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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> | |
c9cf5528 | 7 | #include <linux/poison.h> |
1da177e4 LT |
8 | #include <linux/prefetch.h> |
9 | #include <asm/system.h> | |
10 | ||
1da177e4 LT |
11 | /* |
12 | * Simple doubly linked list implementation. | |
13 | * | |
14 | * Some of the internal functions ("__xxx") are useful when | |
15 | * manipulating whole lists rather than single entries, as | |
16 | * sometimes we already know the next/prev entries and we can | |
17 | * generate better code by using them directly rather than | |
18 | * using the generic single-entry routines. | |
19 | */ | |
20 | ||
21 | struct list_head { | |
22 | struct list_head *next, *prev; | |
23 | }; | |
24 | ||
25 | #define LIST_HEAD_INIT(name) { &(name), &(name) } | |
26 | ||
27 | #define LIST_HEAD(name) \ | |
28 | struct list_head name = LIST_HEAD_INIT(name) | |
29 | ||
490d6ab1 ZB |
30 | static inline void INIT_LIST_HEAD(struct list_head *list) |
31 | { | |
32 | list->next = list; | |
33 | list->prev = list; | |
34 | } | |
1da177e4 LT |
35 | |
36 | /* | |
37 | * Insert a new entry between two known consecutive entries. | |
38 | * | |
39 | * This is only for internal list manipulation where we know | |
40 | * the prev/next entries already! | |
41 | */ | |
42 | static inline void __list_add(struct list_head *new, | |
43 | struct list_head *prev, | |
44 | struct list_head *next) | |
45 | { | |
46 | next->prev = new; | |
47 | new->next = next; | |
48 | new->prev = prev; | |
49 | prev->next = new; | |
50 | } | |
51 | ||
52 | /** | |
53 | * list_add - add a new entry | |
54 | * @new: new entry to be added | |
55 | * @head: list head to add it after | |
56 | * | |
57 | * Insert a new entry after the specified head. | |
58 | * This is good for implementing stacks. | |
59 | */ | |
60 | static inline void list_add(struct list_head *new, struct list_head *head) | |
61 | { | |
62 | __list_add(new, head, head->next); | |
63 | } | |
64 | ||
65 | /** | |
66 | * list_add_tail - add a new entry | |
67 | * @new: new entry to be added | |
68 | * @head: list head to add it before | |
69 | * | |
70 | * Insert a new entry before the specified head. | |
71 | * This is useful for implementing queues. | |
72 | */ | |
73 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
74 | { | |
75 | __list_add(new, head->prev, head); | |
76 | } | |
77 | ||
78 | /* | |
79 | * Insert a new entry between two known consecutive entries. | |
80 | * | |
81 | * This is only for internal list manipulation where we know | |
82 | * the prev/next entries already! | |
83 | */ | |
84 | static inline void __list_add_rcu(struct list_head * new, | |
85 | struct list_head * prev, struct list_head * next) | |
86 | { | |
87 | new->next = next; | |
88 | new->prev = prev; | |
89 | smp_wmb(); | |
90 | next->prev = new; | |
91 | prev->next = new; | |
92 | } | |
93 | ||
94 | /** | |
95 | * list_add_rcu - add a new entry to rcu-protected list | |
96 | * @new: new entry to be added | |
97 | * @head: list head to add it after | |
98 | * | |
99 | * Insert a new entry after the specified head. | |
100 | * This is good for implementing stacks. | |
101 | * | |
102 | * The caller must take whatever precautions are necessary | |
103 | * (such as holding appropriate locks) to avoid racing | |
104 | * with another list-mutation primitive, such as list_add_rcu() | |
105 | * or list_del_rcu(), running on this same list. | |
106 | * However, it is perfectly legal to run concurrently with | |
107 | * the _rcu list-traversal primitives, such as | |
108 | * list_for_each_entry_rcu(). | |
109 | */ | |
110 | static inline void list_add_rcu(struct list_head *new, struct list_head *head) | |
111 | { | |
112 | __list_add_rcu(new, head, head->next); | |
113 | } | |
114 | ||
115 | /** | |
116 | * list_add_tail_rcu - add a new entry to rcu-protected list | |
117 | * @new: new entry to be added | |
118 | * @head: list head to add it before | |
119 | * | |
120 | * Insert a new entry before the specified head. | |
121 | * This is useful for implementing queues. | |
122 | * | |
123 | * The caller must take whatever precautions are necessary | |
124 | * (such as holding appropriate locks) to avoid racing | |
125 | * with another list-mutation primitive, such as list_add_tail_rcu() | |
126 | * or list_del_rcu(), running on this same list. | |
127 | * However, it is perfectly legal to run concurrently with | |
128 | * the _rcu list-traversal primitives, such as | |
129 | * list_for_each_entry_rcu(). | |
130 | */ | |
131 | static inline void list_add_tail_rcu(struct list_head *new, | |
132 | struct list_head *head) | |
133 | { | |
134 | __list_add_rcu(new, head->prev, head); | |
135 | } | |
136 | ||
137 | /* | |
138 | * Delete a list entry by making the prev/next entries | |
139 | * point to each other. | |
140 | * | |
141 | * This is only for internal list manipulation where we know | |
142 | * the prev/next entries already! | |
143 | */ | |
144 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
145 | { | |
146 | next->prev = prev; | |
147 | prev->next = next; | |
148 | } | |
149 | ||
150 | /** | |
151 | * list_del - deletes entry from list. | |
152 | * @entry: the element to delete from the list. | |
153 | * Note: list_empty on entry does not return true after this, the entry is | |
154 | * in an undefined state. | |
155 | */ | |
156 | static inline void list_del(struct list_head *entry) | |
157 | { | |
158 | __list_del(entry->prev, entry->next); | |
159 | entry->next = LIST_POISON1; | |
160 | entry->prev = LIST_POISON2; | |
161 | } | |
162 | ||
163 | /** | |
164 | * list_del_rcu - deletes entry from list without re-initialization | |
165 | * @entry: the element to delete from the list. | |
166 | * | |
167 | * Note: list_empty on entry does not return true after this, | |
168 | * the entry is in an undefined state. It is useful for RCU based | |
169 | * lockfree traversal. | |
170 | * | |
171 | * In particular, it means that we can not poison the forward | |
172 | * pointers that may still be used for walking the list. | |
173 | * | |
174 | * The caller must take whatever precautions are necessary | |
175 | * (such as holding appropriate locks) to avoid racing | |
176 | * with another list-mutation primitive, such as list_del_rcu() | |
177 | * or list_add_rcu(), running on this same list. | |
178 | * However, it is perfectly legal to run concurrently with | |
179 | * the _rcu list-traversal primitives, such as | |
180 | * list_for_each_entry_rcu(). | |
181 | * | |
182 | * Note that the caller is not permitted to immediately free | |
b2b18660 | 183 | * the newly deleted entry. Instead, either synchronize_rcu() |
1da177e4 LT |
184 | * or call_rcu() must be used to defer freeing until an RCU |
185 | * grace period has elapsed. | |
186 | */ | |
187 | static inline void list_del_rcu(struct list_head *entry) | |
188 | { | |
189 | __list_del(entry->prev, entry->next); | |
190 | entry->prev = LIST_POISON2; | |
191 | } | |
192 | ||
54e73770 ON |
193 | /** |
194 | * list_replace - replace old entry by new one | |
195 | * @old : the element to be replaced | |
196 | * @new : the new element to insert | |
197 | * Note: if 'old' was empty, it will be overwritten. | |
198 | */ | |
199 | static inline void list_replace(struct list_head *old, | |
200 | struct list_head *new) | |
201 | { | |
202 | new->next = old->next; | |
203 | new->next->prev = new; | |
204 | new->prev = old->prev; | |
205 | new->prev->next = new; | |
206 | } | |
207 | ||
208 | static inline void list_replace_init(struct list_head *old, | |
209 | struct list_head *new) | |
210 | { | |
211 | list_replace(old, new); | |
212 | INIT_LIST_HEAD(old); | |
213 | } | |
214 | ||
1da177e4 LT |
215 | /* |
216 | * list_replace_rcu - replace old entry by new one | |
217 | * @old : the element to be replaced | |
218 | * @new : the new element to insert | |
219 | * | |
220 | * The old entry will be replaced with the new entry atomically. | |
54e73770 | 221 | * Note: 'old' should not be empty. |
1da177e4 | 222 | */ |
b88cb424 IM |
223 | static inline void list_replace_rcu(struct list_head *old, |
224 | struct list_head *new) | |
225 | { | |
1da177e4 LT |
226 | new->next = old->next; |
227 | new->prev = old->prev; | |
228 | smp_wmb(); | |
229 | new->next->prev = new; | |
230 | new->prev->next = new; | |
b88cb424 | 231 | old->prev = LIST_POISON2; |
1da177e4 LT |
232 | } |
233 | ||
234 | /** | |
235 | * list_del_init - deletes entry from list and reinitialize it. | |
236 | * @entry: the element to delete from the list. | |
237 | */ | |
238 | static inline void list_del_init(struct list_head *entry) | |
239 | { | |
240 | __list_del(entry->prev, entry->next); | |
241 | INIT_LIST_HEAD(entry); | |
242 | } | |
243 | ||
244 | /** | |
245 | * list_move - delete from one list and add as another's head | |
246 | * @list: the entry to move | |
247 | * @head: the head that will precede our entry | |
248 | */ | |
249 | static inline void list_move(struct list_head *list, struct list_head *head) | |
250 | { | |
251 | __list_del(list->prev, list->next); | |
252 | list_add(list, head); | |
253 | } | |
254 | ||
255 | /** | |
256 | * list_move_tail - delete from one list and add as another's tail | |
257 | * @list: the entry to move | |
258 | * @head: the head that will follow our entry | |
259 | */ | |
260 | static inline void list_move_tail(struct list_head *list, | |
261 | struct list_head *head) | |
262 | { | |
263 | __list_del(list->prev, list->next); | |
264 | list_add_tail(list, head); | |
265 | } | |
266 | ||
267 | /** | |
268 | * list_empty - tests whether a list is empty | |
269 | * @head: the list to test. | |
270 | */ | |
271 | static inline int list_empty(const struct list_head *head) | |
272 | { | |
273 | return head->next == head; | |
274 | } | |
275 | ||
276 | /** | |
fe96e57d RD |
277 | * list_empty_careful - tests whether a list is empty and not being modified |
278 | * @head: the list to test | |
279 | * | |
280 | * Description: | |
281 | * tests whether a list is empty _and_ checks that no other CPU might be | |
282 | * in the process of modifying either member (next or prev) | |
1da177e4 LT |
283 | * |
284 | * NOTE: using list_empty_careful() without synchronization | |
285 | * can only be safe if the only activity that can happen | |
286 | * to the list entry is list_del_init(). Eg. it cannot be used | |
287 | * if another CPU could re-list_add() it. | |
1da177e4 LT |
288 | */ |
289 | static inline int list_empty_careful(const struct list_head *head) | |
290 | { | |
291 | struct list_head *next = head->next; | |
292 | return (next == head) && (next == head->prev); | |
293 | } | |
294 | ||
295 | static inline void __list_splice(struct list_head *list, | |
296 | struct list_head *head) | |
297 | { | |
298 | struct list_head *first = list->next; | |
299 | struct list_head *last = list->prev; | |
300 | struct list_head *at = head->next; | |
301 | ||
302 | first->prev = head; | |
303 | head->next = first; | |
304 | ||
305 | last->next = at; | |
306 | at->prev = last; | |
307 | } | |
308 | ||
309 | /** | |
310 | * list_splice - join two lists | |
311 | * @list: the new list to add. | |
312 | * @head: the place to add it in the first list. | |
313 | */ | |
314 | static inline void list_splice(struct list_head *list, struct list_head *head) | |
315 | { | |
316 | if (!list_empty(list)) | |
317 | __list_splice(list, head); | |
318 | } | |
319 | ||
320 | /** | |
321 | * list_splice_init - join two lists and reinitialise the emptied list. | |
322 | * @list: the new list to add. | |
323 | * @head: the place to add it in the first list. | |
324 | * | |
325 | * The list at @list is reinitialised | |
326 | */ | |
327 | static inline void list_splice_init(struct list_head *list, | |
328 | struct list_head *head) | |
329 | { | |
330 | if (!list_empty(list)) { | |
331 | __list_splice(list, head); | |
332 | INIT_LIST_HEAD(list); | |
333 | } | |
334 | } | |
335 | ||
336 | /** | |
337 | * list_entry - get the struct for this entry | |
338 | * @ptr: the &struct list_head pointer. | |
339 | * @type: the type of the struct this is embedded in. | |
340 | * @member: the name of the list_struct within the struct. | |
341 | */ | |
342 | #define list_entry(ptr, type, member) \ | |
343 | container_of(ptr, type, member) | |
344 | ||
345 | /** | |
346 | * list_for_each - iterate over a list | |
8e3a67a9 | 347 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
348 | * @head: the head for your list. |
349 | */ | |
350 | #define list_for_each(pos, head) \ | |
351 | for (pos = (head)->next; prefetch(pos->next), pos != (head); \ | |
352 | pos = pos->next) | |
353 | ||
354 | /** | |
355 | * __list_for_each - iterate over a list | |
8e3a67a9 | 356 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
357 | * @head: the head for your list. |
358 | * | |
359 | * This variant differs from list_for_each() in that it's the | |
360 | * simplest possible list iteration code, no prefetching is done. | |
361 | * Use this for code that knows the list to be very short (empty | |
362 | * or 1 entry) most of the time. | |
363 | */ | |
364 | #define __list_for_each(pos, head) \ | |
365 | for (pos = (head)->next; pos != (head); pos = pos->next) | |
366 | ||
367 | /** | |
368 | * list_for_each_prev - iterate over a list backwards | |
8e3a67a9 | 369 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
370 | * @head: the head for your list. |
371 | */ | |
372 | #define list_for_each_prev(pos, head) \ | |
373 | for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ | |
374 | pos = pos->prev) | |
375 | ||
376 | /** | |
fe96e57d | 377 | * list_for_each_safe - iterate over a list safe against removal of list entry |
8e3a67a9 | 378 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
379 | * @n: another &struct list_head to use as temporary storage |
380 | * @head: the head for your list. | |
381 | */ | |
382 | #define list_for_each_safe(pos, n, head) \ | |
383 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
384 | pos = n, n = pos->next) | |
385 | ||
386 | /** | |
387 | * list_for_each_entry - iterate over list of given type | |
8e3a67a9 | 388 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
389 | * @head: the head for your list. |
390 | * @member: the name of the list_struct within the struct. | |
391 | */ | |
392 | #define list_for_each_entry(pos, head, member) \ | |
393 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
394 | prefetch(pos->member.next), &pos->member != (head); \ | |
395 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
396 | ||
397 | /** | |
398 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
8e3a67a9 | 399 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
400 | * @head: the head for your list. |
401 | * @member: the name of the list_struct within the struct. | |
402 | */ | |
403 | #define list_for_each_entry_reverse(pos, head, member) \ | |
404 | for (pos = list_entry((head)->prev, typeof(*pos), member); \ | |
405 | prefetch(pos->member.prev), &pos->member != (head); \ | |
406 | pos = list_entry(pos->member.prev, typeof(*pos), member)) | |
407 | ||
408 | /** | |
fe96e57d | 409 | * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue |
1da177e4 LT |
410 | * @pos: the type * to use as a start point |
411 | * @head: the head of the list | |
412 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
413 | * |
414 | * Prepares a pos entry for use as a start point in list_for_each_entry_continue. | |
1da177e4 LT |
415 | */ |
416 | #define list_prepare_entry(pos, head, member) \ | |
417 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
418 | ||
419 | /** | |
fe96e57d | 420 | * list_for_each_entry_continue - continue iteration over list of given type |
8e3a67a9 | 421 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
422 | * @head: the head for your list. |
423 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
424 | * |
425 | * Continue to iterate over list of given type, continuing after | |
426 | * the current position. | |
1da177e4 LT |
427 | */ |
428 | #define list_for_each_entry_continue(pos, head, member) \ | |
429 | for (pos = list_entry(pos->member.next, typeof(*pos), member); \ | |
430 | prefetch(pos->member.next), &pos->member != (head); \ | |
431 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
432 | ||
e229c2fb | 433 | /** |
fe96e57d | 434 | * list_for_each_entry_from - iterate over list of given type from the current point |
8e3a67a9 | 435 | * @pos: the type * to use as a loop cursor. |
e229c2fb ACM |
436 | * @head: the head for your list. |
437 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
438 | * |
439 | * Iterate over list of given type, continuing from current position. | |
e229c2fb ACM |
440 | */ |
441 | #define list_for_each_entry_from(pos, head, member) \ | |
442 | for (; prefetch(pos->member.next), &pos->member != (head); \ | |
443 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
444 | ||
1da177e4 LT |
445 | /** |
446 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 | 447 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
448 | * @n: another type * to use as temporary storage |
449 | * @head: the head for your list. | |
450 | * @member: the name of the list_struct within the struct. | |
451 | */ | |
452 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
453 | for (pos = list_entry((head)->next, typeof(*pos), member), \ | |
454 | n = list_entry(pos->member.next, typeof(*pos), member); \ | |
455 | &pos->member != (head); \ | |
456 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
457 | ||
74459dc7 | 458 | /** |
fe96e57d | 459 | * list_for_each_entry_safe_continue |
8e3a67a9 | 460 | * @pos: the type * to use as a loop cursor. |
74459dc7 ACM |
461 | * @n: another type * to use as temporary storage |
462 | * @head: the head for your list. | |
463 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
464 | * |
465 | * Iterate over list of given type, continuing after current point, | |
466 | * safe against removal of list entry. | |
74459dc7 ACM |
467 | */ |
468 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8c60f3fa ACM |
469 | for (pos = list_entry(pos->member.next, typeof(*pos), member), \ |
470 | n = list_entry(pos->member.next, typeof(*pos), member); \ | |
d8dcffee ACM |
471 | &pos->member != (head); \ |
472 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
473 | ||
474 | /** | |
fe96e57d | 475 | * list_for_each_entry_safe_from |
8e3a67a9 | 476 | * @pos: the type * to use as a loop cursor. |
d8dcffee ACM |
477 | * @n: another type * to use as temporary storage |
478 | * @head: the head for your list. | |
479 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
480 | * |
481 | * Iterate over list of given type from current point, safe against | |
482 | * removal of list entry. | |
d8dcffee ACM |
483 | */ |
484 | #define list_for_each_entry_safe_from(pos, n, head, member) \ | |
485 | for (n = list_entry(pos->member.next, typeof(*pos), member); \ | |
74459dc7 ACM |
486 | &pos->member != (head); \ |
487 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) | |
488 | ||
0ad42352 | 489 | /** |
fe96e57d | 490 | * list_for_each_entry_safe_reverse |
8e3a67a9 | 491 | * @pos: the type * to use as a loop cursor. |
0ad42352 DH |
492 | * @n: another type * to use as temporary storage |
493 | * @head: the head for your list. | |
494 | * @member: the name of the list_struct within the struct. | |
fe96e57d RD |
495 | * |
496 | * Iterate backwards over list of given type, safe against removal | |
497 | * of list entry. | |
0ad42352 DH |
498 | */ |
499 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
500 | for (pos = list_entry((head)->prev, typeof(*pos), member), \ | |
501 | n = list_entry(pos->member.prev, typeof(*pos), member); \ | |
502 | &pos->member != (head); \ | |
503 | pos = n, n = list_entry(n->member.prev, typeof(*n), member)) | |
504 | ||
1da177e4 LT |
505 | /** |
506 | * list_for_each_rcu - iterate over an rcu-protected list | |
8e3a67a9 | 507 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
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_rcu(pos, head) \ | |
b24d18aa HX |
515 | for (pos = (head)->next; \ |
516 | prefetch(rcu_dereference(pos)->next), pos != (head); \ | |
517 | pos = pos->next) | |
1da177e4 LT |
518 | |
519 | #define __list_for_each_rcu(pos, head) \ | |
b24d18aa HX |
520 | for (pos = (head)->next; \ |
521 | rcu_dereference(pos) != (head); \ | |
522 | pos = pos->next) | |
1da177e4 LT |
523 | |
524 | /** | |
fe96e57d | 525 | * list_for_each_safe_rcu |
8e3a67a9 | 526 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
527 | * @n: another &struct list_head to use as temporary storage |
528 | * @head: the head for your list. | |
529 | * | |
fe96e57d RD |
530 | * Iterate over an rcu-protected list, safe against removal of list entry. |
531 | * | |
1da177e4 LT |
532 | * This list-traversal primitive may safely run concurrently with |
533 | * the _rcu list-mutation primitives such as list_add_rcu() | |
534 | * as long as the traversal is guarded by rcu_read_lock(). | |
535 | */ | |
536 | #define list_for_each_safe_rcu(pos, n, head) \ | |
b24d18aa HX |
537 | for (pos = (head)->next; \ |
538 | n = rcu_dereference(pos)->next, pos != (head); \ | |
539 | pos = n) | |
1da177e4 LT |
540 | |
541 | /** | |
542 | * list_for_each_entry_rcu - iterate over rcu list of given type | |
8e3a67a9 | 543 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
544 | * @head: the head for your list. |
545 | * @member: the name of the list_struct within the struct. | |
546 | * | |
547 | * This list-traversal primitive may safely run concurrently with | |
548 | * the _rcu list-mutation primitives such as list_add_rcu() | |
549 | * as long as the traversal is guarded by rcu_read_lock(). | |
550 | */ | |
b24d18aa HX |
551 | #define list_for_each_entry_rcu(pos, head, member) \ |
552 | for (pos = list_entry((head)->next, typeof(*pos), member); \ | |
553 | prefetch(rcu_dereference(pos)->member.next), \ | |
554 | &pos->member != (head); \ | |
555 | pos = list_entry(pos->member.next, typeof(*pos), member)) | |
1da177e4 LT |
556 | |
557 | ||
558 | /** | |
fe96e57d | 559 | * list_for_each_continue_rcu |
8e3a67a9 | 560 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
561 | * @head: the head for your list. |
562 | * | |
fe96e57d RD |
563 | * Iterate over an rcu-protected list, continuing after current point. |
564 | * | |
1da177e4 LT |
565 | * This list-traversal primitive may safely run concurrently with |
566 | * the _rcu list-mutation primitives such as list_add_rcu() | |
567 | * as long as the traversal is guarded by rcu_read_lock(). | |
568 | */ | |
569 | #define list_for_each_continue_rcu(pos, head) \ | |
b24d18aa HX |
570 | for ((pos) = (pos)->next; \ |
571 | prefetch(rcu_dereference((pos))->next), (pos) != (head); \ | |
572 | (pos) = (pos)->next) | |
1da177e4 LT |
573 | |
574 | /* | |
575 | * Double linked lists with a single pointer list head. | |
576 | * Mostly useful for hash tables where the two pointer list head is | |
577 | * too wasteful. | |
578 | * You lose the ability to access the tail in O(1). | |
579 | */ | |
580 | ||
581 | struct hlist_head { | |
582 | struct hlist_node *first; | |
583 | }; | |
584 | ||
585 | struct hlist_node { | |
586 | struct hlist_node *next, **pprev; | |
587 | }; | |
588 | ||
589 | #define HLIST_HEAD_INIT { .first = NULL } | |
590 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
591 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
490d6ab1 ZB |
592 | static inline void INIT_HLIST_NODE(struct hlist_node *h) |
593 | { | |
594 | h->next = NULL; | |
595 | h->pprev = NULL; | |
596 | } | |
1da177e4 LT |
597 | |
598 | static inline int hlist_unhashed(const struct hlist_node *h) | |
599 | { | |
600 | return !h->pprev; | |
601 | } | |
602 | ||
603 | static inline int hlist_empty(const struct hlist_head *h) | |
604 | { | |
605 | return !h->first; | |
606 | } | |
607 | ||
608 | static inline void __hlist_del(struct hlist_node *n) | |
609 | { | |
610 | struct hlist_node *next = n->next; | |
611 | struct hlist_node **pprev = n->pprev; | |
612 | *pprev = next; | |
613 | if (next) | |
614 | next->pprev = pprev; | |
615 | } | |
616 | ||
617 | static inline void hlist_del(struct hlist_node *n) | |
618 | { | |
619 | __hlist_del(n); | |
620 | n->next = LIST_POISON1; | |
621 | n->pprev = LIST_POISON2; | |
622 | } | |
623 | ||
624 | /** | |
625 | * hlist_del_rcu - deletes entry from hash list without re-initialization | |
626 | * @n: the element to delete from the hash list. | |
627 | * | |
628 | * Note: list_unhashed() on entry does not return true after this, | |
629 | * the entry is in an undefined state. It is useful for RCU based | |
630 | * lockfree traversal. | |
631 | * | |
632 | * In particular, it means that we can not poison the forward | |
633 | * pointers that may still be used for walking the hash list. | |
634 | * | |
635 | * The caller must take whatever precautions are necessary | |
636 | * (such as holding appropriate locks) to avoid racing | |
637 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
638 | * or hlist_del_rcu(), running on this same list. | |
639 | * However, it is perfectly legal to run concurrently with | |
640 | * the _rcu list-traversal primitives, such as | |
641 | * hlist_for_each_entry(). | |
642 | */ | |
643 | static inline void hlist_del_rcu(struct hlist_node *n) | |
644 | { | |
645 | __hlist_del(n); | |
646 | n->pprev = LIST_POISON2; | |
647 | } | |
648 | ||
649 | static inline void hlist_del_init(struct hlist_node *n) | |
650 | { | |
da753bea | 651 | if (!hlist_unhashed(n)) { |
1da177e4 LT |
652 | __hlist_del(n); |
653 | INIT_HLIST_NODE(n); | |
654 | } | |
655 | } | |
656 | ||
b88cb424 IM |
657 | /* |
658 | * hlist_replace_rcu - replace old entry by new one | |
659 | * @old : the element to be replaced | |
660 | * @new : the new element to insert | |
661 | * | |
662 | * The old entry will be replaced with the new entry atomically. | |
663 | */ | |
664 | static inline void hlist_replace_rcu(struct hlist_node *old, | |
665 | struct hlist_node *new) | |
666 | { | |
667 | struct hlist_node *next = old->next; | |
668 | ||
669 | new->next = next; | |
670 | new->pprev = old->pprev; | |
671 | smp_wmb(); | |
672 | if (next) | |
673 | new->next->pprev = &new->next; | |
674 | *new->pprev = new; | |
675 | old->pprev = LIST_POISON2; | |
676 | } | |
677 | ||
1da177e4 LT |
678 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) |
679 | { | |
680 | struct hlist_node *first = h->first; | |
681 | n->next = first; | |
682 | if (first) | |
683 | first->pprev = &n->next; | |
684 | h->first = n; | |
685 | n->pprev = &h->first; | |
686 | } | |
687 | ||
688 | ||
689 | /** | |
fe96e57d | 690 | * hlist_add_head_rcu |
1da177e4 LT |
691 | * @n: the element to add to the hash list. |
692 | * @h: the list to add to. | |
693 | * | |
fe96e57d RD |
694 | * Description: |
695 | * Adds the specified element to the specified hlist, | |
696 | * while permitting racing traversals. | |
697 | * | |
1da177e4 LT |
698 | * The caller must take whatever precautions are necessary |
699 | * (such as holding appropriate locks) to avoid racing | |
700 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
701 | * or hlist_del_rcu(), running on this same list. | |
702 | * However, it is perfectly legal to run concurrently with | |
703 | * the _rcu list-traversal primitives, such as | |
665a7583 | 704 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
1da177e4 LT |
705 | * problems on Alpha CPUs. Regardless of the type of CPU, the |
706 | * list-traversal primitive must be guarded by rcu_read_lock(). | |
707 | */ | |
708 | static inline void hlist_add_head_rcu(struct hlist_node *n, | |
709 | struct hlist_head *h) | |
710 | { | |
711 | struct hlist_node *first = h->first; | |
712 | n->next = first; | |
713 | n->pprev = &h->first; | |
714 | smp_wmb(); | |
715 | if (first) | |
716 | first->pprev = &n->next; | |
717 | h->first = n; | |
718 | } | |
719 | ||
720 | /* next must be != NULL */ | |
721 | static inline void hlist_add_before(struct hlist_node *n, | |
722 | struct hlist_node *next) | |
723 | { | |
724 | n->pprev = next->pprev; | |
725 | n->next = next; | |
726 | next->pprev = &n->next; | |
727 | *(n->pprev) = n; | |
728 | } | |
729 | ||
730 | static inline void hlist_add_after(struct hlist_node *n, | |
731 | struct hlist_node *next) | |
732 | { | |
733 | next->next = n->next; | |
734 | n->next = next; | |
735 | next->pprev = &n->next; | |
736 | ||
737 | if(next->next) | |
738 | next->next->pprev = &next->next; | |
739 | } | |
740 | ||
cf4ef014 | 741 | /** |
fe96e57d | 742 | * hlist_add_before_rcu |
cf4ef014 PM |
743 | * @n: the new element to add to the hash list. |
744 | * @next: the existing element to add the new element before. | |
745 | * | |
fe96e57d RD |
746 | * Description: |
747 | * Adds the specified element to the specified hlist | |
748 | * before the specified node while permitting racing traversals. | |
749 | * | |
cf4ef014 PM |
750 | * The caller must take whatever precautions are necessary |
751 | * (such as holding appropriate locks) to avoid racing | |
752 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
753 | * or hlist_del_rcu(), running on this same list. | |
754 | * However, it is perfectly legal to run concurrently with | |
755 | * the _rcu list-traversal primitives, such as | |
665a7583 | 756 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
cf4ef014 PM |
757 | * problems on Alpha CPUs. |
758 | */ | |
e5b43760 RO |
759 | static inline void hlist_add_before_rcu(struct hlist_node *n, |
760 | struct hlist_node *next) | |
761 | { | |
762 | n->pprev = next->pprev; | |
763 | n->next = next; | |
764 | smp_wmb(); | |
765 | next->pprev = &n->next; | |
766 | *(n->pprev) = n; | |
767 | } | |
768 | ||
cf4ef014 | 769 | /** |
fe96e57d | 770 | * hlist_add_after_rcu |
cf4ef014 PM |
771 | * @prev: the existing element to add the new element after. |
772 | * @n: the new element to add to the hash list. | |
773 | * | |
fe96e57d RD |
774 | * Description: |
775 | * Adds the specified element to the specified hlist | |
776 | * after the specified node while permitting racing traversals. | |
777 | * | |
cf4ef014 PM |
778 | * The caller must take whatever precautions are necessary |
779 | * (such as holding appropriate locks) to avoid racing | |
780 | * with another list-mutation primitive, such as hlist_add_head_rcu() | |
781 | * or hlist_del_rcu(), running on this same list. | |
782 | * However, it is perfectly legal to run concurrently with | |
783 | * the _rcu list-traversal primitives, such as | |
665a7583 | 784 | * hlist_for_each_entry_rcu(), used to prevent memory-consistency |
cf4ef014 PM |
785 | * problems on Alpha CPUs. |
786 | */ | |
e5b43760 RO |
787 | static inline void hlist_add_after_rcu(struct hlist_node *prev, |
788 | struct hlist_node *n) | |
789 | { | |
790 | n->next = prev->next; | |
791 | n->pprev = &prev->next; | |
792 | smp_wmb(); | |
793 | prev->next = n; | |
794 | if (n->next) | |
795 | n->next->pprev = &n->next; | |
796 | } | |
797 | ||
1da177e4 LT |
798 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
799 | ||
800 | #define hlist_for_each(pos, head) \ | |
801 | for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ | |
802 | pos = pos->next) | |
803 | ||
804 | #define hlist_for_each_safe(pos, n, head) \ | |
805 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
806 | pos = n) | |
807 | ||
1da177e4 LT |
808 | /** |
809 | * hlist_for_each_entry - iterate over list of given type | |
8e3a67a9 RD |
810 | * @tpos: the type * to use as a loop cursor. |
811 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
812 | * @head: the head for your list. |
813 | * @member: the name of the hlist_node within the struct. | |
814 | */ | |
815 | #define hlist_for_each_entry(tpos, pos, head, member) \ | |
816 | for (pos = (head)->first; \ | |
817 | pos && ({ prefetch(pos->next); 1;}) && \ | |
818 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
819 | pos = pos->next) | |
820 | ||
821 | /** | |
fe96e57d | 822 | * hlist_for_each_entry_continue - iterate over a hlist continuing after current point |
8e3a67a9 RD |
823 | * @tpos: the type * to use as a loop cursor. |
824 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
825 | * @member: the name of the hlist_node within the struct. |
826 | */ | |
827 | #define hlist_for_each_entry_continue(tpos, pos, member) \ | |
828 | for (pos = (pos)->next; \ | |
829 | pos && ({ prefetch(pos->next); 1;}) && \ | |
830 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
831 | pos = pos->next) | |
832 | ||
833 | /** | |
fe96e57d | 834 | * hlist_for_each_entry_from - iterate over a hlist continuing from current point |
8e3a67a9 RD |
835 | * @tpos: the type * to use as a loop cursor. |
836 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
837 | * @member: the name of the hlist_node within the struct. |
838 | */ | |
839 | #define hlist_for_each_entry_from(tpos, pos, member) \ | |
840 | for (; pos && ({ prefetch(pos->next); 1;}) && \ | |
841 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
842 | pos = pos->next) | |
843 | ||
844 | /** | |
845 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 RD |
846 | * @tpos: the type * to use as a loop cursor. |
847 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
848 | * @n: another &struct hlist_node to use as temporary storage |
849 | * @head: the head for your list. | |
850 | * @member: the name of the hlist_node within the struct. | |
851 | */ | |
852 | #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ | |
853 | for (pos = (head)->first; \ | |
854 | pos && ({ n = pos->next; 1; }) && \ | |
855 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ | |
856 | pos = n) | |
857 | ||
858 | /** | |
859 | * hlist_for_each_entry_rcu - iterate over rcu list of given type | |
8e3a67a9 RD |
860 | * @tpos: the type * to use as a loop cursor. |
861 | * @pos: the &struct hlist_node to use as a loop cursor. | |
1da177e4 LT |
862 | * @head: the head for your list. |
863 | * @member: the name of the hlist_node within the struct. | |
864 | * | |
865 | * This list-traversal primitive may safely run concurrently with | |
e1ba0dab | 866 | * the _rcu list-mutation primitives such as hlist_add_head_rcu() |
1da177e4 LT |
867 | * as long as the traversal is guarded by rcu_read_lock(). |
868 | */ | |
869 | #define hlist_for_each_entry_rcu(tpos, pos, head, member) \ | |
870 | for (pos = (head)->first; \ | |
b24d18aa | 871 | rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \ |
1da177e4 | 872 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
b24d18aa | 873 | pos = pos->next) |
1da177e4 LT |
874 | |
875 | #else | |
876 | #warning "don't include kernel headers in userspace" | |
877 | #endif /* __KERNEL__ */ | |
878 | #endif |