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31 * @(#)queue.h 8.5 (Berkeley) 8/20/94
38 #include <sys/cdefs.h>
41 * This file defines four types of data structures: singly-linked lists,
42 * singly-linked tail queues, lists and tail queues.
44 * A singly-linked list is headed by a single forward pointer. The elements
45 * are singly linked for minimum space and pointer manipulation overhead at
46 * the expense of O(n) removal for arbitrary elements. New elements can be
47 * added to the list after an existing element or at the head of the list.
48 * Elements being removed from the head of the list should use the explicit
49 * macro for this purpose for optimum efficiency. A singly-linked list may
50 * only be traversed in the forward direction. Singly-linked lists are ideal
51 * for applications with large datasets and few or no removals or for
52 * implementing a LIFO queue.
54 * A singly-linked tail queue is headed by a pair of pointers, one to the
55 * head of the list and the other to the tail of the list. The elements are
56 * singly linked for minimum space and pointer manipulation overhead at the
57 * expense of O(n) removal for arbitrary elements. New elements can be added
58 * to the list after an existing element, at the head of the list, or at the
59 * end of the list. Elements being removed from the head of the tail queue
60 * should use the explicit macro for this purpose for optimum efficiency.
61 * A singly-linked tail queue may only be traversed in the forward direction.
62 * Singly-linked tail queues are ideal for applications with large datasets
63 * and few or no removals or for implementing a FIFO queue.
65 * A list is headed by a single forward pointer (or an array of forward
66 * pointers for a hash table header). The elements are doubly linked
67 * so that an arbitrary element can be removed without a need to
68 * traverse the list. New elements can be added to the list before
69 * or after an existing element or at the head of the list. A list
70 * may be traversed in either direction.
72 * A tail queue is headed by a pair of pointers, one to the head of the
73 * list and the other to the tail of the list. The elements are doubly
74 * linked so that an arbitrary element can be removed without a need to
75 * traverse the list. New elements can be added to the list before or
76 * after an existing element, at the head of the list, or at the end of
77 * the list. A tail queue may be traversed in either direction.
79 * For details on the use of these macros, see the queue(3) manual page.
81 * Below is a summary of implemented functions where:
82 * + means the macro is available
83 * - means the macro is not available
84 * s means the macro is available but is slow (runs in O(n) time)
86 * SLIST LIST STAILQ TAILQ
89 * _HEAD_INITIALIZER + + + +
91 * _CLASS_ENTRY + + + +
101 * _FOREACH_FROM + + + +
102 * _FOREACH_SAFE + + + +
103 * _FOREACH_FROM_SAFE + + + +
104 * _FOREACH_REVERSE - - - +
105 * _FOREACH_REVERSE_FROM - - - +
106 * _FOREACH_REVERSE_SAFE - - - +
107 * _FOREACH_REVERSE_FROM_SAFE - - - +
108 * _INSERT_HEAD + + + +
109 * _INSERT_BEFORE - + - +
110 * _INSERT_AFTER + + + +
111 * _INSERT_TAIL - - + +
113 * _REMOVE_AFTER + - + -
114 * _REMOVE_HEAD + - + -
119 #ifdef QUEUE_MACRO_DEBUG
120 #warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH
121 #define QUEUE_MACRO_DEBUG_TRACE
122 #define QUEUE_MACRO_DEBUG_TRASH
125 #ifdef QUEUE_MACRO_DEBUG_TRACE
126 /* Store the last 2 places the queue element or head was altered */
128 unsigned long lastline;
129 unsigned long prevline;
130 const char *lastfile;
131 const char *prevfile;
134 #define TRACEBUF struct qm_trace trace;
135 #define TRACEBUF_INITIALIZER { __LINE__, 0, __FILE__, NULL } ,
137 #define QMD_TRACE_HEAD(head) do { \
138 (head)->trace.prevline = (head)->trace.lastline; \
139 (head)->trace.prevfile = (head)->trace.lastfile; \
140 (head)->trace.lastline = __LINE__; \
141 (head)->trace.lastfile = __FILE__; \
144 #define QMD_TRACE_ELEM(elem) do { \
145 (elem)->trace.prevline = (elem)->trace.lastline; \
146 (elem)->trace.prevfile = (elem)->trace.lastfile; \
147 (elem)->trace.lastline = __LINE__; \
148 (elem)->trace.lastfile = __FILE__; \
151 #else /* !QUEUE_MACRO_DEBUG_TRACE */
152 #define QMD_TRACE_ELEM(elem)
153 #define QMD_TRACE_HEAD(head)
155 #define TRACEBUF_INITIALIZER
156 #endif /* QUEUE_MACRO_DEBUG_TRACE */
158 #ifdef QUEUE_MACRO_DEBUG_TRASH
159 #define QMD_SAVELINK(name, link) void **name = (void *)&(link)
160 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
161 #define QMD_IS_TRASHED(x) ((x) == (void *)(intptr_t)-1)
162 #else /* !QUEUE_MACRO_DEBUG_TRASH */
163 #define QMD_SAVELINK(name, link)
165 #define QMD_IS_TRASHED(x) 0
166 #endif /* QUEUE_MACRO_DEBUG_TRASH */
170 * In C++ there can be structure lists and class lists:
172 #define QUEUE_TYPEOF(type) type
174 #define QUEUE_TYPEOF(type) struct type
178 * Singly-linked List declarations.
180 #define SLIST_HEAD(name, type) \
182 struct type *slh_first; /* first element */ \
185 #define SLIST_CLASS_HEAD(name, type) \
187 class type *slh_first; /* first element */ \
190 #define SLIST_HEAD_INITIALIZER(head) \
193 #define SLIST_ENTRY(type) \
195 struct type *sle_next; /* next element */ \
198 #define SLIST_CLASS_ENTRY(type) \
200 class type *sle_next; /* next element */ \
204 * Singly-linked List functions.
206 #if (defined(_KERNEL) && defined(INVARIANTS))
207 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do { \
208 if (*(prevp) != (elm)) \
209 panic("Bad prevptr *(%p) == %p != %p", \
210 (prevp), *(prevp), (elm)); \
213 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm)
216 #define SLIST_CONCAT(head1, head2, type, field) do { \
217 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \
218 if (curelm == NULL) { \
219 if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \
221 } else if (SLIST_FIRST(head2) != NULL) { \
222 while (SLIST_NEXT(curelm, field) != NULL) \
223 curelm = SLIST_NEXT(curelm, field); \
224 SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \
229 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
231 #define SLIST_FIRST(head) ((head)->slh_first)
233 #define SLIST_FOREACH(var, head, field) \
234 for ((var) = SLIST_FIRST((head)); \
236 (var) = SLIST_NEXT((var), field))
238 #define SLIST_FOREACH_FROM(var, head, field) \
239 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
241 (var) = SLIST_NEXT((var), field))
243 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
244 for ((var) = SLIST_FIRST((head)); \
245 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
248 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
249 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
250 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
253 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
254 for ((varp) = &SLIST_FIRST((head)); \
255 ((var) = *(varp)) != NULL; \
256 (varp) = &SLIST_NEXT((var), field))
258 #define SLIST_INIT(head) do { \
259 SLIST_FIRST((head)) = NULL; \
262 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
263 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
264 SLIST_NEXT((slistelm), field) = (elm); \
267 #define SLIST_INSERT_HEAD(head, elm, field) do { \
268 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
269 SLIST_FIRST((head)) = (elm); \
272 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
274 #define SLIST_REMOVE(head, elm, type, field) do { \
275 QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
276 if (SLIST_FIRST((head)) == (elm)) { \
277 SLIST_REMOVE_HEAD((head), field); \
280 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \
281 while (SLIST_NEXT(curelm, field) != (elm)) \
282 curelm = SLIST_NEXT(curelm, field); \
283 SLIST_REMOVE_AFTER(curelm, field); \
288 #define SLIST_REMOVE_AFTER(elm, field) do { \
289 SLIST_NEXT(elm, field) = \
290 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
293 #define SLIST_REMOVE_HEAD(head, field) do { \
294 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
297 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \
298 QMD_SLIST_CHECK_PREVPTR(prevp, elm); \
299 *(prevp) = SLIST_NEXT(elm, field); \
300 TRASHIT((elm)->field.sle_next); \
303 #define SLIST_SWAP(head1, head2, type) do { \
304 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \
305 SLIST_FIRST(head1) = SLIST_FIRST(head2); \
306 SLIST_FIRST(head2) = swap_first; \
309 #define SLIST_END(head) NULL
312 * Singly-linked Tail queue declarations.
314 #define STAILQ_HEAD(name, type) \
316 struct type *stqh_first;/* first element */ \
317 struct type **stqh_last;/* addr of last next element */ \
320 #define STAILQ_CLASS_HEAD(name, type) \
322 class type *stqh_first; /* first element */ \
323 class type **stqh_last; /* addr of last next element */ \
326 #define STAILQ_HEAD_INITIALIZER(head) \
327 { NULL, &(head).stqh_first }
329 #define STAILQ_ENTRY(type) \
331 struct type *stqe_next; /* next element */ \
334 #define STAILQ_CLASS_ENTRY(type) \
336 class type *stqe_next; /* next element */ \
340 * Singly-linked Tail queue functions.
342 #define STAILQ_CONCAT(head1, head2) do { \
343 if (!STAILQ_EMPTY((head2))) { \
344 *(head1)->stqh_last = (head2)->stqh_first; \
345 (head1)->stqh_last = (head2)->stqh_last; \
346 STAILQ_INIT((head2)); \
350 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
352 #define STAILQ_FIRST(head) ((head)->stqh_first)
354 #define STAILQ_FOREACH(var, head, field) \
355 for((var) = STAILQ_FIRST((head)); \
357 (var) = STAILQ_NEXT((var), field))
359 #define STAILQ_FOREACH_FROM(var, head, field) \
360 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
362 (var) = STAILQ_NEXT((var), field))
364 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
365 for ((var) = STAILQ_FIRST((head)); \
366 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
369 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
370 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
371 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
374 #define STAILQ_INIT(head) do { \
375 STAILQ_FIRST((head)) = NULL; \
376 (head)->stqh_last = &STAILQ_FIRST((head)); \
379 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
380 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
381 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
382 STAILQ_NEXT((tqelm), field) = (elm); \
385 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
386 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
387 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
388 STAILQ_FIRST((head)) = (elm); \
391 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
392 STAILQ_NEXT((elm), field) = NULL; \
393 *(head)->stqh_last = (elm); \
394 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
397 #define STAILQ_LAST(head, type, field) \
398 (STAILQ_EMPTY((head)) ? NULL : \
399 __containerof((head)->stqh_last, \
400 QUEUE_TYPEOF(type), field.stqe_next))
402 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
404 #define STAILQ_REMOVE(head, elm, type, field) do { \
405 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
406 if (STAILQ_FIRST((head)) == (elm)) { \
407 STAILQ_REMOVE_HEAD((head), field); \
410 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \
411 while (STAILQ_NEXT(curelm, field) != (elm)) \
412 curelm = STAILQ_NEXT(curelm, field); \
413 STAILQ_REMOVE_AFTER(head, curelm, field); \
418 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \
419 if ((STAILQ_NEXT(elm, field) = \
420 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
421 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
424 #define STAILQ_REMOVE_HEAD(head, field) do { \
425 if ((STAILQ_FIRST((head)) = \
426 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
427 (head)->stqh_last = &STAILQ_FIRST((head)); \
430 #define STAILQ_SWAP(head1, head2, type) do { \
431 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \
432 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \
433 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
434 (head1)->stqh_last = (head2)->stqh_last; \
435 STAILQ_FIRST(head2) = swap_first; \
436 (head2)->stqh_last = swap_last; \
437 if (STAILQ_EMPTY(head1)) \
438 (head1)->stqh_last = &STAILQ_FIRST(head1); \
439 if (STAILQ_EMPTY(head2)) \
440 (head2)->stqh_last = &STAILQ_FIRST(head2); \
443 #define STAILQ_END(head) NULL
449 #define LIST_HEAD(name, type) \
451 struct type *lh_first; /* first element */ \
454 #define LIST_CLASS_HEAD(name, type) \
456 class type *lh_first; /* first element */ \
459 #define LIST_HEAD_INITIALIZER(head) \
462 #define LIST_ENTRY(type) \
464 struct type *le_next; /* next element */ \
465 struct type **le_prev; /* address of previous next element */ \
468 #define LIST_CLASS_ENTRY(type) \
470 class type *le_next; /* next element */ \
471 class type **le_prev; /* address of previous next element */ \
478 #if (defined(_KERNEL) && defined(INVARIANTS))
480 * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
482 * If the list is non-empty, validates that the first element of the list
483 * points back at 'head.'
485 #define QMD_LIST_CHECK_HEAD(head, field) do { \
486 if (LIST_FIRST((head)) != NULL && \
487 LIST_FIRST((head))->field.le_prev != \
488 &LIST_FIRST((head))) \
489 panic("Bad list head %p first->prev != head", (head)); \
493 * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
495 * If an element follows 'elm' in the list, validates that the next element
496 * points back at 'elm.'
498 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
499 if (LIST_NEXT((elm), field) != NULL && \
500 LIST_NEXT((elm), field)->field.le_prev != \
501 &((elm)->field.le_next)) \
502 panic("Bad link elm %p next->prev != elm", (elm)); \
506 * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
508 * Validates that the previous element (or head of the list) points to 'elm.'
510 #define QMD_LIST_CHECK_PREV(elm, field) do { \
511 if (*(elm)->field.le_prev != (elm)) \
512 panic("Bad link elm %p prev->next != elm", (elm)); \
515 #define QMD_LIST_CHECK_HEAD(head, field)
516 #define QMD_LIST_CHECK_NEXT(elm, field)
517 #define QMD_LIST_CHECK_PREV(elm, field)
518 #endif /* (_KERNEL && INVARIANTS) */
520 #define LIST_CONCAT(head1, head2, type, field) do { \
521 QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \
522 if (curelm == NULL) { \
523 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \
524 LIST_FIRST(head2)->field.le_prev = \
525 &LIST_FIRST((head1)); \
528 } else if (LIST_FIRST(head2) != NULL) { \
529 while (LIST_NEXT(curelm, field) != NULL) \
530 curelm = LIST_NEXT(curelm, field); \
531 LIST_NEXT(curelm, field) = LIST_FIRST(head2); \
532 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
537 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
539 #define LIST_FIRST(head) ((head)->lh_first)
541 #define LIST_FOREACH(var, head, field) \
542 for ((var) = LIST_FIRST((head)); \
544 (var) = LIST_NEXT((var), field))
546 #define LIST_FOREACH_FROM(var, head, field) \
547 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
549 (var) = LIST_NEXT((var), field))
551 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
552 for ((var) = LIST_FIRST((head)); \
553 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
556 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
557 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
558 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
561 #define LIST_INIT(head) do { \
562 LIST_FIRST((head)) = NULL; \
565 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
566 QMD_LIST_CHECK_NEXT(listelm, field); \
567 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
568 LIST_NEXT((listelm), field)->field.le_prev = \
569 &LIST_NEXT((elm), field); \
570 LIST_NEXT((listelm), field) = (elm); \
571 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
574 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
575 QMD_LIST_CHECK_PREV(listelm, field); \
576 (elm)->field.le_prev = (listelm)->field.le_prev; \
577 LIST_NEXT((elm), field) = (listelm); \
578 *(listelm)->field.le_prev = (elm); \
579 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
582 #define LIST_INSERT_HEAD(head, elm, field) do { \
583 QMD_LIST_CHECK_HEAD((head), field); \
584 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
585 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
586 LIST_FIRST((head)) = (elm); \
587 (elm)->field.le_prev = &LIST_FIRST((head)); \
590 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
592 #define LIST_PREV(elm, head, type, field) \
593 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
594 __containerof((elm)->field.le_prev, \
595 QUEUE_TYPEOF(type), field.le_next))
597 #define LIST_REMOVE(elm, field) do { \
598 QMD_SAVELINK(oldnext, (elm)->field.le_next); \
599 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
600 QMD_LIST_CHECK_NEXT(elm, field); \
601 QMD_LIST_CHECK_PREV(elm, field); \
602 if (LIST_NEXT((elm), field) != NULL) \
603 LIST_NEXT((elm), field)->field.le_prev = \
604 (elm)->field.le_prev; \
605 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
610 #define LIST_SWAP(head1, head2, type, field) do { \
611 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \
612 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
613 LIST_FIRST((head2)) = swap_tmp; \
614 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
615 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
616 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
617 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
620 #define LIST_END(head) NULL
623 * Tail queue declarations.
625 #define TAILQ_HEAD(name, type) \
627 struct type *tqh_first; /* first element */ \
628 struct type **tqh_last; /* addr of last next element */ \
632 #define TAILQ_CLASS_HEAD(name, type) \
634 class type *tqh_first; /* first element */ \
635 class type **tqh_last; /* addr of last next element */ \
639 #define TAILQ_HEAD_INITIALIZER(head) \
640 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
642 #define TAILQ_ENTRY(type) \
644 struct type *tqe_next; /* next element */ \
645 struct type **tqe_prev; /* address of previous next element */ \
649 #define TAILQ_CLASS_ENTRY(type) \
651 class type *tqe_next; /* next element */ \
652 class type **tqe_prev; /* address of previous next element */ \
657 * Tail queue functions.
659 #if (defined(_KERNEL) && defined(INVARIANTS))
661 * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
663 * If the tailq is non-empty, validates that the first element of the tailq
664 * points back at 'head.'
666 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \
667 if (!TAILQ_EMPTY(head) && \
668 TAILQ_FIRST((head))->field.tqe_prev != \
669 &TAILQ_FIRST((head))) \
670 panic("Bad tailq head %p first->prev != head", (head)); \
674 * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
676 * Validates that the tail of the tailq is a pointer to pointer to NULL.
678 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \
679 if (*(head)->tqh_last != NULL) \
680 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
684 * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
686 * If an element follows 'elm' in the tailq, validates that the next element
687 * points back at 'elm.'
689 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
690 if (TAILQ_NEXT((elm), field) != NULL && \
691 TAILQ_NEXT((elm), field)->field.tqe_prev != \
692 &((elm)->field.tqe_next)) \
693 panic("Bad link elm %p next->prev != elm", (elm)); \
697 * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
699 * Validates that the previous element (or head of the tailq) points to 'elm.'
701 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \
702 if (*(elm)->field.tqe_prev != (elm)) \
703 panic("Bad link elm %p prev->next != elm", (elm)); \
706 #define QMD_TAILQ_CHECK_HEAD(head, field)
707 #define QMD_TAILQ_CHECK_TAIL(head, headname)
708 #define QMD_TAILQ_CHECK_NEXT(elm, field)
709 #define QMD_TAILQ_CHECK_PREV(elm, field)
710 #endif /* (_KERNEL && INVARIANTS) */
712 #define TAILQ_CONCAT(head1, head2, field) do { \
713 if (!TAILQ_EMPTY(head2)) { \
714 *(head1)->tqh_last = (head2)->tqh_first; \
715 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
716 (head1)->tqh_last = (head2)->tqh_last; \
717 TAILQ_INIT((head2)); \
718 QMD_TRACE_HEAD(head1); \
719 QMD_TRACE_HEAD(head2); \
723 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
725 #define TAILQ_FIRST(head) ((head)->tqh_first)
727 #define TAILQ_FOREACH(var, head, field) \
728 for ((var) = TAILQ_FIRST((head)); \
730 (var) = TAILQ_NEXT((var), field))
732 #define TAILQ_FOREACH_FROM(var, head, field) \
733 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
735 (var) = TAILQ_NEXT((var), field))
737 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
738 for ((var) = TAILQ_FIRST((head)); \
739 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
742 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
743 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
744 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
747 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
748 for ((var) = TAILQ_LAST((head), headname); \
750 (var) = TAILQ_PREV((var), headname, field))
752 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \
753 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
755 (var) = TAILQ_PREV((var), headname, field))
757 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
758 for ((var) = TAILQ_LAST((head), headname); \
759 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
762 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
763 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
764 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
767 #define TAILQ_INIT(head) do { \
768 TAILQ_FIRST((head)) = NULL; \
769 (head)->tqh_last = &TAILQ_FIRST((head)); \
770 QMD_TRACE_HEAD(head); \
773 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
774 QMD_TAILQ_CHECK_NEXT(listelm, field); \
775 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
776 TAILQ_NEXT((elm), field)->field.tqe_prev = \
777 &TAILQ_NEXT((elm), field); \
779 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
780 QMD_TRACE_HEAD(head); \
782 TAILQ_NEXT((listelm), field) = (elm); \
783 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
784 QMD_TRACE_ELEM(&(elm)->field); \
785 QMD_TRACE_ELEM(&(listelm)->field); \
788 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
789 QMD_TAILQ_CHECK_PREV(listelm, field); \
790 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
791 TAILQ_NEXT((elm), field) = (listelm); \
792 *(listelm)->field.tqe_prev = (elm); \
793 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
794 QMD_TRACE_ELEM(&(elm)->field); \
795 QMD_TRACE_ELEM(&(listelm)->field); \
798 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
799 QMD_TAILQ_CHECK_HEAD(head, field); \
800 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
801 TAILQ_FIRST((head))->field.tqe_prev = \
802 &TAILQ_NEXT((elm), field); \
804 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
805 TAILQ_FIRST((head)) = (elm); \
806 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
807 QMD_TRACE_HEAD(head); \
808 QMD_TRACE_ELEM(&(elm)->field); \
811 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
812 QMD_TAILQ_CHECK_TAIL(head, field); \
813 TAILQ_NEXT((elm), field) = NULL; \
814 (elm)->field.tqe_prev = (head)->tqh_last; \
815 *(head)->tqh_last = (elm); \
816 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
817 QMD_TRACE_HEAD(head); \
818 QMD_TRACE_ELEM(&(elm)->field); \
821 #define TAILQ_LAST(head, headname) \
822 (*(((struct headname *)((head)->tqh_last))->tqh_last))
825 * The FAST function is fast in that it causes no data access other
826 * then the access to the head. The standard LAST function above
827 * will cause a data access of both the element you want and
828 * the previous element. FAST is very useful for instances when
829 * you may want to prefetch the last data element.
831 #define TAILQ_LAST_FAST(head, type, field) \
832 (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
834 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
836 #define TAILQ_PREV(elm, headname, field) \
837 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
839 #define TAILQ_PREV_FAST(elm, head, type, field) \
840 ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL : \
841 __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next))
843 #define TAILQ_REMOVE(head, elm, field) do { \
844 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
845 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
846 QMD_TAILQ_CHECK_NEXT(elm, field); \
847 QMD_TAILQ_CHECK_PREV(elm, field); \
848 if ((TAILQ_NEXT((elm), field)) != NULL) \
849 TAILQ_NEXT((elm), field)->field.tqe_prev = \
850 (elm)->field.tqe_prev; \
852 (head)->tqh_last = (elm)->field.tqe_prev; \
853 QMD_TRACE_HEAD(head); \
855 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
858 QMD_TRACE_ELEM(&(elm)->field); \
861 #define TAILQ_SWAP(head1, head2, type, field) do { \
862 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \
863 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \
864 (head1)->tqh_first = (head2)->tqh_first; \
865 (head1)->tqh_last = (head2)->tqh_last; \
866 (head2)->tqh_first = swap_first; \
867 (head2)->tqh_last = swap_last; \
868 if ((swap_first = (head1)->tqh_first) != NULL) \
869 swap_first->field.tqe_prev = &(head1)->tqh_first; \
871 (head1)->tqh_last = &(head1)->tqh_first; \
872 if ((swap_first = (head2)->tqh_first) != NULL) \
873 swap_first->field.tqe_prev = &(head2)->tqh_first; \
875 (head2)->tqh_last = &(head2)->tqh_first; \
878 #define TAILQ_END(head) NULL
880 #endif /* !_SYS_QUEUE_H_ */