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