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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_LIST_H |
3 | #define _LINUX_LIST_H | |
4 | ||
de5d9bf6 | 5 | #include <linux/types.h> |
1da177e4 | 6 | #include <linux/stddef.h> |
c9cf5528 | 7 | #include <linux/poison.h> |
e66eed65 | 8 | #include <linux/const.h> |
8b21d9ca | 9 | #include <linux/kernel.h> |
1da177e4 | 10 | |
1da177e4 LT |
11 | /* |
12 | * Simple doubly linked list implementation. | |
13 | * | |
14 | * Some of the internal functions ("__xxx") are useful when | |
15 | * manipulating whole lists rather than single entries, as | |
16 | * sometimes we already know the next/prev entries and we can | |
17 | * generate better code by using them directly rather than | |
18 | * using the generic single-entry routines. | |
19 | */ | |
20 | ||
1da177e4 LT |
21 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
22 | ||
23 | #define LIST_HEAD(name) \ | |
24 | struct list_head name = LIST_HEAD_INIT(name) | |
25 | ||
490d6ab1 ZB |
26 | static inline void INIT_LIST_HEAD(struct list_head *list) |
27 | { | |
2f073848 | 28 | WRITE_ONCE(list->next, list); |
490d6ab1 ZB |
29 | list->prev = list; |
30 | } | |
1da177e4 | 31 | |
d7c81673 KC |
32 | #ifdef CONFIG_DEBUG_LIST |
33 | extern bool __list_add_valid(struct list_head *new, | |
34 | struct list_head *prev, | |
35 | struct list_head *next); | |
0cd340dc | 36 | extern bool __list_del_entry_valid(struct list_head *entry); |
d7c81673 KC |
37 | #else |
38 | static inline bool __list_add_valid(struct list_head *new, | |
39 | struct list_head *prev, | |
40 | struct list_head *next) | |
41 | { | |
42 | return true; | |
43 | } | |
0cd340dc KC |
44 | static inline bool __list_del_entry_valid(struct list_head *entry) |
45 | { | |
46 | return true; | |
47 | } | |
d7c81673 KC |
48 | #endif |
49 | ||
1da177e4 LT |
50 | /* |
51 | * Insert a new entry between two known consecutive entries. | |
52 | * | |
53 | * This is only for internal list manipulation where we know | |
54 | * the prev/next entries already! | |
55 | */ | |
56 | static inline void __list_add(struct list_head *new, | |
57 | struct list_head *prev, | |
58 | struct list_head *next) | |
59 | { | |
d7c81673 KC |
60 | if (!__list_add_valid(new, prev, next)) |
61 | return; | |
62 | ||
1da177e4 LT |
63 | next->prev = new; |
64 | new->next = next; | |
65 | new->prev = prev; | |
1c97be67 | 66 | WRITE_ONCE(prev->next, new); |
1da177e4 LT |
67 | } |
68 | ||
69 | /** | |
70 | * list_add - add a new entry | |
71 | * @new: new entry to be added | |
72 | * @head: list head to add it after | |
73 | * | |
74 | * Insert a new entry after the specified head. | |
75 | * This is good for implementing stacks. | |
76 | */ | |
77 | static inline void list_add(struct list_head *new, struct list_head *head) | |
78 | { | |
79 | __list_add(new, head, head->next); | |
80 | } | |
199a9afc | 81 | |
1da177e4 LT |
82 | |
83 | /** | |
84 | * list_add_tail - add a new entry | |
85 | * @new: new entry to be added | |
86 | * @head: list head to add it before | |
87 | * | |
88 | * Insert a new entry before the specified head. | |
89 | * This is useful for implementing queues. | |
90 | */ | |
91 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
92 | { | |
93 | __list_add(new, head->prev, head); | |
94 | } | |
95 | ||
1da177e4 LT |
96 | /* |
97 | * Delete a list entry by making the prev/next entries | |
98 | * point to each other. | |
99 | * | |
100 | * This is only for internal list manipulation where we know | |
101 | * the prev/next entries already! | |
102 | */ | |
103 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
104 | { | |
105 | next->prev = prev; | |
7f5f873c | 106 | WRITE_ONCE(prev->next, next); |
1da177e4 LT |
107 | } |
108 | ||
109 | /** | |
110 | * list_del - deletes entry from list. | |
111 | * @entry: the element to delete from the list. | |
72fd4a35 | 112 | * Note: list_empty() on entry does not return true after this, the entry is |
1da177e4 LT |
113 | * in an undefined state. |
114 | */ | |
3c18d4de LT |
115 | static inline void __list_del_entry(struct list_head *entry) |
116 | { | |
0cd340dc KC |
117 | if (!__list_del_entry_valid(entry)) |
118 | return; | |
119 | ||
3c18d4de LT |
120 | __list_del(entry->prev, entry->next); |
121 | } | |
122 | ||
1da177e4 LT |
123 | static inline void list_del(struct list_head *entry) |
124 | { | |
0cd340dc | 125 | __list_del_entry(entry); |
1da177e4 LT |
126 | entry->next = LIST_POISON1; |
127 | entry->prev = LIST_POISON2; | |
128 | } | |
129 | ||
54e73770 ON |
130 | /** |
131 | * list_replace - replace old entry by new one | |
132 | * @old : the element to be replaced | |
133 | * @new : the new element to insert | |
72fd4a35 RD |
134 | * |
135 | * If @old was empty, it will be overwritten. | |
54e73770 ON |
136 | */ |
137 | static inline void list_replace(struct list_head *old, | |
138 | struct list_head *new) | |
139 | { | |
140 | new->next = old->next; | |
141 | new->next->prev = new; | |
142 | new->prev = old->prev; | |
143 | new->prev->next = new; | |
144 | } | |
145 | ||
146 | static inline void list_replace_init(struct list_head *old, | |
147 | struct list_head *new) | |
148 | { | |
149 | list_replace(old, new); | |
150 | INIT_LIST_HEAD(old); | |
151 | } | |
152 | ||
1da177e4 LT |
153 | /** |
154 | * list_del_init - deletes entry from list and reinitialize it. | |
155 | * @entry: the element to delete from the list. | |
156 | */ | |
157 | static inline void list_del_init(struct list_head *entry) | |
158 | { | |
3c18d4de | 159 | __list_del_entry(entry); |
1da177e4 LT |
160 | INIT_LIST_HEAD(entry); |
161 | } | |
162 | ||
163 | /** | |
164 | * list_move - delete from one list and add as another's head | |
165 | * @list: the entry to move | |
166 | * @head: the head that will precede our entry | |
167 | */ | |
168 | static inline void list_move(struct list_head *list, struct list_head *head) | |
169 | { | |
3c18d4de | 170 | __list_del_entry(list); |
78db2ad6 | 171 | list_add(list, head); |
1da177e4 LT |
172 | } |
173 | ||
174 | /** | |
175 | * list_move_tail - delete from one list and add as another's tail | |
176 | * @list: the entry to move | |
177 | * @head: the head that will follow our entry | |
178 | */ | |
179 | static inline void list_move_tail(struct list_head *list, | |
180 | struct list_head *head) | |
181 | { | |
3c18d4de | 182 | __list_del_entry(list); |
78db2ad6 | 183 | list_add_tail(list, head); |
1da177e4 LT |
184 | } |
185 | ||
e8f4d97e SN |
186 | /** |
187 | * list_is_last - tests whether @list is the last entry in list @head | |
188 | * @list: the entry to test | |
189 | * @head: the head of the list | |
190 | */ | |
191 | static inline int list_is_last(const struct list_head *list, | |
192 | const struct list_head *head) | |
193 | { | |
194 | return list->next == head; | |
195 | } | |
196 | ||
1da177e4 LT |
197 | /** |
198 | * list_empty - tests whether a list is empty | |
199 | * @head: the list to test. | |
200 | */ | |
201 | static inline int list_empty(const struct list_head *head) | |
202 | { | |
1658d35e | 203 | return READ_ONCE(head->next) == head; |
1da177e4 LT |
204 | } |
205 | ||
206 | /** | |
fe96e57d RD |
207 | * list_empty_careful - tests whether a list is empty and not being modified |
208 | * @head: the list to test | |
209 | * | |
210 | * Description: | |
211 | * tests whether a list is empty _and_ checks that no other CPU might be | |
212 | * in the process of modifying either member (next or prev) | |
1da177e4 LT |
213 | * |
214 | * NOTE: using list_empty_careful() without synchronization | |
215 | * can only be safe if the only activity that can happen | |
216 | * to the list entry is list_del_init(). Eg. it cannot be used | |
217 | * if another CPU could re-list_add() it. | |
1da177e4 LT |
218 | */ |
219 | static inline int list_empty_careful(const struct list_head *head) | |
220 | { | |
221 | struct list_head *next = head->next; | |
222 | return (next == head) && (next == head->prev); | |
99602572 MH |
223 | } |
224 | ||
5908cdc8 FW |
225 | /** |
226 | * list_rotate_left - rotate the list to the left | |
227 | * @head: the head of the list | |
228 | */ | |
229 | static inline void list_rotate_left(struct list_head *head) | |
230 | { | |
231 | struct list_head *first; | |
232 | ||
233 | if (!list_empty(head)) { | |
234 | first = head->next; | |
235 | list_move_tail(first, head); | |
236 | } | |
237 | } | |
238 | ||
99602572 MH |
239 | /** |
240 | * list_is_singular - tests whether a list has just one entry. | |
241 | * @head: the list to test. | |
242 | */ | |
243 | static inline int list_is_singular(const struct list_head *head) | |
244 | { | |
245 | return !list_empty(head) && (head->next == head->prev); | |
1da177e4 LT |
246 | } |
247 | ||
00e8a4da LR |
248 | static inline void __list_cut_position(struct list_head *list, |
249 | struct list_head *head, struct list_head *entry) | |
250 | { | |
251 | struct list_head *new_first = entry->next; | |
252 | list->next = head->next; | |
253 | list->next->prev = list; | |
254 | list->prev = entry; | |
255 | entry->next = list; | |
256 | head->next = new_first; | |
257 | new_first->prev = head; | |
258 | } | |
259 | ||
260 | /** | |
261 | * list_cut_position - cut a list into two | |
262 | * @list: a new list to add all removed entries | |
263 | * @head: a list with entries | |
264 | * @entry: an entry within head, could be the head itself | |
265 | * and if so we won't cut the list | |
266 | * | |
267 | * This helper moves the initial part of @head, up to and | |
268 | * including @entry, from @head to @list. You should | |
269 | * pass on @entry an element you know is on @head. @list | |
270 | * should be an empty list or a list you do not care about | |
271 | * losing its data. | |
272 | * | |
273 | */ | |
274 | static inline void list_cut_position(struct list_head *list, | |
275 | struct list_head *head, struct list_head *entry) | |
276 | { | |
277 | if (list_empty(head)) | |
278 | return; | |
279 | if (list_is_singular(head) && | |
280 | (head->next != entry && head != entry)) | |
281 | return; | |
282 | if (entry == head) | |
283 | INIT_LIST_HEAD(list); | |
284 | else | |
285 | __list_cut_position(list, head, entry); | |
286 | } | |
287 | ||
95d8c365 | 288 | static inline void __list_splice(const struct list_head *list, |
7d283aee LR |
289 | struct list_head *prev, |
290 | struct list_head *next) | |
1da177e4 LT |
291 | { |
292 | struct list_head *first = list->next; | |
293 | struct list_head *last = list->prev; | |
1da177e4 | 294 | |
7d283aee LR |
295 | first->prev = prev; |
296 | prev->next = first; | |
1da177e4 | 297 | |
7d283aee LR |
298 | last->next = next; |
299 | next->prev = last; | |
1da177e4 LT |
300 | } |
301 | ||
302 | /** | |
7d283aee | 303 | * list_splice - join two lists, this is designed for stacks |
1da177e4 LT |
304 | * @list: the new list to add. |
305 | * @head: the place to add it in the first list. | |
306 | */ | |
95d8c365 RD |
307 | static inline void list_splice(const struct list_head *list, |
308 | struct list_head *head) | |
1da177e4 LT |
309 | { |
310 | if (!list_empty(list)) | |
7d283aee LR |
311 | __list_splice(list, head, head->next); |
312 | } | |
313 | ||
314 | /** | |
315 | * list_splice_tail - join two lists, each list being a queue | |
316 | * @list: the new list to add. | |
317 | * @head: the place to add it in the first list. | |
318 | */ | |
319 | static inline void list_splice_tail(struct list_head *list, | |
320 | struct list_head *head) | |
321 | { | |
322 | if (!list_empty(list)) | |
323 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
324 | } |
325 | ||
326 | /** | |
327 | * list_splice_init - join two lists and reinitialise the emptied list. | |
328 | * @list: the new list to add. | |
329 | * @head: the place to add it in the first list. | |
330 | * | |
331 | * The list at @list is reinitialised | |
332 | */ | |
333 | static inline void list_splice_init(struct list_head *list, | |
334 | struct list_head *head) | |
335 | { | |
336 | if (!list_empty(list)) { | |
7d283aee LR |
337 | __list_splice(list, head, head->next); |
338 | INIT_LIST_HEAD(list); | |
339 | } | |
340 | } | |
341 | ||
342 | /** | |
6724cce8 | 343 | * list_splice_tail_init - join two lists and reinitialise the emptied list |
7d283aee LR |
344 | * @list: the new list to add. |
345 | * @head: the place to add it in the first list. | |
346 | * | |
6724cce8 | 347 | * Each of the lists is a queue. |
7d283aee LR |
348 | * The list at @list is reinitialised |
349 | */ | |
350 | static inline void list_splice_tail_init(struct list_head *list, | |
351 | struct list_head *head) | |
352 | { | |
353 | if (!list_empty(list)) { | |
354 | __list_splice(list, head->prev, head); | |
1da177e4 LT |
355 | INIT_LIST_HEAD(list); |
356 | } | |
357 | } | |
358 | ||
359 | /** | |
360 | * list_entry - get the struct for this entry | |
361 | * @ptr: the &struct list_head pointer. | |
362 | * @type: the type of the struct this is embedded in. | |
3943f42c | 363 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
364 | */ |
365 | #define list_entry(ptr, type, member) \ | |
366 | container_of(ptr, type, member) | |
367 | ||
b5e61818 PE |
368 | /** |
369 | * list_first_entry - get the first element from a list | |
370 | * @ptr: the list head to take the element from. | |
371 | * @type: the type of the struct this is embedded in. | |
3943f42c | 372 | * @member: the name of the list_head within the struct. |
b5e61818 PE |
373 | * |
374 | * Note, that list is expected to be not empty. | |
375 | */ | |
376 | #define list_first_entry(ptr, type, member) \ | |
377 | list_entry((ptr)->next, type, member) | |
378 | ||
93be3c2e ON |
379 | /** |
380 | * list_last_entry - get the last element from a list | |
381 | * @ptr: the list head to take the element from. | |
382 | * @type: the type of the struct this is embedded in. | |
3943f42c | 383 | * @member: the name of the list_head within the struct. |
93be3c2e ON |
384 | * |
385 | * Note, that list is expected to be not empty. | |
386 | */ | |
387 | #define list_last_entry(ptr, type, member) \ | |
388 | list_entry((ptr)->prev, type, member) | |
389 | ||
6d7581e6 JP |
390 | /** |
391 | * list_first_entry_or_null - get the first element from a list | |
392 | * @ptr: the list head to take the element from. | |
393 | * @type: the type of the struct this is embedded in. | |
3943f42c | 394 | * @member: the name of the list_head within the struct. |
6d7581e6 JP |
395 | * |
396 | * Note that if the list is empty, it returns NULL. | |
397 | */ | |
12adfd88 CW |
398 | #define list_first_entry_or_null(ptr, type, member) ({ \ |
399 | struct list_head *head__ = (ptr); \ | |
400 | struct list_head *pos__ = READ_ONCE(head__->next); \ | |
401 | pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ | |
402 | }) | |
6d7581e6 | 403 | |
008208c6 ON |
404 | /** |
405 | * list_next_entry - get the next element in list | |
406 | * @pos: the type * to cursor | |
3943f42c | 407 | * @member: the name of the list_head within the struct. |
008208c6 ON |
408 | */ |
409 | #define list_next_entry(pos, member) \ | |
410 | list_entry((pos)->member.next, typeof(*(pos)), member) | |
411 | ||
412 | /** | |
413 | * list_prev_entry - get the prev element in list | |
414 | * @pos: the type * to cursor | |
3943f42c | 415 | * @member: the name of the list_head within the struct. |
008208c6 ON |
416 | */ |
417 | #define list_prev_entry(pos, member) \ | |
418 | list_entry((pos)->member.prev, typeof(*(pos)), member) | |
419 | ||
1da177e4 LT |
420 | /** |
421 | * list_for_each - iterate over a list | |
8e3a67a9 | 422 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
423 | * @head: the head for your list. |
424 | */ | |
425 | #define list_for_each(pos, head) \ | |
e66eed65 | 426 | for (pos = (head)->next; pos != (head); pos = pos->next) |
1da177e4 | 427 | |
1da177e4 LT |
428 | /** |
429 | * list_for_each_prev - iterate over a list backwards | |
8e3a67a9 | 430 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
431 | * @head: the head for your list. |
432 | */ | |
433 | #define list_for_each_prev(pos, head) \ | |
e66eed65 | 434 | for (pos = (head)->prev; pos != (head); pos = pos->prev) |
1da177e4 LT |
435 | |
436 | /** | |
fe96e57d | 437 | * list_for_each_safe - iterate over a list safe against removal of list entry |
8e3a67a9 | 438 | * @pos: the &struct list_head to use as a loop cursor. |
1da177e4 LT |
439 | * @n: another &struct list_head to use as temporary storage |
440 | * @head: the head for your list. | |
441 | */ | |
442 | #define list_for_each_safe(pos, n, head) \ | |
443 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
444 | pos = n, n = pos->next) | |
445 | ||
37c42524 | 446 | /** |
8f731f7d | 447 | * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry |
37c42524 DL |
448 | * @pos: the &struct list_head to use as a loop cursor. |
449 | * @n: another &struct list_head to use as temporary storage | |
450 | * @head: the head for your list. | |
451 | */ | |
452 | #define list_for_each_prev_safe(pos, n, head) \ | |
453 | for (pos = (head)->prev, n = pos->prev; \ | |
e66eed65 | 454 | pos != (head); \ |
37c42524 DL |
455 | pos = n, n = pos->prev) |
456 | ||
1da177e4 LT |
457 | /** |
458 | * list_for_each_entry - iterate over list of given type | |
8e3a67a9 | 459 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 460 | * @head: the head for your list. |
3943f42c | 461 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
462 | */ |
463 | #define list_for_each_entry(pos, head, member) \ | |
93be3c2e | 464 | for (pos = list_first_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
465 | &pos->member != (head); \ |
466 | pos = list_next_entry(pos, member)) | |
1da177e4 LT |
467 | |
468 | /** | |
469 | * list_for_each_entry_reverse - iterate backwards over list of given type. | |
8e3a67a9 | 470 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 471 | * @head: the head for your list. |
3943f42c | 472 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
473 | */ |
474 | #define list_for_each_entry_reverse(pos, head, member) \ | |
93be3c2e | 475 | for (pos = list_last_entry(head, typeof(*pos), member); \ |
8120e2e5 ON |
476 | &pos->member != (head); \ |
477 | pos = list_prev_entry(pos, member)) | |
1da177e4 LT |
478 | |
479 | /** | |
72fd4a35 | 480 | * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() |
1da177e4 LT |
481 | * @pos: the type * to use as a start point |
482 | * @head: the head of the list | |
3943f42c | 483 | * @member: the name of the list_head within the struct. |
fe96e57d | 484 | * |
72fd4a35 | 485 | * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). |
1da177e4 LT |
486 | */ |
487 | #define list_prepare_entry(pos, head, member) \ | |
488 | ((pos) ? : list_entry(head, typeof(*pos), member)) | |
489 | ||
490 | /** | |
fe96e57d | 491 | * list_for_each_entry_continue - continue iteration over list of given type |
8e3a67a9 | 492 | * @pos: the type * to use as a loop cursor. |
1da177e4 | 493 | * @head: the head for your list. |
3943f42c | 494 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
495 | * |
496 | * Continue to iterate over list of given type, continuing after | |
497 | * the current position. | |
1da177e4 LT |
498 | */ |
499 | #define list_for_each_entry_continue(pos, head, member) \ | |
8120e2e5 ON |
500 | for (pos = list_next_entry(pos, member); \ |
501 | &pos->member != (head); \ | |
502 | pos = list_next_entry(pos, member)) | |
1da177e4 | 503 | |
768f3591 PE |
504 | /** |
505 | * list_for_each_entry_continue_reverse - iterate backwards from the given point | |
506 | * @pos: the type * to use as a loop cursor. | |
507 | * @head: the head for your list. | |
3943f42c | 508 | * @member: the name of the list_head within the struct. |
768f3591 PE |
509 | * |
510 | * Start to iterate over list of given type backwards, continuing after | |
511 | * the current position. | |
512 | */ | |
513 | #define list_for_each_entry_continue_reverse(pos, head, member) \ | |
8120e2e5 ON |
514 | for (pos = list_prev_entry(pos, member); \ |
515 | &pos->member != (head); \ | |
516 | pos = list_prev_entry(pos, member)) | |
768f3591 | 517 | |
e229c2fb | 518 | /** |
fe96e57d | 519 | * list_for_each_entry_from - iterate over list of given type from the current point |
8e3a67a9 | 520 | * @pos: the type * to use as a loop cursor. |
e229c2fb | 521 | * @head: the head for your list. |
3943f42c | 522 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
523 | * |
524 | * Iterate over list of given type, continuing from current position. | |
e229c2fb ACM |
525 | */ |
526 | #define list_for_each_entry_from(pos, head, member) \ | |
8120e2e5 ON |
527 | for (; &pos->member != (head); \ |
528 | pos = list_next_entry(pos, member)) | |
e229c2fb | 529 | |
b862815c JP |
530 | /** |
531 | * list_for_each_entry_from_reverse - iterate backwards over list of given type | |
532 | * from the current point | |
533 | * @pos: the type * to use as a loop cursor. | |
534 | * @head: the head for your list. | |
535 | * @member: the name of the list_head within the struct. | |
536 | * | |
537 | * Iterate backwards over list of given type, continuing from current position. | |
538 | */ | |
539 | #define list_for_each_entry_from_reverse(pos, head, member) \ | |
540 | for (; &pos->member != (head); \ | |
541 | pos = list_prev_entry(pos, member)) | |
542 | ||
1da177e4 LT |
543 | /** |
544 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
8e3a67a9 | 545 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
546 | * @n: another type * to use as temporary storage |
547 | * @head: the head for your list. | |
3943f42c | 548 | * @member: the name of the list_head within the struct. |
1da177e4 LT |
549 | */ |
550 | #define list_for_each_entry_safe(pos, n, head, member) \ | |
93be3c2e | 551 | for (pos = list_first_entry(head, typeof(*pos), member), \ |
8120e2e5 | 552 | n = list_next_entry(pos, member); \ |
1da177e4 | 553 | &pos->member != (head); \ |
8120e2e5 | 554 | pos = n, n = list_next_entry(n, member)) |
1da177e4 | 555 | |
74459dc7 | 556 | /** |
9a86e2ba | 557 | * list_for_each_entry_safe_continue - continue list iteration safe against removal |
8e3a67a9 | 558 | * @pos: the type * to use as a loop cursor. |
74459dc7 ACM |
559 | * @n: another type * to use as temporary storage |
560 | * @head: the head for your list. | |
3943f42c | 561 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
562 | * |
563 | * Iterate over list of given type, continuing after current point, | |
564 | * safe against removal of list entry. | |
74459dc7 ACM |
565 | */ |
566 | #define list_for_each_entry_safe_continue(pos, n, head, member) \ | |
8120e2e5 ON |
567 | for (pos = list_next_entry(pos, member), \ |
568 | n = list_next_entry(pos, member); \ | |
d8dcffee | 569 | &pos->member != (head); \ |
8120e2e5 | 570 | pos = n, n = list_next_entry(n, member)) |
d8dcffee ACM |
571 | |
572 | /** | |
9a86e2ba | 573 | * list_for_each_entry_safe_from - iterate over list from current point safe against removal |
8e3a67a9 | 574 | * @pos: the type * to use as a loop cursor. |
d8dcffee ACM |
575 | * @n: another type * to use as temporary storage |
576 | * @head: the head for your list. | |
3943f42c | 577 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
578 | * |
579 | * Iterate over list of given type from current point, safe against | |
580 | * removal of list entry. | |
d8dcffee ACM |
581 | */ |
582 | #define list_for_each_entry_safe_from(pos, n, head, member) \ | |
8120e2e5 | 583 | for (n = list_next_entry(pos, member); \ |
74459dc7 | 584 | &pos->member != (head); \ |
8120e2e5 | 585 | pos = n, n = list_next_entry(n, member)) |
74459dc7 | 586 | |
0ad42352 | 587 | /** |
9a86e2ba | 588 | * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal |
8e3a67a9 | 589 | * @pos: the type * to use as a loop cursor. |
0ad42352 DH |
590 | * @n: another type * to use as temporary storage |
591 | * @head: the head for your list. | |
3943f42c | 592 | * @member: the name of the list_head within the struct. |
fe96e57d RD |
593 | * |
594 | * Iterate backwards over list of given type, safe against removal | |
595 | * of list entry. | |
0ad42352 DH |
596 | */ |
597 | #define list_for_each_entry_safe_reverse(pos, n, head, member) \ | |
93be3c2e | 598 | for (pos = list_last_entry(head, typeof(*pos), member), \ |
8120e2e5 | 599 | n = list_prev_entry(pos, member); \ |
0ad42352 | 600 | &pos->member != (head); \ |
8120e2e5 | 601 | pos = n, n = list_prev_entry(n, member)) |
0ad42352 | 602 | |
57439f87 | 603 | /** |
604 | * list_safe_reset_next - reset a stale list_for_each_entry_safe loop | |
605 | * @pos: the loop cursor used in the list_for_each_entry_safe loop | |
606 | * @n: temporary storage used in list_for_each_entry_safe | |
3943f42c | 607 | * @member: the name of the list_head within the struct. |
57439f87 | 608 | * |
609 | * list_safe_reset_next is not safe to use in general if the list may be | |
610 | * modified concurrently (eg. the lock is dropped in the loop body). An | |
611 | * exception to this is if the cursor element (pos) is pinned in the list, | |
612 | * and list_safe_reset_next is called after re-taking the lock and before | |
613 | * completing the current iteration of the loop body. | |
614 | */ | |
615 | #define list_safe_reset_next(pos, n, member) \ | |
8120e2e5 | 616 | n = list_next_entry(pos, member) |
57439f87 | 617 | |
1da177e4 LT |
618 | /* |
619 | * Double linked lists with a single pointer list head. | |
620 | * Mostly useful for hash tables where the two pointer list head is | |
621 | * too wasteful. | |
622 | * You lose the ability to access the tail in O(1). | |
623 | */ | |
624 | ||
1da177e4 LT |
625 | #define HLIST_HEAD_INIT { .first = NULL } |
626 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } | |
627 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) | |
490d6ab1 ZB |
628 | static inline void INIT_HLIST_NODE(struct hlist_node *h) |
629 | { | |
630 | h->next = NULL; | |
631 | h->pprev = NULL; | |
632 | } | |
1da177e4 LT |
633 | |
634 | static inline int hlist_unhashed(const struct hlist_node *h) | |
635 | { | |
636 | return !h->pprev; | |
637 | } | |
638 | ||
639 | static inline int hlist_empty(const struct hlist_head *h) | |
640 | { | |
1658d35e | 641 | return !READ_ONCE(h->first); |
1da177e4 LT |
642 | } |
643 | ||
644 | static inline void __hlist_del(struct hlist_node *n) | |
645 | { | |
646 | struct hlist_node *next = n->next; | |
647 | struct hlist_node **pprev = n->pprev; | |
7f5f873c PM |
648 | |
649 | WRITE_ONCE(*pprev, next); | |
1da177e4 LT |
650 | if (next) |
651 | next->pprev = pprev; | |
652 | } | |
653 | ||
654 | static inline void hlist_del(struct hlist_node *n) | |
655 | { | |
656 | __hlist_del(n); | |
657 | n->next = LIST_POISON1; | |
658 | n->pprev = LIST_POISON2; | |
659 | } | |
660 | ||
1da177e4 LT |
661 | static inline void hlist_del_init(struct hlist_node *n) |
662 | { | |
da753bea | 663 | if (!hlist_unhashed(n)) { |
1da177e4 LT |
664 | __hlist_del(n); |
665 | INIT_HLIST_NODE(n); | |
666 | } | |
667 | } | |
668 | ||
669 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) | |
670 | { | |
671 | struct hlist_node *first = h->first; | |
672 | n->next = first; | |
673 | if (first) | |
674 | first->pprev = &n->next; | |
1c97be67 | 675 | WRITE_ONCE(h->first, n); |
1da177e4 LT |
676 | n->pprev = &h->first; |
677 | } | |
678 | ||
1da177e4 LT |
679 | /* next must be != NULL */ |
680 | static inline void hlist_add_before(struct hlist_node *n, | |
681 | struct hlist_node *next) | |
682 | { | |
683 | n->pprev = next->pprev; | |
684 | n->next = next; | |
685 | next->pprev = &n->next; | |
1c97be67 | 686 | WRITE_ONCE(*(n->pprev), n); |
1da177e4 LT |
687 | } |
688 | ||
1d023284 KH |
689 | static inline void hlist_add_behind(struct hlist_node *n, |
690 | struct hlist_node *prev) | |
1da177e4 | 691 | { |
bc18dd33 | 692 | n->next = prev->next; |
1c97be67 | 693 | WRITE_ONCE(prev->next, n); |
bc18dd33 | 694 | n->pprev = &prev->next; |
1da177e4 | 695 | |
bc18dd33 KH |
696 | if (n->next) |
697 | n->next->pprev = &n->next; | |
1da177e4 LT |
698 | } |
699 | ||
756acc2d AV |
700 | /* after that we'll appear to be on some hlist and hlist_del will work */ |
701 | static inline void hlist_add_fake(struct hlist_node *n) | |
702 | { | |
703 | n->pprev = &n->next; | |
704 | } | |
705 | ||
cbedaac6 JB |
706 | static inline bool hlist_fake(struct hlist_node *h) |
707 | { | |
708 | return h->pprev == &h->next; | |
709 | } | |
710 | ||
15dba1e3 TG |
711 | /* |
712 | * Check whether the node is the only node of the head without | |
713 | * accessing head: | |
714 | */ | |
715 | static inline bool | |
716 | hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) | |
717 | { | |
718 | return !n->next && n->pprev == &h->first; | |
719 | } | |
720 | ||
673d62cc VN |
721 | /* |
722 | * Move a list from one list head to another. Fixup the pprev | |
723 | * reference of the first entry if it exists. | |
724 | */ | |
725 | static inline void hlist_move_list(struct hlist_head *old, | |
726 | struct hlist_head *new) | |
727 | { | |
728 | new->first = old->first; | |
729 | if (new->first) | |
730 | new->first->pprev = &new->first; | |
731 | old->first = NULL; | |
732 | } | |
733 | ||
1da177e4 LT |
734 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
735 | ||
736 | #define hlist_for_each(pos, head) \ | |
75d65a42 | 737 | for (pos = (head)->first; pos ; pos = pos->next) |
1da177e4 LT |
738 | |
739 | #define hlist_for_each_safe(pos, n, head) \ | |
740 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ | |
741 | pos = n) | |
742 | ||
b67bfe0d | 743 | #define hlist_entry_safe(ptr, type, member) \ |
f65846a1 PM |
744 | ({ typeof(ptr) ____ptr = (ptr); \ |
745 | ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ | |
746 | }) | |
b67bfe0d | 747 | |
1da177e4 LT |
748 | /** |
749 | * hlist_for_each_entry - iterate over list of given type | |
b67bfe0d | 750 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
751 | * @head: the head for your list. |
752 | * @member: the name of the hlist_node within the struct. | |
753 | */ | |
b67bfe0d SL |
754 | #define hlist_for_each_entry(pos, head, member) \ |
755 | for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ | |
756 | pos; \ | |
757 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
758 | |
759 | /** | |
fe96e57d | 760 | * hlist_for_each_entry_continue - iterate over a hlist continuing after current point |
b67bfe0d | 761 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
762 | * @member: the name of the hlist_node within the struct. |
763 | */ | |
b67bfe0d SL |
764 | #define hlist_for_each_entry_continue(pos, member) \ |
765 | for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ | |
766 | pos; \ | |
767 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
768 | |
769 | /** | |
fe96e57d | 770 | * hlist_for_each_entry_from - iterate over a hlist continuing from current point |
b67bfe0d | 771 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
772 | * @member: the name of the hlist_node within the struct. |
773 | */ | |
b67bfe0d SL |
774 | #define hlist_for_each_entry_from(pos, member) \ |
775 | for (; pos; \ | |
776 | pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) | |
1da177e4 LT |
777 | |
778 | /** | |
779 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
b67bfe0d | 780 | * @pos: the type * to use as a loop cursor. |
1da177e4 LT |
781 | * @n: another &struct hlist_node to use as temporary storage |
782 | * @head: the head for your list. | |
783 | * @member: the name of the hlist_node within the struct. | |
784 | */ | |
b67bfe0d SL |
785 | #define hlist_for_each_entry_safe(pos, n, head, member) \ |
786 | for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ | |
787 | pos && ({ n = pos->member.next; 1; }); \ | |
788 | pos = hlist_entry_safe(n, typeof(*pos), member)) | |
1da177e4 | 789 | |
1da177e4 | 790 | #endif |