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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); | |
0cd340dc | 35 | extern bool __list_del_entry_valid(struct list_head *entry); |
d7c81673 KC |
36 | #else |
37 | static inline bool __list_add_valid(struct list_head *new, | |
38 | struct list_head *prev, | |
39 | struct list_head *next) | |
40 | { | |
41 | return true; | |
42 | } | |
0cd340dc KC |
43 | static inline bool __list_del_entry_valid(struct list_head *entry) |
44 | { | |
45 | return true; | |
46 | } | |
d7c81673 KC |
47 | #endif |
48 | ||
1da177e4 LT |
49 | /* |
50 | * Insert a new entry between two known consecutive entries. | |
51 | * | |
52 | * This is only for internal list manipulation where we know | |
53 | * the prev/next entries already! | |
54 | */ | |
55 | static inline void __list_add(struct list_head *new, | |
56 | struct list_head *prev, | |
57 | struct list_head *next) | |
58 | { | |
d7c81673 KC |
59 | if (!__list_add_valid(new, prev, next)) |
60 | return; | |
61 | ||
1da177e4 LT |
62 | next->prev = new; |
63 | new->next = next; | |
64 | new->prev = prev; | |
1c97be67 | 65 | WRITE_ONCE(prev->next, new); |
1da177e4 LT |
66 | } |
67 | ||
68 | /** | |
69 | * list_add - add a new entry | |
70 | * @new: new entry to be added | |
71 | * @head: list head to add it after | |
72 | * | |
73 | * Insert a new entry after the specified head. | |
74 | * This is good for implementing stacks. | |
75 | */ | |
76 | static inline void list_add(struct list_head *new, struct list_head *head) | |
77 | { | |
78 | __list_add(new, head, head->next); | |
79 | } | |
199a9afc | 80 | |
1da177e4 LT |
81 | |
82 | /** | |
83 | * list_add_tail - add a new entry | |
84 | * @new: new entry to be added | |
85 | * @head: list head to add it before | |
86 | * | |
87 | * Insert a new entry before the specified head. | |
88 | * This is useful for implementing queues. | |
89 | */ | |
90 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
91 | { | |
92 | __list_add(new, head->prev, head); | |
93 | } | |
94 | ||
1da177e4 LT |
95 | /* |
96 | * Delete a list entry by making the prev/next entries | |
97 | * point to each other. | |
98 | * | |
99 | * This is only for internal list manipulation where we know | |
100 | * the prev/next entries already! | |
101 | */ | |
102 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
103 | { | |
104 | next->prev = prev; | |
7f5f873c | 105 | WRITE_ONCE(prev->next, next); |
1da177e4 LT |
106 | } |
107 | ||
108 | /** | |
109 | * list_del - deletes entry from list. | |
110 | * @entry: the element to delete from the list. | |
72fd4a35 | 111 | * Note: list_empty() on entry does not return true after this, the entry is |
1da177e4 LT |
112 | * in an undefined state. |
113 | */ | |
3c18d4de LT |
114 | static inline void __list_del_entry(struct list_head *entry) |
115 | { | |
0cd340dc KC |
116 | if (!__list_del_entry_valid(entry)) |
117 | return; | |
118 | ||
3c18d4de LT |
119 | __list_del(entry->prev, entry->next); |
120 | } | |
121 | ||
1da177e4 LT |
122 | static inline void list_del(struct list_head *entry) |
123 | { | |
0cd340dc | 124 | __list_del_entry(entry); |
1da177e4 LT |
125 | entry->next = LIST_POISON1; |
126 | entry->prev = LIST_POISON2; | |
127 | } | |
128 | ||
54e73770 ON |
129 | /** |
130 | * list_replace - replace old entry by new one | |
131 | * @old : the element to be replaced | |
132 | * @new : the new element to insert | |
72fd4a35 RD |
133 | * |
134 | * If @old was empty, it will be overwritten. | |
54e73770 ON |
135 | */ |
136 | static inline void list_replace(struct list_head *old, | |
137 | struct list_head *new) | |
138 | { | |
139 | new->next = old->next; | |
140 | new->next->prev = new; | |
141 | new->prev = old->prev; | |
142 | new->prev->next = new; | |
143 | } | |
144 | ||
145 | static inline void list_replace_init(struct list_head *old, | |
146 | struct list_head *new) | |
147 | { | |
148 | list_replace(old, new); | |
149 | INIT_LIST_HEAD(old); | |
150 | } | |
151 | ||
1da177e4 LT |
152 | /** |
153 | * list_del_init - deletes entry from list and reinitialize it. | |
154 | * @entry: the element to delete from the list. | |
155 | */ | |
156 | static inline void list_del_init(struct list_head *entry) | |
157 | { | |
3c18d4de | 158 | __list_del_entry(entry); |
1da177e4 LT |
159 | INIT_LIST_HEAD(entry); |
160 | } | |
161 | ||
162 | /** | |
163 | * list_move - delete from one list and add as another's head | |
164 | * @list: the entry to move | |
165 | * @head: the head that will precede our entry | |
166 | */ | |
167 | static inline void list_move(struct list_head *list, struct list_head *head) | |
168 | { | |
3c18d4de | 169 | __list_del_entry(list); |
78db2ad6 | 170 | list_add(list, head); |
1da177e4 LT |
171 | } |
172 | ||
173 | /** | |
174 | * list_move_tail - delete from one list and add as another's tail | |
175 | * @list: the entry to move | |
176 | * @head: the head that will follow our entry | |
177 | */ | |
178 | static inline void list_move_tail(struct list_head *list, | |
179 | struct list_head *head) | |
180 | { | |
3c18d4de | 181 | __list_del_entry(list); |
78db2ad6 | 182 | list_add_tail(list, head); |
1da177e4 LT |
183 | } |
184 | ||
e8f4d97e SN |
185 | /** |
186 | * list_is_last - tests whether @list is the last entry in list @head | |
187 | * @list: the entry to test | |
188 | * @head: the head of the list | |
189 | */ | |
190 | static inline int list_is_last(const struct list_head *list, | |
191 | const struct list_head *head) | |
192 | { | |
193 | return list->next == head; | |
194 | } | |
195 | ||
1da177e4 LT |
196 | /** |
197 | * list_empty - tests whether a list is empty | |
198 | * @head: the list to test. | |
199 | */ | |
200 | static inline int list_empty(const struct list_head *head) | |
201 | { | |
1658d35e | 202 | return READ_ONCE(head->next) == head; |
1da177e4 LT |
203 | } |
204 | ||
205 | /** | |
fe96e57d RD |
206 | * list_empty_careful - tests whether a list is empty and not being modified |
207 | * @head: the list to test | |
208 | * | |
209 | * Description: | |
210 | * tests whether a list is empty _and_ checks that no other CPU might be | |
211 | * in the process of modifying either member (next or prev) | |
1da177e4 LT |
212 | * |
213 | * NOTE: using list_empty_careful() without synchronization | |
214 | * can only be safe if the only activity that can happen | |
215 | * to the list entry is list_del_init(). Eg. it cannot be used | |
216 | * if another CPU could re-list_add() it. | |
1da177e4 LT |
217 | */ |
218 | static inline int list_empty_careful(const struct list_head *head) | |
219 | { | |
220 | struct list_head *next = head->next; | |
221 | return (next == head) && (next == head->prev); | |
99602572 MH |
222 | } |
223 | ||
5908cdc8 FW |
224 | /** |
225 | * list_rotate_left - rotate the list to the left | |
226 | * @head: the head of the list | |
227 | */ | |
228 | static inline void list_rotate_left(struct list_head *head) | |
229 | { | |
230 | struct list_head *first; | |
231 | ||
232 | if (!list_empty(head)) { | |
233 | first = head->next; | |
234 | list_move_tail(first, head); | |
235 | } | |
236 | } | |
237 | ||
99602572 MH |
238 | /** |
239 | * list_is_singular - tests whether a list has just one entry. | |
240 | * @head: the list to test. | |
241 | */ | |
242 | static inline int list_is_singular(const struct list_head *head) | |
243 | { | |
244 | return !list_empty(head) && (head->next == head->prev); | |
1da177e4 LT |
245 | } |
246 | ||
00e8a4da LR |
247 | static inline void __list_cut_position(struct list_head *list, |
248 | struct list_head *head, struct list_head *entry) | |
249 | { | |
250 | struct list_head *new_first = entry->next; | |
251 | list->next = head->next; | |
252 | list->next->prev = list; | |
253 | list->prev = entry; | |
254 | entry->next = list; | |
255 | head->next = new_first; | |
256 | new_first->prev = head; | |
257 | } | |
258 | ||
259 | /** | |
260 | * list_cut_position - cut a list into two | |
261 | * @list: a new list to add all removed entries | |
262 | * @head: a list with entries | |
263 | * @entry: an entry within head, could be the head itself | |
264 | * and if so we won't cut the list | |
265 | * | |
266 | * This helper moves the initial part of @head, up to and | |
267 | * including @entry, from @head to @list. You should | |
268 | * pass on @entry an element you know is on @head. @list | |
269 | * should be an empty list or a list you do not care about | |
270 | * losing its data. | |
271 | * | |
272 | */ | |
273 | static inline void list_cut_position(struct list_head *list, | |
274 | struct list_head *head, struct list_head *entry) | |
275 | { | |
276 | if (list_empty(head)) | |
277 | return; | |
278 | if (list_is_singular(head) && | |
279 | (head->next != entry && head != entry)) | |
280 | return; | |
281 | if (entry == head) | |
282 | INIT_LIST_HEAD(list); | |
283 | else | |
284 | __list_cut_position(list, head, entry); | |
285 | } | |
286 | ||
95d8c365 | 287 | static inline void __list_splice(const struct list_head *list, |
7d283aee LR |
288 | struct list_head *prev, |
289 | struct list_head *next) | |
1da177e4 LT |
290 | { |
291 | struct list_head *first = list->next; | |
292 | struct list_head *last = list->prev; | |
1da177e4 | 293 | |
7d283aee LR |
294 | first->prev = prev; |
295 | prev->next = first; | |
1da177e4 | 296 | |
7d283aee LR |
297 | last->next = next; |
298 | next->prev = last; | |
1da177e4 LT |
299 | } |
300 | ||
301 | /** | |
7d283aee | 302 | * list_splice - join two lists, this is designed for stacks |
1da177e4 LT |
303 | * @list: the new list to add. |
304 | * @head: the place to add it in the first list. | |
305 | */ | |
95d8c365 RD |
306 | static inline void list_splice(const struct list_head *list, |
307 | struct list_head *head) | |
1da177e4 LT |
308 | { |
309 | if (!list_empty(list)) | |
7d283aee LR |
310 | __list_splice(list, head, head->next); |
311 | } | |
312 | ||
313 | /** | |
314 | * list_splice_tail - join two lists, each list being a queue | |
315 | * @list: the new list to add. | |
316 | * @head: the place to add it in the first list. | |
317 | */ | |
318 | static inline void list_splice_tail(struct list_head *list, | |
319 | struct list_head *head) | |
320 | { | |
321 | if (!list_empty(list)) | |
322 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
323 | } |
324 | ||
325 | /** | |
326 | * list_splice_init - join two lists and reinitialise the emptied list. | |
327 | * @list: the new list to add. | |
328 | * @head: the place to add it in the first list. | |
329 | * | |
330 | * The list at @list is reinitialised | |
331 | */ | |
332 | static inline void list_splice_init(struct list_head *list, | |
333 | struct list_head *head) | |
334 | { | |
335 | if (!list_empty(list)) { | |
7d283aee LR |
336 | __list_splice(list, head, head->next); |
337 | INIT_LIST_HEAD(list); | |
338 | } | |
339 | } | |
340 | ||
341 | /** | |
6724cce8 | 342 | * list_splice_tail_init - join two lists and reinitialise the emptied list |
7d283aee LR |
343 | * @list: the new list to add. |
344 | * @head: the place to add it in the first list. | |
345 | * | |
6724cce8 | 346 | * Each of the lists is a queue. |
7d283aee LR |
347 | * The list at @list is reinitialised |
348 | */ | |
349 | static inline void list_splice_tail_init(struct list_head *list, | |
350 | struct list_head *head) | |
351 | { | |
352 | if (!list_empty(list)) { | |
353 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
354 | INIT_LIST_HEAD(list); |
355 | } | |
356 | } | |
357 | ||
358 | /** | |
359 | * list_entry - get the struct for this entry | |
360 | * @ptr: the &struct list_head pointer. | |
361 | * @type: the type of the struct this is embedded in. | |
3943f42c | 362 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
363 | */ |
364 | #define list_entry(ptr, type, member) \ | |
365 | container_of(ptr, type, member) | |
366 | ||
b5e61818 PE |
367 | /** |
368 | * list_first_entry - get the first element from a list | |
369 | * @ptr: the list head to take the element from. | |
370 | * @type: the type of the struct this is embedded in. | |
3943f42c | 371 | * @member: the name of the list_head within the struct. |
b5e61818 PE |
372 | * |
373 | * Note, that list is expected to be not empty. | |
374 | */ | |
375 | #define list_first_entry(ptr, type, member) \ | |
376 | list_entry((ptr)->next, type, member) | |
377 | ||
93be3c2e ON |
378 | /** |
379 | * list_last_entry - get the last element from a list | |
380 | * @ptr: the list head to take the element from. | |
381 | * @type: the type of the struct this is embedded in. | |
3943f42c | 382 | * @member: the name of the list_head within the struct. |
93be3c2e ON |
383 | * |
384 | * Note, that list is expected to be not empty. | |
385 | */ | |
386 | #define list_last_entry(ptr, type, member) \ | |
387 | list_entry((ptr)->prev, type, member) | |
388 | ||
6d7581e6 JP |
389 | /** |
390 | * list_first_entry_or_null - get the first element from a list | |
391 | * @ptr: the list head to take the element from. | |
392 | * @type: the type of the struct this is embedded in. | |
3943f42c | 393 | * @member: the name of the list_head within the struct. |
6d7581e6 JP |
394 | * |
395 | * Note that if the list is empty, it returns NULL. | |
396 | */ | |
12adfd88 CW |
397 | #define list_first_entry_or_null(ptr, type, member) ({ \ |
398 | struct list_head *head__ = (ptr); \ | |
399 | struct list_head *pos__ = READ_ONCE(head__->next); \ | |
400 | pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ | |
401 | }) | |
6d7581e6 | 402 | |
008208c6 ON |
403 | /** |
404 | * list_next_entry - get the next element in list | |
405 | * @pos: the type * to cursor | |
3943f42c | 406 | * @member: the name of the list_head within the struct. |
008208c6 ON |
407 | */ |
408 | #define list_next_entry(pos, member) \ | |
409 | list_entry((pos)->member.next, typeof(*(pos)), member) | |
410 | ||
411 | /** | |
412 | * list_prev_entry - get the prev element in list | |
413 | * @pos: the type * to cursor | |
3943f42c | 414 | * @member: the name of the list_head within the struct. |
008208c6 ON |
415 | */ |
416 | #define list_prev_entry(pos, member) \ | |
417 | list_entry((pos)->member.prev, typeof(*(pos)), member) | |
418 | ||
1da177e4 LT |
419 | /** |
420 | * list_for_each - iterate over a list | |
8e3a67a9 | 421 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
422 | * @head: the head for your list. |
423 | */ | |
424 | #define list_for_each(pos, head) \ | |
e66eed65 | 425 | for (pos = (head)->next; pos != (head); pos = pos->next) |
1da177e4 | 426 | |
1da177e4 LT |
427 | /** |
428 | * list_for_each_prev - iterate over a list backwards | |
8e3a67a9 | 429 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
430 | * @head: the head for your list. |
431 | */ | |
432 | #define list_for_each_prev(pos, head) \ | |
e66eed65 | 433 | for (pos = (head)->prev; pos != (head); pos = pos->prev) |
1da177e4 LT |
434 | |
435 | /** | |
fe96e57d | 436 | * list_for_each_safe - iterate over a list safe against removal of list entry |
8e3a67a9 | 437 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
438 | * @n: another &struct list_head to use as temporary storage |
439 | * @head: the head for your list. | |
440 | */ | |
441 | #define list_for_each_safe(pos, n, head) \ | |
442 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
443 | pos = n, n = pos->next) | |
444 | ||
37c42524 | 445 | /** |
8f731f7d | 446 | * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry |
37c42524 DL |
447 | * @pos: the &struct list_head to use as a loop cursor. |
448 | * @n: another &struct list_head to use as temporary storage | |
449 | * @head: the head for your list. | |
450 | */ | |
451 | #define list_for_each_prev_safe(pos, n, head) \ | |
452 | for (pos = (head)->prev, n = pos->prev; \ | |
e66eed65 | 453 | pos != (head); \ |
37c42524 DL |
454 | pos = n, n = pos->prev) |
455 | ||
1da177e4 LT |
456 | /** |
457 | * list_for_each_entry - iterate over list of given type | |
8e3a67a9 | 458 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 459 | * @head: the head for your list. |
3943f42c | 460 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
461 | */ |
462 | #define list_for_each_entry(pos, head, member) \ | |
93be3c2e | 463 | for (pos = list_first_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
464 | &pos->member != (head); \ |
465 | pos = list_next_entry(pos, member)) | |
1da177e4 LT |
466 | |
467 | /** | |
468 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
8e3a67a9 | 469 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 470 | * @head: the head for your list. |
3943f42c | 471 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
472 | */ |
473 | #define list_for_each_entry_reverse(pos, head, member) \ | |
93be3c2e | 474 | for (pos = list_last_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
475 | &pos->member != (head); \ |
476 | pos = list_prev_entry(pos, member)) | |
1da177e4 LT |
477 | |
478 | /** | |
72fd4a35 | 479 | * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() |
1da177e4 LT |
480 | * @pos: the type * to use as a start point |
481 | * @head: the head of the list | |
3943f42c | 482 | * @member: the name of the list_head within the struct. |
fe96e57d | 483 | * |
72fd4a35 | 484 | * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). |
1da177e4 LT |
485 | */ |
486 | #define list_prepare_entry(pos, head, member) \ | |
487 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
488 | ||
489 | /** | |
fe96e57d | 490 | * list_for_each_entry_continue - continue iteration over list of given type |
8e3a67a9 | 491 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 492 | * @head: the head for your list. |
3943f42c | 493 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
494 | * |
495 | * Continue to iterate over list of given type, continuing after | |
496 | * the current position. | |
1da177e4 LT |
497 | */ |
498 | #define list_for_each_entry_continue(pos, head, member) \ | |
8120e2e5 ON |
499 | for (pos = list_next_entry(pos, member); \ |
500 | &pos->member != (head); \ | |
501 | pos = list_next_entry(pos, member)) | |
1da177e4 | 502 | |
768f3591 PE |
503 | /** |
504 | * list_for_each_entry_continue_reverse - iterate backwards from the given point | |
505 | * @pos: the type * to use as a loop cursor. | |
506 | * @head: the head for your list. | |
3943f42c | 507 | * @member: the name of the list_head within the struct. |
768f3591 PE |
508 | * |
509 | * Start to iterate over list of given type backwards, continuing after | |
510 | * the current position. | |
511 | */ | |
512 | #define list_for_each_entry_continue_reverse(pos, head, member) \ | |
8120e2e5 ON |
513 | for (pos = list_prev_entry(pos, member); \ |
514 | &pos->member != (head); \ | |
515 | pos = list_prev_entry(pos, member)) | |
768f3591 | 516 | |
e229c2fb | 517 | /** |
fe96e57d | 518 | * list_for_each_entry_from - iterate over list of given type from the current point |
8e3a67a9 | 519 | * @pos: the type * to use as a loop cursor. |
e229c2fb | 520 | * @head: the head for your list. |
3943f42c | 521 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
522 | * |
523 | * Iterate over list of given type, continuing from current position. | |
e229c2fb ACM |
524 | */ |
525 | #define list_for_each_entry_from(pos, head, member) \ | |
8120e2e5 ON |
526 | for (; &pos->member != (head); \ |
527 | pos = list_next_entry(pos, member)) | |
e229c2fb | 528 | |
b862815c JP |
529 | /** |
530 | * list_for_each_entry_from_reverse - iterate backwards over list of given type | |
531 | * from the current point | |
532 | * @pos: the type * to use as a loop cursor. | |
533 | * @head: the head for your list. | |
534 | * @member: the name of the list_head within the struct. | |
535 | * | |
536 | * Iterate backwards over list of given type, continuing from current position. | |
537 | */ | |
538 | #define list_for_each_entry_from_reverse(pos, head, member) \ | |
539 | for (; &pos->member != (head); \ | |
540 | pos = list_prev_entry(pos, member)) | |
541 | ||
1da177e4 LT |
542 | /** |
543 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 | 544 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
545 | * @n: another type * to use as temporary storage |
546 | * @head: the head for your list. | |
3943f42c | 547 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
548 | */ |
549 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
93be3c2e | 550 | for (pos = list_first_entry(head, typeof(*pos), member), \ |
8120e2e5 | 551 | n = list_next_entry(pos, member); \ |
1da177e4 | 552 | &pos->member != (head); \ |
8120e2e5 | 553 | pos = n, n = list_next_entry(n, member)) |
1da177e4 | 554 | |
74459dc7 | 555 | /** |
9a86e2ba | 556 | * list_for_each_entry_safe_continue - continue list iteration safe against removal |
8e3a67a9 | 557 | * @pos: the type * to use as a loop cursor. |
74459dc7 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, continuing after current point, | |
563 | * safe against removal of list entry. | |
74459dc7 ACM |
564 | */ |
565 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8120e2e5 ON |
566 | for (pos = list_next_entry(pos, member), \ |
567 | n = list_next_entry(pos, member); \ | |
d8dcffee | 568 | &pos->member != (head); \ |
8120e2e5 | 569 | pos = n, n = list_next_entry(n, member)) |
d8dcffee ACM |
570 | |
571 | /** | |
9a86e2ba | 572 | * list_for_each_entry_safe_from - iterate over list from current point safe against removal |
8e3a67a9 | 573 | * @pos: the type * to use as a loop cursor. |
d8dcffee ACM |
574 | * @n: another type * to use as temporary storage |
575 | * @head: the head for your list. | |
3943f42c | 576 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
577 | * |
578 | * Iterate over list of given type from current point, safe against | |
579 | * removal of list entry. | |
d8dcffee ACM |
580 | */ |
581 | #define list_for_each_entry_safe_from(pos, n, head, member) \ | |
8120e2e5 | 582 | for (n = list_next_entry(pos, member); \ |
74459dc7 | 583 | &pos->member != (head); \ |
8120e2e5 | 584 | pos = n, n = list_next_entry(n, member)) |
74459dc7 | 585 | |
0ad42352 | 586 | /** |
9a86e2ba | 587 | * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal |
8e3a67a9 | 588 | * @pos: the type * to use as a loop cursor. |
0ad42352 DH |
589 | * @n: another type * to use as temporary storage |
590 | * @head: the head for your list. | |
3943f42c | 591 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
592 | * |
593 | * Iterate backwards over list of given type, safe against removal | |
594 | * of list entry. | |
0ad42352 DH |
595 | */ |
596 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
93be3c2e | 597 | for (pos = list_last_entry(head, typeof(*pos), member), \ |
8120e2e5 | 598 | n = list_prev_entry(pos, member); \ |
0ad42352 | 599 | &pos->member != (head); \ |
8120e2e5 | 600 | pos = n, n = list_prev_entry(n, member)) |
0ad42352 | 601 | |
57439f87 | 602 | /** |
603 | * list_safe_reset_next - reset a stale list_for_each_entry_safe loop | |
604 | * @pos: the loop cursor used in the list_for_each_entry_safe loop | |
605 | * @n: temporary storage used in list_for_each_entry_safe | |
3943f42c | 606 | * @member: the name of the list_head within the struct. |
57439f87 | 607 | * |
608 | * list_safe_reset_next is not safe to use in general if the list may be | |
609 | * modified concurrently (eg. the lock is dropped in the loop body). An | |
610 | * exception to this is if the cursor element (pos) is pinned in the list, | |
611 | * and list_safe_reset_next is called after re-taking the lock and before | |
612 | * completing the current iteration of the loop body. | |
613 | */ | |
614 | #define list_safe_reset_next(pos, n, member) \ | |
8120e2e5 | 615 | n = list_next_entry(pos, member) |
57439f87 | 616 | |
1da177e4 LT |
617 | /* |
618 | * Double linked lists with a single pointer list head. | |
619 | * Mostly useful for hash tables where the two pointer list head is | |
620 | * too wasteful. | |
621 | * You lose the ability to access the tail in O(1). | |
622 | */ | |
623 | ||
1da177e4 LT |
624 | #define HLIST_HEAD_INIT { .first = NULL } |
625 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
626 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
490d6ab1 ZB |
627 | static inline void INIT_HLIST_NODE(struct hlist_node *h) |
628 | { | |
629 | h->next = NULL; | |
630 | h->pprev = NULL; | |
631 | } | |
1da177e4 LT |
632 | |
633 | static inline int hlist_unhashed(const struct hlist_node *h) | |
634 | { | |
635 | return !h->pprev; | |
636 | } | |
637 | ||
638 | static inline int hlist_empty(const struct hlist_head *h) | |
639 | { | |
1658d35e | 640 | return !READ_ONCE(h->first); |
1da177e4 LT |
641 | } |
642 | ||
643 | static inline void __hlist_del(struct hlist_node *n) | |
644 | { | |
645 | struct hlist_node *next = n->next; | |
646 | struct hlist_node **pprev = n->pprev; | |
7f5f873c PM |
647 | |
648 | WRITE_ONCE(*pprev, next); | |
1da177e4 LT |
649 | if (next) |
650 | next->pprev = pprev; | |
651 | } | |
652 | ||
653 | static inline void hlist_del(struct hlist_node *n) | |
654 | { | |
655 | __hlist_del(n); | |
656 | n->next = LIST_POISON1; | |
657 | n->pprev = LIST_POISON2; | |
658 | } | |
659 | ||
1da177e4 LT |
660 | static inline void hlist_del_init(struct hlist_node *n) |
661 | { | |
da753bea | 662 | if (!hlist_unhashed(n)) { |
1da177e4 LT |
663 | __hlist_del(n); |
664 | INIT_HLIST_NODE(n); | |
665 | } | |
666 | } | |
667 | ||
668 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) | |
669 | { | |
670 | struct hlist_node *first = h->first; | |
671 | n->next = first; | |
672 | if (first) | |
673 | first->pprev = &n->next; | |
1c97be67 | 674 | WRITE_ONCE(h->first, n); |
1da177e4 LT |
675 | n->pprev = &h->first; |
676 | } | |
677 | ||
1da177e4 LT |
678 | /* next must be != NULL */ |
679 | static inline void hlist_add_before(struct hlist_node *n, | |
680 | struct hlist_node *next) | |
681 | { | |
682 | n->pprev = next->pprev; | |
683 | n->next = next; | |
684 | next->pprev = &n->next; | |
1c97be67 | 685 | WRITE_ONCE(*(n->pprev), n); |
1da177e4 LT |
686 | } |
687 | ||
1d023284 KH |
688 | static inline void hlist_add_behind(struct hlist_node *n, |
689 | struct hlist_node *prev) | |
1da177e4 | 690 | { |
bc18dd33 | 691 | n->next = prev->next; |
1c97be67 | 692 | WRITE_ONCE(prev->next, n); |
bc18dd33 | 693 | n->pprev = &prev->next; |
1da177e4 | 694 | |
bc18dd33 KH |
695 | if (n->next) |
696 | n->next->pprev = &n->next; | |
1da177e4 LT |
697 | } |
698 | ||
756acc2d AV |
699 | /* after that we'll appear to be on some hlist and hlist_del will work */ |
700 | static inline void hlist_add_fake(struct hlist_node *n) | |
701 | { | |
702 | n->pprev = &n->next; | |
703 | } | |
704 | ||
cbedaac6 JB |
705 | static inline bool hlist_fake(struct hlist_node *h) |
706 | { | |
707 | return h->pprev == &h->next; | |
708 | } | |
709 | ||
15dba1e3 TG |
710 | /* |
711 | * Check whether the node is the only node of the head without | |
712 | * accessing head: | |
713 | */ | |
714 | static inline bool | |
715 | hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) | |
716 | { | |
717 | return !n->next && n->pprev == &h->first; | |
718 | } | |
719 | ||
673d62cc VN |
720 | /* |
721 | * Move a list from one list head to another. Fixup the pprev | |
722 | * reference of the first entry if it exists. | |
723 | */ | |
724 | static inline void hlist_move_list(struct hlist_head *old, | |
725 | struct hlist_head *new) | |
726 | { | |
727 | new->first = old->first; | |
728 | if (new->first) | |
729 | new->first->pprev = &new->first; | |
730 | old->first = NULL; | |
731 | } | |
732 | ||
1da177e4 LT |
733 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
734 | ||
735 | #define hlist_for_each(pos, head) \ | |
75d65a42 | 736 | for (pos = (head)->first; pos ; pos = pos->next) |
1da177e4 LT |
737 | |
738 | #define hlist_for_each_safe(pos, n, head) \ | |
739 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
740 | pos = n) | |
741 | ||
b67bfe0d | 742 | #define hlist_entry_safe(ptr, type, member) \ |
f65846a1 PM |
743 | ({ typeof(ptr) ____ptr = (ptr); \ |
744 | ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ | |
745 | }) | |
b67bfe0d | 746 | |
1da177e4 LT |
747 | /** |
748 | * hlist_for_each_entry - iterate over list of given type | |
b67bfe0d | 749 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
750 | * @head: the head for your list. |
751 | * @member: the name of the hlist_node within the struct. | |
752 | */ | |
b67bfe0d SL |
753 | #define hlist_for_each_entry(pos, head, member) \ |
754 | for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ | |
755 | pos; \ | |
756 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
757 | |
758 | /** | |
fe96e57d | 759 | * hlist_for_each_entry_continue - iterate over a hlist continuing after current point |
b67bfe0d | 760 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
761 | * @member: the name of the hlist_node within the struct. |
762 | */ | |
b67bfe0d SL |
763 | #define hlist_for_each_entry_continue(pos, member) \ |
764 | for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ | |
765 | pos; \ | |
766 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
767 | |
768 | /** | |
fe96e57d | 769 | * hlist_for_each_entry_from - iterate over a hlist continuing from current point |
b67bfe0d | 770 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
771 | * @member: the name of the hlist_node within the struct. |
772 | */ | |
b67bfe0d SL |
773 | #define hlist_for_each_entry_from(pos, member) \ |
774 | for (; pos; \ | |
775 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
776 | |
777 | /** | |
778 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
b67bfe0d | 779 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
780 | * @n: another &struct hlist_node to use as temporary storage |
781 | * @head: the head for your list. | |
782 | * @member: the name of the hlist_node within the struct. | |
783 | */ | |
b67bfe0d SL |
784 | #define hlist_for_each_entry_safe(pos, n, head, member) \ |
785 | for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ | |
786 | pos && ({ n = pos->member.next; 1; }); \ | |
787 | pos = hlist_entry_safe(n, typeof(*pos), member)) | |
1da177e4 | 788 | |
1da177e4 | 789 | #endif |