1/*
2 * @TAG(OTHER_GPL)
3 */
4#pragma once
5
6#include <stddef.h>
7
8#define LIST_POISON1  ((void *) 0x0)
9#define LIST_POISON2  ((void *) 0x0)
10
11#pragma once
12static inline void prefetch(const void *x) {;}
13
14/*
15 * Simple doubly linked list implementation.
16 *
17 * Some of the internal functions ("__xxx") are useful when
18 * manipulating whole lists rather than single entries, as
19 * sometimes we already know the next/prev entries and we can
20 * generate better code by using them directly rather than
21 * using the generic single-entry routines.
22 */
23
24struct list_head {
25    struct list_head *next, *prev;
26};
27
28#define LIST_HEAD_INIT(name) { &(name), &(name) }
29
30#define LIST_HEAD(name) \
31    struct list_head name = LIST_HEAD_INIT(name)
32
33static inline void INIT_LIST_HEAD(struct list_head *list)
34{
35    list->next = list;
36    list->prev = list;
37}
38
39/*
40 * Insert a new entry between two known consecutive entries.
41 *
42 * This is only for internal list manipulation where we know
43 * the prev/next entries already!
44 */
45static inline void __list_add(struct list_head *new,
46                              struct list_head *prev,
47                              struct list_head *next)
48{
49    next->prev = new;
50    new->next = next;
51    new->prev = prev;
52    prev->next = new;
53}
54
55/**
56 * list_add - add a new entry
57 * @new: new entry to be added
58 * @head: list head to add it after
59 *
60 * Insert a new entry after the specified head.
61 * This is good for implementing stacks.
62 */
63static inline void list_add(struct list_head *new, struct list_head *head)
64{
65    __list_add(new, head, head->next);
66}
67
68/**
69 * list_add_tail - add a new entry
70 * @new: new entry to be added
71 * @head: list head to add it before
72 *
73 * Insert a new entry before the specified head.
74 * This is useful for implementing queues.
75 */
76static inline void list_add_tail(struct list_head *new, struct list_head *head)
77{
78    __list_add(new, head->prev, head);
79}
80
81/*
82 * Delete a list entry by making the prev/next entries
83 * point to each other.
84 *
85 * This is only for internal list manipulation where we know
86 * the prev/next entries already!
87 */
88static inline void __list_del(struct list_head *prev, struct list_head *next)
89{
90    next->prev = prev;
91    prev->next = next;
92}
93
94/**
95 * list_del - deletes entry from list.
96 * @entry: the element to delete from the list.
97 * Note: list_empty() on entry does not return true after this, the entry is
98 * in an undefined state.
99 */
100static inline void list_del(struct list_head *entry)
101{
102    __list_del(entry->prev, entry->next);
103    entry->next = LIST_POISON1;
104    entry->prev = LIST_POISON2;
105}
106
107/**
108 * list_replace - replace old entry by new one
109 * @old : the element to be replaced
110 * @new : the new element to insert
111 *
112 * If @old was empty, it will be overwritten.
113 */
114static inline void list_replace(struct list_head *old,
115                                struct list_head *new)
116{
117    new->next = old->next;
118    new->next->prev = new;
119    new->prev = old->prev;
120    new->prev->next = new;
121}
122
123static inline void list_replace_init(struct list_head *old,
124                                     struct list_head *new)
125{
126    list_replace(old, new);
127    INIT_LIST_HEAD(old);
128}
129
130/**
131 * list_del_init - deletes entry from list and reinitialize it.
132 * @entry: the element to delete from the list.
133 */
134static inline void list_del_init(struct list_head *entry)
135{
136    __list_del(entry->prev, entry->next);
137    INIT_LIST_HEAD(entry);
138}
139
140/**
141 * list_move - delete from one list and add as another's head
142 * @list: the entry to move
143 * @head: the head that will precede our entry
144 */
145static inline void list_move(struct list_head *list, struct list_head *head)
146{
147    __list_del(list->prev, list->next);
148    list_add(list, head);
149}
150
151/**
152 * list_move_tail - delete from one list and add as another's tail
153 * @list: the entry to move
154 * @head: the head that will follow our entry
155 */
156static inline void list_move_tail(struct list_head *list,
157                                  struct list_head *head)
158{
159    __list_del(list->prev, list->next);
160    list_add_tail(list, head);
161}
162
163/**
164 * list_is_last - tests whether @list is the last entry in list @head
165 * @list: the entry to test
166 * @head: the head of the list
167 */
168static inline int list_is_last(const struct list_head *list,
169                               const struct list_head *head)
170{
171    return list->next == head;
172}
173
174/**
175 * list_empty - tests whether a list is empty
176 * @head: the list to test.
177 */
178static inline int list_empty(const struct list_head *head)
179{
180    return head->next == head;
181}
182
183/**
184 * list_empty_careful - tests whether a list is empty and not being modified
185 * @head: the list to test
186 *
187 * Description:
188 * tests whether a list is empty _and_ checks that no other CPU might be
189 * in the process of modifying either member (next or prev)
190 *
191 * NOTE: using list_empty_careful() without synchronization
192 * can only be safe if the only activity that can happen
193 * to the list entry is list_del_init(). Eg. it cannot be used
194 * if another CPU could re-list_add() it.
195 */
196static inline int list_empty_careful(const struct list_head *head)
197{
198    struct list_head *next = head->next;
199    return (next == head) && (next == head->prev);
200}
201
202/**
203 * list_is_singular - tests whether a list has just one entry.
204 * @head: the list to test.
205 */
206static inline int list_is_singular(const struct list_head *head)
207{
208    return !list_empty(head) && (head->next == head->prev);
209}
210
211static inline void __list_cut_position(struct list_head *list,
212                                       struct list_head *head, struct list_head *entry)
213{
214    struct list_head *new_first = entry->next;
215    list->next = head->next;
216    list->next->prev = list;
217    list->prev = entry;
218    entry->next = list;
219    head->next = new_first;
220    new_first->prev = head;
221}
222
223/**
224 * list_cut_position - cut a list into two
225 * @list: a new list to add all removed entries
226 * @head: a list with entries
227 * @entry: an entry within head, could be the head itself
228 *  and if so we won't cut the list
229 *
230 * This helper moves the initial part of @head, up to and
231 * including @entry, from @head to @list. You should
232 * pass on @entry an element you know is on @head. @list
233 * should be an empty list or a list you do not care about
234 * losing its data.
235 *
236 */
237static inline void list_cut_position(struct list_head *list,
238                                     struct list_head *head, struct list_head *entry)
239{
240    if (list_empty(head)) {
241        return;
242    }
243    if (list_is_singular(head) &&
244        (head->next != entry && head != entry)) {
245        return;
246    }
247    if (entry == head) {
248        INIT_LIST_HEAD(list);
249    } else {
250        __list_cut_position(list, head, entry);
251    }
252}
253
254static inline void __list_splice(const struct list_head *list,
255                                 struct list_head *prev,
256                                 struct list_head *next)
257{
258    struct list_head *first = list->next;
259    struct list_head *last = list->prev;
260
261    first->prev = prev;
262    prev->next = first;
263
264    last->next = next;
265    next->prev = last;
266}
267
268/**
269 * list_splice - join two lists, this is designed for stacks
270 * @list: the new list to add.
271 * @head: the place to add it in the first list.
272 */
273static inline void list_splice(const struct list_head *list,
274                               struct list_head *head)
275{
276    if (!list_empty(list)) {
277        __list_splice(list, head, head->next);
278    }
279}
280
281/**
282 * list_splice_tail - join two lists, each list being a queue
283 * @list: the new list to add.
284 * @head: the place to add it in the first list.
285 */
286static inline void list_splice_tail(struct list_head *list,
287                                    struct list_head *head)
288{
289    if (!list_empty(list)) {
290        __list_splice(list, head->prev, head);
291    }
292}
293
294/**
295 * list_splice_init - join two lists and reinitialise the emptied list.
296 * @list: the new list to add.
297 * @head: the place to add it in the first list.
298 *
299 * The list at @list is reinitialised
300 */
301static inline void list_splice_init(struct list_head *list,
302                                    struct list_head *head)
303{
304    if (!list_empty(list)) {
305        __list_splice(list, head, head->next);
306        INIT_LIST_HEAD(list);
307    }
308}
309
310/**
311 * list_splice_tail_init - join two lists and reinitialise the emptied list
312 * @list: the new list to add.
313 * @head: the place to add it in the first list.
314 *
315 * Each of the lists is a queue.
316 * The list at @list is reinitialised
317 */
318static inline void list_splice_tail_init(struct list_head *list,
319                                         struct list_head *head)
320{
321    if (!list_empty(list)) {
322        __list_splice(list, head->prev, head);
323        INIT_LIST_HEAD(list);
324    }
325}
326
327/**
328 * list_entry - get the struct for this entry
329 * @ptr:    the &struct list_head pointer.
330 * @type:   the type of the struct this is embedded in.
331 * @member: the name of the list_struct within the struct.
332 */
333#define list_entry(ptr, type, member) \
334    container_of(ptr, type, member)
335
336/**
337 * list_first_entry - get the first element from a list
338 * @ptr:    the list head to take the element from.
339 * @type:   the type of the struct this is embedded in.
340 * @member: the name of the list_struct within the struct.
341 *
342 * Note, that list is expected to be not empty.
343 */
344#define list_first_entry(ptr, type, member) \
345    list_entry((ptr)->next, type, member)
346
347/**
348 * list_for_each    -   iterate over a list
349 * @pos:    the &struct list_head to use as a loop cursor.
350 * @head:   the head for your list.
351 */
352#define list_for_each(pos, head) \
353    for (pos = (head)->next; prefetch(pos->next), pos != (head); \
354        pos = pos->next)
355
356/**
357 * __list_for_each  -   iterate over a list
358 * @pos:    the &struct list_head to use as a loop cursor.
359 * @head:   the head for your list.
360 *
361 * This variant differs from list_for_each() in that it's the
362 * simplest possible list iteration code, no prefetching is done.
363 * Use this for code that knows the list to be very short (empty
364 * or 1 entry) most of the time.
365 */
366#define __list_for_each(pos, head) \
367    for (pos = (head)->next; pos != (head); pos = pos->next)
368
369/**
370 * list_for_each_prev   -   iterate over a list backwards
371 * @pos:    the &struct list_head to use as a loop cursor.
372 * @head:   the head for your list.
373 */
374#define list_for_each_prev(pos, head) \
375    for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
376        pos = pos->prev)
377
378/**
379 * list_for_each_safe - iterate over a list safe against removal of list entry
380 * @pos:    the &struct list_head to use as a loop cursor.
381 * @n:      another &struct list_head to use as temporary storage
382 * @head:   the head for your list.
383 */
384#define list_for_each_safe(pos, n, head) \
385    for (pos = (head)->next, n = pos->next; pos != (head); \
386        pos = n, n = pos->next)
387
388/**
389 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
390 * @pos:    the &struct list_head to use as a loop cursor.
391 * @n:      another &struct list_head to use as temporary storage
392 * @head:   the head for your list.
393 */
394#define list_for_each_prev_safe(pos, n, head) \
395    for (pos = (head)->prev, n = pos->prev; \
396         prefetch(pos->prev), pos != (head); \
397         pos = n, n = pos->prev)
398
399/**
400 * list_for_each_entry  -   iterate over list of given type
401 * @pos:    the type * to use as a loop cursor.
402 * @head:   the head for your list.
403 * @member: the name of the list_struct within the struct.
404 */
405#define list_for_each_entry(pos, head, member)              \
406    for (pos = list_entry((head)->next, typeof(*pos), member);  \
407         prefetch(pos->member.next), &pos->member != (head);    \
408         pos = list_entry(pos->member.next, typeof(*pos), member))
409
410/**
411 * list_for_each_entry_reverse - iterate backwards over list of given type.
412 * @pos:    the type * to use as a loop cursor.
413 * @head:   the head for your list.
414 * @member: the name of the list_struct within the struct.
415 */
416#define list_for_each_entry_reverse(pos, head, member)          \
417    for (pos = list_entry((head)->prev, typeof(*pos), member);  \
418         prefetch(pos->member.prev), &pos->member != (head);    \
419         pos = list_entry(pos->member.prev, typeof(*pos), member))
420
421/**
422 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
423 * @pos:    the type * to use as a start point
424 * @head:   the head of the list
425 * @member: the name of the list_struct within the struct.
426 *
427 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
428 */
429#define list_prepare_entry(pos, head, member) \
430    ((pos) ? : list_entry(head, typeof(*pos), member))
431
432/**
433 * list_for_each_entry_continue - continue iteration over list of given type
434 * @pos:    the type * to use as a loop cursor.
435 * @head:   the head for your list.
436 * @member: the name of the list_struct within the struct.
437 *
438 * Continue to iterate over list of given type, continuing after
439 * the current position.
440 */
441#define list_for_each_entry_continue(pos, head, member)         \
442    for (pos = list_entry(pos->member.next, typeof(*pos), member);  \
443         prefetch(pos->member.next), &pos->member != (head);    \
444         pos = list_entry(pos->member.next, typeof(*pos), member))
445
446/**
447 * list_for_each_entry_continue_reverse - iterate backwards from the given point
448 * @pos:    the type * to use as a loop cursor.
449 * @head:   the head for your list.
450 * @member: the name of the list_struct within the struct.
451 *
452 * Start to iterate over list of given type backwards, continuing after
453 * the current position.
454 */
455#define list_for_each_entry_continue_reverse(pos, head, member)     \
456    for (pos = list_entry(pos->member.prev, typeof(*pos), member);  \
457         prefetch(pos->member.prev), &pos->member != (head);    \
458         pos = list_entry(pos->member.prev, typeof(*pos), member))
459
460/**
461 * list_for_each_entry_from - iterate over list of given type from the current point
462 * @pos:    the type * to use as a loop cursor.
463 * @head:   the head for your list.
464 * @member: the name of the list_struct within the struct.
465 *
466 * Iterate over list of given type, continuing from current position.
467 */
468#define list_for_each_entry_from(pos, head, member)         \
469    for (; prefetch(pos->member.next), &pos->member != (head);  \
470         pos = list_entry(pos->member.next, typeof(*pos), member))
471
472/**
473 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
474 * @pos:    the type * to use as a loop cursor.
475 * @n:      another type * to use as temporary storage
476 * @head:   the head for your list.
477 * @member: the name of the list_struct within the struct.
478 */
479#define list_for_each_entry_safe(pos, n, head, member)          \
480    for (pos = list_entry((head)->next, typeof(*pos), member),  \
481        n = list_entry(pos->member.next, typeof(*pos), member); \
482         &pos->member != (head);                    \
483         pos = n, n = list_entry(n->member.next, typeof(*n), member))
484
485/**
486 * list_for_each_entry_safe_continue
487 * @pos:    the type * to use as a loop cursor.
488 * @n:      another type * to use as temporary storage
489 * @head:   the head for your list.
490 * @member: the name of the list_struct within the struct.
491 *
492 * Iterate over list of given type, continuing after current point,
493 * safe against removal of list entry.
494 */
495#define list_for_each_entry_safe_continue(pos, n, head, member)         \
496    for (pos = list_entry(pos->member.next, typeof(*pos), member),      \
497        n = list_entry(pos->member.next, typeof(*pos), member);     \
498         &pos->member != (head);                        \
499         pos = n, n = list_entry(n->member.next, typeof(*n), member))
500
501/**
502 * list_for_each_entry_safe_from
503 * @pos:    the type * to use as a loop cursor.
504 * @n:      another type * to use as temporary storage
505 * @head:   the head for your list.
506 * @member: the name of the list_struct within the struct.
507 *
508 * Iterate over list of given type from current point, safe against
509 * removal of list entry.
510 */
511#define list_for_each_entry_safe_from(pos, n, head, member)         \
512    for (n = list_entry(pos->member.next, typeof(*pos), member);        \
513         &pos->member != (head);                        \
514         pos = n, n = list_entry(n->member.next, typeof(*n), member))
515
516/**
517 * list_for_each_entry_safe_reverse
518 * @pos:    the type * to use as a loop cursor.
519 * @n:      another type * to use as temporary storage
520 * @head:   the head for your list.
521 * @member: the name of the list_struct within the struct.
522 *
523 * Iterate backwards over list of given type, safe against removal
524 * of list entry.
525 */
526#define list_for_each_entry_safe_reverse(pos, n, head, member)      \
527    for (pos = list_entry((head)->prev, typeof(*pos), member),  \
528        n = list_entry(pos->member.prev, typeof(*pos), member); \
529         &pos->member != (head);                    \
530         pos = n, n = list_entry(n->member.prev, typeof(*n), member))
531
532/*
533 * Double linked lists with a single pointer list head.
534 * Mostly useful for hash tables where the two pointer list head is
535 * too wasteful.
536 * You lose the ability to access the tail in O(1).
537 */
538
539struct hlist_head {
540    struct hlist_node *first;
541};
542
543struct hlist_node {
544    struct hlist_node *next, * *pprev;
545};
546
547#define HLIST_HEAD_INIT { .first = NULL }
548#define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
549#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
550static inline void INIT_HLIST_NODE(struct hlist_node *h)
551{
552    h->next = NULL;
553    h->pprev = NULL;
554}
555
556static inline int hlist_unhashed(const struct hlist_node *h)
557{
558    return !h->pprev;
559}
560
561static inline int hlist_empty(const struct hlist_head *h)
562{
563    return !h->first;
564}
565
566static inline void __hlist_del(struct hlist_node *n)
567{
568    struct hlist_node *next = n->next;
569    struct hlist_node **pprev = n->pprev;
570    *pprev = next;
571    if (next) {
572        next->pprev = pprev;
573    }
574}
575
576static inline void hlist_del(struct hlist_node *n)
577{
578    __hlist_del(n);
579    n->next = LIST_POISON1;
580    n->pprev = LIST_POISON2;
581}
582
583static inline void hlist_del_init(struct hlist_node *n)
584{
585    if (!hlist_unhashed(n)) {
586        __hlist_del(n);
587        INIT_HLIST_NODE(n);
588    }
589}
590
591static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
592{
593    struct hlist_node *first = h->first;
594    n->next = first;
595    if (first) {
596        first->pprev = &n->next;
597    }
598    h->first = n;
599    n->pprev = &h->first;
600}
601
602/* next must be != NULL */
603static inline void hlist_add_before(struct hlist_node *n,
604                                    struct hlist_node *next)
605{
606    n->pprev = next->pprev;
607    n->next = next;
608    next->pprev = &n->next;
609    *(n->pprev) = n;
610}
611
612static inline void hlist_add_after(struct hlist_node *n,
613                                   struct hlist_node *next)
614{
615    next->next = n->next;
616    n->next = next;
617    next->pprev = &n->next;
618
619    if (next->next) {
620        next->next->pprev  = &next->next;
621    }
622}
623
624#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
625
626#define hlist_for_each(pos, head) \
627    for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
628         pos = pos->next)
629
630#define hlist_for_each_safe(pos, n, head) \
631    for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
632         pos = n)
633
634/**
635 * hlist_for_each_entry - iterate over list of given type
636 * @tpos:   the type * to use as a loop cursor.
637 * @pos:    the &struct hlist_node to use as a loop cursor.
638 * @head:   the head for your list.
639 * @member: the name of the hlist_node within the struct.
640 */
641#define hlist_for_each_entry(tpos, pos, head, member)            \
642    for (pos = (head)->first;                    \
643         pos && ({ prefetch(pos->next); 1;}) &&          \
644        ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
645         pos = pos->next)
646
647/**
648 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
649 * @tpos:   the type * to use as a loop cursor.
650 * @pos:    the &struct hlist_node to use as a loop cursor.
651 * @member: the name of the hlist_node within the struct.
652 */
653#define hlist_for_each_entry_continue(tpos, pos, member)         \
654    for (pos = (pos)->next;                      \
655         pos && ({ prefetch(pos->next); 1;}) &&          \
656        ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
657         pos = pos->next)
658
659/**
660 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
661 * @tpos:   the type * to use as a loop cursor.
662 * @pos:    the &struct hlist_node to use as a loop cursor.
663 * @member: the name of the hlist_node within the struct.
664 */
665#define hlist_for_each_entry_from(tpos, pos, member)             \
666    for (; pos && ({ prefetch(pos->next); 1;}) &&            \
667        ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
668         pos = pos->next)
669
670/**
671 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
672 * @tpos:   the type * to use as a loop cursor.
673 * @pos:    the &struct hlist_node to use as a loop cursor.
674 * @n:      another &struct hlist_node to use as temporary storage
675 * @head:   the head for your list.
676 * @member: the name of the hlist_node within the struct.
677 */
678#define hlist_for_each_entry_safe(tpos, pos, n, head, member)        \
679    for (pos = (head)->first;                    \
680         pos && ({ n = pos->next; 1; }) &&               \
681        ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
682         pos = n)
683