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Franck Bui-Huu82524742008-05-12 21:21:05 +02001#ifndef _LINUX_RCULIST_H
2#define _LINUX_RCULIST_H
3
4#ifdef __KERNEL__
5
6/*
7 * RCU-protected list version
8 */
9#include <linux/list.h>
Franck Bui-Huu10aa9d22008-05-12 21:21:06 +020010#include <linux/rcupdate.h>
Franck Bui-Huu82524742008-05-12 21:21:05 +020011
12/*
Paul E. McKenney65e6bf42010-08-19 21:43:09 -070013 * Why is there no list_empty_rcu()? Because list_empty() serves this
14 * purpose. The list_empty() function fetches the RCU-protected pointer
15 * and compares it to the address of the list head, but neither dereferences
16 * this pointer itself nor provides this pointer to the caller. Therefore,
17 * it is not necessary to use rcu_dereference(), so that list_empty() can
18 * be used anywhere you would want to use a list_empty_rcu().
19 */
20
21/*
Paul E. McKenney2a855b62013-08-23 09:40:42 -070022 * INIT_LIST_HEAD_RCU - Initialize a list_head visible to RCU readers
23 * @list: list to be initialized
24 *
25 * You should instead use INIT_LIST_HEAD() for normal initialization and
26 * cleanup tasks, when readers have no access to the list being initialized.
27 * However, if the list being initialized is visible to readers, you
28 * need to keep the compiler from being too mischievous.
29 */
30static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
31{
32 ACCESS_ONCE(list->next) = list;
33 ACCESS_ONCE(list->prev) = list;
34}
35
36/*
Arnd Bergmann67bdbff2010-02-25 16:55:13 +010037 * return the ->next pointer of a list_head in an rcu safe
38 * way, we must not access it directly
39 */
40#define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next)))
41
42/*
Franck Bui-Huu82524742008-05-12 21:21:05 +020043 * Insert a new entry between two known consecutive entries.
44 *
45 * This is only for internal list manipulation where we know
46 * the prev/next entries already!
47 */
Dave Jones559f9ba2012-03-14 22:17:39 -040048#ifndef CONFIG_DEBUG_LIST
Franck Bui-Huu82524742008-05-12 21:21:05 +020049static inline void __list_add_rcu(struct list_head *new,
50 struct list_head *prev, struct list_head *next)
51{
52 new->next = next;
53 new->prev = prev;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +010054 rcu_assign_pointer(list_next_rcu(prev), new);
Franck Bui-Huu82524742008-05-12 21:21:05 +020055 next->prev = new;
Franck Bui-Huu82524742008-05-12 21:21:05 +020056}
Dave Jones559f9ba2012-03-14 22:17:39 -040057#else
Teodora Baluta584dc4c2013-11-11 17:11:23 +020058void __list_add_rcu(struct list_head *new,
59 struct list_head *prev, struct list_head *next);
Dave Jones559f9ba2012-03-14 22:17:39 -040060#endif
Franck Bui-Huu82524742008-05-12 21:21:05 +020061
62/**
63 * list_add_rcu - add a new entry to rcu-protected list
64 * @new: new entry to be added
65 * @head: list head to add it after
66 *
67 * Insert a new entry after the specified head.
68 * This is good for implementing stacks.
69 *
70 * The caller must take whatever precautions are necessary
71 * (such as holding appropriate locks) to avoid racing
72 * with another list-mutation primitive, such as list_add_rcu()
73 * or list_del_rcu(), running on this same list.
74 * However, it is perfectly legal to run concurrently with
75 * the _rcu list-traversal primitives, such as
76 * list_for_each_entry_rcu().
77 */
78static inline void list_add_rcu(struct list_head *new, struct list_head *head)
79{
80 __list_add_rcu(new, head, head->next);
81}
82
83/**
84 * list_add_tail_rcu - add a new entry to rcu-protected list
85 * @new: new entry to be added
86 * @head: list head to add it before
87 *
88 * Insert a new entry before the specified head.
89 * This is useful for implementing queues.
90 *
91 * The caller must take whatever precautions are necessary
92 * (such as holding appropriate locks) to avoid racing
93 * with another list-mutation primitive, such as list_add_tail_rcu()
94 * or list_del_rcu(), running on this same list.
95 * However, it is perfectly legal to run concurrently with
96 * the _rcu list-traversal primitives, such as
97 * list_for_each_entry_rcu().
98 */
99static inline void list_add_tail_rcu(struct list_head *new,
100 struct list_head *head)
101{
102 __list_add_rcu(new, head->prev, head);
103}
104
105/**
106 * list_del_rcu - deletes entry from list without re-initialization
107 * @entry: the element to delete from the list.
108 *
109 * Note: list_empty() on entry does not return true after this,
110 * the entry is in an undefined state. It is useful for RCU based
111 * lockfree traversal.
112 *
113 * In particular, it means that we can not poison the forward
114 * pointers that may still be used for walking the list.
115 *
116 * The caller must take whatever precautions are necessary
117 * (such as holding appropriate locks) to avoid racing
118 * with another list-mutation primitive, such as list_del_rcu()
119 * or list_add_rcu(), running on this same list.
120 * However, it is perfectly legal to run concurrently with
121 * the _rcu list-traversal primitives, such as
122 * list_for_each_entry_rcu().
123 *
124 * Note that the caller is not permitted to immediately free
125 * the newly deleted entry. Instead, either synchronize_rcu()
126 * or call_rcu() must be used to defer freeing until an RCU
127 * grace period has elapsed.
128 */
129static inline void list_del_rcu(struct list_head *entry)
130{
Dave Jones559f9ba2012-03-14 22:17:39 -0400131 __list_del_entry(entry);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200132 entry->prev = LIST_POISON2;
133}
134
135/**
Andrea Arcangeli6beeac72008-07-28 15:46:22 -0700136 * hlist_del_init_rcu - deletes entry from hash list with re-initialization
137 * @n: the element to delete from the hash list.
138 *
139 * Note: list_unhashed() on the node return true after this. It is
140 * useful for RCU based read lockfree traversal if the writer side
141 * must know if the list entry is still hashed or already unhashed.
142 *
143 * In particular, it means that we can not poison the forward pointers
144 * that may still be used for walking the hash list and we can only
145 * zero the pprev pointer so list_unhashed() will return true after
146 * this.
147 *
148 * The caller must take whatever precautions are necessary (such as
149 * holding appropriate locks) to avoid racing with another
150 * list-mutation primitive, such as hlist_add_head_rcu() or
151 * hlist_del_rcu(), running on this same list. However, it is
152 * perfectly legal to run concurrently with the _rcu list-traversal
153 * primitives, such as hlist_for_each_entry_rcu().
154 */
155static inline void hlist_del_init_rcu(struct hlist_node *n)
156{
157 if (!hlist_unhashed(n)) {
158 __hlist_del(n);
159 n->pprev = NULL;
160 }
161}
162
163/**
Franck Bui-Huu82524742008-05-12 21:21:05 +0200164 * list_replace_rcu - replace old entry by new one
165 * @old : the element to be replaced
166 * @new : the new element to insert
167 *
168 * The @old entry will be replaced with the @new entry atomically.
169 * Note: @old should not be empty.
170 */
171static inline void list_replace_rcu(struct list_head *old,
172 struct list_head *new)
173{
174 new->next = old->next;
175 new->prev = old->prev;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100176 rcu_assign_pointer(list_next_rcu(new->prev), new);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200177 new->next->prev = new;
Franck Bui-Huu82524742008-05-12 21:21:05 +0200178 old->prev = LIST_POISON2;
179}
180
181/**
182 * list_splice_init_rcu - splice an RCU-protected list into an existing list.
183 * @list: the RCU-protected list to splice
184 * @head: the place in the list to splice the first list into
185 * @sync: function to sync: synchronize_rcu(), synchronize_sched(), ...
186 *
187 * @head can be RCU-read traversed concurrently with this function.
188 *
189 * Note that this function blocks.
190 *
191 * Important note: the caller must take whatever action is necessary to
192 * prevent any other updates to @head. In principle, it is possible
193 * to modify the list as soon as sync() begins execution.
194 * If this sort of thing becomes necessary, an alternative version
195 * based on call_rcu() could be created. But only if -really-
196 * needed -- there is no shortage of RCU API members.
197 */
198static inline void list_splice_init_rcu(struct list_head *list,
199 struct list_head *head,
200 void (*sync)(void))
201{
202 struct list_head *first = list->next;
203 struct list_head *last = list->prev;
204 struct list_head *at = head->next;
205
Jan H. Schönherr7f708932011-07-19 21:10:26 +0200206 if (list_empty(list))
Franck Bui-Huu82524742008-05-12 21:21:05 +0200207 return;
208
Paul E. McKenney2a855b62013-08-23 09:40:42 -0700209 /*
210 * "first" and "last" tracking list, so initialize it. RCU readers
211 * have access to this list, so we must use INIT_LIST_HEAD_RCU()
212 * instead of INIT_LIST_HEAD().
213 */
Franck Bui-Huu82524742008-05-12 21:21:05 +0200214
Paul E. McKenney2a855b62013-08-23 09:40:42 -0700215 INIT_LIST_HEAD_RCU(list);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200216
217 /*
218 * At this point, the list body still points to the source list.
219 * Wait for any readers to finish using the list before splicing
220 * the list body into the new list. Any new readers will see
221 * an empty list.
222 */
223
224 sync();
225
226 /*
227 * Readers are finished with the source list, so perform splice.
228 * The order is important if the new list is global and accessible
229 * to concurrent RCU readers. Note that RCU readers are not
230 * permitted to traverse the prev pointers without excluding
231 * this function.
232 */
233
234 last->next = at;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100235 rcu_assign_pointer(list_next_rcu(head), first);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200236 first->prev = head;
237 at->prev = last;
238}
239
Jiri Pirko72c6a982009-04-14 17:33:57 +0200240/**
241 * list_entry_rcu - get the struct for this entry
242 * @ptr: the &struct list_head pointer.
243 * @type: the type of the struct this is embedded in.
Andrey Utkin3943f422014-11-14 05:09:55 +0400244 * @member: the name of the list_head within the struct.
Jiri Pirko72c6a982009-04-14 17:33:57 +0200245 *
246 * This primitive may safely run concurrently with the _rcu list-mutation
247 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
248 */
249#define list_entry_rcu(ptr, type, member) \
Joe Perches0adab9b2013-12-05 16:19:15 -0800250({ \
251 typeof(*ptr) __rcu *__ptr = (typeof(*ptr) __rcu __force *)ptr; \
252 container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member); \
253})
Jiri Pirko72c6a982009-04-14 17:33:57 +0200254
255/**
Michel Machadof88022a2012-04-10 14:07:40 -0400256 * Where are list_empty_rcu() and list_first_entry_rcu()?
257 *
258 * Implementing those functions following their counterparts list_empty() and
259 * list_first_entry() is not advisable because they lead to subtle race
260 * conditions as the following snippet shows:
261 *
262 * if (!list_empty_rcu(mylist)) {
263 * struct foo *bar = list_first_entry_rcu(mylist, struct foo, list_member);
264 * do_something(bar);
265 * }
266 *
267 * The list may not be empty when list_empty_rcu checks it, but it may be when
268 * list_first_entry_rcu rereads the ->next pointer.
269 *
270 * Rereading the ->next pointer is not a problem for list_empty() and
271 * list_first_entry() because they would be protected by a lock that blocks
272 * writers.
273 *
274 * See list_first_or_null_rcu for an alternative.
275 */
276
277/**
278 * list_first_or_null_rcu - get the first element from a list
Jiri Pirko72c6a982009-04-14 17:33:57 +0200279 * @ptr: the list head to take the element from.
280 * @type: the type of the struct this is embedded in.
Andrey Utkin3943f422014-11-14 05:09:55 +0400281 * @member: the name of the list_head within the struct.
Jiri Pirko72c6a982009-04-14 17:33:57 +0200282 *
Michel Machadof88022a2012-04-10 14:07:40 -0400283 * Note that if the list is empty, it returns NULL.
Jiri Pirko72c6a982009-04-14 17:33:57 +0200284 *
285 * This primitive may safely run concurrently with the _rcu list-mutation
286 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
287 */
Michel Machadof88022a2012-04-10 14:07:40 -0400288#define list_first_or_null_rcu(ptr, type, member) \
Joe Perches0adab9b2013-12-05 16:19:15 -0800289({ \
290 struct list_head *__ptr = (ptr); \
291 struct list_head *__next = ACCESS_ONCE(__ptr->next); \
292 likely(__ptr != __next) ? list_entry_rcu(__next, type, member) : NULL; \
293})
Jiri Pirko72c6a982009-04-14 17:33:57 +0200294
Franck Bui-Huu82524742008-05-12 21:21:05 +0200295/**
296 * list_for_each_entry_rcu - iterate over rcu list of given type
297 * @pos: the type * to use as a loop cursor.
298 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400299 * @member: the name of the list_head within the struct.
Franck Bui-Huu82524742008-05-12 21:21:05 +0200300 *
301 * This list-traversal primitive may safely run concurrently with
302 * the _rcu list-mutation primitives such as list_add_rcu()
303 * as long as the traversal is guarded by rcu_read_lock().
304 */
305#define list_for_each_entry_rcu(pos, head, member) \
Jiri Pirko72c6a982009-04-14 17:33:57 +0200306 for (pos = list_entry_rcu((head)->next, typeof(*pos), member); \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700307 &pos->member != (head); \
Jiri Pirko72c6a982009-04-14 17:33:57 +0200308 pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
Franck Bui-Huu82524742008-05-12 21:21:05 +0200309
Franck Bui-Huu82524742008-05-12 21:21:05 +0200310/**
stephen hemminger254245d2009-11-10 07:54:47 +0000311 * list_for_each_entry_continue_rcu - continue iteration over list of given type
312 * @pos: the type * to use as a loop cursor.
313 * @head: the head for your list.
Andrey Utkin3943f422014-11-14 05:09:55 +0400314 * @member: the name of the list_head within the struct.
stephen hemminger254245d2009-11-10 07:54:47 +0000315 *
316 * Continue to iterate over list of given type, continuing after
317 * the current position.
318 */
319#define list_for_each_entry_continue_rcu(pos, head, member) \
320 for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \
Linus Torvaldse66eed62011-05-19 14:15:29 -0700321 &pos->member != (head); \
stephen hemminger254245d2009-11-10 07:54:47 +0000322 pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
323
324/**
Franck Bui-Huu82524742008-05-12 21:21:05 +0200325 * hlist_del_rcu - deletes entry from hash list without re-initialization
326 * @n: the element to delete from the hash list.
327 *
328 * Note: list_unhashed() on entry does not return true after this,
329 * the entry is in an undefined state. It is useful for RCU based
330 * lockfree traversal.
331 *
332 * In particular, it means that we can not poison the forward
333 * pointers that may still be used for walking the hash list.
334 *
335 * The caller must take whatever precautions are necessary
336 * (such as holding appropriate locks) to avoid racing
337 * with another list-mutation primitive, such as hlist_add_head_rcu()
338 * or hlist_del_rcu(), running on this same list.
339 * However, it is perfectly legal to run concurrently with
340 * the _rcu list-traversal primitives, such as
341 * hlist_for_each_entry().
342 */
343static inline void hlist_del_rcu(struct hlist_node *n)
344{
345 __hlist_del(n);
346 n->pprev = LIST_POISON2;
347}
348
349/**
350 * hlist_replace_rcu - replace old entry by new one
351 * @old : the element to be replaced
352 * @new : the new element to insert
353 *
354 * The @old entry will be replaced with the @new entry atomically.
355 */
356static inline void hlist_replace_rcu(struct hlist_node *old,
357 struct hlist_node *new)
358{
359 struct hlist_node *next = old->next;
360
361 new->next = next;
362 new->pprev = old->pprev;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100363 rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200364 if (next)
365 new->next->pprev = &new->next;
Franck Bui-Huu82524742008-05-12 21:21:05 +0200366 old->pprev = LIST_POISON2;
367}
368
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100369/*
370 * return the first or the next element in an RCU protected hlist
371 */
372#define hlist_first_rcu(head) (*((struct hlist_node __rcu **)(&(head)->first)))
373#define hlist_next_rcu(node) (*((struct hlist_node __rcu **)(&(node)->next)))
374#define hlist_pprev_rcu(node) (*((struct hlist_node __rcu **)((node)->pprev)))
375
Franck Bui-Huu82524742008-05-12 21:21:05 +0200376/**
377 * hlist_add_head_rcu
378 * @n: the element to add to the hash list.
379 * @h: the list to add to.
380 *
381 * Description:
382 * Adds the specified element to the specified hlist,
383 * while permitting racing traversals.
384 *
385 * The caller must take whatever precautions are necessary
386 * (such as holding appropriate locks) to avoid racing
387 * with another list-mutation primitive, such as hlist_add_head_rcu()
388 * or hlist_del_rcu(), running on this same list.
389 * However, it is perfectly legal to run concurrently with
390 * the _rcu list-traversal primitives, such as
391 * hlist_for_each_entry_rcu(), used to prevent memory-consistency
392 * problems on Alpha CPUs. Regardless of the type of CPU, the
393 * list-traversal primitive must be guarded by rcu_read_lock().
394 */
395static inline void hlist_add_head_rcu(struct hlist_node *n,
396 struct hlist_head *h)
397{
398 struct hlist_node *first = h->first;
Franck Bui-Huu10aa9d22008-05-12 21:21:06 +0200399
Franck Bui-Huu82524742008-05-12 21:21:05 +0200400 n->next = first;
401 n->pprev = &h->first;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100402 rcu_assign_pointer(hlist_first_rcu(h), n);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200403 if (first)
404 first->pprev = &n->next;
Franck Bui-Huu82524742008-05-12 21:21:05 +0200405}
406
407/**
408 * hlist_add_before_rcu
409 * @n: the new element to add to the hash list.
410 * @next: the existing element to add the new element before.
411 *
412 * Description:
413 * Adds the specified element to the specified hlist
414 * before the specified node while permitting racing traversals.
415 *
416 * The caller must take whatever precautions are necessary
417 * (such as holding appropriate locks) to avoid racing
418 * with another list-mutation primitive, such as hlist_add_head_rcu()
419 * or hlist_del_rcu(), running on this same list.
420 * However, it is perfectly legal to run concurrently with
421 * the _rcu list-traversal primitives, such as
422 * hlist_for_each_entry_rcu(), used to prevent memory-consistency
423 * problems on Alpha CPUs.
424 */
425static inline void hlist_add_before_rcu(struct hlist_node *n,
426 struct hlist_node *next)
427{
428 n->pprev = next->pprev;
429 n->next = next;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100430 rcu_assign_pointer(hlist_pprev_rcu(n), n);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200431 next->pprev = &n->next;
Franck Bui-Huu82524742008-05-12 21:21:05 +0200432}
433
434/**
Ken Helias1d023282014-08-06 16:09:16 -0700435 * hlist_add_behind_rcu
Franck Bui-Huu82524742008-05-12 21:21:05 +0200436 * @n: the new element to add to the hash list.
Ken Helias1d023282014-08-06 16:09:16 -0700437 * @prev: the existing element to add the new element after.
Franck Bui-Huu82524742008-05-12 21:21:05 +0200438 *
439 * Description:
440 * Adds the specified element to the specified hlist
441 * after the specified node while permitting racing traversals.
442 *
443 * The caller must take whatever precautions are necessary
444 * (such as holding appropriate locks) to avoid racing
445 * with another list-mutation primitive, such as hlist_add_head_rcu()
446 * or hlist_del_rcu(), running on this same list.
447 * However, it is perfectly legal to run concurrently with
448 * the _rcu list-traversal primitives, such as
449 * hlist_for_each_entry_rcu(), used to prevent memory-consistency
450 * problems on Alpha CPUs.
451 */
Ken Helias1d023282014-08-06 16:09:16 -0700452static inline void hlist_add_behind_rcu(struct hlist_node *n,
453 struct hlist_node *prev)
Franck Bui-Huu82524742008-05-12 21:21:05 +0200454{
455 n->next = prev->next;
456 n->pprev = &prev->next;
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100457 rcu_assign_pointer(hlist_next_rcu(prev), n);
Franck Bui-Huu82524742008-05-12 21:21:05 +0200458 if (n->next)
459 n->next->pprev = &n->next;
460}
461
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100462#define __hlist_for_each_rcu(pos, head) \
463 for (pos = rcu_dereference(hlist_first_rcu(head)); \
Linus Torvalds75d65a42011-05-19 13:50:07 -0700464 pos; \
Arnd Bergmann67bdbff2010-02-25 16:55:13 +0100465 pos = rcu_dereference(hlist_next_rcu(pos)))
stephen hemminger1cc52322010-02-22 07:57:17 +0000466
Franck Bui-Huu82524742008-05-12 21:21:05 +0200467/**
468 * hlist_for_each_entry_rcu - iterate over rcu list of given type
Sasha Levinb67bfe02013-02-27 17:06:00 -0800469 * @pos: the type * to use as a loop cursor.
Franck Bui-Huu82524742008-05-12 21:21:05 +0200470 * @head: the head for your list.
471 * @member: the name of the hlist_node within the struct.
472 *
473 * This list-traversal primitive may safely run concurrently with
474 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
475 * as long as the traversal is guarded by rcu_read_lock().
476 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800477#define hlist_for_each_entry_rcu(pos, head, member) \
478 for (pos = hlist_entry_safe (rcu_dereference_raw(hlist_first_rcu(head)),\
479 typeof(*(pos)), member); \
480 pos; \
481 pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\
482 &(pos)->member)), typeof(*(pos)), member))
Franck Bui-Huu82524742008-05-12 21:21:05 +0200483
stephen hemminger5c578ae2010-03-17 20:31:11 +0000484/**
Steven Rostedt12bcbe62013-05-28 14:38:42 -0400485 * hlist_for_each_entry_rcu_notrace - iterate over rcu list of given type (for tracing)
486 * @pos: the type * to use as a loop cursor.
487 * @head: the head for your list.
488 * @member: the name of the hlist_node within the struct.
489 *
490 * This list-traversal primitive may safely run concurrently with
491 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
492 * as long as the traversal is guarded by rcu_read_lock().
493 *
494 * This is the same as hlist_for_each_entry_rcu() except that it does
495 * not do any RCU debugging or tracing.
496 */
497#define hlist_for_each_entry_rcu_notrace(pos, head, member) \
498 for (pos = hlist_entry_safe (rcu_dereference_raw_notrace(hlist_first_rcu(head)),\
499 typeof(*(pos)), member); \
500 pos; \
501 pos = hlist_entry_safe(rcu_dereference_raw_notrace(hlist_next_rcu(\
502 &(pos)->member)), typeof(*(pos)), member))
503
504/**
Eric Dumazet4f70ecc2010-05-03 10:50:14 +0000505 * hlist_for_each_entry_rcu_bh - iterate over rcu list of given type
Sasha Levinb67bfe02013-02-27 17:06:00 -0800506 * @pos: the type * to use as a loop cursor.
Eric Dumazet4f70ecc2010-05-03 10:50:14 +0000507 * @head: the head for your list.
508 * @member: the name of the hlist_node within the struct.
509 *
510 * This list-traversal primitive may safely run concurrently with
511 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
512 * as long as the traversal is guarded by rcu_read_lock().
513 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800514#define hlist_for_each_entry_rcu_bh(pos, head, member) \
515 for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_first_rcu(head)),\
516 typeof(*(pos)), member); \
517 pos; \
518 pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu(\
519 &(pos)->member)), typeof(*(pos)), member))
Eric Dumazet4f70ecc2010-05-03 10:50:14 +0000520
521/**
stephen hemminger5c578ae2010-03-17 20:31:11 +0000522 * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point
Sasha Levinb67bfe02013-02-27 17:06:00 -0800523 * @pos: the type * to use as a loop cursor.
stephen hemminger5c578ae2010-03-17 20:31:11 +0000524 * @member: the name of the hlist_node within the struct.
525 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800526#define hlist_for_each_entry_continue_rcu(pos, member) \
527 for (pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\
528 typeof(*(pos)), member); \
529 pos; \
530 pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\
531 typeof(*(pos)), member))
stephen hemminger5c578ae2010-03-17 20:31:11 +0000532
Eric Dumazet4f70ecc2010-05-03 10:50:14 +0000533/**
534 * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point
Sasha Levinb67bfe02013-02-27 17:06:00 -0800535 * @pos: the type * to use as a loop cursor.
Eric Dumazet4f70ecc2010-05-03 10:50:14 +0000536 * @member: the name of the hlist_node within the struct.
537 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800538#define hlist_for_each_entry_continue_rcu_bh(pos, member) \
539 for (pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\
540 typeof(*(pos)), member); \
541 pos; \
542 pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\
543 typeof(*(pos)), member))
Eric Dumazet4f70ecc2010-05-03 10:50:14 +0000544
Ying Xue97ede292014-12-02 15:00:30 +0800545/**
546 * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point
547 * @pos: the type * to use as a loop cursor.
548 * @member: the name of the hlist_node within the struct.
549 */
550#define hlist_for_each_entry_from_rcu(pos, member) \
551 for (; pos; \
552 pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\
553 typeof(*(pos)), member))
stephen hemminger5c578ae2010-03-17 20:31:11 +0000554
Franck Bui-Huu82524742008-05-12 21:21:05 +0200555#endif /* __KERNEL__ */
556#endif