1 #ifndef _LINUX_LIST_H
2 #define _LINUX_LIST_H
3
4 #undef offsetof
5 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
6
7 /**
8 * container_of - cast a member of a structure out to the containing structure
9 *
10 * @ptr: the pointer to the member.
11 * @type: the type of the container struct this is embedded in.
12 * @member: the name of the member within the struct.
13 *
14 */
15 #define container_of(ptr, type, member) ({ \
16 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
17 (type *)( (char *)__mptr - offsetof(type,member) );})
18
19 /*
20 * Check at compile time that something is of a particular type.
21 * Always evaluates to 1 so you may use it easily in comparisons.
22 */
23 #define typecheck(type,x) \
24 ({ type __dummy; \
25 typeof(x) __dummy2; \
26 (void)(&__dummy == &__dummy2); \
27 1; \
28 })
29
30 #define prefetch(x) ((void)0)
31
32 /* empty define to make this work in userspace -HW */
33 #define smp_wmb()
34
35 /*
36 * These are non-NULL pointers that will result in page faults
37 * under normal circumstances, used to verify that nobody uses
38 * non-initialized list entries.
39 */
40 #define LIST_POISON1 ((void *) 0x00100100)
41 #define LIST_POISON2 ((void *) 0x00200200)
42
43 /*
44 * Simple doubly linked list implementation.
45 *
46 * Some of the internal functions ("__xxx") are useful when
47 * manipulating whole lists rather than single entries, as
48 * sometimes we already know the next/prev entries and we can
49 * generate better code by using them directly rather than
50 * using the generic single-entry routines.
51 */
52
53 struct list_head {
54 struct list_head *next, *prev;
55 };
56
57 #define LIST_HEAD_INIT(name) { &(name), &(name) }
58
59 #define LIST_HEAD(name) \
60 struct list_head name = LIST_HEAD_INIT(name)
61
62 #define INIT_LIST_HEAD(ptr) do { \
63 (ptr)->next = (ptr); (ptr)->prev = (ptr); \
64 } while (0)
65
66 /*
67 * Insert a new entry between two known consecutive entries.
68 *
69 * This is only for internal list manipulation where we know
70 * the prev/next entries already!
71 */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)72 static inline void __list_add(struct list_head *new,
73 struct list_head *prev,
74 struct list_head *next)
75 {
76 next->prev = new;
77 new->next = next;
78 new->prev = prev;
79 prev->next = new;
80 }
81
82 /**
83 * list_add - add a new entry
84 * @new: new entry to be added
85 * @head: list head to add it after
86 *
87 * Insert a new entry after the specified head.
88 * This is good for implementing stacks.
89 */
list_add(struct list_head * new,struct list_head * head)90 static inline void list_add(struct list_head *new, struct list_head *head)
91 {
92 __list_add(new, head, head->next);
93 }
94
95 /**
96 * list_add_tail - add a new entry
97 * @new: new entry to be added
98 * @head: list head to add it before
99 *
100 * Insert a new entry before the specified head.
101 * This is useful for implementing queues.
102 */
list_add_tail(struct list_head * new,struct list_head * head)103 static inline void list_add_tail(struct list_head *new, struct list_head *head)
104 {
105 __list_add(new, head->prev, head);
106 }
107
108 /*
109 * Insert a new entry between two known consecutive entries.
110 *
111 * This is only for internal list manipulation where we know
112 * the prev/next entries already!
113 */
__list_add_rcu(struct list_head * new,struct list_head * prev,struct list_head * next)114 static inline void __list_add_rcu(struct list_head * new,
115 struct list_head * prev, struct list_head * next)
116 {
117 new->next = next;
118 new->prev = prev;
119 smp_wmb();
120 next->prev = new;
121 prev->next = new;
122 }
123
124 /**
125 * list_add_rcu - add a new entry to rcu-protected list
126 * @new: new entry to be added
127 * @head: list head to add it after
128 *
129 * Insert a new entry after the specified head.
130 * This is good for implementing stacks.
131 *
132 * The caller must take whatever precautions are necessary
133 * (such as holding appropriate locks) to avoid racing
134 * with another list-mutation primitive, such as list_add_rcu()
135 * or list_del_rcu(), running on this same list.
136 * However, it is perfectly legal to run concurrently with
137 * the _rcu list-traversal primitives, such as
138 * list_for_each_entry_rcu().
139 */
list_add_rcu(struct list_head * new,struct list_head * head)140 static inline void list_add_rcu(struct list_head *new, struct list_head *head)
141 {
142 __list_add_rcu(new, head, head->next);
143 }
144
145 /**
146 * list_add_tail_rcu - add a new entry to rcu-protected list
147 * @new: new entry to be added
148 * @head: list head to add it before
149 *
150 * Insert a new entry before the specified head.
151 * This is useful for implementing queues.
152 *
153 * The caller must take whatever precautions are necessary
154 * (such as holding appropriate locks) to avoid racing
155 * with another list-mutation primitive, such as list_add_tail_rcu()
156 * or list_del_rcu(), running on this same list.
157 * However, it is perfectly legal to run concurrently with
158 * the _rcu list-traversal primitives, such as
159 * list_for_each_entry_rcu().
160 */
list_add_tail_rcu(struct list_head * new,struct list_head * head)161 static inline void list_add_tail_rcu(struct list_head *new,
162 struct list_head *head)
163 {
164 __list_add_rcu(new, head->prev, head);
165 }
166
167 /*
168 * Delete a list entry by making the prev/next entries
169 * point to each other.
170 *
171 * This is only for internal list manipulation where we know
172 * the prev/next entries already!
173 */
__list_del(struct list_head * prev,struct list_head * next)174 static inline void __list_del(struct list_head * prev, struct list_head * next)
175 {
176 next->prev = prev;
177 prev->next = next;
178 }
179
180 /**
181 * list_del - deletes entry from list.
182 * @entry: the element to delete from the list.
183 * Note: list_empty on entry does not return true after this, the entry is
184 * in an undefined state.
185 */
list_del(struct list_head * entry)186 static inline void list_del(struct list_head *entry)
187 {
188 __list_del(entry->prev, entry->next);
189 entry->next = LIST_POISON1;
190 entry->prev = LIST_POISON2;
191 }
192
193 /**
194 * list_del_rcu - deletes entry from list without re-initialization
195 * @entry: the element to delete from the list.
196 *
197 * Note: list_empty on entry does not return true after this,
198 * the entry is in an undefined state. It is useful for RCU based
199 * lockfree traversal.
200 *
201 * In particular, it means that we can not poison the forward
202 * pointers that may still be used for walking the list.
203 *
204 * The caller must take whatever precautions are necessary
205 * (such as holding appropriate locks) to avoid racing
206 * with another list-mutation primitive, such as list_del_rcu()
207 * or list_add_rcu(), running on this same list.
208 * However, it is perfectly legal to run concurrently with
209 * the _rcu list-traversal primitives, such as
210 * list_for_each_entry_rcu().
211 *
212 * Note that the caller is not permitted to immediately free
213 * the newly deleted entry. Instead, either synchronize_kernel()
214 * or call_rcu() must be used to defer freeing until an RCU
215 * grace period has elapsed.
216 */
list_del_rcu(struct list_head * entry)217 static inline void list_del_rcu(struct list_head *entry)
218 {
219 __list_del(entry->prev, entry->next);
220 entry->prev = LIST_POISON2;
221 }
222
223 /**
224 * list_del_init - deletes entry from list and reinitialize it.
225 * @entry: the element to delete from the list.
226 */
list_del_init(struct list_head * entry)227 static inline void list_del_init(struct list_head *entry)
228 {
229 __list_del(entry->prev, entry->next);
230 INIT_LIST_HEAD(entry);
231 }
232
233 /**
234 * list_move - delete from one list and add as another's head
235 * @list: the entry to move
236 * @head: the head that will precede our entry
237 */
list_move(struct list_head * list,struct list_head * head)238 static inline void list_move(struct list_head *list, struct list_head *head)
239 {
240 __list_del(list->prev, list->next);
241 list_add(list, head);
242 }
243
244 /**
245 * list_move_tail - delete from one list and add as another's tail
246 * @list: the entry to move
247 * @head: the head that will follow our entry
248 */
list_move_tail(struct list_head * list,struct list_head * head)249 static inline void list_move_tail(struct list_head *list,
250 struct list_head *head)
251 {
252 __list_del(list->prev, list->next);
253 list_add_tail(list, head);
254 }
255
256 /**
257 * list_empty - tests whether a list is empty
258 * @head: the list to test.
259 */
list_empty(const struct list_head * head)260 static inline int list_empty(const struct list_head *head)
261 {
262 return head->next == head;
263 }
264
265 /**
266 * list_empty_careful - tests whether a list is
267 * empty _and_ checks that no other CPU might be
268 * in the process of still modifying either member
269 *
270 * NOTE: using list_empty_careful() without synchronization
271 * can only be safe if the only activity that can happen
272 * to the list entry is list_del_init(). Eg. it cannot be used
273 * if another CPU could re-list_add() it.
274 *
275 * @head: the list to test.
276 */
list_empty_careful(const struct list_head * head)277 static inline int list_empty_careful(const struct list_head *head)
278 {
279 struct list_head *next = head->next;
280 return (next == head) && (next == head->prev);
281 }
282
__list_splice(struct list_head * list,struct list_head * head)283 static inline void __list_splice(struct list_head *list,
284 struct list_head *head)
285 {
286 struct list_head *first = list->next;
287 struct list_head *last = list->prev;
288 struct list_head *at = head->next;
289
290 first->prev = head;
291 head->next = first;
292
293 last->next = at;
294 at->prev = last;
295 }
296
297 /**
298 * list_splice - join two lists
299 * @list: the new list to add.
300 * @head: the place to add it in the first list.
301 */
list_splice(struct list_head * list,struct list_head * head)302 static inline void list_splice(struct list_head *list, struct list_head *head)
303 {
304 if (!list_empty(list))
305 __list_splice(list, head);
306 }
307
308 /**
309 * list_splice_init - join two lists and reinitialise the emptied list.
310 * @list: the new list to add.
311 * @head: the place to add it in the first list.
312 *
313 * The list at @list is reinitialised
314 */
list_splice_init(struct list_head * list,struct list_head * head)315 static inline void list_splice_init(struct list_head *list,
316 struct list_head *head)
317 {
318 if (!list_empty(list)) {
319 __list_splice(list, head);
320 INIT_LIST_HEAD(list);
321 }
322 }
323
324 /**
325 * list_entry - get the struct for this entry
326 * @ptr: the &struct list_head pointer.
327 * @type: the type of the struct this is embedded in.
328 * @member: the name of the list_struct within the struct.
329 */
330 #define list_entry(ptr, type, member) \
331 container_of(ptr, type, member)
332
333 /**
334 * list_for_each - iterate over a list
335 * @pos: the &struct list_head to use as a loop counter.
336 * @head: the head for your list.
337 */
338 #define list_for_each(pos, head) \
339 for (pos = (head)->next, prefetch(pos->next); pos != (head); \
340 pos = pos->next, prefetch(pos->next))
341
342 /**
343 * __list_for_each - iterate over a list
344 * @pos: the &struct list_head to use as a loop counter.
345 * @head: the head for your list.
346 *
347 * This variant differs from list_for_each() in that it's the
348 * simplest possible list iteration code, no prefetching is done.
349 * Use this for code that knows the list to be very short (empty
350 * or 1 entry) most of the time.
351 */
352 #define __list_for_each(pos, head) \
353 for (pos = (head)->next; pos != (head); pos = pos->next)
354
355 /**
356 * list_for_each_prev - iterate over a list backwards
357 * @pos: the &struct list_head to use as a loop counter.
358 * @head: the head for your list.
359 */
360 #define list_for_each_prev(pos, head) \
361 for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \
362 pos = pos->prev, prefetch(pos->prev))
363
364 /**
365 * list_for_each_safe - iterate over a list safe against removal of list entry
366 * @pos: the &struct list_head to use as a loop counter.
367 * @n: another &struct list_head to use as temporary storage
368 * @head: the head for your list.
369 */
370 #define list_for_each_safe(pos, n, head) \
371 for (pos = (head)->next, n = pos->next; pos != (head); \
372 pos = n, n = pos->next)
373
374 /**
375 * list_for_each_entry - iterate over list of given type
376 * @pos: the type * to use as a loop counter.
377 * @head: the head for your list.
378 * @member: the name of the list_struct within the struct.
379 */
380 #define list_for_each_entry(pos, head, member) \
381 for (pos = list_entry((head)->next, typeof(*pos), member), \
382 prefetch(pos->member.next); \
383 &pos->member != (head); \
384 pos = list_entry(pos->member.next, typeof(*pos), member), \
385 prefetch(pos->member.next))
386
387 /**
388 * list_for_each_entry_reverse - iterate backwards over list of given type.
389 * @pos: the type * to use as a loop counter.
390 * @head: the head for your list.
391 * @member: the name of the list_struct within the struct.
392 */
393 #define list_for_each_entry_reverse(pos, head, member) \
394 for (pos = list_entry((head)->prev, typeof(*pos), member), \
395 prefetch(pos->member.prev); \
396 &pos->member != (head); \
397 pos = list_entry(pos->member.prev, typeof(*pos), member), \
398 prefetch(pos->member.prev))
399
400 /**
401 * list_prepare_entry - prepare a pos entry for use as a start point in
402 * list_for_each_entry_continue
403 * @pos: the type * to use as a start point
404 * @head: the head of the list
405 * @member: the name of the list_struct within the struct.
406 */
407 #define list_prepare_entry(pos, head, member) \
408 ((pos) ? : list_entry(head, typeof(*pos), member))
409
410 /**
411 * list_for_each_entry_continue - iterate over list of given type
412 * continuing after existing point
413 * @pos: the type * to use as a loop counter.
414 * @head: the head for your list.
415 * @member: the name of the list_struct within the struct.
416 */
417 #define list_for_each_entry_continue(pos, head, member) \
418 for (pos = list_entry(pos->member.next, typeof(*pos), member), \
419 prefetch(pos->member.next); \
420 &pos->member != (head); \
421 pos = list_entry(pos->member.next, typeof(*pos), member), \
422 prefetch(pos->member.next))
423
424 /**
425 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
426 * @pos: the type * to use as a loop counter.
427 * @n: another type * to use as temporary storage
428 * @head: the head for your list.
429 * @member: the name of the list_struct within the struct.
430 */
431 #define list_for_each_entry_safe(pos, n, head, member) \
432 for (pos = list_entry((head)->next, typeof(*pos), member), \
433 n = list_entry(pos->member.next, typeof(*pos), member); \
434 &pos->member != (head); \
435 pos = n, n = list_entry(n->member.next, typeof(*n), member))
436
437 /**
438 * list_for_each_rcu - iterate over an rcu-protected list
439 * @pos: the &struct list_head to use as a loop counter.
440 * @head: the head for your list.
441 *
442 * This list-traversal primitive may safely run concurrently with
443 * the _rcu list-mutation primitives such as list_add_rcu()
444 * as long as the traversal is guarded by rcu_read_lock().
445 */
446 #define list_for_each_rcu(pos, head) \
447 for (pos = (head)->next, prefetch(pos->next); pos != (head); \
448 pos = pos->next, ({ smp_read_barrier_depends(); 0;}), prefetch(pos->next))
449
450 #define __list_for_each_rcu(pos, head) \
451 for (pos = (head)->next; pos != (head); \
452 pos = pos->next, ({ smp_read_barrier_depends(); 0;}))
453
454 /**
455 * list_for_each_safe_rcu - iterate over an rcu-protected list safe
456 * against removal of list entry
457 * @pos: the &struct list_head to use as a loop counter.
458 * @n: another &struct list_head to use as temporary storage
459 * @head: the head for your list.
460 *
461 * This list-traversal primitive may safely run concurrently with
462 * the _rcu list-mutation primitives such as list_add_rcu()
463 * as long as the traversal is guarded by rcu_read_lock().
464 */
465 #define list_for_each_safe_rcu(pos, n, head) \
466 for (pos = (head)->next, n = pos->next; pos != (head); \
467 pos = n, ({ smp_read_barrier_depends(); 0;}), n = pos->next)
468
469 /**
470 * list_for_each_entry_rcu - iterate over rcu list of given type
471 * @pos: the type * to use as a loop counter.
472 * @head: the head for your list.
473 * @member: the name of the list_struct within the struct.
474 *
475 * This list-traversal primitive may safely run concurrently with
476 * the _rcu list-mutation primitives such as list_add_rcu()
477 * as long as the traversal is guarded by rcu_read_lock().
478 */
479 #define list_for_each_entry_rcu(pos, head, member) \
480 for (pos = list_entry((head)->next, typeof(*pos), member), \
481 prefetch(pos->member.next); \
482 &pos->member != (head); \
483 pos = list_entry(pos->member.next, typeof(*pos), member), \
484 ({ smp_read_barrier_depends(); 0;}), \
485 prefetch(pos->member.next))
486
487
488 /**
489 * list_for_each_continue_rcu - iterate over an rcu-protected list
490 * continuing after existing point.
491 * @pos: the &struct list_head to use as a loop counter.
492 * @head: the head for your list.
493 *
494 * This list-traversal primitive may safely run concurrently with
495 * the _rcu list-mutation primitives such as list_add_rcu()
496 * as long as the traversal is guarded by rcu_read_lock().
497 */
498 #define list_for_each_continue_rcu(pos, head) \
499 for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \
500 (pos) = (pos)->next, ({ smp_read_barrier_depends(); 0;}), prefetch((pos)->next))
501
502 /*
503 * Double linked lists with a single pointer list head.
504 * Mostly useful for hash tables where the two pointer list head is
505 * too wasteful.
506 * You lose the ability to access the tail in O(1).
507 */
508
509 struct hlist_head {
510 struct hlist_node *first;
511 };
512
513 struct hlist_node {
514 struct hlist_node *next, **pprev;
515 };
516
517 #define HLIST_HEAD_INIT { .first = NULL }
518 #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
519 #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
520 #define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL)
521
hlist_unhashed(const struct hlist_node * h)522 static inline int hlist_unhashed(const struct hlist_node *h)
523 {
524 return !h->pprev;
525 }
526
hlist_empty(const struct hlist_head * h)527 static inline int hlist_empty(const struct hlist_head *h)
528 {
529 return !h->first;
530 }
531
__hlist_del(struct hlist_node * n)532 static inline void __hlist_del(struct hlist_node *n)
533 {
534 struct hlist_node *next = n->next;
535 struct hlist_node **pprev = n->pprev;
536 *pprev = next;
537 if (next)
538 next->pprev = pprev;
539 }
540
hlist_del(struct hlist_node * n)541 static inline void hlist_del(struct hlist_node *n)
542 {
543 __hlist_del(n);
544 n->next = LIST_POISON1;
545 n->pprev = LIST_POISON2;
546 }
547
548 /**
549 * hlist_del_rcu - deletes entry from hash list without re-initialization
550 * @n: the element to delete from the hash list.
551 *
552 * Note: list_unhashed() on entry does not return true after this,
553 * the entry is in an undefined state. It is useful for RCU based
554 * lockfree traversal.
555 *
556 * In particular, it means that we can not poison the forward
557 * pointers that may still be used for walking the hash list.
558 *
559 * The caller must take whatever precautions are necessary
560 * (such as holding appropriate locks) to avoid racing
561 * with another list-mutation primitive, such as hlist_add_head_rcu()
562 * or hlist_del_rcu(), running on this same list.
563 * However, it is perfectly legal to run concurrently with
564 * the _rcu list-traversal primitives, such as
565 * hlist_for_each_entry().
566 */
hlist_del_rcu(struct hlist_node * n)567 static inline void hlist_del_rcu(struct hlist_node *n)
568 {
569 __hlist_del(n);
570 n->pprev = LIST_POISON2;
571 }
572
hlist_del_init(struct hlist_node * n)573 static inline void hlist_del_init(struct hlist_node *n)
574 {
575 if (n->pprev) {
576 __hlist_del(n);
577 INIT_HLIST_NODE(n);
578 }
579 }
580
581 #define hlist_del_rcu_init hlist_del_init
582
hlist_add_head(struct hlist_node * n,struct hlist_head * h)583 static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
584 {
585 struct hlist_node *first = h->first;
586 n->next = first;
587 if (first)
588 first->pprev = &n->next;
589 h->first = n;
590 n->pprev = &h->first;
591 }
592
593
594 /**
595 * hlist_add_head_rcu - adds the specified element to the specified hlist,
596 * while permitting racing traversals.
597 * @n: the element to add to the hash list.
598 * @h: the list to add to.
599 *
600 * The caller must take whatever precautions are necessary
601 * (such as holding appropriate locks) to avoid racing
602 * with another list-mutation primitive, such as hlist_add_head_rcu()
603 * or hlist_del_rcu(), running on this same list.
604 * However, it is perfectly legal to run concurrently with
605 * the _rcu list-traversal primitives, such as
606 * hlist_for_each_entry(), but only if smp_read_barrier_depends()
607 * is used to prevent memory-consistency problems on Alpha CPUs.
608 * Regardless of the type of CPU, the list-traversal primitive
609 * must be guarded by rcu_read_lock().
610 *
611 * OK, so why don't we have an hlist_for_each_entry_rcu()???
612 */
hlist_add_head_rcu(struct hlist_node * n,struct hlist_head * h)613 static inline void hlist_add_head_rcu(struct hlist_node *n,
614 struct hlist_head *h)
615 {
616 struct hlist_node *first = h->first;
617 n->next = first;
618 n->pprev = &h->first;
619 smp_wmb();
620 if (first)
621 first->pprev = &n->next;
622 h->first = n;
623 }
624
625 /* next must be != NULL */
hlist_add_before(struct hlist_node * n,struct hlist_node * next)626 static inline void hlist_add_before(struct hlist_node *n,
627 struct hlist_node *next)
628 {
629 n->pprev = next->pprev;
630 n->next = next;
631 next->pprev = &n->next;
632 *(n->pprev) = n;
633 }
634
hlist_add_after(struct hlist_node * n,struct hlist_node * next)635 static inline void hlist_add_after(struct hlist_node *n,
636 struct hlist_node *next)
637 {
638 next->next = n->next;
639 n->next = next;
640 next->pprev = &n->next;
641
642 if(next->next)
643 next->next->pprev = &next->next;
644 }
645
646 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
647
648 #define hlist_for_each(pos, head) \
649 for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
650 pos = pos->next)
651
652 #define hlist_for_each_safe(pos, n, head) \
653 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
654 pos = n)
655
656 /**
657 * hlist_for_each_entry - iterate over list of given type
658 * @tpos: the type * to use as a loop counter.
659 * @pos: the &struct hlist_node to use as a loop counter.
660 * @head: the head for your list.
661 * @member: the name of the hlist_node within the struct.
662 */
663 #define hlist_for_each_entry(tpos, pos, head, member) \
664 for (pos = (head)->first; \
665 pos && ({ prefetch(pos->next); 1;}) && \
666 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
667 pos = pos->next)
668
669 /**
670 * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point
671 * @tpos: the type * to use as a loop counter.
672 * @pos: the &struct hlist_node to use as a loop counter.
673 * @member: the name of the hlist_node within the struct.
674 */
675 #define hlist_for_each_entry_continue(tpos, pos, member) \
676 for (pos = (pos)->next; \
677 pos && ({ prefetch(pos->next); 1;}) && \
678 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
679 pos = pos->next)
680
681 /**
682 * hlist_for_each_entry_from - iterate over a hlist continuing from existing point
683 * @tpos: the type * to use as a loop counter.
684 * @pos: the &struct hlist_node to use as a loop counter.
685 * @member: the name of the hlist_node within the struct.
686 */
687 #define hlist_for_each_entry_from(tpos, pos, member) \
688 for (; pos && ({ prefetch(pos->next); 1;}) && \
689 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
690 pos = pos->next)
691
692 /**
693 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
694 * @tpos: the type * to use as a loop counter.
695 * @pos: the &struct hlist_node to use as a loop counter.
696 * @n: another &struct hlist_node to use as temporary storage
697 * @head: the head for your list.
698 * @member: the name of the hlist_node within the struct.
699 */
700 #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \
701 for (pos = (head)->first; \
702 pos && ({ n = pos->next; 1; }) && \
703 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
704 pos = n)
705
706 /**
707 * hlist_for_each_entry_rcu - iterate over rcu list of given type
708 * @pos: the type * to use as a loop counter.
709 * @pos: the &struct hlist_node to use as a loop counter.
710 * @head: the head for your list.
711 * @member: the name of the hlist_node within the struct.
712 *
713 * This list-traversal primitive may safely run concurrently with
714 * the _rcu list-mutation primitives such as hlist_add_rcu()
715 * as long as the traversal is guarded by rcu_read_lock().
716 */
717 #define hlist_for_each_entry_rcu(tpos, pos, head, member) \
718 for (pos = (head)->first; \
719 pos && ({ prefetch(pos->next); 1;}) && \
720 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
721 pos = pos->next, ({ smp_read_barrier_depends(); 0; }) )
722
723 #endif
724