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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 LT |
30 | |
31 | /* | |
32 | * Insert a new entry between two known consecutive entries. | |
33 | * | |
34 | * This is only for internal list manipulation where we know | |
35 | * the prev/next entries already! | |
36 | */ | |
199a9afc | 37 | #ifndef CONFIG_DEBUG_LIST |
1da177e4 LT |
38 | static inline void __list_add(struct list_head *new, |
39 | struct list_head *prev, | |
40 | struct list_head *next) | |
41 | { | |
42 | next->prev = new; | |
43 | new->next = next; | |
44 | new->prev = prev; | |
1c97be67 | 45 | WRITE_ONCE(prev->next, new); |
1da177e4 | 46 | } |
199a9afc DJ |
47 | #else |
48 | extern void __list_add(struct list_head *new, | |
49 | struct list_head *prev, | |
50 | struct list_head *next); | |
51 | #endif | |
1da177e4 LT |
52 | |
53 | /** | |
54 | * list_add - add a new entry | |
55 | * @new: new entry to be added | |
56 | * @head: list head to add it after | |
57 | * | |
58 | * Insert a new entry after the specified head. | |
59 | * This is good for implementing stacks. | |
60 | */ | |
61 | static inline void list_add(struct list_head *new, struct list_head *head) | |
62 | { | |
63 | __list_add(new, head, head->next); | |
64 | } | |
199a9afc | 65 | |
1da177e4 LT |
66 | |
67 | /** | |
68 | * list_add_tail - add a new entry | |
69 | * @new: new entry to be added | |
70 | * @head: list head to add it before | |
71 | * | |
72 | * Insert a new entry before the specified head. | |
73 | * This is useful for implementing queues. | |
74 | */ | |
75 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
76 | { | |
77 | __list_add(new, head->prev, head); | |
78 | } | |
79 | ||
1da177e4 LT |
80 | /* |
81 | * Delete a list entry by making the prev/next entries | |
82 | * point to each other. | |
83 | * | |
84 | * This is only for internal list manipulation where we know | |
85 | * the prev/next entries already! | |
86 | */ | |
87 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
88 | { | |
89 | next->prev = prev; | |
7f5f873c | 90 | WRITE_ONCE(prev->next, next); |
1da177e4 LT |
91 | } |
92 | ||
93 | /** | |
94 | * list_del - deletes entry from list. | |
95 | * @entry: the element to delete from the list. | |
72fd4a35 | 96 | * Note: list_empty() on entry does not return true after this, the entry is |
1da177e4 LT |
97 | * in an undefined state. |
98 | */ | |
199a9afc | 99 | #ifndef CONFIG_DEBUG_LIST |
3c18d4de LT |
100 | static inline void __list_del_entry(struct list_head *entry) |
101 | { | |
102 | __list_del(entry->prev, entry->next); | |
103 | } | |
104 | ||
1da177e4 LT |
105 | static inline void list_del(struct list_head *entry) |
106 | { | |
107 | __list_del(entry->prev, entry->next); | |
108 | entry->next = LIST_POISON1; | |
109 | entry->prev = LIST_POISON2; | |
110 | } | |
199a9afc | 111 | #else |
3c18d4de | 112 | extern void __list_del_entry(struct list_head *entry); |
199a9afc DJ |
113 | extern void list_del(struct list_head *entry); |
114 | #endif | |
1da177e4 | 115 | |
5c2c2587 DW |
116 | #ifdef CONFIG_DEBUG_LIST |
117 | /* | |
118 | * See devm_memremap_pages() which wants DEBUG_LIST=y to assert if one | |
119 | * of the pages it allocates is ever passed to list_add() | |
120 | */ | |
121 | extern void list_force_poison(struct list_head *entry); | |
122 | #else | |
123 | /* fallback to the less strict LIST_POISON* definitions */ | |
124 | #define list_force_poison list_del | |
125 | #endif | |
126 | ||
54e73770 ON |
127 | /** |
128 | * list_replace - replace old entry by new one | |
129 | * @old : the element to be replaced | |
130 | * @new : the new element to insert | |
72fd4a35 RD |
131 | * |
132 | * If @old was empty, it will be overwritten. | |
54e73770 ON |
133 | */ |
134 | static inline void list_replace(struct list_head *old, | |
135 | struct list_head *new) | |
136 | { | |
137 | new->next = old->next; | |
138 | new->next->prev = new; | |
139 | new->prev = old->prev; | |
140 | new->prev->next = new; | |
141 | } | |
142 | ||
143 | static inline void list_replace_init(struct list_head *old, | |
144 | struct list_head *new) | |
145 | { | |
146 | list_replace(old, new); | |
147 | INIT_LIST_HEAD(old); | |
148 | } | |
149 | ||
1da177e4 LT |
150 | /** |
151 | * list_del_init - deletes entry from list and reinitialize it. | |
152 | * @entry: the element to delete from the list. | |
153 | */ | |
154 | static inline void list_del_init(struct list_head *entry) | |
155 | { | |
3c18d4de | 156 | __list_del_entry(entry); |
1da177e4 LT |
157 | INIT_LIST_HEAD(entry); |
158 | } | |
159 | ||
160 | /** | |
161 | * list_move - delete from one list and add as another's head | |
162 | * @list: the entry to move | |
163 | * @head: the head that will precede our entry | |
164 | */ | |
165 | static inline void list_move(struct list_head *list, struct list_head *head) | |
166 | { | |
3c18d4de | 167 | __list_del_entry(list); |
78db2ad6 | 168 | list_add(list, head); |
1da177e4 LT |
169 | } |
170 | ||
171 | /** | |
172 | * list_move_tail - delete from one list and add as another's tail | |
173 | * @list: the entry to move | |
174 | * @head: the head that will follow our entry | |
175 | */ | |
176 | static inline void list_move_tail(struct list_head *list, | |
177 | struct list_head *head) | |
178 | { | |
3c18d4de | 179 | __list_del_entry(list); |
78db2ad6 | 180 | list_add_tail(list, head); |
1da177e4 LT |
181 | } |
182 | ||
e8f4d97e SN |
183 | /** |
184 | * list_is_last - tests whether @list is the last entry in list @head | |
185 | * @list: the entry to test | |
186 | * @head: the head of the list | |
187 | */ | |
188 | static inline int list_is_last(const struct list_head *list, | |
189 | const struct list_head *head) | |
190 | { | |
191 | return list->next == head; | |
192 | } | |
193 | ||
1da177e4 LT |
194 | /** |
195 | * list_empty - tests whether a list is empty | |
196 | * @head: the list to test. | |
197 | */ | |
198 | static inline int list_empty(const struct list_head *head) | |
199 | { | |
1658d35e | 200 | return READ_ONCE(head->next) == head; |
1da177e4 LT |
201 | } |
202 | ||
203 | /** | |
fe96e57d RD |
204 | * list_empty_careful - tests whether a list is empty and not being modified |
205 | * @head: the list to test | |
206 | * | |
207 | * Description: | |
208 | * tests whether a list is empty _and_ checks that no other CPU might be | |
209 | * in the process of modifying either member (next or prev) | |
1da177e4 LT |
210 | * |
211 | * NOTE: using list_empty_careful() without synchronization | |
212 | * can only be safe if the only activity that can happen | |
213 | * to the list entry is list_del_init(). Eg. it cannot be used | |
214 | * if another CPU could re-list_add() it. | |
1da177e4 LT |
215 | */ |
216 | static inline int list_empty_careful(const struct list_head *head) | |
217 | { | |
218 | struct list_head *next = head->next; | |
219 | return (next == head) && (next == head->prev); | |
99602572 MH |
220 | } |
221 | ||
5908cdc8 FW |
222 | /** |
223 | * list_rotate_left - rotate the list to the left | |
224 | * @head: the head of the list | |
225 | */ | |
226 | static inline void list_rotate_left(struct list_head *head) | |
227 | { | |
228 | struct list_head *first; | |
229 | ||
230 | if (!list_empty(head)) { | |
231 | first = head->next; | |
232 | list_move_tail(first, head); | |
233 | } | |
234 | } | |
235 | ||
99602572 MH |
236 | /** |
237 | * list_is_singular - tests whether a list has just one entry. | |
238 | * @head: the list to test. | |
239 | */ | |
240 | static inline int list_is_singular(const struct list_head *head) | |
241 | { | |
242 | return !list_empty(head) && (head->next == head->prev); | |
1da177e4 LT |
243 | } |
244 | ||
00e8a4da LR |
245 | static inline void __list_cut_position(struct list_head *list, |
246 | struct list_head *head, struct list_head *entry) | |
247 | { | |
248 | struct list_head *new_first = entry->next; | |
249 | list->next = head->next; | |
250 | list->next->prev = list; | |
251 | list->prev = entry; | |
252 | entry->next = list; | |
253 | head->next = new_first; | |
254 | new_first->prev = head; | |
255 | } | |
256 | ||
257 | /** | |
258 | * list_cut_position - cut a list into two | |
259 | * @list: a new list to add all removed entries | |
260 | * @head: a list with entries | |
261 | * @entry: an entry within head, could be the head itself | |
262 | * and if so we won't cut the list | |
263 | * | |
264 | * This helper moves the initial part of @head, up to and | |
265 | * including @entry, from @head to @list. You should | |
266 | * pass on @entry an element you know is on @head. @list | |
267 | * should be an empty list or a list you do not care about | |
268 | * losing its data. | |
269 | * | |
270 | */ | |
271 | static inline void list_cut_position(struct list_head *list, | |
272 | struct list_head *head, struct list_head *entry) | |
273 | { | |
274 | if (list_empty(head)) | |
275 | return; | |
276 | if (list_is_singular(head) && | |
277 | (head->next != entry && head != entry)) | |
278 | return; | |
279 | if (entry == head) | |
280 | INIT_LIST_HEAD(list); | |
281 | else | |
282 | __list_cut_position(list, head, entry); | |
283 | } | |
284 | ||
95d8c365 | 285 | static inline void __list_splice(const struct list_head *list, |
7d283aee LR |
286 | struct list_head *prev, |
287 | struct list_head *next) | |
1da177e4 LT |
288 | { |
289 | struct list_head *first = list->next; | |
290 | struct list_head *last = list->prev; | |
1da177e4 | 291 | |
7d283aee LR |
292 | first->prev = prev; |
293 | prev->next = first; | |
1da177e4 | 294 | |
7d283aee LR |
295 | last->next = next; |
296 | next->prev = last; | |
1da177e4 LT |
297 | } |
298 | ||
299 | /** | |
7d283aee | 300 | * list_splice - join two lists, this is designed for stacks |
1da177e4 LT |
301 | * @list: the new list to add. |
302 | * @head: the place to add it in the first list. | |
303 | */ | |
95d8c365 RD |
304 | static inline void list_splice(const struct list_head *list, |
305 | struct list_head *head) | |
1da177e4 LT |
306 | { |
307 | if (!list_empty(list)) | |
7d283aee LR |
308 | __list_splice(list, head, head->next); |
309 | } | |
310 | ||
311 | /** | |
312 | * list_splice_tail - join two lists, each list being a queue | |
313 | * @list: the new list to add. | |
314 | * @head: the place to add it in the first list. | |
315 | */ | |
316 | static inline void list_splice_tail(struct list_head *list, | |
317 | struct list_head *head) | |
318 | { | |
319 | if (!list_empty(list)) | |
320 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
321 | } |
322 | ||
323 | /** | |
324 | * list_splice_init - join two lists and reinitialise the emptied list. | |
325 | * @list: the new list to add. | |
326 | * @head: the place to add it in the first list. | |
327 | * | |
328 | * The list at @list is reinitialised | |
329 | */ | |
330 | static inline void list_splice_init(struct list_head *list, | |
331 | struct list_head *head) | |
332 | { | |
333 | if (!list_empty(list)) { | |
7d283aee LR |
334 | __list_splice(list, head, head->next); |
335 | INIT_LIST_HEAD(list); | |
336 | } | |
337 | } | |
338 | ||
339 | /** | |
6724cce8 | 340 | * list_splice_tail_init - join two lists and reinitialise the emptied list |
7d283aee LR |
341 | * @list: the new list to add. |
342 | * @head: the place to add it in the first list. | |
343 | * | |
6724cce8 | 344 | * Each of the lists is a queue. |
7d283aee LR |
345 | * The list at @list is reinitialised |
346 | */ | |
347 | static inline void list_splice_tail_init(struct list_head *list, | |
348 | struct list_head *head) | |
349 | { | |
350 | if (!list_empty(list)) { | |
351 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
352 | INIT_LIST_HEAD(list); |
353 | } | |
354 | } | |
355 | ||
356 | /** | |
357 | * list_entry - get the struct for this entry | |
358 | * @ptr: the &struct list_head pointer. | |
359 | * @type: the type of the struct this is embedded in. | |
3943f42c | 360 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
361 | */ |
362 | #define list_entry(ptr, type, member) \ | |
363 | container_of(ptr, type, member) | |
364 | ||
b5e61818 PE |
365 | /** |
366 | * list_first_entry - get the first element from a list | |
367 | * @ptr: the list head to take the element from. | |
368 | * @type: the type of the struct this is embedded in. | |
3943f42c | 369 | * @member: the name of the list_head within the struct. |
b5e61818 PE |
370 | * |
371 | * Note, that list is expected to be not empty. | |
372 | */ | |
373 | #define list_first_entry(ptr, type, member) \ | |
374 | list_entry((ptr)->next, type, member) | |
375 | ||
93be3c2e ON |
376 | /** |
377 | * list_last_entry - get the last element from a list | |
378 | * @ptr: the list head to take the element from. | |
379 | * @type: the type of the struct this is embedded in. | |
3943f42c | 380 | * @member: the name of the list_head within the struct. |
93be3c2e ON |
381 | * |
382 | * Note, that list is expected to be not empty. | |
383 | */ | |
384 | #define list_last_entry(ptr, type, member) \ | |
385 | list_entry((ptr)->prev, type, member) | |
386 | ||
6d7581e6 JP |
387 | /** |
388 | * list_first_entry_or_null - get the first element from a list | |
389 | * @ptr: the list head to take the element from. | |
390 | * @type: the type of the struct this is embedded in. | |
3943f42c | 391 | * @member: the name of the list_head within the struct. |
6d7581e6 JP |
392 | * |
393 | * Note that if the list is empty, it returns NULL. | |
394 | */ | |
395 | #define list_first_entry_or_null(ptr, type, member) \ | |
396 | (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL) | |
397 | ||
008208c6 ON |
398 | /** |
399 | * list_next_entry - get the next element in list | |
400 | * @pos: the type * to cursor | |
3943f42c | 401 | * @member: the name of the list_head within the struct. |
008208c6 ON |
402 | */ |
403 | #define list_next_entry(pos, member) \ | |
404 | list_entry((pos)->member.next, typeof(*(pos)), member) | |
405 | ||
406 | /** | |
407 | * list_prev_entry - get the prev element in list | |
408 | * @pos: the type * to cursor | |
3943f42c | 409 | * @member: the name of the list_head within the struct. |
008208c6 ON |
410 | */ |
411 | #define list_prev_entry(pos, member) \ | |
412 | list_entry((pos)->member.prev, typeof(*(pos)), member) | |
413 | ||
1da177e4 LT |
414 | /** |
415 | * list_for_each - iterate over a list | |
8e3a67a9 | 416 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
417 | * @head: the head for your list. |
418 | */ | |
419 | #define list_for_each(pos, head) \ | |
e66eed65 | 420 | for (pos = (head)->next; pos != (head); pos = pos->next) |
1da177e4 | 421 | |
1da177e4 LT |
422 | /** |
423 | * list_for_each_prev - iterate over a list backwards | |
8e3a67a9 | 424 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
425 | * @head: the head for your list. |
426 | */ | |
427 | #define list_for_each_prev(pos, head) \ | |
e66eed65 | 428 | for (pos = (head)->prev; pos != (head); pos = pos->prev) |
1da177e4 LT |
429 | |
430 | /** | |
fe96e57d | 431 | * list_for_each_safe - iterate over a list safe against removal of list entry |
8e3a67a9 | 432 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
433 | * @n: another &struct list_head to use as temporary storage |
434 | * @head: the head for your list. | |
435 | */ | |
436 | #define list_for_each_safe(pos, n, head) \ | |
437 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
438 | pos = n, n = pos->next) | |
439 | ||
37c42524 | 440 | /** |
8f731f7d | 441 | * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry |
37c42524 DL |
442 | * @pos: the &struct list_head to use as a loop cursor. |
443 | * @n: another &struct list_head to use as temporary storage | |
444 | * @head: the head for your list. | |
445 | */ | |
446 | #define list_for_each_prev_safe(pos, n, head) \ | |
447 | for (pos = (head)->prev, n = pos->prev; \ | |
e66eed65 | 448 | pos != (head); \ |
37c42524 DL |
449 | pos = n, n = pos->prev) |
450 | ||
1da177e4 LT |
451 | /** |
452 | * list_for_each_entry - iterate over list of given type | |
8e3a67a9 | 453 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 454 | * @head: the head for your list. |
3943f42c | 455 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
456 | */ |
457 | #define list_for_each_entry(pos, head, member) \ | |
93be3c2e | 458 | for (pos = list_first_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
459 | &pos->member != (head); \ |
460 | pos = list_next_entry(pos, member)) | |
1da177e4 LT |
461 | |
462 | /** | |
463 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
8e3a67a9 | 464 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 465 | * @head: the head for your list. |
3943f42c | 466 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
467 | */ |
468 | #define list_for_each_entry_reverse(pos, head, member) \ | |
93be3c2e | 469 | for (pos = list_last_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
470 | &pos->member != (head); \ |
471 | pos = list_prev_entry(pos, member)) | |
1da177e4 LT |
472 | |
473 | /** | |
72fd4a35 | 474 | * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() |
1da177e4 LT |
475 | * @pos: the type * to use as a start point |
476 | * @head: the head of the list | |
3943f42c | 477 | * @member: the name of the list_head within the struct. |
fe96e57d | 478 | * |
72fd4a35 | 479 | * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). |
1da177e4 LT |
480 | */ |
481 | #define list_prepare_entry(pos, head, member) \ | |
482 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
483 | ||
484 | /** | |
fe96e57d | 485 | * list_for_each_entry_continue - continue iteration over list of given type |
8e3a67a9 | 486 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 487 | * @head: the head for your list. |
3943f42c | 488 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
489 | * |
490 | * Continue to iterate over list of given type, continuing after | |
491 | * the current position. | |
1da177e4 LT |
492 | */ |
493 | #define list_for_each_entry_continue(pos, head, member) \ | |
8120e2e5 ON |
494 | for (pos = list_next_entry(pos, member); \ |
495 | &pos->member != (head); \ | |
496 | pos = list_next_entry(pos, member)) | |
1da177e4 | 497 | |
768f3591 PE |
498 | /** |
499 | * list_for_each_entry_continue_reverse - iterate backwards from the given point | |
500 | * @pos: the type * to use as a loop cursor. | |
501 | * @head: the head for your list. | |
3943f42c | 502 | * @member: the name of the list_head within the struct. |
768f3591 PE |
503 | * |
504 | * Start to iterate over list of given type backwards, continuing after | |
505 | * the current position. | |
506 | */ | |
507 | #define list_for_each_entry_continue_reverse(pos, head, member) \ | |
8120e2e5 ON |
508 | for (pos = list_prev_entry(pos, member); \ |
509 | &pos->member != (head); \ | |
510 | pos = list_prev_entry(pos, member)) | |
768f3591 | 511 | |
e229c2fb | 512 | /** |
fe96e57d | 513 | * list_for_each_entry_from - iterate over list of given type from the current point |
8e3a67a9 | 514 | * @pos: the type * to use as a loop cursor. |
e229c2fb | 515 | * @head: the head for your list. |
3943f42c | 516 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
517 | * |
518 | * Iterate over list of given type, continuing from current position. | |
e229c2fb ACM |
519 | */ |
520 | #define list_for_each_entry_from(pos, head, member) \ | |
8120e2e5 ON |
521 | for (; &pos->member != (head); \ |
522 | pos = list_next_entry(pos, member)) | |
e229c2fb | 523 | |
1da177e4 LT |
524 | /** |
525 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 | 526 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
527 | * @n: another type * to use as temporary storage |
528 | * @head: the head for your list. | |
3943f42c | 529 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
530 | */ |
531 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
93be3c2e | 532 | for (pos = list_first_entry(head, typeof(*pos), member), \ |
8120e2e5 | 533 | n = list_next_entry(pos, member); \ |
1da177e4 | 534 | &pos->member != (head); \ |
8120e2e5 | 535 | pos = n, n = list_next_entry(n, member)) |
1da177e4 | 536 | |
74459dc7 | 537 | /** |
9a86e2ba | 538 | * list_for_each_entry_safe_continue - continue list iteration safe against removal |
8e3a67a9 | 539 | * @pos: the type * to use as a loop cursor. |
74459dc7 ACM |
540 | * @n: another type * to use as temporary storage |
541 | * @head: the head for your list. | |
3943f42c | 542 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
543 | * |
544 | * Iterate over list of given type, continuing after current point, | |
545 | * safe against removal of list entry. | |
74459dc7 ACM |
546 | */ |
547 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8120e2e5 ON |
548 | for (pos = list_next_entry(pos, member), \ |
549 | n = list_next_entry(pos, member); \ | |
d8dcffee | 550 | &pos->member != (head); \ |
8120e2e5 | 551 | pos = n, n = list_next_entry(n, member)) |
d8dcffee ACM |
552 | |
553 | /** | |
9a86e2ba | 554 | * list_for_each_entry_safe_from - iterate over list from current point safe against removal |
8e3a67a9 | 555 | * @pos: the type * to use as a loop cursor. |
d8dcffee ACM |
556 | * @n: another type * to use as temporary storage |
557 | * @head: the head for your list. | |
3943f42c | 558 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
559 | * |
560 | * Iterate over list of given type from current point, safe against | |
561 | * removal of list entry. | |
d8dcffee ACM |
562 | */ |
563 | #define list_for_each_entry_safe_from(pos, n, head, member) \ | |
8120e2e5 | 564 | for (n = list_next_entry(pos, member); \ |
74459dc7 | 565 | &pos->member != (head); \ |
8120e2e5 | 566 | pos = n, n = list_next_entry(n, member)) |
74459dc7 | 567 | |
0ad42352 | 568 | /** |
9a86e2ba | 569 | * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal |
8e3a67a9 | 570 | * @pos: the type * to use as a loop cursor. |
0ad42352 DH |
571 | * @n: another type * to use as temporary storage |
572 | * @head: the head for your list. | |
3943f42c | 573 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
574 | * |
575 | * Iterate backwards over list of given type, safe against removal | |
576 | * of list entry. | |
0ad42352 DH |
577 | */ |
578 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
93be3c2e | 579 | for (pos = list_last_entry(head, typeof(*pos), member), \ |
8120e2e5 | 580 | n = list_prev_entry(pos, member); \ |
0ad42352 | 581 | &pos->member != (head); \ |
8120e2e5 | 582 | pos = n, n = list_prev_entry(n, member)) |
0ad42352 | 583 | |
57439f87 | 584 | /** |
585 | * list_safe_reset_next - reset a stale list_for_each_entry_safe loop | |
586 | * @pos: the loop cursor used in the list_for_each_entry_safe loop | |
587 | * @n: temporary storage used in list_for_each_entry_safe | |
3943f42c | 588 | * @member: the name of the list_head within the struct. |
57439f87 | 589 | * |
590 | * list_safe_reset_next is not safe to use in general if the list may be | |
591 | * modified concurrently (eg. the lock is dropped in the loop body). An | |
592 | * exception to this is if the cursor element (pos) is pinned in the list, | |
593 | * and list_safe_reset_next is called after re-taking the lock and before | |
594 | * completing the current iteration of the loop body. | |
595 | */ | |
596 | #define list_safe_reset_next(pos, n, member) \ | |
8120e2e5 | 597 | n = list_next_entry(pos, member) |
57439f87 | 598 | |
1da177e4 LT |
599 | /* |
600 | * Double linked lists with a single pointer list head. | |
601 | * Mostly useful for hash tables where the two pointer list head is | |
602 | * too wasteful. | |
603 | * You lose the ability to access the tail in O(1). | |
604 | */ | |
605 | ||
1da177e4 LT |
606 | #define HLIST_HEAD_INIT { .first = NULL } |
607 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
608 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
490d6ab1 ZB |
609 | static inline void INIT_HLIST_NODE(struct hlist_node *h) |
610 | { | |
611 | h->next = NULL; | |
612 | h->pprev = NULL; | |
613 | } | |
1da177e4 LT |
614 | |
615 | static inline int hlist_unhashed(const struct hlist_node *h) | |
616 | { | |
617 | return !h->pprev; | |
618 | } | |
619 | ||
620 | static inline int hlist_empty(const struct hlist_head *h) | |
621 | { | |
1658d35e | 622 | return !READ_ONCE(h->first); |
1da177e4 LT |
623 | } |
624 | ||
625 | static inline void __hlist_del(struct hlist_node *n) | |
626 | { | |
627 | struct hlist_node *next = n->next; | |
628 | struct hlist_node **pprev = n->pprev; | |
7f5f873c PM |
629 | |
630 | WRITE_ONCE(*pprev, next); | |
1da177e4 LT |
631 | if (next) |
632 | next->pprev = pprev; | |
633 | } | |
634 | ||
635 | static inline void hlist_del(struct hlist_node *n) | |
636 | { | |
637 | __hlist_del(n); | |
638 | n->next = LIST_POISON1; | |
639 | n->pprev = LIST_POISON2; | |
640 | } | |
641 | ||
1da177e4 LT |
642 | static inline void hlist_del_init(struct hlist_node *n) |
643 | { | |
da753bea | 644 | if (!hlist_unhashed(n)) { |
1da177e4 LT |
645 | __hlist_del(n); |
646 | INIT_HLIST_NODE(n); | |
647 | } | |
648 | } | |
649 | ||
650 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) | |
651 | { | |
652 | struct hlist_node *first = h->first; | |
653 | n->next = first; | |
654 | if (first) | |
655 | first->pprev = &n->next; | |
1c97be67 | 656 | WRITE_ONCE(h->first, n); |
1da177e4 LT |
657 | n->pprev = &h->first; |
658 | } | |
659 | ||
1da177e4 LT |
660 | /* next must be != NULL */ |
661 | static inline void hlist_add_before(struct hlist_node *n, | |
662 | struct hlist_node *next) | |
663 | { | |
664 | n->pprev = next->pprev; | |
665 | n->next = next; | |
666 | next->pprev = &n->next; | |
1c97be67 | 667 | WRITE_ONCE(*(n->pprev), n); |
1da177e4 LT |
668 | } |
669 | ||
1d023284 KH |
670 | static inline void hlist_add_behind(struct hlist_node *n, |
671 | struct hlist_node *prev) | |
1da177e4 | 672 | { |
bc18dd33 | 673 | n->next = prev->next; |
1c97be67 | 674 | WRITE_ONCE(prev->next, n); |
bc18dd33 | 675 | n->pprev = &prev->next; |
1da177e4 | 676 | |
bc18dd33 KH |
677 | if (n->next) |
678 | n->next->pprev = &n->next; | |
1da177e4 LT |
679 | } |
680 | ||
756acc2d AV |
681 | /* after that we'll appear to be on some hlist and hlist_del will work */ |
682 | static inline void hlist_add_fake(struct hlist_node *n) | |
683 | { | |
684 | n->pprev = &n->next; | |
685 | } | |
686 | ||
cbedaac6 JB |
687 | static inline bool hlist_fake(struct hlist_node *h) |
688 | { | |
689 | return h->pprev == &h->next; | |
690 | } | |
691 | ||
673d62cc VN |
692 | /* |
693 | * Move a list from one list head to another. Fixup the pprev | |
694 | * reference of the first entry if it exists. | |
695 | */ | |
696 | static inline void hlist_move_list(struct hlist_head *old, | |
697 | struct hlist_head *new) | |
698 | { | |
699 | new->first = old->first; | |
700 | if (new->first) | |
701 | new->first->pprev = &new->first; | |
702 | old->first = NULL; | |
703 | } | |
704 | ||
1da177e4 LT |
705 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
706 | ||
707 | #define hlist_for_each(pos, head) \ | |
75d65a42 | 708 | for (pos = (head)->first; pos ; pos = pos->next) |
1da177e4 LT |
709 | |
710 | #define hlist_for_each_safe(pos, n, head) \ | |
711 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
712 | pos = n) | |
713 | ||
b67bfe0d | 714 | #define hlist_entry_safe(ptr, type, member) \ |
f65846a1 PM |
715 | ({ typeof(ptr) ____ptr = (ptr); \ |
716 | ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ | |
717 | }) | |
b67bfe0d | 718 | |
1da177e4 LT |
719 | /** |
720 | * hlist_for_each_entry - iterate over list of given type | |
b67bfe0d | 721 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
722 | * @head: the head for your list. |
723 | * @member: the name of the hlist_node within the struct. | |
724 | */ | |
b67bfe0d SL |
725 | #define hlist_for_each_entry(pos, head, member) \ |
726 | for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ | |
727 | pos; \ | |
728 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
729 | |
730 | /** | |
fe96e57d | 731 | * hlist_for_each_entry_continue - iterate over a hlist continuing after current point |
b67bfe0d | 732 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
733 | * @member: the name of the hlist_node within the struct. |
734 | */ | |
b67bfe0d SL |
735 | #define hlist_for_each_entry_continue(pos, member) \ |
736 | for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ | |
737 | pos; \ | |
738 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
739 | |
740 | /** | |
fe96e57d | 741 | * hlist_for_each_entry_from - iterate over a hlist continuing from current point |
b67bfe0d | 742 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
743 | * @member: the name of the hlist_node within the struct. |
744 | */ | |
b67bfe0d SL |
745 | #define hlist_for_each_entry_from(pos, member) \ |
746 | for (; pos; \ | |
747 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
748 | |
749 | /** | |
750 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
b67bfe0d | 751 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
752 | * @n: another &struct hlist_node to use as temporary storage |
753 | * @head: the head for your list. | |
754 | * @member: the name of the hlist_node within the struct. | |
755 | */ | |
b67bfe0d SL |
756 | #define hlist_for_each_entry_safe(pos, n, head, member) \ |
757 | for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ | |
758 | pos && ({ n = pos->member.next; 1; }); \ | |
759 | pos = hlist_entry_safe(n, typeof(*pos), member)) | |
1da177e4 | 760 | |
1da177e4 | 761 | #endif |