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1da177e4 LT |
1 | #ifndef _LINUX_LIST_H |
2 | #define _LINUX_LIST_H | |
3 | ||
4 | #ifdef __KERNEL__ | |
5 | ||
6 | #include <linux/stddef.h> | |
7 | #include <linux/prefetch.h> | |
8 | #include <asm/system.h> | |
9 | ||
10 | /* | |
11 | * These are non-NULL pointers that will result in page faults | |
12 | * under normal circumstances, used to verify that nobody uses | |
13 | * non-initialized list entries. | |
14 | */ | |
15 | #define LIST_POISON1 ((void *) 0x00100100) | |
16 | #define LIST_POISON2 ((void *) 0x00200200) | |
17 | ||
18 | /* | |
19 | * Simple doubly linked list implementation. | |
20 | * | |
21 | * Some of the internal functions ("__xxx") are useful when | |
22 | * manipulating whole lists rather than single entries, as | |
23 | * sometimes we already know the next/prev entries and we can | |
24 | * generate better code by using them directly rather than | |
25 | * using the generic single-entry routines. | |
26 | */ | |
27 | ||
28 | struct list_head { | |
29 | struct list_head *next, *prev; | |
30 | }; | |
31 | ||
32 | #define LIST_HEAD_INIT(name) { &(name), &(name) } | |
33 | ||
34 | #define LIST_HEAD(name) \ | |
35 | struct list_head name = LIST_HEAD_INIT(name) | |
36 | ||
37 | #define INIT_LIST_HEAD(ptr) do { \ | |
38 | (ptr)->next = (ptr); (ptr)->prev = (ptr); \ | |
39 | } while (0) | |
40 | ||
41 | /* | |
42 | * Insert a new entry between two known consecutive entries. | |
43 | * | |
44 | * This is only for internal list manipulation where we know | |
45 | * the prev/next entries already! | |
46 | */ | |
47 | static inline void __list_add(struct list_head *new, | |
48 | struct list_head *prev, | |
49 | struct list_head *next) | |
50 | { | |
51 | next->prev = new; | |
52 | new->next = next; | |
53 | new->prev = prev; | |
54 | prev->next = new; | |
55 | } | |
56 | ||
57 | /** | |
58 | * list_add - add a new entry | |
59 | * @new: new entry to be added | |
60 | * @head: list head to add it after | |
61 | * | |
62 | * Insert a new entry after the specified head. | |
63 | * This is good for implementing stacks. | |
64 | */ | |
65 | static inline void list_add(struct list_head *new, struct list_head *head) | |
66 | { | |
67 | __list_add(new, head, head->next); | |
68 | } | |
69 | ||
70 | /** | |
71 | * list_add_tail - add a new entry | |
72 | * @new: new entry to be added | |
73 | * @head: list head to add it before | |
74 | * | |
75 | * Insert a new entry before the specified head. | |
76 | * This is useful for implementing queues. | |
77 | */ | |
78 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
79 | { | |
80 | __list_add(new, head->prev, head); | |
81 | } | |
82 | ||
83 | /* | |
84 | * Insert a new entry between two known consecutive entries. | |
85 | * | |
86 | * This is only for internal list manipulation where we know | |
87 | * the prev/next entries already! | |
88 | */ | |
89 | static inline void __list_add_rcu(struct list_head * new, | |
90 | struct list_head * prev, struct list_head * next) | |
91 | { | |
92 | new->next = next; | |
93 | new->prev = prev; | |
94 | smp_wmb(); | |
95 | next->prev = new; | |
96 | prev->next = new; | |
97 | } | |
98 | ||
99 | /** | |
100 | * list_add_rcu - add a new entry to rcu-protected list | |
101 | * @new: new entry to be added | |
102 | * @head: list head to add it after | |
103 | * | |
104 | * Insert a new entry after the specified head. | |
105 | * This is good for implementing stacks. | |
106 | * | |
107 | * The caller must take whatever precautions are necessary | |
108 | * (such as holding appropriate locks) to avoid racing | |
109 | * with another list-mutation primitive, such as list_add_rcu() | |
110 | * or list_del_rcu(), running on this same list. | |
111 | * However, it is perfectly legal to run concurrently with | |
112 | * the _rcu list-traversal primitives, such as | |
113 | * list_for_each_entry_rcu(). | |
114 | */ | |
115 | static inline void list_add_rcu(struct list_head *new, struct list_head *head) | |
116 | { | |
117 | __list_add_rcu(new, head, head->next); | |
118 | } | |
119 | ||
120 | /** | |
121 | * list_add_tail_rcu - add a new entry to rcu-protected list | |
122 | * @new: new entry to be added | |
123 | * @head: list head to add it before | |
124 | * | |
125 | * Insert a new entry before the specified head. | |
126 | * This is useful for implementing queues. | |
127 | * | |
128 | * The caller must take whatever precautions are necessary | |
129 | * (such as holding appropriate locks) to avoid racing | |
130 | * with another list-mutation primitive, such as list_add_tail_rcu() | |
131 | * or list_del_rcu(), running on this same list. | |
132 | * However, it is perfectly legal to run concurrently with | |
133 | * the _rcu list-traversal primitives, such as | |
134 | * list_for_each_entry_rcu(). | |
135 | */ | |
136 | static inline void list_add_tail_rcu(struct list_head *new, | |
137 | struct list_head *head) | |
138 | { | |
139 | __list_add_rcu(new, head->prev, head); | |
140 | } | |
141 | ||
142 | /* | |
143 | * Delete a list entry by making the prev/next entries | |
144 | * point to each other. | |
145 | * | |
146 | * This is only for internal list manipulation where we know | |
147 | * the prev/next entries already! | |
148 | */ | |
149 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
150 | { | |
151 | next->prev = prev; | |
152 | prev->next = next; | |
153 | } | |
154 | ||
155 | /** | |
156 | * list_del - deletes entry from list. | |
157 | * @entry: the element to delete from the list. | |
158 | * Note: list_empty on entry does not return true after this, the entry is | |
159 | * in an undefined state. | |
160 | */ | |
161 | static inline void list_del(struct list_head *entry) | |
162 | { | |
163 | __list_del(entry->prev, entry->next); | |
164 | entry->next = LIST_POISON1; | |
165 | entry->prev = LIST_POISON2; | |
166 | } | |
167 | ||
168 | /** | |
169 | * list_del_rcu - deletes entry from list without re-initialization | |
170 | * @entry: the element to delete from the list. | |
171 | * | |
172 | * Note: list_empty on entry does not return true after this, | |
173 | * the entry is in an undefined state. It is useful for RCU based | |
174 | * lockfree traversal. | |
175 | * | |
176 | * In particular, it means that we can not poison the forward | |
177 | * pointers that may still be used for walking the list. | |
178 | * | |
179 | * The caller must take whatever precautions are necessary | |
180 | * (such as holding appropriate locks) to avoid racing | |
181 | * with another list-mutation primitive, such as list_del_rcu() | |
182 | * or list_add_rcu(), running on this same list. | |
183 | * However, it is perfectly legal to run concurrently with | |
184 | * the _rcu list-traversal primitives, such as | |
185 | * list_for_each_entry_rcu(). | |
186 | * | |
187 | * Note that the caller is not permitted to immediately free | |
b2b18660 | 188 | * the newly deleted entry. Instead, either synchronize_rcu() |
1da177e4 LT |
189 | * or call_rcu() must be used to defer freeing until an RCU |
190 | * grace period has elapsed. | |
191 | */ | |
192 | static inline void list_del_rcu(struct list_head *entry) | |
193 | { | |
194 | __list_del(entry->prev, entry->next); | |
195 | entry->prev = LIST_POISON2; | |
196 | } | |
197 | ||
198 | /* | |
199 | * list_replace_rcu - replace old entry by new one | |
200 | * @old : the element to be replaced | |
201 | * @new : the new element to insert | |
202 | * | |
203 | * The old entry will be replaced with the new entry atomically. | |
204 | */ | |
b88cb424 IM |
205 | static inline void list_replace_rcu(struct list_head *old, |
206 | struct list_head *new) | |
207 | { | |
1da177e4 LT |
208 | new->next = old->next; |
209 | new->prev = old->prev; | |
210 | smp_wmb(); | |
211 | new->next->prev = new; | |
212 | new->prev->next = new; | |
b88cb424 | 213 | old->prev = LIST_POISON2; |
1da177e4 LT |
214 | } |
215 | ||
216 | /** | |
217 | * list_del_init - deletes entry from list and reinitialize it. | |
218 | * @entry: the element to delete from the list. | |
219 | */ | |
220 | static inline void list_del_init(struct list_head *entry) | |
221 | { | |
222 | __list_del(entry->prev, entry->next); | |
223 | INIT_LIST_HEAD(entry); | |
224 | } | |
225 | ||
226 | /** | |
227 | * list_move - delete from one list and add as another's head | |
228 | * @list: the entry to move | |
229 | * @head: the head that will precede our entry | |
230 | */ | |
231 | static inline void list_move(struct list_head *list, struct list_head *head) | |
232 | { | |
233 | __list_del(list->prev, list->next); | |
234 | list_add(list, head); | |
235 | } | |
236 | ||
237 | /** | |
238 | * list_move_tail - delete from one list and add as another's tail | |
239 | * @list: the entry to move | |
240 | * @head: the head that will follow our entry | |
241 | */ | |
242 | static inline void list_move_tail(struct list_head *list, | |
243 | struct list_head *head) | |
244 | { | |
245 | __list_del(list->prev, list->next); | |
246 | list_add_tail(list, head); | |
247 | } | |
248 | ||
249 | /** | |
250 | * list_empty - tests whether a list is empty | |
251 | * @head: the list to test. | |
252 | */ | |
253 | static inline int list_empty(const struct list_head *head) | |
254 | { | |
255 | return head->next == head; | |
256 | } | |
257 | ||
258 | /** | |
259 | * list_empty_careful - tests whether a list is | |
260 | * empty _and_ checks that no other CPU might be | |
261 | * in the process of still modifying either member | |
262 | * | |
263 | * NOTE: using list_empty_careful() without synchronization | |
264 | * can only be safe if the only activity that can happen | |
265 | * to the list entry is list_del_init(). Eg. it cannot be used | |
266 | * if another CPU could re-list_add() it. | |
267 | * | |
268 | * @head: the list to test. | |
269 | */ | |
270 | static inline int list_empty_careful(const struct list_head *head) | |
271 | { | |
272 | struct list_head *next = head->next; | |
273 | return (next == head) && (next == head->prev); | |
274 | } | |
275 | ||
276 | static inline void __list_splice(struct list_head *list, | |
277 | struct list_head *head) | |
278 | { | |
279 | struct list_head *first = list->next; | |
280 | struct list_head *last = list->prev; | |
281 | struct list_head *at = head->next; | |
282 | ||
283 | first->prev = head; | |
284 | head->next = first; | |
285 | ||
286 | last->next = at; | |
287 | at->prev = last; | |
288 | } | |
289 | ||
290 | /** | |
291 | * list_splice - join two lists | |
292 | * @list: the new list to add. | |
293 | * @head: the place to add it in the first list. | |
294 | */ | |
295 | static inline void list_splice(struct list_head *list, struct list_head *head) | |
296 | { | |
297 | if (!list_empty(list)) | |
298 | __list_splice(list, head); | |
299 | } | |
300 | ||
301 | /** | |
302 | * list_splice_init - join two lists and reinitialise the emptied list. | |
303 | * @list: the new list to add. | |
304 | * @head: the place to add it in the first list. | |
305 | * | |
306 | * The list at @list is reinitialised | |
307 | */ | |
308 | static inline void list_splice_init(struct list_head *list, | |
309 | struct list_head *head) | |
310 | { | |
311 | if (!list_empty(list)) { | |
312 | __list_splice(list, head); | |
313 | INIT_LIST_HEAD(list); | |
314 | } | |
315 | } | |
316 | ||
317 | /** | |
318 | * list_entry - get the struct for this entry | |
319 | * @ptr: the &struct list_head pointer. | |
320 | * @type: the type of the struct this is embedded in. | |
321 | * @member: the name of the list_struct within the struct. | |
322 | */ | |
323 | #define list_entry(ptr, type, member) \ | |
324 | container_of(ptr, type, member) | |
325 | ||
326 | /** | |
327 | * list_for_each - iterate over a list | |
328 | * @pos: the &struct list_head to use as a loop counter. | |
329 | * @head: the head for your list. | |
330 | */ | |
331 | #define list_for_each(pos, head) \ | |
332 | for (pos = (head)->next; prefetch(pos->next), pos != (head); \ | |
333 | pos = pos->next) | |
334 | ||
335 | /** | |
336 | * __list_for_each - iterate over a list | |
337 | * @pos: the &struct list_head to use as a loop counter. | |
338 | * @head: the head for your list. | |
339 | * | |
340 | * This variant differs from list_for_each() in that it's the | |
341 | * simplest possible list iteration code, no prefetching is done. | |
342 | * Use this for code that knows the list to be very short (empty | |
343 | * or 1 entry) most of the time. | |
344 | */ | |
345 | #define __list_for_each(pos, head) \ | |
346 | for (pos = (head)->next; pos != (head); pos = pos->next) | |
347 | ||
348 | /** | |
349 | * list_for_each_prev - iterate over a list backwards | |
350 | * @pos: the &struct list_head to use as a loop counter. | |
351 | * @head: the head for your list. | |
352 | */ | |
353 | #define list_for_each_prev(pos, head) \ | |
354 | for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ | |
355 | pos = pos->prev) | |
356 | ||
357 | /** | |
358 | * list_for_each_safe - iterate over a list safe against removal of list entry | |
359 | * @pos: the &struct list_head to use as a loop counter. | |
360 | * @n: another &struct list_head to use as temporary storage | |
361 | * @head: the head for your list. | |
362 | */ | |
363 | #define list_for_each_safe(pos, n, head) \ | |
364 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
365 | pos = n, n = pos->next) | |
366 | ||
367 | /** | |
368 | * list_for_each_entry - iterate over list of given type | |
369 | * @pos: the type * to use as a loop counter. | |
370 | * @head: the head for your list. | |
371 | * @member: the name of the list_struct within the struct. | |
372 | */ | |
373 | #define list_for_each_entry(pos, head, member) \ | |
374 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
375 | prefetch(pos->member.next), &pos->member != (head); \ | |
376 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
377 | ||
378 | /** | |
379 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
380 | * @pos: the type * to use as a loop counter. | |
381 | * @head: the head for your list. | |
382 | * @member: the name of the list_struct within the struct. | |
383 | */ | |
384 | #define list_for_each_entry_reverse(pos, head, member) \ | |
385 | for (pos = list_entry((head)->prev, typeof(*pos), member); \ | |
386 | prefetch(pos->member.prev), &pos->member != (head); \ | |
387 | pos = list_entry(pos->member.prev, typeof(*pos), member)) | |
388 | ||
389 | /** | |
390 | * list_prepare_entry - prepare a pos entry for use as a start point in | |
391 | * list_for_each_entry_continue | |
392 | * @pos: the type * to use as a start point | |
393 | * @head: the head of the list | |
394 | * @member: the name of the list_struct within the struct. | |
395 | */ | |
396 | #define list_prepare_entry(pos, head, member) \ | |
397 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
398 | ||
399 | /** | |
400 | * list_for_each_entry_continue - iterate over list of given type | |
401 | * continuing after existing point | |
402 | * @pos: the type * to use as a loop counter. | |
403 | * @head: the head for your list. | |
404 | * @member: the name of the list_struct within the struct. | |
405 | */ | |
406 | #define list_for_each_entry_continue(pos, head, member) \ | |
407 | for (pos = list_entry(pos->member.next, typeof(*pos), member); \ | |
408 | prefetch(pos->member.next), &pos->member != (head); \ | |
409 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
410 | ||
411 | /** | |
412 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
413 | * @pos: the type * to use as a loop counter. | |
414 | * @n: another type * to use as temporary storage | |
415 | * @head: the head for your list. | |
416 | * @member: the name of the list_struct within the struct. | |
417 | */ | |
418 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
419 | for (pos = list_entry((head)->next, typeof(*pos), member), \ | |
420 | n = list_entry(pos->member.next, typeof(*pos), member); \ | |
421 | &pos->member != (head); \ | |
422 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
423 | ||
74459dc7 ACM |
424 | /** |
425 | * list_for_each_entry_safe_continue - iterate over list of given type | |
426 | * continuing after existing point safe against removal of list entry | |
427 | * @pos: the type * to use as a loop counter. | |
428 | * @n: another type * to use as temporary storage | |
429 | * @head: the head for your list. | |
430 | * @member: the name of the list_struct within the struct. | |
431 | */ | |
432 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8c60f3fa ACM |
433 | for (pos = list_entry(pos->member.next, typeof(*pos), member), \ |
434 | n = list_entry(pos->member.next, typeof(*pos), member); \ | |
74459dc7 ACM |
435 | &pos->member != (head); \ |
436 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
437 | ||
0ad42352 DH |
438 | /** |
439 | * list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against | |
440 | * removal of list entry | |
441 | * @pos: the type * to use as a loop counter. | |
442 | * @n: another type * to use as temporary storage | |
443 | * @head: the head for your list. | |
444 | * @member: the name of the list_struct within the struct. | |
445 | */ | |
446 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
447 | for (pos = list_entry((head)->prev, typeof(*pos), member), \ | |
448 | n = list_entry(pos->member.prev, typeof(*pos), member); \ | |
449 | &pos->member != (head); \ | |
450 | pos = n, n = list_entry(n->member.prev, typeof(*n), member)) | |
451 | ||
1da177e4 LT |
452 | /** |
453 | * list_for_each_rcu - iterate over an rcu-protected list | |
454 | * @pos: the &struct list_head to use as a loop counter. | |
455 | * @head: the head for your list. | |
456 | * | |
457 | * This list-traversal primitive may safely run concurrently with | |
458 | * the _rcu list-mutation primitives such as list_add_rcu() | |
459 | * as long as the traversal is guarded by rcu_read_lock(). | |
460 | */ | |
461 | #define list_for_each_rcu(pos, head) \ | |
b24d18aa HX |
462 | for (pos = (head)->next; \ |
463 | prefetch(rcu_dereference(pos)->next), pos != (head); \ | |
464 | pos = pos->next) | |
1da177e4 LT |
465 | |
466 | #define __list_for_each_rcu(pos, head) \ | |
b24d18aa HX |
467 | for (pos = (head)->next; \ |
468 | rcu_dereference(pos) != (head); \ | |
469 | pos = pos->next) | |
1da177e4 LT |
470 | |
471 | /** | |
472 | * list_for_each_safe_rcu - iterate over an rcu-protected list safe | |
473 | * against removal of list entry | |
474 | * @pos: the &struct list_head to use as a loop counter. | |
475 | * @n: another &struct list_head to use as temporary storage | |
476 | * @head: the head for your list. | |
477 | * | |
478 | * This list-traversal primitive may safely run concurrently with | |
479 | * the _rcu list-mutation primitives such as list_add_rcu() | |
480 | * as long as the traversal is guarded by rcu_read_lock(). | |
481 | */ | |
482 | #define list_for_each_safe_rcu(pos, n, head) \ | |
b24d18aa HX |
483 | for (pos = (head)->next; \ |
484 | n = rcu_dereference(pos)->next, pos != (head); \ | |
485 | pos = n) | |
1da177e4 LT |
486 | |
487 | /** | |
488 | * list_for_each_entry_rcu - iterate over rcu list of given type | |
489 | * @pos: the type * to use as a loop counter. | |
490 | * @head: the head for your list. | |
491 | * @member: the name of the list_struct within the struct. | |
492 | * | |
493 | * This list-traversal primitive may safely run concurrently with | |
494 | * the _rcu list-mutation primitives such as list_add_rcu() | |
495 | * as long as the traversal is guarded by rcu_read_lock(). | |
496 | */ | |
b24d18aa HX |
497 | #define list_for_each_entry_rcu(pos, head, member) \ |
498 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
499 | prefetch(rcu_dereference(pos)->member.next), \ | |
500 | &pos->member != (head); \ | |
501 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
1da177e4 LT |
502 | |
503 | ||
504 | /** | |
505 | * list_for_each_continue_rcu - iterate over an rcu-protected list | |
506 | * continuing after existing point. | |
507 | * @pos: the &struct list_head to use as a loop counter. | |
508 | * @head: the head for your list. | |
509 | * | |
510 | * This list-traversal primitive may safely run concurrently with | |
511 | * the _rcu list-mutation primitives such as list_add_rcu() | |
512 | * as long as the traversal is guarded by rcu_read_lock(). | |
513 | */ | |
514 | #define list_for_each_continue_rcu(pos, head) \ | |
b24d18aa HX |
515 | for ((pos) = (pos)->next; \ |
516 | prefetch(rcu_dereference((pos))->next), (pos) != (head); \ | |
517 | (pos) = (pos)->next) | |
1da177e4 LT |
518 | |
519 | /* | |
520 | * Double linked lists with a single pointer list head. | |
521 | * Mostly useful for hash tables where the two pointer list head is | |
522 | * too wasteful. | |
523 | * You lose the ability to access the tail in O(1). | |
524 | */ | |
525 | ||
526 | struct hlist_head { | |
527 | struct hlist_node *first; | |
528 | }; | |
529 | ||
530 | struct hlist_node { | |
531 | struct hlist_node *next, **pprev; | |
532 | }; | |
533 | ||
534 | #define HLIST_HEAD_INIT { .first = NULL } | |
535 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
536 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
537 | #define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL) | |
538 | ||
539 | static inline int hlist_unhashed(const struct hlist_node *h) | |
540 | { | |
541 | return !h->pprev; | |
542 | } | |
543 | ||
544 | static inline int hlist_empty(const struct hlist_head *h) | |
545 | { | |
546 | return !h->first; | |
547 | } | |
548 | ||
549 | static inline void __hlist_del(struct hlist_node *n) | |
550 | { | |
551 | struct hlist_node *next = n->next; | |
552 | struct hlist_node **pprev = n->pprev; | |
553 | *pprev = next; | |
554 | if (next) | |
555 | next->pprev = pprev; | |
556 | } | |
557 | ||
558 | static inline void hlist_del(struct hlist_node *n) | |
559 | { | |
560 | __hlist_del(n); | |
561 | n->next = LIST_POISON1; | |
562 | n->pprev = LIST_POISON2; | |
563 | } | |
564 | ||
565 | /** | |
566 | * hlist_del_rcu - deletes entry from hash list without re-initialization | |
567 | * @n: the element to delete from the hash list. | |
568 | * | |
569 | * Note: list_unhashed() on entry does not return true after this, | |
570 | * the entry is in an undefined state. It is useful for RCU based | |
571 | * lockfree traversal. | |
572 | * | |
573 | * In particular, it means that we can not poison the forward | |
574 | * pointers that may still be used for walking the hash list. | |
575 | * | |
576 | * The caller must take whatever precautions are necessary | |
577 | * (such as holding appropriate locks) to avoid racing | |
578 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
579 | * or hlist_del_rcu(), running on this same list. | |
580 | * However, it is perfectly legal to run concurrently with | |
581 | * the _rcu list-traversal primitives, such as | |
582 | * hlist_for_each_entry(). | |
583 | */ | |
584 | static inline void hlist_del_rcu(struct hlist_node *n) | |
585 | { | |
586 | __hlist_del(n); | |
587 | n->pprev = LIST_POISON2; | |
588 | } | |
589 | ||
590 | static inline void hlist_del_init(struct hlist_node *n) | |
591 | { | |
592 | if (n->pprev) { | |
593 | __hlist_del(n); | |
594 | INIT_HLIST_NODE(n); | |
595 | } | |
596 | } | |
597 | ||
b88cb424 IM |
598 | /* |
599 | * hlist_replace_rcu - replace old entry by new one | |
600 | * @old : the element to be replaced | |
601 | * @new : the new element to insert | |
602 | * | |
603 | * The old entry will be replaced with the new entry atomically. | |
604 | */ | |
605 | static inline void hlist_replace_rcu(struct hlist_node *old, | |
606 | struct hlist_node *new) | |
607 | { | |
608 | struct hlist_node *next = old->next; | |
609 | ||
610 | new->next = next; | |
611 | new->pprev = old->pprev; | |
612 | smp_wmb(); | |
613 | if (next) | |
614 | new->next->pprev = &new->next; | |
615 | *new->pprev = new; | |
616 | old->pprev = LIST_POISON2; | |
617 | } | |
618 | ||
1da177e4 LT |
619 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) |
620 | { | |
621 | struct hlist_node *first = h->first; | |
622 | n->next = first; | |
623 | if (first) | |
624 | first->pprev = &n->next; | |
625 | h->first = n; | |
626 | n->pprev = &h->first; | |
627 | } | |
628 | ||
629 | ||
630 | /** | |
631 | * hlist_add_head_rcu - adds the specified element to the specified hlist, | |
632 | * while permitting racing traversals. | |
633 | * @n: the element to add to the hash list. | |
634 | * @h: the list to add to. | |
635 | * | |
636 | * The caller must take whatever precautions are necessary | |
637 | * (such as holding appropriate locks) to avoid racing | |
638 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
639 | * or hlist_del_rcu(), running on this same list. | |
640 | * However, it is perfectly legal to run concurrently with | |
641 | * the _rcu list-traversal primitives, such as | |
665a7583 | 642 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
1da177e4 LT |
643 | * problems on Alpha CPUs. Regardless of the type of CPU, the |
644 | * list-traversal primitive must be guarded by rcu_read_lock(). | |
645 | */ | |
646 | static inline void hlist_add_head_rcu(struct hlist_node *n, | |
647 | struct hlist_head *h) | |
648 | { | |
649 | struct hlist_node *first = h->first; | |
650 | n->next = first; | |
651 | n->pprev = &h->first; | |
652 | smp_wmb(); | |
653 | if (first) | |
654 | first->pprev = &n->next; | |
655 | h->first = n; | |
656 | } | |
657 | ||
658 | /* next must be != NULL */ | |
659 | static inline void hlist_add_before(struct hlist_node *n, | |
660 | struct hlist_node *next) | |
661 | { | |
662 | n->pprev = next->pprev; | |
663 | n->next = next; | |
664 | next->pprev = &n->next; | |
665 | *(n->pprev) = n; | |
666 | } | |
667 | ||
668 | static inline void hlist_add_after(struct hlist_node *n, | |
669 | struct hlist_node *next) | |
670 | { | |
671 | next->next = n->next; | |
672 | n->next = next; | |
673 | next->pprev = &n->next; | |
674 | ||
675 | if(next->next) | |
676 | next->next->pprev = &next->next; | |
677 | } | |
678 | ||
cf4ef014 PM |
679 | /** |
680 | * hlist_add_before_rcu - adds the specified element to the specified hlist | |
681 | * before the specified node while permitting racing traversals. | |
682 | * @n: the new element to add to the hash list. | |
683 | * @next: the existing element to add the new element before. | |
684 | * | |
685 | * The caller must take whatever precautions are necessary | |
686 | * (such as holding appropriate locks) to avoid racing | |
687 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
688 | * or hlist_del_rcu(), running on this same list. | |
689 | * However, it is perfectly legal to run concurrently with | |
690 | * the _rcu list-traversal primitives, such as | |
665a7583 | 691 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
cf4ef014 PM |
692 | * problems on Alpha CPUs. |
693 | */ | |
e5b43760 RO |
694 | static inline void hlist_add_before_rcu(struct hlist_node *n, |
695 | struct hlist_node *next) | |
696 | { | |
697 | n->pprev = next->pprev; | |
698 | n->next = next; | |
699 | smp_wmb(); | |
700 | next->pprev = &n->next; | |
701 | *(n->pprev) = n; | |
702 | } | |
703 | ||
cf4ef014 PM |
704 | /** |
705 | * hlist_add_after_rcu - adds the specified element to the specified hlist | |
706 | * after the specified node while permitting racing traversals. | |
707 | * @prev: the existing element to add the new element after. | |
708 | * @n: the new element to add to the hash list. | |
709 | * | |
710 | * The caller must take whatever precautions are necessary | |
711 | * (such as holding appropriate locks) to avoid racing | |
712 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
713 | * or hlist_del_rcu(), running on this same list. | |
714 | * However, it is perfectly legal to run concurrently with | |
715 | * the _rcu list-traversal primitives, such as | |
665a7583 | 716 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
cf4ef014 PM |
717 | * problems on Alpha CPUs. |
718 | */ | |
e5b43760 RO |
719 | static inline void hlist_add_after_rcu(struct hlist_node *prev, |
720 | struct hlist_node *n) | |
721 | { | |
722 | n->next = prev->next; | |
723 | n->pprev = &prev->next; | |
724 | smp_wmb(); | |
725 | prev->next = n; | |
726 | if (n->next) | |
727 | n->next->pprev = &n->next; | |
728 | } | |
729 | ||
1da177e4 LT |
730 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
731 | ||
732 | #define hlist_for_each(pos, head) \ | |
733 | for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ | |
734 | pos = pos->next) | |
735 | ||
736 | #define hlist_for_each_safe(pos, n, head) \ | |
737 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
738 | pos = n) | |
739 | ||
1da177e4 LT |
740 | /** |
741 | * hlist_for_each_entry - iterate over list of given type | |
742 | * @tpos: the type * to use as a loop counter. | |
743 | * @pos: the &struct hlist_node to use as a loop counter. | |
744 | * @head: the head for your list. | |
745 | * @member: the name of the hlist_node within the struct. | |
746 | */ | |
747 | #define hlist_for_each_entry(tpos, pos, head, member) \ | |
748 | for (pos = (head)->first; \ | |
749 | pos && ({ prefetch(pos->next); 1;}) && \ | |
750 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
751 | pos = pos->next) | |
752 | ||
753 | /** | |
754 | * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point | |
755 | * @tpos: the type * to use as a loop counter. | |
756 | * @pos: the &struct hlist_node to use as a loop counter. | |
757 | * @member: the name of the hlist_node within the struct. | |
758 | */ | |
759 | #define hlist_for_each_entry_continue(tpos, pos, member) \ | |
760 | for (pos = (pos)->next; \ | |
761 | pos && ({ prefetch(pos->next); 1;}) && \ | |
762 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
763 | pos = pos->next) | |
764 | ||
765 | /** | |
766 | * hlist_for_each_entry_from - iterate over a hlist continuing from existing point | |
767 | * @tpos: the type * to use as a loop counter. | |
768 | * @pos: the &struct hlist_node to use as a loop counter. | |
769 | * @member: the name of the hlist_node within the struct. | |
770 | */ | |
771 | #define hlist_for_each_entry_from(tpos, pos, member) \ | |
772 | for (; pos && ({ prefetch(pos->next); 1;}) && \ | |
773 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
774 | pos = pos->next) | |
775 | ||
776 | /** | |
777 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
778 | * @tpos: the type * to use as a loop counter. | |
779 | * @pos: the &struct hlist_node to use as a loop counter. | |
780 | * @n: another &struct hlist_node to use as temporary storage | |
781 | * @head: the head for your list. | |
782 | * @member: the name of the hlist_node within the struct. | |
783 | */ | |
784 | #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ | |
785 | for (pos = (head)->first; \ | |
786 | pos && ({ n = pos->next; 1; }) && \ | |
787 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
788 | pos = n) | |
789 | ||
790 | /** | |
791 | * hlist_for_each_entry_rcu - iterate over rcu list of given type | |
665a7583 | 792 | * @tpos: the type * to use as a loop counter. |
1da177e4 LT |
793 | * @pos: the &struct hlist_node to use as a loop counter. |
794 | * @head: the head for your list. | |
795 | * @member: the name of the hlist_node within the struct. | |
796 | * | |
797 | * This list-traversal primitive may safely run concurrently with | |
e1ba0dab | 798 | * the _rcu list-mutation primitives such as hlist_add_head_rcu() |
1da177e4 LT |
799 | * as long as the traversal is guarded by rcu_read_lock(). |
800 | */ | |
801 | #define hlist_for_each_entry_rcu(tpos, pos, head, member) \ | |
802 | for (pos = (head)->first; \ | |
b24d18aa | 803 | rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \ |
1da177e4 | 804 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
b24d18aa | 805 | pos = pos->next) |
1da177e4 LT |
806 | |
807 | #else | |
808 | #warning "don't include kernel headers in userspace" | |
809 | #endif /* __KERNEL__ */ | |
810 | #endif |