - iterate over list of given type from the current point
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.
467 * Iterate over list of given type, continuing from current position.
469 #define list_for_each_entry_from(pos, head, member) \
470 for (; prefetch(pos->member.next), &pos->member != (head); \
471 pos = list_entry(pos->member.next, typeof(*pos), member))
474 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
475 * @pos: the type * to use as a loop cursor.
476 * @n: another type * to use as temporary storage
477 * @head: the head for your list.
478 * @member: the name of the list_struct within the struct.
480 #define list_for_each_entry_safe(pos, n, head, member) \
481 for (pos = list_entry((head)->next, typeof(*pos), member), \
482 n = list_entry(pos->member.next, typeof(*pos), member); \
483 &pos->member != (head); \
484 pos = n, n = list_entry(n->member.next, typeof(*n), member))
487 * list_for_each_entry_safe_continue
488 * @pos: the type * to use as a loop cursor.
489 * @n: another type * to use as temporary storage
490 * @head: the head for your list.
491 * @member: the name of the list_struct within the struct.
493 * Iterate over list of given type, continuing after current point,
494 * safe against removal of list entry.
496 #define list_for_each_entry_safe_continue(pos, n, head, member) \
497 for (pos = list_entry(pos->member.next, typeof(*pos), member), \
498 n = list_entry(pos->member.next, typeof(*pos), member); \
499 &pos->member != (head); \
500 pos = n, n = list_entry(n->member.next, typeof(*n), member))
503 * list_for_each_entry_safe_from
504 * @pos: the type * to use as a loop cursor.
505 * @n: another type * to use as temporary storage
506 * @head: the head for your list.
507 * @member: the name of the list_struct within the struct.
509 * Iterate over list of given type from current point, safe against
510 * removal of list entry.
512 #define list_for_each_entry_safe_from(pos, n, head, member) \
513 for (n = list_entry(pos->member.next, typeof(*pos), member); \
514 &pos->member != (head); \
515 pos = n, n = list_entry(n->member.next, typeof(*n), member))
518 * list_for_each_entry_safe_reverse
519 * @pos: the type * to use as a loop cursor.
520 * @n: another type * to use as temporary storage
521 * @head: the head for your list.
522 * @member: the name of the list_struct within the struct.
524 * Iterate backwards over list of given type, safe against removal
527 #define list_for_each_entry_safe_reverse(pos, n, head, member) \
528 for (pos = list_entry((head)->prev, typeof(*pos), member), \
529 n = list_entry(pos->member.prev, typeof(*pos), member); \
530 &pos->member != (head); \
531 pos = n, n = list_entry(n->member.prev, typeof(*n), member))
534 * Double linked lists with a single pointer list head.
535 * Mostly useful for hash tables where the two pointer list head is
537 * You lose the ability to access the tail in O(1).
541 struct hlist_node
*first
;
545 struct hlist_node
*next
, **pprev
;
548 #define HLIST_HEAD_INIT { .first = NULL }
549 #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
550 #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
551 static inline void INIT_HLIST_NODE(struct hlist_node
*h
)
557 static inline int hlist_unhashed(const struct hlist_node
*h
)
562 static inline int hlist_empty(const struct hlist_head
*h
)
567 static inline void __hlist_del(struct hlist_node
*n
)
569 struct hlist_node
*next
= n
->next
;
570 struct hlist_node
**pprev
= n
->pprev
;
576 static inline void hlist_del(struct hlist_node
*n
)
579 n
->next
= LIST_POISON1
;
580 n
->pprev
= LIST_POISON2
;
583 static inline void hlist_del_init(struct hlist_node
*n
)
585 if (!hlist_unhashed(n
)) {
591 static inline void hlist_add_head(struct hlist_node
*n
, struct hlist_head
*h
)
593 struct hlist_node
*first
= h
->first
;
596 first
->pprev
= &n
->next
;
598 n
->pprev
= &h
->first
;
601 /* next must be != NULL */
602 static inline void hlist_add_before(struct hlist_node
*n
,
603 struct hlist_node
*next
)
605 n
->pprev
= next
->pprev
;
607 next
->pprev
= &n
->next
;
611 static inline void hlist_add_after(struct hlist_node
*n
,
612 struct hlist_node
*next
)
614 next
->next
= n
->next
;
616 next
->pprev
= &n
->next
;
619 next
->next
->pprev
= &next
->next
;
623 * Move a list from one list head to another. Fixup the pprev
624 * reference of the first entry if it exists.
626 static inline void hlist_move_list(struct hlist_head
*old
,
627 struct hlist_head
*new)
629 new->first
= old
->first
;
631 new->first
->pprev
= &new->first
;
635 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
637 #define hlist_for_each(pos, head) \
638 for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
641 #define hlist_for_each_safe(pos, n, head) \
642 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
646 * hlist_for_each_entry - iterate over list of given type
647 * @tpos: the type * to use as a loop cursor.
648 * @pos: the &struct hlist_node to use as a loop cursor.
649 * @head: the head for your list.
650 * @member: the name of the hlist_node within the struct.
652 #define hlist_for_each_entry(tpos, pos, head, member) \
653 for (pos = (head)->first; \
654 pos && ({ prefetch(pos->next); 1;}) && \
655 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
659 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
660 * @tpos: the type * to use as a loop cursor.
661 * @pos: the &struct hlist_node to use as a loop cursor.
662 * @member: the name of the hlist_node within the struct.
664 #define hlist_for_each_entry_continue(tpos, pos, member) \
665 for (pos = (pos)->next; \
666 pos && ({ prefetch(pos->next); 1;}) && \
667 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
671 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
672 * @tpos: the type * to use as a loop cursor.
673 * @pos: the &struct hlist_node to use as a loop cursor.
674 * @member: the name of the hlist_node within the struct.
676 #define hlist_for_each_entry_from(tpos, pos, member) \
677 for (; pos && ({ prefetch(pos->next); 1;}) && \
678 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
682 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
683 * @tpos: the type * to use as a loop cursor.
684 * @pos: the &struct hlist_node to use as a loop cursor.
685 * @n: another &struct hlist_node to use as temporary storage
686 * @head: the head for your list.
687 * @member: the name of the hlist_node within the struct.
689 #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \
690 for (pos = (head)->first; \
691 pos && ({ n = pos->next; 1; }) && \
692 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \