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4 * Copyright (c) 1991, 1993
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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 if (SLIST_FIRST((head)) == (elm)) { \
276 SLIST_REMOVE_HEAD((head), field); \
279 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \
280 while (SLIST_NEXT(curelm, field) != (elm)) \
281 curelm = SLIST_NEXT(curelm, field); \
282 SLIST_REMOVE_AFTER(curelm, field); \
286 #define SLIST_REMOVE_AFTER(elm, field) do { \
287 QMD_SAVELINK(oldnext, SLIST_NEXT(elm, field)->field.sle_next); \
288 SLIST_NEXT(elm, field) = \
289 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
293 #define SLIST_REMOVE_HEAD(head, field) do { \
294 QMD_SAVELINK(oldnext, SLIST_FIRST(head)->field.sle_next); \
295 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
299 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \
300 QMD_SLIST_CHECK_PREVPTR(prevp, elm); \
301 *(prevp) = SLIST_NEXT(elm, field); \
302 TRASHIT((elm)->field.sle_next); \
305 #define SLIST_SWAP(head1, head2, type) do { \
306 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \
307 SLIST_FIRST(head1) = SLIST_FIRST(head2); \
308 SLIST_FIRST(head2) = swap_first; \
311 #define SLIST_END(head) NULL
314 * Singly-linked Tail queue declarations.
316 #define STAILQ_HEAD(name, type) \
318 struct type *stqh_first;/* first element */ \
319 struct type **stqh_last;/* addr of last next element */ \
322 #define STAILQ_CLASS_HEAD(name, type) \
324 class type *stqh_first; /* first element */ \
325 class type **stqh_last; /* addr of last next element */ \
328 #define STAILQ_HEAD_INITIALIZER(head) \
329 { NULL, &(head).stqh_first }
331 #define STAILQ_ENTRY(type) \
333 struct type *stqe_next; /* next element */ \
336 #define STAILQ_CLASS_ENTRY(type) \
338 class type *stqe_next; /* next element */ \
342 * Singly-linked Tail queue functions.
344 #define STAILQ_CONCAT(head1, head2) do { \
345 if (!STAILQ_EMPTY((head2))) { \
346 *(head1)->stqh_last = (head2)->stqh_first; \
347 (head1)->stqh_last = (head2)->stqh_last; \
348 STAILQ_INIT((head2)); \
352 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
354 #define STAILQ_FIRST(head) ((head)->stqh_first)
356 #define STAILQ_FOREACH(var, head, field) \
357 for((var) = STAILQ_FIRST((head)); \
359 (var) = STAILQ_NEXT((var), field))
361 #define STAILQ_FOREACH_FROM(var, head, field) \
362 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
364 (var) = STAILQ_NEXT((var), field))
366 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
367 for ((var) = STAILQ_FIRST((head)); \
368 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
371 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
372 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
373 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
376 #define STAILQ_INIT(head) do { \
377 STAILQ_FIRST((head)) = NULL; \
378 (head)->stqh_last = &STAILQ_FIRST((head)); \
381 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
382 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
383 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
384 STAILQ_NEXT((tqelm), field) = (elm); \
387 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
388 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
389 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
390 STAILQ_FIRST((head)) = (elm); \
393 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
394 STAILQ_NEXT((elm), field) = NULL; \
395 *(head)->stqh_last = (elm); \
396 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
399 #define STAILQ_LAST(head, type, field) \
400 (STAILQ_EMPTY((head)) ? NULL : \
401 __containerof((head)->stqh_last, \
402 QUEUE_TYPEOF(type), field.stqe_next))
404 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
406 #define STAILQ_REMOVE(head, elm, type, field) do { \
407 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
408 if (STAILQ_FIRST((head)) == (elm)) { \
409 STAILQ_REMOVE_HEAD((head), field); \
412 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \
413 while (STAILQ_NEXT(curelm, field) != (elm)) \
414 curelm = STAILQ_NEXT(curelm, field); \
415 STAILQ_REMOVE_AFTER(head, curelm, field); \
420 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \
421 if ((STAILQ_NEXT(elm, field) = \
422 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
423 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
426 #define STAILQ_REMOVE_HEAD(head, field) do { \
427 if ((STAILQ_FIRST((head)) = \
428 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
429 (head)->stqh_last = &STAILQ_FIRST((head)); \
432 #define STAILQ_SWAP(head1, head2, type) do { \
433 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \
434 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \
435 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
436 (head1)->stqh_last = (head2)->stqh_last; \
437 STAILQ_FIRST(head2) = swap_first; \
438 (head2)->stqh_last = swap_last; \
439 if (STAILQ_EMPTY(head1)) \
440 (head1)->stqh_last = &STAILQ_FIRST(head1); \
441 if (STAILQ_EMPTY(head2)) \
442 (head2)->stqh_last = &STAILQ_FIRST(head2); \
445 #define STAILQ_END(head) NULL
451 #define LIST_HEAD(name, type) \
453 struct type *lh_first; /* first element */ \
456 #define LIST_CLASS_HEAD(name, type) \
458 class type *lh_first; /* first element */ \
461 #define LIST_HEAD_INITIALIZER(head) \
464 #define LIST_ENTRY(type) \
466 struct type *le_next; /* next element */ \
467 struct type **le_prev; /* address of previous next element */ \
470 #define LIST_CLASS_ENTRY(type) \
472 class type *le_next; /* next element */ \
473 class type **le_prev; /* address of previous next element */ \
480 #if (defined(_KERNEL) && defined(INVARIANTS))
482 * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
484 * If the list is non-empty, validates that the first element of the list
485 * points back at 'head.'
487 #define QMD_LIST_CHECK_HEAD(head, field) do { \
488 if (LIST_FIRST((head)) != NULL && \
489 LIST_FIRST((head))->field.le_prev != \
490 &LIST_FIRST((head))) \
491 panic("Bad list head %p first->prev != head", (head)); \
495 * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
497 * If an element follows 'elm' in the list, validates that the next element
498 * points back at 'elm.'
500 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
501 if (LIST_NEXT((elm), field) != NULL && \
502 LIST_NEXT((elm), field)->field.le_prev != \
503 &((elm)->field.le_next)) \
504 panic("Bad link elm %p next->prev != elm", (elm)); \
508 * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
510 * Validates that the previous element (or head of the list) points to 'elm.'
512 #define QMD_LIST_CHECK_PREV(elm, field) do { \
513 if (*(elm)->field.le_prev != (elm)) \
514 panic("Bad link elm %p prev->next != elm", (elm)); \
517 #define QMD_LIST_CHECK_HEAD(head, field)
518 #define QMD_LIST_CHECK_NEXT(elm, field)
519 #define QMD_LIST_CHECK_PREV(elm, field)
520 #endif /* (_KERNEL && INVARIANTS) */
522 #define LIST_CONCAT(head1, head2, type, field) do { \
523 QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \
524 if (curelm == NULL) { \
525 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \
526 LIST_FIRST(head2)->field.le_prev = \
527 &LIST_FIRST((head1)); \
530 } else if (LIST_FIRST(head2) != NULL) { \
531 while (LIST_NEXT(curelm, field) != NULL) \
532 curelm = LIST_NEXT(curelm, field); \
533 LIST_NEXT(curelm, field) = LIST_FIRST(head2); \
534 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
539 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
541 #define LIST_FIRST(head) ((head)->lh_first)
543 #define LIST_FOREACH(var, head, field) \
544 for ((var) = LIST_FIRST((head)); \
546 (var) = LIST_NEXT((var), field))
548 #define LIST_FOREACH_FROM(var, head, field) \
549 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
551 (var) = LIST_NEXT((var), field))
553 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
554 for ((var) = LIST_FIRST((head)); \
555 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
558 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
559 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
560 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
563 #define LIST_INIT(head) do { \
564 LIST_FIRST((head)) = NULL; \
567 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
568 QMD_LIST_CHECK_NEXT(listelm, field); \
569 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
570 LIST_NEXT((listelm), field)->field.le_prev = \
571 &LIST_NEXT((elm), field); \
572 LIST_NEXT((listelm), field) = (elm); \
573 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
576 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
577 QMD_LIST_CHECK_PREV(listelm, field); \
578 (elm)->field.le_prev = (listelm)->field.le_prev; \
579 LIST_NEXT((elm), field) = (listelm); \
580 *(listelm)->field.le_prev = (elm); \
581 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
584 #define LIST_INSERT_HEAD(head, elm, field) do { \
585 QMD_LIST_CHECK_HEAD((head), field); \
586 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
587 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
588 LIST_FIRST((head)) = (elm); \
589 (elm)->field.le_prev = &LIST_FIRST((head)); \
592 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
594 #define LIST_PREV(elm, head, type, field) \
595 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
596 __containerof((elm)->field.le_prev, \
597 QUEUE_TYPEOF(type), field.le_next))
599 #define LIST_REMOVE(elm, field) do { \
600 QMD_SAVELINK(oldnext, (elm)->field.le_next); \
601 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
602 QMD_LIST_CHECK_NEXT(elm, field); \
603 QMD_LIST_CHECK_PREV(elm, field); \
604 if (LIST_NEXT((elm), field) != NULL) \
605 LIST_NEXT((elm), field)->field.le_prev = \
606 (elm)->field.le_prev; \
607 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
612 #define LIST_SWAP(head1, head2, type, field) do { \
613 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \
614 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
615 LIST_FIRST((head2)) = swap_tmp; \
616 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
617 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
618 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
619 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
622 #define LIST_END(head) NULL
625 * Tail queue declarations.
627 #define TAILQ_HEAD(name, type) \
629 struct type *tqh_first; /* first element */ \
630 struct type **tqh_last; /* addr of last next element */ \
634 #define TAILQ_CLASS_HEAD(name, type) \
636 class type *tqh_first; /* first element */ \
637 class type **tqh_last; /* addr of last next element */ \
641 #define TAILQ_HEAD_INITIALIZER(head) \
642 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
644 #define TAILQ_ENTRY(type) \
646 struct type *tqe_next; /* next element */ \
647 struct type **tqe_prev; /* address of previous next element */ \
651 #define TAILQ_CLASS_ENTRY(type) \
653 class type *tqe_next; /* next element */ \
654 class type **tqe_prev; /* address of previous next element */ \
659 * Tail queue functions.
661 #if (defined(_KERNEL) && defined(INVARIANTS))
663 * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
665 * If the tailq is non-empty, validates that the first element of the tailq
666 * points back at 'head.'
668 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \
669 if (!TAILQ_EMPTY(head) && \
670 TAILQ_FIRST((head))->field.tqe_prev != \
671 &TAILQ_FIRST((head))) \
672 panic("Bad tailq head %p first->prev != head", (head)); \
676 * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
678 * Validates that the tail of the tailq is a pointer to pointer to NULL.
680 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \
681 if (*(head)->tqh_last != NULL) \
682 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
686 * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
688 * If an element follows 'elm' in the tailq, validates that the next element
689 * points back at 'elm.'
691 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
692 if (TAILQ_NEXT((elm), field) != NULL && \
693 TAILQ_NEXT((elm), field)->field.tqe_prev != \
694 &((elm)->field.tqe_next)) \
695 panic("Bad link elm %p next->prev != elm", (elm)); \
699 * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
701 * Validates that the previous element (or head of the tailq) points to 'elm.'
703 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \
704 if (*(elm)->field.tqe_prev != (elm)) \
705 panic("Bad link elm %p prev->next != elm", (elm)); \
708 #define QMD_TAILQ_CHECK_HEAD(head, field)
709 #define QMD_TAILQ_CHECK_TAIL(head, headname)
710 #define QMD_TAILQ_CHECK_NEXT(elm, field)
711 #define QMD_TAILQ_CHECK_PREV(elm, field)
712 #endif /* (_KERNEL && INVARIANTS) */
714 #define TAILQ_CONCAT(head1, head2, field) do { \
715 if (!TAILQ_EMPTY(head2)) { \
716 *(head1)->tqh_last = (head2)->tqh_first; \
717 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
718 (head1)->tqh_last = (head2)->tqh_last; \
719 TAILQ_INIT((head2)); \
720 QMD_TRACE_HEAD(head1); \
721 QMD_TRACE_HEAD(head2); \
725 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
727 #define TAILQ_FIRST(head) ((head)->tqh_first)
729 #define TAILQ_FOREACH(var, head, field) \
730 for ((var) = TAILQ_FIRST((head)); \
732 (var) = TAILQ_NEXT((var), field))
734 #define TAILQ_FOREACH_FROM(var, head, field) \
735 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
737 (var) = TAILQ_NEXT((var), field))
739 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
740 for ((var) = TAILQ_FIRST((head)); \
741 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
744 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
745 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
746 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
749 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
750 for ((var) = TAILQ_LAST((head), headname); \
752 (var) = TAILQ_PREV((var), headname, field))
754 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \
755 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
757 (var) = TAILQ_PREV((var), headname, field))
759 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
760 for ((var) = TAILQ_LAST((head), headname); \
761 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
764 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
765 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
766 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
769 #define TAILQ_INIT(head) do { \
770 TAILQ_FIRST((head)) = NULL; \
771 (head)->tqh_last = &TAILQ_FIRST((head)); \
772 QMD_TRACE_HEAD(head); \
775 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
776 QMD_TAILQ_CHECK_NEXT(listelm, field); \
777 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
778 TAILQ_NEXT((elm), field)->field.tqe_prev = \
779 &TAILQ_NEXT((elm), field); \
781 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
782 QMD_TRACE_HEAD(head); \
784 TAILQ_NEXT((listelm), field) = (elm); \
785 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
786 QMD_TRACE_ELEM(&(elm)->field); \
787 QMD_TRACE_ELEM(&(listelm)->field); \
790 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
791 QMD_TAILQ_CHECK_PREV(listelm, field); \
792 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
793 TAILQ_NEXT((elm), field) = (listelm); \
794 *(listelm)->field.tqe_prev = (elm); \
795 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
796 QMD_TRACE_ELEM(&(elm)->field); \
797 QMD_TRACE_ELEM(&(listelm)->field); \
800 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
801 QMD_TAILQ_CHECK_HEAD(head, field); \
802 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
803 TAILQ_FIRST((head))->field.tqe_prev = \
804 &TAILQ_NEXT((elm), field); \
806 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
807 TAILQ_FIRST((head)) = (elm); \
808 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
809 QMD_TRACE_HEAD(head); \
810 QMD_TRACE_ELEM(&(elm)->field); \
813 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
814 QMD_TAILQ_CHECK_TAIL(head, field); \
815 TAILQ_NEXT((elm), field) = NULL; \
816 (elm)->field.tqe_prev = (head)->tqh_last; \
817 *(head)->tqh_last = (elm); \
818 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
819 QMD_TRACE_HEAD(head); \
820 QMD_TRACE_ELEM(&(elm)->field); \
823 #define TAILQ_LAST(head, headname) \
824 (*(((struct headname *)((head)->tqh_last))->tqh_last))
827 * The FAST function is fast in that it causes no data access other
828 * then the access to the head. The standard LAST function above
829 * will cause a data access of both the element you want and
830 * the previous element. FAST is very useful for instances when
831 * you may want to prefetch the last data element.
833 #define TAILQ_LAST_FAST(head, type, field) \
834 (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
836 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
838 #define TAILQ_PREV(elm, headname, field) \
839 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
841 #define TAILQ_PREV_FAST(elm, head, type, field) \
842 ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL : \
843 __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next))
845 #define TAILQ_REMOVE(head, elm, field) do { \
846 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
847 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
848 QMD_TAILQ_CHECK_NEXT(elm, field); \
849 QMD_TAILQ_CHECK_PREV(elm, field); \
850 if ((TAILQ_NEXT((elm), field)) != NULL) \
851 TAILQ_NEXT((elm), field)->field.tqe_prev = \
852 (elm)->field.tqe_prev; \
854 (head)->tqh_last = (elm)->field.tqe_prev; \
855 QMD_TRACE_HEAD(head); \
857 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
860 QMD_TRACE_ELEM(&(elm)->field); \
863 #define TAILQ_SWAP(head1, head2, type, field) do { \
864 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \
865 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \
866 (head1)->tqh_first = (head2)->tqh_first; \
867 (head1)->tqh_last = (head2)->tqh_last; \
868 (head2)->tqh_first = swap_first; \
869 (head2)->tqh_last = swap_last; \
870 if ((swap_first = (head1)->tqh_first) != NULL) \
871 swap_first->field.tqe_prev = &(head1)->tqh_first; \
873 (head1)->tqh_last = &(head1)->tqh_first; \
874 if ((swap_first = (head2)->tqh_first) != NULL) \
875 swap_first->field.tqe_prev = &(head2)->tqh_first; \
877 (head2)->tqh_last = &(head2)->tqh_first; \
880 #define TAILQ_END(head) NULL
882 #endif /* !_SYS_QUEUE_H_ */