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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 | ||
490d6ab1 ZB |
37 | static inline void INIT_LIST_HEAD(struct list_head *list) |
38 | { | |
39 | list->next = list; | |
40 | list->prev = list; | |
41 | } | |
1da177e4 LT |
42 | |
43 | /* | |
44 | * Insert a new entry between two known consecutive entries. | |
45 | * | |
46 | * This is only for internal list manipulation where we know | |
47 | * the prev/next entries already! | |
48 | */ | |
49 | static inline void __list_add(struct list_head *new, | |
50 | struct list_head *prev, | |
51 | struct list_head *next) | |
52 | { | |
53 | next->prev = new; | |
54 | new->next = next; | |
55 | new->prev = prev; | |
56 | prev->next = new; | |
57 | } | |
58 | ||
59 | /** | |
60 | * list_add - add a new entry | |
61 | * @new: new entry to be added | |
62 | * @head: list head to add it after | |
63 | * | |
64 | * Insert a new entry after the specified head. | |
65 | * This is good for implementing stacks. | |
66 | */ | |
67 | static inline void list_add(struct list_head *new, struct list_head *head) | |
68 | { | |
69 | __list_add(new, head, head->next); | |
70 | } | |
71 | ||
72 | /** | |
73 | * list_add_tail - add a new entry | |
74 | * @new: new entry to be added | |
75 | * @head: list head to add it before | |
76 | * | |
77 | * Insert a new entry before the specified head. | |
78 | * This is useful for implementing queues. | |
79 | */ | |
80 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
81 | { | |
82 | __list_add(new, head->prev, head); | |
83 | } | |
84 | ||
85 | /* | |
86 | * Insert a new entry between two known consecutive entries. | |
87 | * | |
88 | * This is only for internal list manipulation where we know | |
89 | * the prev/next entries already! | |
90 | */ | |
91 | static inline void __list_add_rcu(struct list_head * new, | |
92 | struct list_head * prev, struct list_head * next) | |
93 | { | |
94 | new->next = next; | |
95 | new->prev = prev; | |
96 | smp_wmb(); | |
97 | next->prev = new; | |
98 | prev->next = new; | |
99 | } | |
100 | ||
101 | /** | |
102 | * list_add_rcu - add a new entry to rcu-protected list | |
103 | * @new: new entry to be added | |
104 | * @head: list head to add it after | |
105 | * | |
106 | * Insert a new entry after the specified head. | |
107 | * This is good for implementing stacks. | |
108 | * | |
109 | * The caller must take whatever precautions are necessary | |
110 | * (such as holding appropriate locks) to avoid racing | |
111 | * with another list-mutation primitive, such as list_add_rcu() | |
112 | * or list_del_rcu(), running on this same list. | |
113 | * However, it is perfectly legal to run concurrently with | |
114 | * the _rcu list-traversal primitives, such as | |
115 | * list_for_each_entry_rcu(). | |
116 | */ | |
117 | static inline void list_add_rcu(struct list_head *new, struct list_head *head) | |
118 | { | |
119 | __list_add_rcu(new, head, head->next); | |
120 | } | |
121 | ||
122 | /** | |
123 | * list_add_tail_rcu - add a new entry to rcu-protected list | |
124 | * @new: new entry to be added | |
125 | * @head: list head to add it before | |
126 | * | |
127 | * Insert a new entry before the specified head. | |
128 | * This is useful for implementing queues. | |
129 | * | |
130 | * The caller must take whatever precautions are necessary | |
131 | * (such as holding appropriate locks) to avoid racing | |
132 | * with another list-mutation primitive, such as list_add_tail_rcu() | |
133 | * or list_del_rcu(), running on this same list. | |
134 | * However, it is perfectly legal to run concurrently with | |
135 | * the _rcu list-traversal primitives, such as | |
136 | * list_for_each_entry_rcu(). | |
137 | */ | |
138 | static inline void list_add_tail_rcu(struct list_head *new, | |
139 | struct list_head *head) | |
140 | { | |
141 | __list_add_rcu(new, head->prev, head); | |
142 | } | |
143 | ||
144 | /* | |
145 | * Delete a list entry by making the prev/next entries | |
146 | * point to each other. | |
147 | * | |
148 | * This is only for internal list manipulation where we know | |
149 | * the prev/next entries already! | |
150 | */ | |
151 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
152 | { | |
153 | next->prev = prev; | |
154 | prev->next = next; | |
155 | } | |
156 | ||
157 | /** | |
158 | * list_del - deletes entry from list. | |
159 | * @entry: the element to delete from the list. | |
160 | * Note: list_empty on entry does not return true after this, the entry is | |
161 | * in an undefined state. | |
162 | */ | |
163 | static inline void list_del(struct list_head *entry) | |
164 | { | |
165 | __list_del(entry->prev, entry->next); | |
166 | entry->next = LIST_POISON1; | |
167 | entry->prev = LIST_POISON2; | |
168 | } | |
169 | ||
170 | /** | |
171 | * list_del_rcu - deletes entry from list without re-initialization | |
172 | * @entry: the element to delete from the list. | |
173 | * | |
174 | * Note: list_empty on entry does not return true after this, | |
175 | * the entry is in an undefined state. It is useful for RCU based | |
176 | * lockfree traversal. | |
177 | * | |
178 | * In particular, it means that we can not poison the forward | |
179 | * pointers that may still be used for walking the list. | |
180 | * | |
181 | * The caller must take whatever precautions are necessary | |
182 | * (such as holding appropriate locks) to avoid racing | |
183 | * with another list-mutation primitive, such as list_del_rcu() | |
184 | * or list_add_rcu(), running on this same list. | |
185 | * However, it is perfectly legal to run concurrently with | |
186 | * the _rcu list-traversal primitives, such as | |
187 | * list_for_each_entry_rcu(). | |
188 | * | |
189 | * Note that the caller is not permitted to immediately free | |
b2b18660 | 190 | * the newly deleted entry. Instead, either synchronize_rcu() |
1da177e4 LT |
191 | * or call_rcu() must be used to defer freeing until an RCU |
192 | * grace period has elapsed. | |
193 | */ | |
194 | static inline void list_del_rcu(struct list_head *entry) | |
195 | { | |
196 | __list_del(entry->prev, entry->next); | |
197 | entry->prev = LIST_POISON2; | |
198 | } | |
199 | ||
54e73770 ON |
200 | /** |
201 | * list_replace - replace old entry by new one | |
202 | * @old : the element to be replaced | |
203 | * @new : the new element to insert | |
204 | * Note: if 'old' was empty, it will be overwritten. | |
205 | */ | |
206 | static inline void list_replace(struct list_head *old, | |
207 | struct list_head *new) | |
208 | { | |
209 | new->next = old->next; | |
210 | new->next->prev = new; | |
211 | new->prev = old->prev; | |
212 | new->prev->next = new; | |
213 | } | |
214 | ||
215 | static inline void list_replace_init(struct list_head *old, | |
216 | struct list_head *new) | |
217 | { | |
218 | list_replace(old, new); | |
219 | INIT_LIST_HEAD(old); | |
220 | } | |
221 | ||
1da177e4 LT |
222 | /* |
223 | * list_replace_rcu - replace old entry by new one | |
224 | * @old : the element to be replaced | |
225 | * @new : the new element to insert | |
226 | * | |
227 | * The old entry will be replaced with the new entry atomically. | |
54e73770 | 228 | * Note: 'old' should not be empty. |
1da177e4 | 229 | */ |
b88cb424 IM |
230 | static inline void list_replace_rcu(struct list_head *old, |
231 | struct list_head *new) | |
232 | { | |
1da177e4 LT |
233 | new->next = old->next; |
234 | new->prev = old->prev; | |
235 | smp_wmb(); | |
236 | new->next->prev = new; | |
237 | new->prev->next = new; | |
b88cb424 | 238 | old->prev = LIST_POISON2; |
1da177e4 LT |
239 | } |
240 | ||
241 | /** | |
242 | * list_del_init - deletes entry from list and reinitialize it. | |
243 | * @entry: the element to delete from the list. | |
244 | */ | |
245 | static inline void list_del_init(struct list_head *entry) | |
246 | { | |
247 | __list_del(entry->prev, entry->next); | |
248 | INIT_LIST_HEAD(entry); | |
249 | } | |
250 | ||
251 | /** | |
252 | * list_move - delete from one list and add as another's head | |
253 | * @list: the entry to move | |
254 | * @head: the head that will precede our entry | |
255 | */ | |
256 | static inline void list_move(struct list_head *list, struct list_head *head) | |
257 | { | |
258 | __list_del(list->prev, list->next); | |
259 | list_add(list, head); | |
260 | } | |
261 | ||
262 | /** | |
263 | * list_move_tail - delete from one list and add as another's tail | |
264 | * @list: the entry to move | |
265 | * @head: the head that will follow our entry | |
266 | */ | |
267 | static inline void list_move_tail(struct list_head *list, | |
268 | struct list_head *head) | |
269 | { | |
270 | __list_del(list->prev, list->next); | |
271 | list_add_tail(list, head); | |
272 | } | |
273 | ||
274 | /** | |
275 | * list_empty - tests whether a list is empty | |
276 | * @head: the list to test. | |
277 | */ | |
278 | static inline int list_empty(const struct list_head *head) | |
279 | { | |
280 | return head->next == head; | |
281 | } | |
282 | ||
283 | /** | |
fe96e57d RD |
284 | * list_empty_careful - tests whether a list is empty and not being modified |
285 | * @head: the list to test | |
286 | * | |
287 | * Description: | |
288 | * tests whether a list is empty _and_ checks that no other CPU might be | |
289 | * in the process of modifying either member (next or prev) | |
1da177e4 LT |
290 | * |
291 | * NOTE: using list_empty_careful() without synchronization | |
292 | * can only be safe if the only activity that can happen | |
293 | * to the list entry is list_del_init(). Eg. it cannot be used | |
294 | * if another CPU could re-list_add() it. | |
1da177e4 LT |
295 | */ |
296 | static inline int list_empty_careful(const struct list_head *head) | |
297 | { | |
298 | struct list_head *next = head->next; | |
299 | return (next == head) && (next == head->prev); | |
300 | } | |
301 | ||
302 | static inline void __list_splice(struct list_head *list, | |
303 | struct list_head *head) | |
304 | { | |
305 | struct list_head *first = list->next; | |
306 | struct list_head *last = list->prev; | |
307 | struct list_head *at = head->next; | |
308 | ||
309 | first->prev = head; | |
310 | head->next = first; | |
311 | ||
312 | last->next = at; | |
313 | at->prev = last; | |
314 | } | |
315 | ||
316 | /** | |
317 | * list_splice - join two lists | |
318 | * @list: the new list to add. | |
319 | * @head: the place to add it in the first list. | |
320 | */ | |
321 | static inline void list_splice(struct list_head *list, struct list_head *head) | |
322 | { | |
323 | if (!list_empty(list)) | |
324 | __list_splice(list, head); | |
325 | } | |
326 | ||
327 | /** | |
328 | * list_splice_init - join two lists and reinitialise the emptied list. | |
329 | * @list: the new list to add. | |
330 | * @head: the place to add it in the first list. | |
331 | * | |
332 | * The list at @list is reinitialised | |
333 | */ | |
334 | static inline void list_splice_init(struct list_head *list, | |
335 | struct list_head *head) | |
336 | { | |
337 | if (!list_empty(list)) { | |
338 | __list_splice(list, head); | |
339 | INIT_LIST_HEAD(list); | |
340 | } | |
341 | } | |
342 | ||
343 | /** | |
344 | * list_entry - get the struct for this entry | |
345 | * @ptr: the &struct list_head pointer. | |
346 | * @type: the type of the struct this is embedded in. | |
347 | * @member: the name of the list_struct within the struct. | |
348 | */ | |
349 | #define list_entry(ptr, type, member) \ | |
350 | container_of(ptr, type, member) | |
351 | ||
352 | /** | |
353 | * list_for_each - iterate over a list | |
8e3a67a9 | 354 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
355 | * @head: the head for your list. |
356 | */ | |
357 | #define list_for_each(pos, head) \ | |
358 | for (pos = (head)->next; prefetch(pos->next), pos != (head); \ | |
359 | pos = pos->next) | |
360 | ||
361 | /** | |
362 | * __list_for_each - iterate over a list | |
8e3a67a9 | 363 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
364 | * @head: the head for your list. |
365 | * | |
366 | * This variant differs from list_for_each() in that it's the | |
367 | * simplest possible list iteration code, no prefetching is done. | |
368 | * Use this for code that knows the list to be very short (empty | |
369 | * or 1 entry) most of the time. | |
370 | */ | |
371 | #define __list_for_each(pos, head) \ | |
372 | for (pos = (head)->next; pos != (head); pos = pos->next) | |
373 | ||
374 | /** | |
375 | * list_for_each_prev - iterate over a list backwards | |
8e3a67a9 | 376 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
377 | * @head: the head for your list. |
378 | */ | |
379 | #define list_for_each_prev(pos, head) \ | |
380 | for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ | |
381 | pos = pos->prev) | |
382 | ||
383 | /** | |
fe96e57d | 384 | * list_for_each_safe - iterate over a list safe against removal of list entry |
8e3a67a9 | 385 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
386 | * @n: another &struct list_head to use as temporary storage |
387 | * @head: the head for your list. | |
388 | */ | |
389 | #define list_for_each_safe(pos, n, head) \ | |
390 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
391 | pos = n, n = pos->next) | |
392 | ||
393 | /** | |
394 | * list_for_each_entry - iterate over list of given type | |
8e3a67a9 | 395 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
396 | * @head: the head for your list. |
397 | * @member: the name of the list_struct within the struct. | |
398 | */ | |
399 | #define list_for_each_entry(pos, head, member) \ | |
400 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
401 | prefetch(pos->member.next), &pos->member != (head); \ | |
402 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
403 | ||
404 | /** | |
405 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
8e3a67a9 | 406 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
407 | * @head: the head for your list. |
408 | * @member: the name of the list_struct within the struct. | |
409 | */ | |
410 | #define list_for_each_entry_reverse(pos, head, member) \ | |
411 | for (pos = list_entry((head)->prev, typeof(*pos), member); \ | |
412 | prefetch(pos->member.prev), &pos->member != (head); \ | |
413 | pos = list_entry(pos->member.prev, typeof(*pos), member)) | |
414 | ||
415 | /** | |
fe96e57d | 416 | * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue |
1da177e4 LT |
417 | * @pos: the type * to use as a start point |
418 | * @head: the head of the list | |
419 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
420 | * |
421 | * Prepares a pos entry for use as a start point in list_for_each_entry_continue. | |
1da177e4 LT |
422 | */ |
423 | #define list_prepare_entry(pos, head, member) \ | |
424 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
425 | ||
426 | /** | |
fe96e57d | 427 | * list_for_each_entry_continue - continue iteration over list of given type |
8e3a67a9 | 428 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
429 | * @head: the head for your list. |
430 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
431 | * |
432 | * Continue to iterate over list of given type, continuing after | |
433 | * the current position. | |
1da177e4 LT |
434 | */ |
435 | #define list_for_each_entry_continue(pos, head, member) \ | |
436 | for (pos = list_entry(pos->member.next, typeof(*pos), member); \ | |
437 | prefetch(pos->member.next), &pos->member != (head); \ | |
438 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
439 | ||
e229c2fb | 440 | /** |
fe96e57d | 441 | * list_for_each_entry_from - iterate over list of given type from the current point |
8e3a67a9 | 442 | * @pos: the type * to use as a loop cursor. |
e229c2fb ACM |
443 | * @head: the head for your list. |
444 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
445 | * |
446 | * Iterate over list of given type, continuing from current position. | |
e229c2fb ACM |
447 | */ |
448 | #define list_for_each_entry_from(pos, head, member) \ | |
449 | for (; prefetch(pos->member.next), &pos->member != (head); \ | |
450 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
451 | ||
1da177e4 LT |
452 | /** |
453 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 | 454 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
455 | * @n: another type * to use as temporary storage |
456 | * @head: the head for your list. | |
457 | * @member: the name of the list_struct within the struct. | |
458 | */ | |
459 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
460 | for (pos = list_entry((head)->next, typeof(*pos), member), \ | |
461 | n = list_entry(pos->member.next, typeof(*pos), member); \ | |
462 | &pos->member != (head); \ | |
463 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
464 | ||
74459dc7 | 465 | /** |
fe96e57d | 466 | * list_for_each_entry_safe_continue |
8e3a67a9 | 467 | * @pos: the type * to use as a loop cursor. |
74459dc7 ACM |
468 | * @n: another type * to use as temporary storage |
469 | * @head: the head for your list. | |
470 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
471 | * |
472 | * Iterate over list of given type, continuing after current point, | |
473 | * safe against removal of list entry. | |
74459dc7 ACM |
474 | */ |
475 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8c60f3fa ACM |
476 | for (pos = list_entry(pos->member.next, typeof(*pos), member), \ |
477 | n = list_entry(pos->member.next, typeof(*pos), member); \ | |
d8dcffee ACM |
478 | &pos->member != (head); \ |
479 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
480 | ||
481 | /** | |
fe96e57d | 482 | * list_for_each_entry_safe_from |
8e3a67a9 | 483 | * @pos: the type * to use as a loop cursor. |
d8dcffee ACM |
484 | * @n: another type * to use as temporary storage |
485 | * @head: the head for your list. | |
486 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
487 | * |
488 | * Iterate over list of given type from current point, safe against | |
489 | * removal of list entry. | |
d8dcffee ACM |
490 | */ |
491 | #define list_for_each_entry_safe_from(pos, n, head, member) \ | |
492 | for (n = list_entry(pos->member.next, typeof(*pos), member); \ | |
74459dc7 ACM |
493 | &pos->member != (head); \ |
494 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
495 | ||
0ad42352 | 496 | /** |
fe96e57d | 497 | * list_for_each_entry_safe_reverse |
8e3a67a9 | 498 | * @pos: the type * to use as a loop cursor. |
0ad42352 DH |
499 | * @n: another type * to use as temporary storage |
500 | * @head: the head for your list. | |
501 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
502 | * |
503 | * Iterate backwards over list of given type, safe against removal | |
504 | * of list entry. | |
0ad42352 DH |
505 | */ |
506 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
507 | for (pos = list_entry((head)->prev, typeof(*pos), member), \ | |
508 | n = list_entry(pos->member.prev, typeof(*pos), member); \ | |
509 | &pos->member != (head); \ | |
510 | pos = n, n = list_entry(n->member.prev, typeof(*n), member)) | |
511 | ||
1da177e4 LT |
512 | /** |
513 | * list_for_each_rcu - iterate over an rcu-protected list | |
8e3a67a9 | 514 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
515 | * @head: the head for your list. |
516 | * | |
517 | * This list-traversal primitive may safely run concurrently with | |
518 | * the _rcu list-mutation primitives such as list_add_rcu() | |
519 | * as long as the traversal is guarded by rcu_read_lock(). | |
520 | */ | |
521 | #define list_for_each_rcu(pos, head) \ | |
b24d18aa HX |
522 | for (pos = (head)->next; \ |
523 | prefetch(rcu_dereference(pos)->next), pos != (head); \ | |
524 | pos = pos->next) | |
1da177e4 LT |
525 | |
526 | #define __list_for_each_rcu(pos, head) \ | |
b24d18aa HX |
527 | for (pos = (head)->next; \ |
528 | rcu_dereference(pos) != (head); \ | |
529 | pos = pos->next) | |
1da177e4 LT |
530 | |
531 | /** | |
fe96e57d | 532 | * list_for_each_safe_rcu |
8e3a67a9 | 533 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
534 | * @n: another &struct list_head to use as temporary storage |
535 | * @head: the head for your list. | |
536 | * | |
fe96e57d RD |
537 | * Iterate over an rcu-protected list, safe against removal of list entry. |
538 | * | |
1da177e4 LT |
539 | * This list-traversal primitive may safely run concurrently with |
540 | * the _rcu list-mutation primitives such as list_add_rcu() | |
541 | * as long as the traversal is guarded by rcu_read_lock(). | |
542 | */ | |
543 | #define list_for_each_safe_rcu(pos, n, head) \ | |
b24d18aa HX |
544 | for (pos = (head)->next; \ |
545 | n = rcu_dereference(pos)->next, pos != (head); \ | |
546 | pos = n) | |
1da177e4 LT |
547 | |
548 | /** | |
549 | * list_for_each_entry_rcu - iterate over rcu list of given type | |
8e3a67a9 | 550 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
551 | * @head: the head for your list. |
552 | * @member: the name of the list_struct within the struct. | |
553 | * | |
554 | * This list-traversal primitive may safely run concurrently with | |
555 | * the _rcu list-mutation primitives such as list_add_rcu() | |
556 | * as long as the traversal is guarded by rcu_read_lock(). | |
557 | */ | |
b24d18aa HX |
558 | #define list_for_each_entry_rcu(pos, head, member) \ |
559 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
560 | prefetch(rcu_dereference(pos)->member.next), \ | |
561 | &pos->member != (head); \ | |
562 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
1da177e4 LT |
563 | |
564 | ||
565 | /** | |
fe96e57d | 566 | * list_for_each_continue_rcu |
8e3a67a9 | 567 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
568 | * @head: the head for your list. |
569 | * | |
fe96e57d RD |
570 | * Iterate over an rcu-protected list, continuing after current point. |
571 | * | |
1da177e4 LT |
572 | * This list-traversal primitive may safely run concurrently with |
573 | * the _rcu list-mutation primitives such as list_add_rcu() | |
574 | * as long as the traversal is guarded by rcu_read_lock(). | |
575 | */ | |
576 | #define list_for_each_continue_rcu(pos, head) \ | |
b24d18aa HX |
577 | for ((pos) = (pos)->next; \ |
578 | prefetch(rcu_dereference((pos))->next), (pos) != (head); \ | |
579 | (pos) = (pos)->next) | |
1da177e4 LT |
580 | |
581 | /* | |
582 | * Double linked lists with a single pointer list head. | |
583 | * Mostly useful for hash tables where the two pointer list head is | |
584 | * too wasteful. | |
585 | * You lose the ability to access the tail in O(1). | |
586 | */ | |
587 | ||
588 | struct hlist_head { | |
589 | struct hlist_node *first; | |
590 | }; | |
591 | ||
592 | struct hlist_node { | |
593 | struct hlist_node *next, **pprev; | |
594 | }; | |
595 | ||
596 | #define HLIST_HEAD_INIT { .first = NULL } | |
597 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
598 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
490d6ab1 ZB |
599 | static inline void INIT_HLIST_NODE(struct hlist_node *h) |
600 | { | |
601 | h->next = NULL; | |
602 | h->pprev = NULL; | |
603 | } | |
1da177e4 LT |
604 | |
605 | static inline int hlist_unhashed(const struct hlist_node *h) | |
606 | { | |
607 | return !h->pprev; | |
608 | } | |
609 | ||
610 | static inline int hlist_empty(const struct hlist_head *h) | |
611 | { | |
612 | return !h->first; | |
613 | } | |
614 | ||
615 | static inline void __hlist_del(struct hlist_node *n) | |
616 | { | |
617 | struct hlist_node *next = n->next; | |
618 | struct hlist_node **pprev = n->pprev; | |
619 | *pprev = next; | |
620 | if (next) | |
621 | next->pprev = pprev; | |
622 | } | |
623 | ||
624 | static inline void hlist_del(struct hlist_node *n) | |
625 | { | |
626 | __hlist_del(n); | |
627 | n->next = LIST_POISON1; | |
628 | n->pprev = LIST_POISON2; | |
629 | } | |
630 | ||
631 | /** | |
632 | * hlist_del_rcu - deletes entry from hash list without re-initialization | |
633 | * @n: the element to delete from the hash list. | |
634 | * | |
635 | * Note: list_unhashed() on entry does not return true after this, | |
636 | * the entry is in an undefined state. It is useful for RCU based | |
637 | * lockfree traversal. | |
638 | * | |
639 | * In particular, it means that we can not poison the forward | |
640 | * pointers that may still be used for walking the hash list. | |
641 | * | |
642 | * The caller must take whatever precautions are necessary | |
643 | * (such as holding appropriate locks) to avoid racing | |
644 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
645 | * or hlist_del_rcu(), running on this same list. | |
646 | * However, it is perfectly legal to run concurrently with | |
647 | * the _rcu list-traversal primitives, such as | |
648 | * hlist_for_each_entry(). | |
649 | */ | |
650 | static inline void hlist_del_rcu(struct hlist_node *n) | |
651 | { | |
652 | __hlist_del(n); | |
653 | n->pprev = LIST_POISON2; | |
654 | } | |
655 | ||
656 | static inline void hlist_del_init(struct hlist_node *n) | |
657 | { | |
da753bea | 658 | if (!hlist_unhashed(n)) { |
1da177e4 LT |
659 | __hlist_del(n); |
660 | INIT_HLIST_NODE(n); | |
661 | } | |
662 | } | |
663 | ||
b88cb424 IM |
664 | /* |
665 | * hlist_replace_rcu - replace old entry by new one | |
666 | * @old : the element to be replaced | |
667 | * @new : the new element to insert | |
668 | * | |
669 | * The old entry will be replaced with the new entry atomically. | |
670 | */ | |
671 | static inline void hlist_replace_rcu(struct hlist_node *old, | |
672 | struct hlist_node *new) | |
673 | { | |
674 | struct hlist_node *next = old->next; | |
675 | ||
676 | new->next = next; | |
677 | new->pprev = old->pprev; | |
678 | smp_wmb(); | |
679 | if (next) | |
680 | new->next->pprev = &new->next; | |
681 | *new->pprev = new; | |
682 | old->pprev = LIST_POISON2; | |
683 | } | |
684 | ||
1da177e4 LT |
685 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) |
686 | { | |
687 | struct hlist_node *first = h->first; | |
688 | n->next = first; | |
689 | if (first) | |
690 | first->pprev = &n->next; | |
691 | h->first = n; | |
692 | n->pprev = &h->first; | |
693 | } | |
694 | ||
695 | ||
696 | /** | |
fe96e57d | 697 | * hlist_add_head_rcu |
1da177e4 LT |
698 | * @n: the element to add to the hash list. |
699 | * @h: the list to add to. | |
700 | * | |
fe96e57d RD |
701 | * Description: |
702 | * Adds the specified element to the specified hlist, | |
703 | * while permitting racing traversals. | |
704 | * | |
1da177e4 LT |
705 | * The caller must take whatever precautions are necessary |
706 | * (such as holding appropriate locks) to avoid racing | |
707 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
708 | * or hlist_del_rcu(), running on this same list. | |
709 | * However, it is perfectly legal to run concurrently with | |
710 | * the _rcu list-traversal primitives, such as | |
665a7583 | 711 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
1da177e4 LT |
712 | * problems on Alpha CPUs. Regardless of the type of CPU, the |
713 | * list-traversal primitive must be guarded by rcu_read_lock(). | |
714 | */ | |
715 | static inline void hlist_add_head_rcu(struct hlist_node *n, | |
716 | struct hlist_head *h) | |
717 | { | |
718 | struct hlist_node *first = h->first; | |
719 | n->next = first; | |
720 | n->pprev = &h->first; | |
721 | smp_wmb(); | |
722 | if (first) | |
723 | first->pprev = &n->next; | |
724 | h->first = n; | |
725 | } | |
726 | ||
727 | /* next must be != NULL */ | |
728 | static inline void hlist_add_before(struct hlist_node *n, | |
729 | struct hlist_node *next) | |
730 | { | |
731 | n->pprev = next->pprev; | |
732 | n->next = next; | |
733 | next->pprev = &n->next; | |
734 | *(n->pprev) = n; | |
735 | } | |
736 | ||
737 | static inline void hlist_add_after(struct hlist_node *n, | |
738 | struct hlist_node *next) | |
739 | { | |
740 | next->next = n->next; | |
741 | n->next = next; | |
742 | next->pprev = &n->next; | |
743 | ||
744 | if(next->next) | |
745 | next->next->pprev = &next->next; | |
746 | } | |
747 | ||
cf4ef014 | 748 | /** |
fe96e57d | 749 | * hlist_add_before_rcu |
cf4ef014 PM |
750 | * @n: the new element to add to the hash list. |
751 | * @next: the existing element to add the new element before. | |
752 | * | |
fe96e57d RD |
753 | * Description: |
754 | * Adds the specified element to the specified hlist | |
755 | * before the specified node while permitting racing traversals. | |
756 | * | |
cf4ef014 PM |
757 | * The caller must take whatever precautions are necessary |
758 | * (such as holding appropriate locks) to avoid racing | |
759 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
760 | * or hlist_del_rcu(), running on this same list. | |
761 | * However, it is perfectly legal to run concurrently with | |
762 | * the _rcu list-traversal primitives, such as | |
665a7583 | 763 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
cf4ef014 PM |
764 | * problems on Alpha CPUs. |
765 | */ | |
e5b43760 RO |
766 | static inline void hlist_add_before_rcu(struct hlist_node *n, |
767 | struct hlist_node *next) | |
768 | { | |
769 | n->pprev = next->pprev; | |
770 | n->next = next; | |
771 | smp_wmb(); | |
772 | next->pprev = &n->next; | |
773 | *(n->pprev) = n; | |
774 | } | |
775 | ||
cf4ef014 | 776 | /** |
fe96e57d | 777 | * hlist_add_after_rcu |
cf4ef014 PM |
778 | * @prev: the existing element to add the new element after. |
779 | * @n: the new element to add to the hash list. | |
780 | * | |
fe96e57d RD |
781 | * Description: |
782 | * Adds the specified element to the specified hlist | |
783 | * after the specified node while permitting racing traversals. | |
784 | * | |
cf4ef014 PM |
785 | * The caller must take whatever precautions are necessary |
786 | * (such as holding appropriate locks) to avoid racing | |
787 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
788 | * or hlist_del_rcu(), running on this same list. | |
789 | * However, it is perfectly legal to run concurrently with | |
790 | * the _rcu list-traversal primitives, such as | |
665a7583 | 791 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
cf4ef014 PM |
792 | * problems on Alpha CPUs. |
793 | */ | |
e5b43760 RO |
794 | static inline void hlist_add_after_rcu(struct hlist_node *prev, |
795 | struct hlist_node *n) | |
796 | { | |
797 | n->next = prev->next; | |
798 | n->pprev = &prev->next; | |
799 | smp_wmb(); | |
800 | prev->next = n; | |
801 | if (n->next) | |
802 | n->next->pprev = &n->next; | |
803 | } | |
804 | ||
1da177e4 LT |
805 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
806 | ||
807 | #define hlist_for_each(pos, head) \ | |
808 | for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ | |
809 | pos = pos->next) | |
810 | ||
811 | #define hlist_for_each_safe(pos, n, head) \ | |
812 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
813 | pos = n) | |
814 | ||
1da177e4 LT |
815 | /** |
816 | * hlist_for_each_entry - iterate over list of given type | |
8e3a67a9 RD |
817 | * @tpos: the type * to use as a loop cursor. |
818 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
819 | * @head: the head for your list. |
820 | * @member: the name of the hlist_node within the struct. | |
821 | */ | |
822 | #define hlist_for_each_entry(tpos, pos, head, member) \ | |
823 | for (pos = (head)->first; \ | |
824 | pos && ({ prefetch(pos->next); 1;}) && \ | |
825 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
826 | pos = pos->next) | |
827 | ||
828 | /** | |
fe96e57d | 829 | * hlist_for_each_entry_continue - iterate over a hlist continuing after current point |
8e3a67a9 RD |
830 | * @tpos: the type * to use as a loop cursor. |
831 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
832 | * @member: the name of the hlist_node within the struct. |
833 | */ | |
834 | #define hlist_for_each_entry_continue(tpos, pos, member) \ | |
835 | for (pos = (pos)->next; \ | |
836 | pos && ({ prefetch(pos->next); 1;}) && \ | |
837 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
838 | pos = pos->next) | |
839 | ||
840 | /** | |
fe96e57d | 841 | * hlist_for_each_entry_from - iterate over a hlist continuing from current point |
8e3a67a9 RD |
842 | * @tpos: the type * to use as a loop cursor. |
843 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
844 | * @member: the name of the hlist_node within the struct. |
845 | */ | |
846 | #define hlist_for_each_entry_from(tpos, pos, member) \ | |
847 | for (; pos && ({ prefetch(pos->next); 1;}) && \ | |
848 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
849 | pos = pos->next) | |
850 | ||
851 | /** | |
852 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 RD |
853 | * @tpos: the type * to use as a loop cursor. |
854 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
855 | * @n: another &struct hlist_node to use as temporary storage |
856 | * @head: the head for your list. | |
857 | * @member: the name of the hlist_node within the struct. | |
858 | */ | |
859 | #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ | |
860 | for (pos = (head)->first; \ | |
861 | pos && ({ n = pos->next; 1; }) && \ | |
862 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
863 | pos = n) | |
864 | ||
865 | /** | |
866 | * hlist_for_each_entry_rcu - iterate over rcu list of given type | |
8e3a67a9 RD |
867 | * @tpos: the type * to use as a loop cursor. |
868 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
869 | * @head: the head for your list. |
870 | * @member: the name of the hlist_node within the struct. | |
871 | * | |
872 | * This list-traversal primitive may safely run concurrently with | |
e1ba0dab | 873 | * the _rcu list-mutation primitives such as hlist_add_head_rcu() |
1da177e4 LT |
874 | * as long as the traversal is guarded by rcu_read_lock(). |
875 | */ | |
876 | #define hlist_for_each_entry_rcu(tpos, pos, head, member) \ | |
877 | for (pos = (head)->first; \ | |
b24d18aa | 878 | rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \ |
1da177e4 | 879 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
b24d18aa | 880 | pos = pos->next) |
1da177e4 LT |
881 | |
882 | #else | |
883 | #warning "don't include kernel headers in userspace" | |
884 | #endif /* __KERNEL__ */ | |
885 | #endif |