1 #ifndef _LINUX_LIST_H
2 #define _LINUX_LIST_H
3 
4 #include <stddef.h>
5 
prefetch(const void * x)6 static inline void prefetch(const void *x) {;}
7 
8 #ifndef offsetof
9 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
10 #endif
11 
12 #ifdef QEMU_OLD
13 /**
14  * container_of - cast a member of a structure out to the containing structure
15  *
16  * @ptr:	the pointer to the member.
17  * @type:	the type of the container struct this is embedded in.
18  * @member:	the name of the member within the struct.
19  *
20  */
21 #define container_of(ptr, type, member) ({			\
22         const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
23         (type *)( (char *)__mptr - offsetof(type,member) );})
24 #endif
25 
26 /*
27  * These are non-NULL pointers that will result in page faults
28  * under normal circumstances, used to verify that nobody uses
29  * non-initialized list entries.
30  */
31 #define LIST_POISON1  ((void *) 0x00100100)
32 #define LIST_POISON2  ((void *) 0x00200200)
33 
34 /*
35  * Simple doubly linked list implementation.
36  *
37  * Some of the internal functions ("__xxx") are useful when
38  * manipulating whole lists rather than single entries, as
39  * sometimes we already know the next/prev entries and we can
40  * generate better code by using them directly rather than
41  * using the generic single-entry routines.
42  */
43 
44 struct list_head {
45 	struct list_head *next, *prev;
46 };
47 
48 #define LIST_HEAD_INIT(name) { &(name), &(name) }
49 
50 #define LIST_HEAD(name) \
51 	struct list_head name = LIST_HEAD_INIT(name)
52 
53 #define INIT_LIST_HEAD(ptr) do { \
54 	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
55 } while (0)
56 
57 /*
58  * Insert a new entry between two known consecutive entries.
59  *
60  * This is only for internal list manipulation where we know
61  * the prev/next entries already!
62  */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)63 static inline void __list_add(struct list_head *new,
64 			      struct list_head *prev,
65 			      struct list_head *next)
66 {
67 	next->prev = new;
68 	new->next = next;
69 	new->prev = prev;
70 	prev->next = new;
71 }
72 
73 /**
74  * list_add - add a new entry
75  * @new: new entry to be added
76  * @head: list head to add it after
77  *
78  * Insert a new entry after the specified head.
79  * This is good for implementing stacks.
80  */
list_add(struct list_head * new,struct list_head * head)81 static inline void list_add(struct list_head *new, struct list_head *head)
82 {
83 	__list_add(new, head, head->next);
84 }
85 
86 /**
87  * list_add_tail - add a new entry
88  * @new: new entry to be added
89  * @head: list head to add it before
90  *
91  * Insert a new entry before the specified head.
92  * This is useful for implementing queues.
93  */
list_add_tail(struct list_head * new,struct list_head * head)94 static inline void list_add_tail(struct list_head *new, struct list_head *head)
95 {
96 	__list_add(new, head->prev, head);
97 }
98 
99 /*
100  * Delete a list entry by making the prev/next entries
101  * point to each other.
102  *
103  * This is only for internal list manipulation where we know
104  * the prev/next entries already!
105  */
__list_del(struct list_head * prev,struct list_head * next)106 static inline void __list_del(struct list_head * prev, struct list_head * next)
107 {
108 	next->prev = prev;
109 	prev->next = next;
110 }
111 
112 /**
113  * list_del - deletes entry from list.
114  * @entry: the element to delete from the list.
115  * Note: list_empty on entry does not return true after this, the entry is
116  * in an undefined state.
117  */
list_del(struct list_head * entry)118 static inline void list_del(struct list_head *entry)
119 {
120 	__list_del(entry->prev, entry->next);
121 	entry->next = LIST_POISON1;
122 	entry->prev = LIST_POISON2;
123 }
124 
125 /**
126  * list_del_init - deletes entry from list and reinitialize it.
127  * @entry: the element to delete from the list.
128  */
list_del_init(struct list_head * entry)129 static inline void list_del_init(struct list_head *entry)
130 {
131 	__list_del(entry->prev, entry->next);
132 	INIT_LIST_HEAD(entry);
133 }
134 
135 /**
136  * list_move - delete from one list and add as another's head
137  * @list: the entry to move
138  * @head: the head that will precede our entry
139  */
list_move(struct list_head * list,struct list_head * head)140 static inline void list_move(struct list_head *list, struct list_head *head)
141 {
142         __list_del(list->prev, list->next);
143         list_add(list, head);
144 }
145 
146 /**
147  * list_move_tail - delete from one list and add as another's tail
148  * @list: the entry to move
149  * @head: the head that will follow our entry
150  */
list_move_tail(struct list_head * list,struct list_head * head)151 static inline void list_move_tail(struct list_head *list,
152 				  struct list_head *head)
153 {
154         __list_del(list->prev, list->next);
155         list_add_tail(list, head);
156 }
157 
158 /**
159  * list_empty - tests whether a list is empty
160  * @head: the list to test.
161  */
list_empty(const struct list_head * head)162 static inline int list_empty(const struct list_head *head)
163 {
164 	return head->next == head;
165 }
166 
167 /**
168  * list_empty_careful - tests whether a list is
169  * empty _and_ checks that no other CPU might be
170  * in the process of still modifying either member
171  *
172  * NOTE: using list_empty_careful() without synchronization
173  * can only be safe if the only activity that can happen
174  * to the list entry is list_del_init(). Eg. it cannot be used
175  * if another CPU could re-list_add() it.
176  *
177  * @head: the list to test.
178  */
list_empty_careful(const struct list_head * head)179 static inline int list_empty_careful(const struct list_head *head)
180 {
181 	struct list_head *next = head->next;
182 	return (next == head) && (next == head->prev);
183 }
184 
__list_splice(struct list_head * list,struct list_head * head)185 static inline void __list_splice(struct list_head *list,
186 				 struct list_head *head)
187 {
188 	struct list_head *first = list->next;
189 	struct list_head *last = list->prev;
190 	struct list_head *at = head->next;
191 
192 	first->prev = head;
193 	head->next = first;
194 
195 	last->next = at;
196 	at->prev = last;
197 }
198 
199 /**
200  * list_splice - join two lists
201  * @list: the new list to add.
202  * @head: the place to add it in the first list.
203  */
list_splice(struct list_head * list,struct list_head * head)204 static inline void list_splice(struct list_head *list, struct list_head *head)
205 {
206 	if (!list_empty(list))
207 		__list_splice(list, head);
208 }
209 
210 /**
211  * list_splice_init - join two lists and reinitialise the emptied list.
212  * @list: the new list to add.
213  * @head: the place to add it in the first list.
214  *
215  * The list at @list is reinitialised
216  */
list_splice_init(struct list_head * list,struct list_head * head)217 static inline void list_splice_init(struct list_head *list,
218 				    struct list_head *head)
219 {
220 	if (!list_empty(list)) {
221 		__list_splice(list, head);
222 		INIT_LIST_HEAD(list);
223 	}
224 }
225 
226 /**
227  * list_entry - get the struct for this entry
228  * @ptr:	the &struct list_head pointer.
229  * @type:	the type of the struct this is embedded in.
230  * @member:	the name of the list_struct within the struct.
231  */
232 #define list_entry(ptr, type, member) \
233 	container_of(ptr, type, member)
234 
235 /**
236  * list_for_each	-	iterate over a list
237  * @pos:	the &struct list_head to use as a loop counter.
238  * @head:	the head for your list.
239  */
240 #define list_for_each(pos, head) \
241 	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
242         	pos = pos->next)
243 
244 /**
245  * __list_for_each	-	iterate over a list
246  * @pos:	the &struct list_head to use as a loop counter.
247  * @head:	the head for your list.
248  *
249  * This variant differs from list_for_each() in that it's the
250  * simplest possible list iteration code, no prefetching is done.
251  * Use this for code that knows the list to be very short (empty
252  * or 1 entry) most of the time.
253  */
254 #define __list_for_each(pos, head) \
255 	for (pos = (head)->next; pos != (head); pos = pos->next)
256 
257 /**
258  * list_for_each_prev	-	iterate over a list backwards
259  * @pos:	the &struct list_head to use as a loop counter.
260  * @head:	the head for your list.
261  */
262 #define list_for_each_prev(pos, head) \
263 	for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
264         	pos = pos->prev)
265 
266 /**
267  * list_for_each_safe	-	iterate over a list safe against removal of list entry
268  * @pos:	the &struct list_head to use as a loop counter.
269  * @n:		another &struct list_head to use as temporary storage
270  * @head:	the head for your list.
271  */
272 #define list_for_each_safe(pos, n, head) \
273 	for (pos = (head)->next, n = pos->next; pos != (head); \
274 		pos = n, n = pos->next)
275 
276 /**
277  * list_for_each_entry	-	iterate over list of given type
278  * @pos:	the type * to use as a loop counter.
279  * @head:	the head for your list.
280  * @member:	the name of the list_struct within the struct.
281  */
282 #define list_for_each_entry(pos, head, member)				\
283 	for (pos = list_entry((head)->next, typeof(*pos), member);	\
284 	     prefetch(pos->member.next), &pos->member != (head); 	\
285 	     pos = list_entry(pos->member.next, typeof(*pos), member))
286 
287 /**
288  * list_for_each_entry_reverse - iterate backwards over list of given type.
289  * @pos:	the type * to use as a loop counter.
290  * @head:	the head for your list.
291  * @member:	the name of the list_struct within the struct.
292  */
293 #define list_for_each_entry_reverse(pos, head, member)			\
294 	for (pos = list_entry((head)->prev, typeof(*pos), member);	\
295 	     prefetch(pos->member.prev), &pos->member != (head); 	\
296 	     pos = list_entry(pos->member.prev, typeof(*pos), member))
297 
298 /**
299  * list_prepare_entry - prepare a pos entry for use as a start point in
300  *			list_for_each_entry_continue
301  * @pos:	the type * to use as a start point
302  * @head:	the head of the list
303  * @member:	the name of the list_struct within the struct.
304  */
305 #define list_prepare_entry(pos, head, member) \
306 	((pos) ? : list_entry(head, typeof(*pos), member))
307 
308 /**
309  * list_for_each_entry_continue -	iterate over list of given type
310  *			continuing after existing point
311  * @pos:	the type * to use as a loop counter.
312  * @head:	the head for your list.
313  * @member:	the name of the list_struct within the struct.
314  */
315 #define list_for_each_entry_continue(pos, head, member) 		\
316 	for (pos = list_entry(pos->member.next, typeof(*pos), member);	\
317 	     prefetch(pos->member.next), &pos->member != (head);	\
318 	     pos = list_entry(pos->member.next, typeof(*pos), member))
319 
320 /**
321  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
322  * @pos:	the type * to use as a loop counter.
323  * @n:		another type * to use as temporary storage
324  * @head:	the head for your list.
325  * @member:	the name of the list_struct within the struct.
326  */
327 #define list_for_each_entry_safe(pos, n, head, member)			\
328 	for (pos = list_entry((head)->next, typeof(*pos), member),	\
329 		n = list_entry(pos->member.next, typeof(*pos), member);	\
330 	     &pos->member != (head); 					\
331 	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
332 
333 /**
334  * list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against removal of list entry.
335  * @pos:	the type * to use as a loop counter.
336  * @n:		another type * to use as temporary storage
337  * @head:	the head for your list.
338  * @member:	the name of the list_struct within the struct.
339  */
340 #define list_for_each_entry_safe_reverse(pos, n, head, member)		\
341 	for (pos = list_entry((head)->prev, typeof(*pos), member),	\
342 		n = list_entry(pos->member.prev, typeof(*pos), member);	\
343 	     prefetch(pos->member.prev), &pos->member != (head); 	\
344 	     pos = n, n = list_entry(n->member.prev, typeof(*n), member))
345 
346 /**
347  * list_for_each_rcu	-	iterate over an rcu-protected list
348  * @pos:	the &struct list_head to use as a loop counter.
349  * @head:	the head for your list.
350  *
351  * This list-traversal primitive may safely run concurrently with
352  * the _rcu list-mutation primitives such as list_add_rcu()
353  * as long as the traversal is guarded by rcu_read_lock().
354  */
355 #define list_for_each_rcu(pos, head) \
356 	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
357         	pos = rcu_dereference(pos->next))
358 
359 #define __list_for_each_rcu(pos, head) \
360 	for (pos = (head)->next; pos != (head); \
361         	pos = rcu_dereference(pos->next))
362 
363 /**
364  * list_for_each_safe_rcu	-	iterate over an rcu-protected list safe
365  *					against removal of list entry
366  * @pos:	the &struct list_head to use as a loop counter.
367  * @n:		another &struct list_head to use as temporary storage
368  * @head:	the head for your list.
369  *
370  * This list-traversal primitive may safely run concurrently with
371  * the _rcu list-mutation primitives such as list_add_rcu()
372  * as long as the traversal is guarded by rcu_read_lock().
373  */
374 #define list_for_each_safe_rcu(pos, n, head) \
375 	for (pos = (head)->next, n = pos->next; pos != (head); \
376 		pos = rcu_dereference(n), n = pos->next)
377 
378 /**
379  * list_for_each_entry_rcu	-	iterate over rcu list of given type
380  * @pos:	the type * to use as a loop counter.
381  * @head:	the head for your list.
382  * @member:	the name of the list_struct within the struct.
383  *
384  * This list-traversal primitive may safely run concurrently with
385  * the _rcu list-mutation primitives such as list_add_rcu()
386  * as long as the traversal is guarded by rcu_read_lock().
387  */
388 #define list_for_each_entry_rcu(pos, head, member)			\
389 	for (pos = list_entry((head)->next, typeof(*pos), member);	\
390 	     prefetch(pos->member.next), &pos->member != (head); 	\
391 	     pos = rcu_dereference(list_entry(pos->member.next, 	\
392 					typeof(*pos), member)))
393 
394 
395 /**
396  * list_for_each_continue_rcu	-	iterate over an rcu-protected list
397  *			continuing after existing point.
398  * @pos:	the &struct list_head to use as a loop counter.
399  * @head:	the head for your list.
400  *
401  * This list-traversal primitive may safely run concurrently with
402  * the _rcu list-mutation primitives such as list_add_rcu()
403  * as long as the traversal is guarded by rcu_read_lock().
404  */
405 #define list_for_each_continue_rcu(pos, head) \
406 	for ((pos) = (pos)->next; prefetch((pos)->next), (pos) != (head); \
407         	(pos) = rcu_dereference((pos)->next))
408 
409 /*
410  * Double linked lists with a single pointer list head.
411  * Mostly useful for hash tables where the two pointer list head is
412  * too wasteful.
413  * You lose the ability to access the tail in O(1).
414  */
415 
416 struct hlist_head {
417 	struct hlist_node *first;
418 };
419 
420 struct hlist_node {
421 	struct hlist_node *next, **pprev;
422 };
423 
424 #define HLIST_HEAD_INIT { .first = NULL }
425 #define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
426 #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
427 #define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL)
428 
hlist_unhashed(const struct hlist_node * h)429 static inline int hlist_unhashed(const struct hlist_node *h)
430 {
431 	return !h->pprev;
432 }
433 
hlist_empty(const struct hlist_head * h)434 static inline int hlist_empty(const struct hlist_head *h)
435 {
436 	return !h->first;
437 }
438 
__hlist_del(struct hlist_node * n)439 static inline void __hlist_del(struct hlist_node *n)
440 {
441 	struct hlist_node *next = n->next;
442 	struct hlist_node **pprev = n->pprev;
443 	*pprev = next;
444 	if (next)
445 		next->pprev = pprev;
446 }
447 
hlist_del(struct hlist_node * n)448 static inline void hlist_del(struct hlist_node *n)
449 {
450 	__hlist_del(n);
451 	n->next = LIST_POISON1;
452 	n->pprev = LIST_POISON2;
453 }
454 
455 /**
456  * hlist_del_rcu - deletes entry from hash list without re-initialization
457  * @n: the element to delete from the hash list.
458  *
459  * Note: list_unhashed() on entry does not return true after this,
460  * the entry is in an undefined state. It is useful for RCU based
461  * lockfree traversal.
462  *
463  * In particular, it means that we can not poison the forward
464  * pointers that may still be used for walking the hash list.
465  *
466  * The caller must take whatever precautions are necessary
467  * (such as holding appropriate locks) to avoid racing
468  * with another list-mutation primitive, such as hlist_add_head_rcu()
469  * or hlist_del_rcu(), running on this same list.
470  * However, it is perfectly legal to run concurrently with
471  * the _rcu list-traversal primitives, such as
472  * hlist_for_each_entry().
473  */
hlist_del_rcu(struct hlist_node * n)474 static inline void hlist_del_rcu(struct hlist_node *n)
475 {
476 	__hlist_del(n);
477 	n->pprev = LIST_POISON2;
478 }
479 
hlist_del_init(struct hlist_node * n)480 static inline void hlist_del_init(struct hlist_node *n)
481 {
482 	if (n->pprev)  {
483 		__hlist_del(n);
484 		INIT_HLIST_NODE(n);
485 	}
486 }
487 
hlist_add_head(struct hlist_node * n,struct hlist_head * h)488 static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
489 {
490 	struct hlist_node *first = h->first;
491 	n->next = first;
492 	if (first)
493 		first->pprev = &n->next;
494 	h->first = n;
495 	n->pprev = &h->first;
496 }
497 
498 /* next must be != NULL */
hlist_add_before(struct hlist_node * n,struct hlist_node * next)499 static inline void hlist_add_before(struct hlist_node *n,
500 					struct hlist_node *next)
501 {
502 	n->pprev = next->pprev;
503 	n->next = next;
504 	next->pprev = &n->next;
505 	*(n->pprev) = n;
506 }
507 
hlist_add_after(struct hlist_node * n,struct hlist_node * next)508 static inline void hlist_add_after(struct hlist_node *n,
509 					struct hlist_node *next)
510 {
511 	next->next = n->next;
512 	n->next = next;
513 	next->pprev = &n->next;
514 
515 	if(next->next)
516 		next->next->pprev  = &next->next;
517 }
518 
519 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
520 
521 #define hlist_for_each(pos, head) \
522 	for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
523 	     pos = pos->next)
524 
525 #define hlist_for_each_safe(pos, n, head) \
526 	for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
527 	     pos = n)
528 
529 #define hlist_for_each_rcu(pos, head) \
530 	for ((pos) = (head)->first; pos && ({ prefetch((pos)->next); 1; }); \
531 		(pos) = rcu_dereference((pos)->next))
532 
533 /**
534  * hlist_for_each_entry	- iterate over list of given type
535  * @tpos:	the type * to use as a loop counter.
536  * @pos:	the &struct hlist_node to use as a loop counter.
537  * @head:	the head for your list.
538  * @member:	the name of the hlist_node within the struct.
539  */
540 #define hlist_for_each_entry(tpos, pos, head, member)			 \
541 	for (pos = (head)->first;					 \
542 	     pos && ({ prefetch(pos->next); 1;}) &&			 \
543 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
544 	     pos = pos->next)
545 
546 /**
547  * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point
548  * @tpos:	the type * to use as a loop counter.
549  * @pos:	the &struct hlist_node to use as a loop counter.
550  * @member:	the name of the hlist_node within the struct.
551  */
552 #define hlist_for_each_entry_continue(tpos, pos, member)		 \
553 	for (pos = (pos)->next;						 \
554 	     pos && ({ prefetch(pos->next); 1;}) &&			 \
555 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
556 	     pos = pos->next)
557 
558 /**
559  * hlist_for_each_entry_from - iterate over a hlist continuing from existing point
560  * @tpos:	the type * to use as a loop counter.
561  * @pos:	the &struct hlist_node to use as a loop counter.
562  * @member:	the name of the hlist_node within the struct.
563  */
564 #define hlist_for_each_entry_from(tpos, pos, member)			 \
565 	for (; pos && ({ prefetch(pos->next); 1;}) &&			 \
566 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
567 	     pos = pos->next)
568 
569 /**
570  * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
571  * @tpos:	the type * to use as a loop counter.
572  * @pos:	the &struct hlist_node to use as a loop counter.
573  * @n:		another &struct hlist_node to use as temporary storage
574  * @head:	the head for your list.
575  * @member:	the name of the hlist_node within the struct.
576  */
577 #define hlist_for_each_entry_safe(tpos, pos, n, head, member) 		 \
578 	for (pos = (head)->first;					 \
579 	     pos && ({ n = pos->next; 1; }) && 				 \
580 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
581 	     pos = n)
582 
583 /**
584  * hlist_for_each_entry_rcu - iterate over rcu list of given type
585  * @pos:	the type * to use as a loop counter.
586  * @pos:	the &struct hlist_node to use as a loop counter.
587  * @head:	the head for your list.
588  * @member:	the name of the hlist_node within the struct.
589  *
590  * This list-traversal primitive may safely run concurrently with
591  * the _rcu list-mutation primitives such as hlist_add_head_rcu()
592  * as long as the traversal is guarded by rcu_read_lock().
593  */
594 #define hlist_for_each_entry_rcu(tpos, pos, head, member)		 \
595 	for (pos = (head)->first;					 \
596 	     pos && ({ prefetch(pos->next); 1;}) &&			 \
597 		({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
598 	     pos = rcu_dereference(pos->next))
599 
600 #endif	/* _LINUX_LIST_H */
601