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1da177e4 LT |
1 | #ifndef _LINUX_LIST_H |
2 | #define _LINUX_LIST_H | |
3 | ||
de5d9bf6 | 4 | #include <linux/types.h> |
1da177e4 | 5 | #include <linux/stddef.h> |
c9cf5528 | 6 | #include <linux/poison.h> |
e66eed65 | 7 | #include <linux/const.h> |
8b21d9ca | 8 | #include <linux/kernel.h> |
1da177e4 | 9 | |
1da177e4 LT |
10 | /* |
11 | * Simple doubly linked list implementation. | |
12 | * | |
13 | * Some of the internal functions ("__xxx") are useful when | |
14 | * manipulating whole lists rather than single entries, as | |
15 | * sometimes we already know the next/prev entries and we can | |
16 | * generate better code by using them directly rather than | |
17 | * using the generic single-entry routines. | |
18 | */ | |
19 | ||
1da177e4 LT |
20 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
21 | ||
22 | #define LIST_HEAD(name) \ | |
23 | struct list_head name = LIST_HEAD_INIT(name) | |
24 | ||
490d6ab1 ZB |
25 | static inline void INIT_LIST_HEAD(struct list_head *list) |
26 | { | |
2f073848 | 27 | WRITE_ONCE(list->next, list); |
490d6ab1 ZB |
28 | list->prev = list; |
29 | } | |
1da177e4 | 30 | |
d7c81673 KC |
31 | #ifdef CONFIG_DEBUG_LIST |
32 | extern bool __list_add_valid(struct list_head *new, | |
33 | struct list_head *prev, | |
34 | struct list_head *next); | |
35 | #else | |
36 | static inline bool __list_add_valid(struct list_head *new, | |
37 | struct list_head *prev, | |
38 | struct list_head *next) | |
39 | { | |
40 | return true; | |
41 | } | |
42 | #endif | |
43 | ||
1da177e4 LT |
44 | /* |
45 | * Insert a new entry between two known consecutive entries. | |
46 | * | |
47 | * This is only for internal list manipulation where we know | |
48 | * the prev/next entries already! | |
49 | */ | |
50 | static inline void __list_add(struct list_head *new, | |
51 | struct list_head *prev, | |
52 | struct list_head *next) | |
53 | { | |
d7c81673 KC |
54 | if (!__list_add_valid(new, prev, next)) |
55 | return; | |
56 | ||
1da177e4 LT |
57 | next->prev = new; |
58 | new->next = next; | |
59 | new->prev = prev; | |
1c97be67 | 60 | WRITE_ONCE(prev->next, new); |
1da177e4 LT |
61 | } |
62 | ||
63 | /** | |
64 | * list_add - add a new entry | |
65 | * @new: new entry to be added | |
66 | * @head: list head to add it after | |
67 | * | |
68 | * Insert a new entry after the specified head. | |
69 | * This is good for implementing stacks. | |
70 | */ | |
71 | static inline void list_add(struct list_head *new, struct list_head *head) | |
72 | { | |
73 | __list_add(new, head, head->next); | |
74 | } | |
199a9afc | 75 | |
1da177e4 LT |
76 | |
77 | /** | |
78 | * list_add_tail - add a new entry | |
79 | * @new: new entry to be added | |
80 | * @head: list head to add it before | |
81 | * | |
82 | * Insert a new entry before the specified head. | |
83 | * This is useful for implementing queues. | |
84 | */ | |
85 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
86 | { | |
87 | __list_add(new, head->prev, head); | |
88 | } | |
89 | ||
1da177e4 LT |
90 | /* |
91 | * Delete a list entry by making the prev/next entries | |
92 | * point to each other. | |
93 | * | |
94 | * This is only for internal list manipulation where we know | |
95 | * the prev/next entries already! | |
96 | */ | |
97 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
98 | { | |
99 | next->prev = prev; | |
7f5f873c | 100 | WRITE_ONCE(prev->next, next); |
1da177e4 LT |
101 | } |
102 | ||
103 | /** | |
104 | * list_del - deletes entry from list. | |
105 | * @entry: the element to delete from the list. | |
72fd4a35 | 106 | * Note: list_empty() on entry does not return true after this, the entry is |
1da177e4 LT |
107 | * in an undefined state. |
108 | */ | |
199a9afc | 109 | #ifndef CONFIG_DEBUG_LIST |
3c18d4de LT |
110 | static inline void __list_del_entry(struct list_head *entry) |
111 | { | |
112 | __list_del(entry->prev, entry->next); | |
113 | } | |
114 | ||
1da177e4 LT |
115 | static inline void list_del(struct list_head *entry) |
116 | { | |
117 | __list_del(entry->prev, entry->next); | |
118 | entry->next = LIST_POISON1; | |
119 | entry->prev = LIST_POISON2; | |
120 | } | |
199a9afc | 121 | #else |
3c18d4de | 122 | extern void __list_del_entry(struct list_head *entry); |
199a9afc DJ |
123 | extern void list_del(struct list_head *entry); |
124 | #endif | |
1da177e4 | 125 | |
54e73770 ON |
126 | /** |
127 | * list_replace - replace old entry by new one | |
128 | * @old : the element to be replaced | |
129 | * @new : the new element to insert | |
72fd4a35 RD |
130 | * |
131 | * If @old was empty, it will be overwritten. | |
54e73770 ON |
132 | */ |
133 | static inline void list_replace(struct list_head *old, | |
134 | struct list_head *new) | |
135 | { | |
136 | new->next = old->next; | |
137 | new->next->prev = new; | |
138 | new->prev = old->prev; | |
139 | new->prev->next = new; | |
140 | } | |
141 | ||
142 | static inline void list_replace_init(struct list_head *old, | |
143 | struct list_head *new) | |
144 | { | |
145 | list_replace(old, new); | |
146 | INIT_LIST_HEAD(old); | |
147 | } | |
148 | ||
1da177e4 LT |
149 | /** |
150 | * list_del_init - deletes entry from list and reinitialize it. | |
151 | * @entry: the element to delete from the list. | |
152 | */ | |
153 | static inline void list_del_init(struct list_head *entry) | |
154 | { | |
3c18d4de | 155 | __list_del_entry(entry); |
1da177e4 LT |
156 | INIT_LIST_HEAD(entry); |
157 | } | |
158 | ||
159 | /** | |
160 | * list_move - delete from one list and add as another's head | |
161 | * @list: the entry to move | |
162 | * @head: the head that will precede our entry | |
163 | */ | |
164 | static inline void list_move(struct list_head *list, struct list_head *head) | |
165 | { | |
3c18d4de | 166 | __list_del_entry(list); |
78db2ad6 | 167 | list_add(list, head); |
1da177e4 LT |
168 | } |
169 | ||
170 | /** | |
171 | * list_move_tail - delete from one list and add as another's tail | |
172 | * @list: the entry to move | |
173 | * @head: the head that will follow our entry | |
174 | */ | |
175 | static inline void list_move_tail(struct list_head *list, | |
176 | struct list_head *head) | |
177 | { | |
3c18d4de | 178 | __list_del_entry(list); |
78db2ad6 | 179 | list_add_tail(list, head); |
1da177e4 LT |
180 | } |
181 | ||
e8f4d97e SN |
182 | /** |
183 | * list_is_last - tests whether @list is the last entry in list @head | |
184 | * @list: the entry to test | |
185 | * @head: the head of the list | |
186 | */ | |
187 | static inline int list_is_last(const struct list_head *list, | |
188 | const struct list_head *head) | |
189 | { | |
190 | return list->next == head; | |
191 | } | |
192 | ||
1da177e4 LT |
193 | /** |
194 | * list_empty - tests whether a list is empty | |
195 | * @head: the list to test. | |
196 | */ | |
197 | static inline int list_empty(const struct list_head *head) | |
198 | { | |
1658d35e | 199 | return READ_ONCE(head->next) == head; |
1da177e4 LT |
200 | } |
201 | ||
202 | /** | |
fe96e57d RD |
203 | * list_empty_careful - tests whether a list is empty and not being modified |
204 | * @head: the list to test | |
205 | * | |
206 | * Description: | |
207 | * tests whether a list is empty _and_ checks that no other CPU might be | |
208 | * in the process of modifying either member (next or prev) | |
1da177e4 LT |
209 | * |
210 | * NOTE: using list_empty_careful() without synchronization | |
211 | * can only be safe if the only activity that can happen | |
212 | * to the list entry is list_del_init(). Eg. it cannot be used | |
213 | * if another CPU could re-list_add() it. | |
1da177e4 LT |
214 | */ |
215 | static inline int list_empty_careful(const struct list_head *head) | |
216 | { | |
217 | struct list_head *next = head->next; | |
218 | return (next == head) && (next == head->prev); | |
99602572 MH |
219 | } |
220 | ||
5908cdc8 FW |
221 | /** |
222 | * list_rotate_left - rotate the list to the left | |
223 | * @head: the head of the list | |
224 | */ | |
225 | static inline void list_rotate_left(struct list_head *head) | |
226 | { | |
227 | struct list_head *first; | |
228 | ||
229 | if (!list_empty(head)) { | |
230 | first = head->next; | |
231 | list_move_tail(first, head); | |
232 | } | |
233 | } | |
234 | ||
99602572 MH |
235 | /** |
236 | * list_is_singular - tests whether a list has just one entry. | |
237 | * @head: the list to test. | |
238 | */ | |
239 | static inline int list_is_singular(const struct list_head *head) | |
240 | { | |
241 | return !list_empty(head) && (head->next == head->prev); | |
1da177e4 LT |
242 | } |
243 | ||
00e8a4da LR |
244 | static inline void __list_cut_position(struct list_head *list, |
245 | struct list_head *head, struct list_head *entry) | |
246 | { | |
247 | struct list_head *new_first = entry->next; | |
248 | list->next = head->next; | |
249 | list->next->prev = list; | |
250 | list->prev = entry; | |
251 | entry->next = list; | |
252 | head->next = new_first; | |
253 | new_first->prev = head; | |
254 | } | |
255 | ||
256 | /** | |
257 | * list_cut_position - cut a list into two | |
258 | * @list: a new list to add all removed entries | |
259 | * @head: a list with entries | |
260 | * @entry: an entry within head, could be the head itself | |
261 | * and if so we won't cut the list | |
262 | * | |
263 | * This helper moves the initial part of @head, up to and | |
264 | * including @entry, from @head to @list. You should | |
265 | * pass on @entry an element you know is on @head. @list | |
266 | * should be an empty list or a list you do not care about | |
267 | * losing its data. | |
268 | * | |
269 | */ | |
270 | static inline void list_cut_position(struct list_head *list, | |
271 | struct list_head *head, struct list_head *entry) | |
272 | { | |
273 | if (list_empty(head)) | |
274 | return; | |
275 | if (list_is_singular(head) && | |
276 | (head->next != entry && head != entry)) | |
277 | return; | |
278 | if (entry == head) | |
279 | INIT_LIST_HEAD(list); | |
280 | else | |
281 | __list_cut_position(list, head, entry); | |
282 | } | |
283 | ||
95d8c365 | 284 | static inline void __list_splice(const struct list_head *list, |
7d283aee LR |
285 | struct list_head *prev, |
286 | struct list_head *next) | |
1da177e4 LT |
287 | { |
288 | struct list_head *first = list->next; | |
289 | struct list_head *last = list->prev; | |
1da177e4 | 290 | |
7d283aee LR |
291 | first->prev = prev; |
292 | prev->next = first; | |
1da177e4 | 293 | |
7d283aee LR |
294 | last->next = next; |
295 | next->prev = last; | |
1da177e4 LT |
296 | } |
297 | ||
298 | /** | |
7d283aee | 299 | * list_splice - join two lists, this is designed for stacks |
1da177e4 LT |
300 | * @list: the new list to add. |
301 | * @head: the place to add it in the first list. | |
302 | */ | |
95d8c365 RD |
303 | static inline void list_splice(const struct list_head *list, |
304 | struct list_head *head) | |
1da177e4 LT |
305 | { |
306 | if (!list_empty(list)) | |
7d283aee LR |
307 | __list_splice(list, head, head->next); |
308 | } | |
309 | ||
310 | /** | |
311 | * list_splice_tail - join two lists, each list being a queue | |
312 | * @list: the new list to add. | |
313 | * @head: the place to add it in the first list. | |
314 | */ | |
315 | static inline void list_splice_tail(struct list_head *list, | |
316 | struct list_head *head) | |
317 | { | |
318 | if (!list_empty(list)) | |
319 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
320 | } |
321 | ||
322 | /** | |
323 | * list_splice_init - join two lists and reinitialise the emptied list. | |
324 | * @list: the new list to add. | |
325 | * @head: the place to add it in the first list. | |
326 | * | |
327 | * The list at @list is reinitialised | |
328 | */ | |
329 | static inline void list_splice_init(struct list_head *list, | |
330 | struct list_head *head) | |
331 | { | |
332 | if (!list_empty(list)) { | |
7d283aee LR |
333 | __list_splice(list, head, head->next); |
334 | INIT_LIST_HEAD(list); | |
335 | } | |
336 | } | |
337 | ||
338 | /** | |
6724cce8 | 339 | * list_splice_tail_init - join two lists and reinitialise the emptied list |
7d283aee LR |
340 | * @list: the new list to add. |
341 | * @head: the place to add it in the first list. | |
342 | * | |
6724cce8 | 343 | * Each of the lists is a queue. |
7d283aee LR |
344 | * The list at @list is reinitialised |
345 | */ | |
346 | static inline void list_splice_tail_init(struct list_head *list, | |
347 | struct list_head *head) | |
348 | { | |
349 | if (!list_empty(list)) { | |
350 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
351 | INIT_LIST_HEAD(list); |
352 | } | |
353 | } | |
354 | ||
355 | /** | |
356 | * list_entry - get the struct for this entry | |
357 | * @ptr: the &struct list_head pointer. | |
358 | * @type: the type of the struct this is embedded in. | |
3943f42c | 359 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
360 | */ |
361 | #define list_entry(ptr, type, member) \ | |
362 | container_of(ptr, type, member) | |
363 | ||
b5e61818 PE |
364 | /** |
365 | * list_first_entry - get the first element from a list | |
366 | * @ptr: the list head to take the element from. | |
367 | * @type: the type of the struct this is embedded in. | |
3943f42c | 368 | * @member: the name of the list_head within the struct. |
b5e61818 PE |
369 | * |
370 | * Note, that list is expected to be not empty. | |
371 | */ | |
372 | #define list_first_entry(ptr, type, member) \ | |
373 | list_entry((ptr)->next, type, member) | |
374 | ||
93be3c2e ON |
375 | /** |
376 | * list_last_entry - get the last element from a list | |
377 | * @ptr: the list head to take the element from. | |
378 | * @type: the type of the struct this is embedded in. | |
3943f42c | 379 | * @member: the name of the list_head within the struct. |
93be3c2e ON |
380 | * |
381 | * Note, that list is expected to be not empty. | |
382 | */ | |
383 | #define list_last_entry(ptr, type, member) \ | |
384 | list_entry((ptr)->prev, type, member) | |
385 | ||
6d7581e6 JP |
386 | /** |
387 | * list_first_entry_or_null - get the first element from a list | |
388 | * @ptr: the list head to take the element from. | |
389 | * @type: the type of the struct this is embedded in. | |
3943f42c | 390 | * @member: the name of the list_head within the struct. |
6d7581e6 JP |
391 | * |
392 | * Note that if the list is empty, it returns NULL. | |
393 | */ | |
12adfd88 CW |
394 | #define list_first_entry_or_null(ptr, type, member) ({ \ |
395 | struct list_head *head__ = (ptr); \ | |
396 | struct list_head *pos__ = READ_ONCE(head__->next); \ | |
397 | pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ | |
398 | }) | |
6d7581e6 | 399 | |
008208c6 ON |
400 | /** |
401 | * list_next_entry - get the next element in list | |
402 | * @pos: the type * to cursor | |
3943f42c | 403 | * @member: the name of the list_head within the struct. |
008208c6 ON |
404 | */ |
405 | #define list_next_entry(pos, member) \ | |
406 | list_entry((pos)->member.next, typeof(*(pos)), member) | |
407 | ||
408 | /** | |
409 | * list_prev_entry - get the prev element in list | |
410 | * @pos: the type * to cursor | |
3943f42c | 411 | * @member: the name of the list_head within the struct. |
008208c6 ON |
412 | */ |
413 | #define list_prev_entry(pos, member) \ | |
414 | list_entry((pos)->member.prev, typeof(*(pos)), member) | |
415 | ||
1da177e4 LT |
416 | /** |
417 | * list_for_each - iterate over a list | |
8e3a67a9 | 418 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
419 | * @head: the head for your list. |
420 | */ | |
421 | #define list_for_each(pos, head) \ | |
e66eed65 | 422 | for (pos = (head)->next; pos != (head); pos = pos->next) |
1da177e4 | 423 | |
1da177e4 LT |
424 | /** |
425 | * list_for_each_prev - iterate over a list backwards | |
8e3a67a9 | 426 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
427 | * @head: the head for your list. |
428 | */ | |
429 | #define list_for_each_prev(pos, head) \ | |
e66eed65 | 430 | for (pos = (head)->prev; pos != (head); pos = pos->prev) |
1da177e4 LT |
431 | |
432 | /** | |
fe96e57d | 433 | * list_for_each_safe - iterate over a list safe against removal of list entry |
8e3a67a9 | 434 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
435 | * @n: another &struct list_head to use as temporary storage |
436 | * @head: the head for your list. | |
437 | */ | |
438 | #define list_for_each_safe(pos, n, head) \ | |
439 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
440 | pos = n, n = pos->next) | |
441 | ||
37c42524 | 442 | /** |
8f731f7d | 443 | * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry |
37c42524 DL |
444 | * @pos: the &struct list_head to use as a loop cursor. |
445 | * @n: another &struct list_head to use as temporary storage | |
446 | * @head: the head for your list. | |
447 | */ | |
448 | #define list_for_each_prev_safe(pos, n, head) \ | |
449 | for (pos = (head)->prev, n = pos->prev; \ | |
e66eed65 | 450 | pos != (head); \ |
37c42524 DL |
451 | pos = n, n = pos->prev) |
452 | ||
1da177e4 LT |
453 | /** |
454 | * list_for_each_entry - iterate over list of given type | |
8e3a67a9 | 455 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 456 | * @head: the head for your list. |
3943f42c | 457 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
458 | */ |
459 | #define list_for_each_entry(pos, head, member) \ | |
93be3c2e | 460 | for (pos = list_first_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
461 | &pos->member != (head); \ |
462 | pos = list_next_entry(pos, member)) | |
1da177e4 LT |
463 | |
464 | /** | |
465 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
8e3a67a9 | 466 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 467 | * @head: the head for your list. |
3943f42c | 468 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
469 | */ |
470 | #define list_for_each_entry_reverse(pos, head, member) \ | |
93be3c2e | 471 | for (pos = list_last_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
472 | &pos->member != (head); \ |
473 | pos = list_prev_entry(pos, member)) | |
1da177e4 LT |
474 | |
475 | /** | |
72fd4a35 | 476 | * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() |
1da177e4 LT |
477 | * @pos: the type * to use as a start point |
478 | * @head: the head of the list | |
3943f42c | 479 | * @member: the name of the list_head within the struct. |
fe96e57d | 480 | * |
72fd4a35 | 481 | * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). |
1da177e4 LT |
482 | */ |
483 | #define list_prepare_entry(pos, head, member) \ | |
484 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
485 | ||
486 | /** | |
fe96e57d | 487 | * list_for_each_entry_continue - continue iteration over list of given type |
8e3a67a9 | 488 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 489 | * @head: the head for your list. |
3943f42c | 490 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
491 | * |
492 | * Continue to iterate over list of given type, continuing after | |
493 | * the current position. | |
1da177e4 LT |
494 | */ |
495 | #define list_for_each_entry_continue(pos, head, member) \ | |
8120e2e5 ON |
496 | for (pos = list_next_entry(pos, member); \ |
497 | &pos->member != (head); \ | |
498 | pos = list_next_entry(pos, member)) | |
1da177e4 | 499 | |
768f3591 PE |
500 | /** |
501 | * list_for_each_entry_continue_reverse - iterate backwards from the given point | |
502 | * @pos: the type * to use as a loop cursor. | |
503 | * @head: the head for your list. | |
3943f42c | 504 | * @member: the name of the list_head within the struct. |
768f3591 PE |
505 | * |
506 | * Start to iterate over list of given type backwards, continuing after | |
507 | * the current position. | |
508 | */ | |
509 | #define list_for_each_entry_continue_reverse(pos, head, member) \ | |
8120e2e5 ON |
510 | for (pos = list_prev_entry(pos, member); \ |
511 | &pos->member != (head); \ | |
512 | pos = list_prev_entry(pos, member)) | |
768f3591 | 513 | |
e229c2fb | 514 | /** |
fe96e57d | 515 | * list_for_each_entry_from - iterate over list of given type from the current point |
8e3a67a9 | 516 | * @pos: the type * to use as a loop cursor. |
e229c2fb | 517 | * @head: the head for your list. |
3943f42c | 518 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
519 | * |
520 | * Iterate over list of given type, continuing from current position. | |
e229c2fb ACM |
521 | */ |
522 | #define list_for_each_entry_from(pos, head, member) \ | |
8120e2e5 ON |
523 | for (; &pos->member != (head); \ |
524 | pos = list_next_entry(pos, member)) | |
e229c2fb | 525 | |
1da177e4 LT |
526 | /** |
527 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 | 528 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
529 | * @n: another type * to use as temporary storage |
530 | * @head: the head for your list. | |
3943f42c | 531 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
532 | */ |
533 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
93be3c2e | 534 | for (pos = list_first_entry(head, typeof(*pos), member), \ |
8120e2e5 | 535 | n = list_next_entry(pos, member); \ |
1da177e4 | 536 | &pos->member != (head); \ |
8120e2e5 | 537 | pos = n, n = list_next_entry(n, member)) |
1da177e4 | 538 | |
74459dc7 | 539 | /** |
9a86e2ba | 540 | * list_for_each_entry_safe_continue - continue list iteration safe against removal |
8e3a67a9 | 541 | * @pos: the type * to use as a loop cursor. |
74459dc7 ACM |
542 | * @n: another type * to use as temporary storage |
543 | * @head: the head for your list. | |
3943f42c | 544 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
545 | * |
546 | * Iterate over list of given type, continuing after current point, | |
547 | * safe against removal of list entry. | |
74459dc7 ACM |
548 | */ |
549 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8120e2e5 ON |
550 | for (pos = list_next_entry(pos, member), \ |
551 | n = list_next_entry(pos, member); \ | |
d8dcffee | 552 | &pos->member != (head); \ |
8120e2e5 | 553 | pos = n, n = list_next_entry(n, member)) |
d8dcffee ACM |
554 | |
555 | /** | |
9a86e2ba | 556 | * list_for_each_entry_safe_from - iterate over list from current point safe against removal |
8e3a67a9 | 557 | * @pos: the type * to use as a loop cursor. |
d8dcffee ACM |
558 | * @n: another type * to use as temporary storage |
559 | * @head: the head for your list. | |
3943f42c | 560 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
561 | * |
562 | * Iterate over list of given type from current point, safe against | |
563 | * removal of list entry. | |
d8dcffee ACM |
564 | */ |
565 | #define list_for_each_entry_safe_from(pos, n, head, member) \ | |
8120e2e5 | 566 | for (n = list_next_entry(pos, member); \ |
74459dc7 | 567 | &pos->member != (head); \ |
8120e2e5 | 568 | pos = n, n = list_next_entry(n, member)) |
74459dc7 | 569 | |
0ad42352 | 570 | /** |
9a86e2ba | 571 | * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal |
8e3a67a9 | 572 | * @pos: the type * to use as a loop cursor. |
0ad42352 DH |
573 | * @n: another type * to use as temporary storage |
574 | * @head: the head for your list. | |
3943f42c | 575 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
576 | * |
577 | * Iterate backwards over list of given type, safe against removal | |
578 | * of list entry. | |
0ad42352 DH |
579 | */ |
580 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
93be3c2e | 581 | for (pos = list_last_entry(head, typeof(*pos), member), \ |
8120e2e5 | 582 | n = list_prev_entry(pos, member); \ |
0ad42352 | 583 | &pos->member != (head); \ |
8120e2e5 | 584 | pos = n, n = list_prev_entry(n, member)) |
0ad42352 | 585 | |
57439f87 NP |
586 | /** |
587 | * list_safe_reset_next - reset a stale list_for_each_entry_safe loop | |
588 | * @pos: the loop cursor used in the list_for_each_entry_safe loop | |
589 | * @n: temporary storage used in list_for_each_entry_safe | |
3943f42c | 590 | * @member: the name of the list_head within the struct. |
57439f87 NP |
591 | * |
592 | * list_safe_reset_next is not safe to use in general if the list may be | |
593 | * modified concurrently (eg. the lock is dropped in the loop body). An | |
594 | * exception to this is if the cursor element (pos) is pinned in the list, | |
595 | * and list_safe_reset_next is called after re-taking the lock and before | |
596 | * completing the current iteration of the loop body. | |
597 | */ | |
598 | #define list_safe_reset_next(pos, n, member) \ | |
8120e2e5 | 599 | n = list_next_entry(pos, member) |
57439f87 | 600 | |
1da177e4 LT |
601 | /* |
602 | * Double linked lists with a single pointer list head. | |
603 | * Mostly useful for hash tables where the two pointer list head is | |
604 | * too wasteful. | |
605 | * You lose the ability to access the tail in O(1). | |
606 | */ | |
607 | ||
1da177e4 LT |
608 | #define HLIST_HEAD_INIT { .first = NULL } |
609 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
610 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
490d6ab1 ZB |
611 | static inline void INIT_HLIST_NODE(struct hlist_node *h) |
612 | { | |
613 | h->next = NULL; | |
614 | h->pprev = NULL; | |
615 | } | |
1da177e4 LT |
616 | |
617 | static inline int hlist_unhashed(const struct hlist_node *h) | |
618 | { | |
619 | return !h->pprev; | |
620 | } | |
621 | ||
622 | static inline int hlist_empty(const struct hlist_head *h) | |
623 | { | |
1658d35e | 624 | return !READ_ONCE(h->first); |
1da177e4 LT |
625 | } |
626 | ||
627 | static inline void __hlist_del(struct hlist_node *n) | |
628 | { | |
629 | struct hlist_node *next = n->next; | |
630 | struct hlist_node **pprev = n->pprev; | |
7f5f873c PM |
631 | |
632 | WRITE_ONCE(*pprev, next); | |
1da177e4 LT |
633 | if (next) |
634 | next->pprev = pprev; | |
635 | } | |
636 | ||
637 | static inline void hlist_del(struct hlist_node *n) | |
638 | { | |
639 | __hlist_del(n); | |
640 | n->next = LIST_POISON1; | |
641 | n->pprev = LIST_POISON2; | |
642 | } | |
643 | ||
1da177e4 LT |
644 | static inline void hlist_del_init(struct hlist_node *n) |
645 | { | |
da753bea | 646 | if (!hlist_unhashed(n)) { |
1da177e4 LT |
647 | __hlist_del(n); |
648 | INIT_HLIST_NODE(n); | |
649 | } | |
650 | } | |
651 | ||
652 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) | |
653 | { | |
654 | struct hlist_node *first = h->first; | |
655 | n->next = first; | |
656 | if (first) | |
657 | first->pprev = &n->next; | |
1c97be67 | 658 | WRITE_ONCE(h->first, n); |
1da177e4 LT |
659 | n->pprev = &h->first; |
660 | } | |
661 | ||
1da177e4 LT |
662 | /* next must be != NULL */ |
663 | static inline void hlist_add_before(struct hlist_node *n, | |
664 | struct hlist_node *next) | |
665 | { | |
666 | n->pprev = next->pprev; | |
667 | n->next = next; | |
668 | next->pprev = &n->next; | |
1c97be67 | 669 | WRITE_ONCE(*(n->pprev), n); |
1da177e4 LT |
670 | } |
671 | ||
1d023284 KH |
672 | static inline void hlist_add_behind(struct hlist_node *n, |
673 | struct hlist_node *prev) | |
1da177e4 | 674 | { |
bc18dd33 | 675 | n->next = prev->next; |
1c97be67 | 676 | WRITE_ONCE(prev->next, n); |
bc18dd33 | 677 | n->pprev = &prev->next; |
1da177e4 | 678 | |
bc18dd33 KH |
679 | if (n->next) |
680 | n->next->pprev = &n->next; | |
1da177e4 LT |
681 | } |
682 | ||
756acc2d AV |
683 | /* after that we'll appear to be on some hlist and hlist_del will work */ |
684 | static inline void hlist_add_fake(struct hlist_node *n) | |
685 | { | |
686 | n->pprev = &n->next; | |
687 | } | |
688 | ||
cbedaac6 JB |
689 | static inline bool hlist_fake(struct hlist_node *h) |
690 | { | |
691 | return h->pprev == &h->next; | |
692 | } | |
693 | ||
15dba1e3 TG |
694 | /* |
695 | * Check whether the node is the only node of the head without | |
696 | * accessing head: | |
697 | */ | |
698 | static inline bool | |
699 | hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) | |
700 | { | |
701 | return !n->next && n->pprev == &h->first; | |
702 | } | |
703 | ||
673d62cc VN |
704 | /* |
705 | * Move a list from one list head to another. Fixup the pprev | |
706 | * reference of the first entry if it exists. | |
707 | */ | |
708 | static inline void hlist_move_list(struct hlist_head *old, | |
709 | struct hlist_head *new) | |
710 | { | |
711 | new->first = old->first; | |
712 | if (new->first) | |
713 | new->first->pprev = &new->first; | |
714 | old->first = NULL; | |
715 | } | |
716 | ||
1da177e4 LT |
717 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
718 | ||
719 | #define hlist_for_each(pos, head) \ | |
75d65a42 | 720 | for (pos = (head)->first; pos ; pos = pos->next) |
1da177e4 LT |
721 | |
722 | #define hlist_for_each_safe(pos, n, head) \ | |
723 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
724 | pos = n) | |
725 | ||
b67bfe0d | 726 | #define hlist_entry_safe(ptr, type, member) \ |
f65846a1 PM |
727 | ({ typeof(ptr) ____ptr = (ptr); \ |
728 | ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ | |
729 | }) | |
b67bfe0d | 730 | |
1da177e4 LT |
731 | /** |
732 | * hlist_for_each_entry - iterate over list of given type | |
b67bfe0d | 733 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
734 | * @head: the head for your list. |
735 | * @member: the name of the hlist_node within the struct. | |
736 | */ | |
b67bfe0d SL |
737 | #define hlist_for_each_entry(pos, head, member) \ |
738 | for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ | |
739 | pos; \ | |
740 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
741 | |
742 | /** | |
fe96e57d | 743 | * hlist_for_each_entry_continue - iterate over a hlist continuing after current point |
b67bfe0d | 744 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
745 | * @member: the name of the hlist_node within the struct. |
746 | */ | |
b67bfe0d SL |
747 | #define hlist_for_each_entry_continue(pos, member) \ |
748 | for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ | |
749 | pos; \ | |
750 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
751 | |
752 | /** | |
fe96e57d | 753 | * hlist_for_each_entry_from - iterate over a hlist continuing from current point |
b67bfe0d | 754 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
755 | * @member: the name of the hlist_node within the struct. |
756 | */ | |
b67bfe0d SL |
757 | #define hlist_for_each_entry_from(pos, member) \ |
758 | for (; pos; \ | |
759 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
760 | |
761 | /** | |
762 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
b67bfe0d | 763 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
764 | * @n: another &struct hlist_node to use as temporary storage |
765 | * @head: the head for your list. | |
766 | * @member: the name of the hlist_node within the struct. | |
767 | */ | |
b67bfe0d SL |
768 | #define hlist_for_each_entry_safe(pos, n, head, member) \ |
769 | for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ | |
770 | pos && ({ n = pos->member.next; 1; }); \ | |
771 | pos = hlist_entry_safe(n, typeof(*pos), member)) | |
1da177e4 | 772 | |
1da177e4 | 773 | #endif |