xref: /openbmc/u-boot/include/linux/list.h (revision 13bdce8f8cadf07bc81d7000a04e48f3028de543)
1  #ifndef _LINUX_LIST_H
2  #define _LINUX_LIST_H
3  
4  #include <linux/stddef.h>
5  #include <linux/poison.h>
6  
7  #ifndef ARCH_HAS_PREFETCH
8  #define ARCH_HAS_PREFETCH
9  static inline void prefetch(const void *x) {;}
10  #endif
11  
12  /*
13   * Simple doubly linked list implementation.
14   *
15   * Some of the internal functions ("__xxx") are useful when
16   * manipulating whole lists rather than single entries, as
17   * sometimes we already know the next/prev entries and we can
18   * generate better code by using them directly rather than
19   * using the generic single-entry routines.
20   */
21  
22  struct list_head {
23  	struct list_head *next, *prev;
24  };
25  
26  #define LIST_HEAD_INIT(name) { &(name), &(name) }
27  
28  #define LIST_HEAD(name) \
29  	struct list_head name = LIST_HEAD_INIT(name)
30  
31  static inline void INIT_LIST_HEAD(struct list_head *list)
32  {
33  	list->next = list;
34  	list->prev = list;
35  }
36  
37  /*
38   * Insert a new entry between two known consecutive entries.
39   *
40   * This is only for internal list manipulation where we know
41   * the prev/next entries already!
42   */
43  static inline void __list_add(struct list_head *new,
44  			      struct list_head *prev,
45  			      struct list_head *next)
46  {
47  	next->prev = new;
48  	new->next = next;
49  	new->prev = prev;
50  	prev->next = new;
51  }
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  }
65  
66  /**
67   * list_add_tail - add a new entry
68   * @new: new entry to be added
69   * @head: list head to add it before
70   *
71   * Insert a new entry before the specified head.
72   * This is useful for implementing queues.
73   */
74  static inline void list_add_tail(struct list_head *new, struct list_head *head)
75  {
76  	__list_add(new, head->prev, head);
77  }
78  
79  /*
80   * Delete a list entry by making the prev/next entries
81   * point to each other.
82   *
83   * This is only for internal list manipulation where we know
84   * the prev/next entries already!
85   */
86  static inline void __list_del(struct list_head *prev, struct list_head *next)
87  {
88  	next->prev = prev;
89  	prev->next = next;
90  }
91  
92  /**
93   * list_del - deletes entry from list.
94   * @entry: the element to delete from the list.
95   * Note: list_empty() on entry does not return true after this, the entry is
96   * in an undefined state.
97   */
98  static inline void list_del(struct list_head *entry)
99  {
100  	__list_del(entry->prev, entry->next);
101  	entry->next = LIST_POISON1;
102  	entry->prev = LIST_POISON2;
103  }
104  
105  /**
106   * list_replace - replace old entry by new one
107   * @old : the element to be replaced
108   * @new : the new element to insert
109   *
110   * If @old was empty, it will be overwritten.
111   */
112  static inline void list_replace(struct list_head *old,
113  				struct list_head *new)
114  {
115  	new->next = old->next;
116  	new->next->prev = new;
117  	new->prev = old->prev;
118  	new->prev->next = new;
119  }
120  
121  static inline void list_replace_init(struct list_head *old,
122  					struct list_head *new)
123  {
124  	list_replace(old, new);
125  	INIT_LIST_HEAD(old);
126  }
127  
128  /**
129   * list_del_init - deletes entry from list and reinitialize it.
130   * @entry: the element to delete from the list.
131   */
132  static inline void list_del_init(struct list_head *entry)
133  {
134  	__list_del(entry->prev, entry->next);
135  	INIT_LIST_HEAD(entry);
136  }
137  
138  /**
139   * list_move - delete from one list and add as another's head
140   * @list: the entry to move
141   * @head: the head that will precede our entry
142   */
143  static inline void list_move(struct list_head *list, struct list_head *head)
144  {
145  	__list_del(list->prev, list->next);
146  	list_add(list, head);
147  }
148  
149  /**
150   * list_move_tail - delete from one list and add as another's tail
151   * @list: the entry to move
152   * @head: the head that will follow our entry
153   */
154  static inline void list_move_tail(struct list_head *list,
155  				  struct list_head *head)
156  {
157  	__list_del(list->prev, list->next);
158  	list_add_tail(list, head);
159  }
160  
161  /**
162   * list_is_last - tests whether @list is the last entry in list @head
163   * @list: the entry to test
164   * @head: the head of the list
165   */
166  static inline int list_is_last(const struct list_head *list,
167  				const struct list_head *head)
168  {
169  	return list->next == head;
170  }
171  
172  /**
173   * list_empty - tests whether a list is empty
174   * @head: the list to test.
175   */
176  static inline int list_empty(const struct list_head *head)
177  {
178  	return head->next == head;
179  }
180  
181  /**
182   * list_empty_careful - tests whether a list is empty and not being modified
183   * @head: the list to test
184   *
185   * Description:
186   * tests whether a list is empty _and_ checks that no other CPU might be
187   * in the process of modifying either member (next or prev)
188   *
189   * NOTE: using list_empty_careful() without synchronization
190   * can only be safe if the only activity that can happen
191   * to the list entry is list_del_init(). Eg. it cannot be used
192   * if another CPU could re-list_add() it.
193   */
194  static inline int list_empty_careful(const struct list_head *head)
195  {
196  	struct list_head *next = head->next;
197  	return (next == head) && (next == head->prev);
198  }
199  
200  /**
201   * list_is_singular - tests whether a list has just one entry.
202   * @head: the list to test.
203   */
204  static inline int list_is_singular(const struct list_head *head)
205  {
206  	return !list_empty(head) && (head->next == head->prev);
207  }
208  
209  static inline void __list_cut_position(struct list_head *list,
210  		struct list_head *head, struct list_head *entry)
211  {
212  	struct list_head *new_first = entry->next;
213  	list->next = head->next;
214  	list->next->prev = list;
215  	list->prev = entry;
216  	entry->next = list;
217  	head->next = new_first;
218  	new_first->prev = head;
219  }
220  
221  /**
222   * list_cut_position - cut a list into two
223   * @list: a new list to add all removed entries
224   * @head: a list with entries
225   * @entry: an entry within head, could be the head itself
226   *	and if so we won't cut the list
227   *
228   * This helper moves the initial part of @head, up to and
229   * including @entry, from @head to @list. You should
230   * pass on @entry an element you know is on @head. @list
231   * should be an empty list or a list you do not care about
232   * losing its data.
233   *
234   */
235  static inline void list_cut_position(struct list_head *list,
236  		struct list_head *head, struct list_head *entry)
237  {
238  	if (list_empty(head))
239  		return;
240  	if (list_is_singular(head) &&
241  		(head->next != entry && head != entry))
242  		return;
243  	if (entry == head)
244  		INIT_LIST_HEAD(list);
245  	else
246  		__list_cut_position(list, head, entry);
247  }
248  
249  static inline void __list_splice(const struct list_head *list,
250  				 struct list_head *prev,
251  				 struct list_head *next)
252  {
253  	struct list_head *first = list->next;
254  	struct list_head *last = list->prev;
255  
256  	first->prev = prev;
257  	prev->next = first;
258  
259  	last->next = next;
260  	next->prev = last;
261  }
262  
263  /**
264   * list_splice - join two lists, this is designed for stacks
265   * @list: the new list to add.
266   * @head: the place to add it in the first list.
267   */
268  static inline void list_splice(const struct list_head *list,
269  				struct list_head *head)
270  {
271  	if (!list_empty(list))
272  		__list_splice(list, head, head->next);
273  }
274  
275  /**
276   * list_splice_tail - join two lists, each list being a queue
277   * @list: the new list to add.
278   * @head: the place to add it in the first list.
279   */
280  static inline void list_splice_tail(struct list_head *list,
281  				struct list_head *head)
282  {
283  	if (!list_empty(list))
284  		__list_splice(list, head->prev, head);
285  }
286  
287  /**
288   * list_splice_init - join two lists and reinitialise the emptied list.
289   * @list: the new list to add.
290   * @head: the place to add it in the first list.
291   *
292   * The list at @list is reinitialised
293   */
294  static inline void list_splice_init(struct list_head *list,
295  				    struct list_head *head)
296  {
297  	if (!list_empty(list)) {
298  		__list_splice(list, head, head->next);
299  		INIT_LIST_HEAD(list);
300  	}
301  }
302  
303  /**
304   * list_splice_tail_init - join two lists and reinitialise the emptied list
305   * @list: the new list to add.
306   * @head: the place to add it in the first list.
307   *
308   * Each of the lists is a queue.
309   * The list at @list is reinitialised
310   */
311  static inline void list_splice_tail_init(struct list_head *list,
312  					 struct list_head *head)
313  {
314  	if (!list_empty(list)) {
315  		__list_splice(list, head->prev, head);
316  		INIT_LIST_HEAD(list);
317  	}
318  }
319  
320  /**
321   * list_entry - get the struct for this entry
322   * @ptr:	the &struct list_head pointer.
323   * @type:	the type of the struct this is embedded in.
324   * @member:	the name of the list_struct within the struct.
325   */
326  #define list_entry(ptr, type, member) \
327  	container_of(ptr, type, member)
328  
329  /**
330   * list_first_entry - get the first element from a list
331   * @ptr:	the list head to take the element from.
332   * @type:	the type of the struct this is embedded in.
333   * @member:	the name of the list_struct within the struct.
334   *
335   * Note, that list is expected to be not empty.
336   */
337  #define list_first_entry(ptr, type, member) \
338  	list_entry((ptr)->next, type, member)
339  
340  /**
341   * list_last_entry - get the last element from a list
342   * @ptr:	the list head to take the element from.
343   * @type:	the type of the struct this is embedded in.
344   * @member:	the name of the list_struct within the struct.
345   *
346   * Note, that list is expected to be not empty.
347   */
348  #define list_last_entry(ptr, type, member) \
349  	list_entry((ptr)->prev, type, member)
350  
351  /**
352   * list_for_each	-	iterate over a list
353   * @pos:	the &struct list_head to use as a loop cursor.
354   * @head:	the head for your list.
355   */
356  #define list_for_each(pos, head) \
357  	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
358  		pos = pos->next)
359  
360  /**
361   * __list_for_each	-	iterate over a list
362   * @pos:	the &struct list_head to use as a loop cursor.
363   * @head:	the head for your list.
364   *
365   * This variant differs from list_for_each() in that it's the
366   * simplest possible list iteration code, no prefetching is done.
367   * Use this for code that knows the list to be very short (empty
368   * or 1 entry) most of the time.
369   */
370  #define __list_for_each(pos, head) \
371  	for (pos = (head)->next; pos != (head); pos = pos->next)
372  
373  /**
374   * list_for_each_prev	-	iterate over a list backwards
375   * @pos:	the &struct list_head to use as a loop cursor.
376   * @head:	the head for your list.
377   */
378  #define list_for_each_prev(pos, head) \
379  	for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
380  		pos = pos->prev)
381  
382  /**
383   * list_for_each_safe - iterate over a list safe against removal of list entry
384   * @pos:	the &struct list_head to use as a loop cursor.
385   * @n:		another &struct list_head to use as temporary storage
386   * @head:	the head for your list.
387   */
388  #define list_for_each_safe(pos, n, head) \
389  	for (pos = (head)->next, n = pos->next; pos != (head); \
390  		pos = n, n = pos->next)
391  
392  /**
393   * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
394   * @pos:	the &struct list_head to use as a loop cursor.
395   * @n:		another &struct list_head to use as temporary storage
396   * @head:	the head for your list.
397   */
398  #define list_for_each_prev_safe(pos, n, head) \
399  	for (pos = (head)->prev, n = pos->prev; \
400  	     prefetch(pos->prev), pos != (head); \
401  	     pos = n, n = pos->prev)
402  
403  /**
404   * list_for_each_entry	-	iterate over list of given type
405   * @pos:	the type * to use as a loop cursor.
406   * @head:	the head for your list.
407   * @member:	the name of the list_struct within the struct.
408   */
409  #define list_for_each_entry(pos, head, member)				\
410  	for (pos = list_entry((head)->next, typeof(*pos), member);	\
411  	     prefetch(pos->member.next), &pos->member != (head);	\
412  	     pos = list_entry(pos->member.next, typeof(*pos), member))
413  
414  /**
415   * list_for_each_entry_reverse - iterate backwards over list of given type.
416   * @pos:	the type * to use as a loop cursor.
417   * @head:	the head for your list.
418   * @member:	the name of the list_struct within the struct.
419   */
420  #define list_for_each_entry_reverse(pos, head, member)			\
421  	for (pos = list_entry((head)->prev, typeof(*pos), member);	\
422  	     prefetch(pos->member.prev), &pos->member != (head);	\
423  	     pos = list_entry(pos->member.prev, typeof(*pos), member))
424  
425  /**
426   * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
427   * @pos:	the type * to use as a start point
428   * @head:	the head of the list
429   * @member:	the name of the list_struct within the struct.
430   *
431   * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
432   */
433  #define list_prepare_entry(pos, head, member) \
434  	((pos) ? : list_entry(head, typeof(*pos), member))
435  
436  /**
437   * list_for_each_entry_continue - continue iteration over list of given type
438   * @pos:	the type * to use as a loop cursor.
439   * @head:	the head for your list.
440   * @member:	the name of the list_struct within the struct.
441   *
442   * Continue to iterate over list of given type, continuing after
443   * the current position.
444   */
445  #define list_for_each_entry_continue(pos, head, member) 		\
446  	for (pos = list_entry(pos->member.next, typeof(*pos), member);	\
447  	     prefetch(pos->member.next), &pos->member != (head);	\
448  	     pos = list_entry(pos->member.next, typeof(*pos), member))
449  
450  /**
451   * list_for_each_entry_continue_reverse - iterate backwards from the given point
452   * @pos:	the type * to use as a loop cursor.
453   * @head:	the head for your list.
454   * @member:	the name of the list_struct within the struct.
455   *
456   * Start to iterate over list of given type backwards, continuing after
457   * the current position.
458   */
459  #define list_for_each_entry_continue_reverse(pos, head, member)		\
460  	for (pos = list_entry(pos->member.prev, typeof(*pos), member);	\
461  	     prefetch(pos->member.prev), &pos->member != (head);	\
462  	     pos = list_entry(pos->member.prev, typeof(*pos), member))
463  
464  /**
465   * list_for_each_entry_from - iterate over list of given type from the current point
466   * @pos:	the type * to use as a loop cursor.
467   * @head:	the head for your list.
468   * @member:	the name of the list_struct within the struct.
469   *
470   * Iterate over list of given type, continuing from current position.
471   */
472  #define list_for_each_entry_from(pos, head, member)			\
473  	for (; prefetch(pos->member.next), &pos->member != (head);	\
474  	     pos = list_entry(pos->member.next, typeof(*pos), member))
475  
476  /**
477   * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
478   * @pos:	the type * to use as a loop cursor.
479   * @n:		another type * to use as temporary storage
480   * @head:	the head for your list.
481   * @member:	the name of the list_struct within the struct.
482   */
483  #define list_for_each_entry_safe(pos, n, head, member)			\
484  	for (pos = list_entry((head)->next, typeof(*pos), member),	\
485  		n = list_entry(pos->member.next, typeof(*pos), member);	\
486  	     &pos->member != (head);					\
487  	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
488  
489  /**
490   * list_for_each_entry_safe_continue
491   * @pos:	the type * to use as a loop cursor.
492   * @n:		another type * to use as temporary storage
493   * @head:	the head for your list.
494   * @member:	the name of the list_struct within the struct.
495   *
496   * Iterate over list of given type, continuing after current point,
497   * safe against removal of list entry.
498   */
499  #define list_for_each_entry_safe_continue(pos, n, head, member) 		\
500  	for (pos = list_entry(pos->member.next, typeof(*pos), member),		\
501  		n = list_entry(pos->member.next, typeof(*pos), member);		\
502  	     &pos->member != (head);						\
503  	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
504  
505  /**
506   * list_for_each_entry_safe_from
507   * @pos:	the type * to use as a loop cursor.
508   * @n:		another type * to use as temporary storage
509   * @head:	the head for your list.
510   * @member:	the name of the list_struct within the struct.
511   *
512   * Iterate over list of given type from current point, safe against
513   * removal of list entry.
514   */
515  #define list_for_each_entry_safe_from(pos, n, head, member)			\
516  	for (n = list_entry(pos->member.next, typeof(*pos), member);		\
517  	     &pos->member != (head);						\
518  	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
519  
520  /**
521   * list_for_each_entry_safe_reverse
522   * @pos:	the type * to use as a loop cursor.
523   * @n:		another type * to use as temporary storage
524   * @head:	the head for your list.
525   * @member:	the name of the list_struct within the struct.
526   *
527   * Iterate backwards over list of given type, safe against removal
528   * of list entry.
529   */
530  #define list_for_each_entry_safe_reverse(pos, n, head, member)		\
531  	for (pos = list_entry((head)->prev, typeof(*pos), member),	\
532  		n = list_entry(pos->member.prev, typeof(*pos), member);	\
533  	     &pos->member != (head);					\
534  	     pos = n, n = list_entry(n->member.prev, typeof(*n), member))
535  
536  /*
537   * Double linked lists with a single pointer list head.
538   * Mostly useful for hash tables where the two pointer list head is
539   * too wasteful.
540   * You lose the ability to access the tail in O(1).
541   */
542  
543  struct hlist_head {
544  	struct hlist_node *first;
545  };
546  
547  struct hlist_node {
548  	struct hlist_node *next, **pprev;
549  };
550  
551  #define HLIST_HEAD_INIT { .first = NULL }
552  #define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
553  #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
554  static inline void INIT_HLIST_NODE(struct hlist_node *h)
555  {
556  	h->next = NULL;
557  	h->pprev = NULL;
558  }
559  
560  static inline int hlist_unhashed(const struct hlist_node *h)
561  {
562  	return !h->pprev;
563  }
564  
565  static inline int hlist_empty(const struct hlist_head *h)
566  {
567  	return !h->first;
568  }
569  
570  static inline void __hlist_del(struct hlist_node *n)
571  {
572  	struct hlist_node *next = n->next;
573  	struct hlist_node **pprev = n->pprev;
574  	*pprev = next;
575  	if (next)
576  		next->pprev = pprev;
577  }
578  
579  static inline void hlist_del(struct hlist_node *n)
580  {
581  	__hlist_del(n);
582  	n->next = LIST_POISON1;
583  	n->pprev = LIST_POISON2;
584  }
585  
586  static inline void hlist_del_init(struct hlist_node *n)
587  {
588  	if (!hlist_unhashed(n)) {
589  		__hlist_del(n);
590  		INIT_HLIST_NODE(n);
591  	}
592  }
593  
594  static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
595  {
596  	struct hlist_node *first = h->first;
597  	n->next = first;
598  	if (first)
599  		first->pprev = &n->next;
600  	h->first = n;
601  	n->pprev = &h->first;
602  }
603  
604  /* next must be != NULL */
605  static inline void hlist_add_before(struct hlist_node *n,
606  					struct hlist_node *next)
607  {
608  	n->pprev = next->pprev;
609  	n->next = next;
610  	next->pprev = &n->next;
611  	*(n->pprev) = n;
612  }
613  
614  static inline void hlist_add_after(struct hlist_node *n,
615  					struct hlist_node *next)
616  {
617  	next->next = n->next;
618  	n->next = next;
619  	next->pprev = &n->next;
620  
621  	if(next->next)
622  		next->next->pprev  = &next->next;
623  }
624  
625  #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
626  
627  #define hlist_for_each(pos, head) \
628  	for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
629  	     pos = pos->next)
630  
631  #define hlist_for_each_safe(pos, n, head) \
632  	for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
633  	     pos = n)
634  
635  /**
636   * hlist_for_each_entry	- iterate over list of given type
637   * @tpos:	the type * to use as a loop cursor.
638   * @pos:	the &struct hlist_node to use as a loop cursor.
639   * @head:	the head for your list.
640   * @member:	the name of the hlist_node within the struct.
641   */
642  #define hlist_for_each_entry(tpos, pos, head, member)			 \
643  	for (pos = (head)->first;					 \
644  	     pos && ({ prefetch(pos->next); 1;}) &&			 \
645  		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
646  	     pos = pos->next)
647  
648  /**
649   * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
650   * @tpos:	the type * to use as a loop cursor.
651   * @pos:	the &struct hlist_node to use as a loop cursor.
652   * @member:	the name of the hlist_node within the struct.
653   */
654  #define hlist_for_each_entry_continue(tpos, pos, member)		 \
655  	for (pos = (pos)->next;						 \
656  	     pos && ({ prefetch(pos->next); 1;}) &&			 \
657  		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
658  	     pos = pos->next)
659  
660  /**
661   * hlist_for_each_entry_from - iterate over a hlist continuing from current point
662   * @tpos:	the type * to use as a loop cursor.
663   * @pos:	the &struct hlist_node to use as a loop cursor.
664   * @member:	the name of the hlist_node within the struct.
665   */
666  #define hlist_for_each_entry_from(tpos, pos, member)			 \
667  	for (; pos && ({ prefetch(pos->next); 1;}) &&			 \
668  		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
669  	     pos = pos->next)
670  
671  /**
672   * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
673   * @tpos:	the type * to use as a loop cursor.
674   * @pos:	the &struct hlist_node to use as a loop cursor.
675   * @n:		another &struct hlist_node to use as temporary storage
676   * @head:	the head for your list.
677   * @member:	the name of the hlist_node within the struct.
678   */
679  #define hlist_for_each_entry_safe(tpos, pos, n, head, member)		 \
680  	for (pos = (head)->first;					 \
681  	     pos && ({ n = pos->next; 1; }) &&				 \
682  		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
683  	     pos = n)
684  
685  #endif
686