2 * SPDX-License-Identifier: BSD-3-Clause
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 + + + +
100 * _FOREACH_FROM + + + +
101 * _FOREACH_SAFE + + + +
102 * _FOREACH_FROM_SAFE + + + +
103 * _FOREACH_REVERSE - - - +
104 * _FOREACH_REVERSE_FROM - - - +
105 * _FOREACH_REVERSE_SAFE - - - +
106 * _FOREACH_REVERSE_FROM_SAFE - - - +
107 * _INSERT_HEAD + + + +
108 * _INSERT_BEFORE - + - +
109 * _INSERT_AFTER + + + +
110 * _INSERT_TAIL - - + +
112 * _REMOVE_AFTER + - + -
113 * _REMOVE_HEAD + - + -
118 #ifdef QUEUE_MACRO_DEBUG
119 #warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH
120 #define QUEUE_MACRO_DEBUG_TRACE
121 #define QUEUE_MACRO_DEBUG_TRASH
124 #ifdef QUEUE_MACRO_DEBUG_TRACE
125 /* Store the last 2 places the queue element or head was altered */
127 unsigned long lastline;
128 unsigned long prevline;
129 const char *lastfile;
130 const char *prevfile;
133 #define TRACEBUF struct qm_trace trace;
134 #define TRACEBUF_INITIALIZER { __LINE__, 0, __FILE__, NULL } ,
136 #define QMD_TRACE_HEAD(head) do { \
137 (head)->trace.prevline = (head)->trace.lastline; \
138 (head)->trace.prevfile = (head)->trace.lastfile; \
139 (head)->trace.lastline = __LINE__; \
140 (head)->trace.lastfile = __FILE__; \
143 #define QMD_TRACE_ELEM(elem) do { \
144 (elem)->trace.prevline = (elem)->trace.lastline; \
145 (elem)->trace.prevfile = (elem)->trace.lastfile; \
146 (elem)->trace.lastline = __LINE__; \
147 (elem)->trace.lastfile = __FILE__; \
150 #else /* !QUEUE_MACRO_DEBUG_TRACE */
151 #define QMD_TRACE_ELEM(elem)
152 #define QMD_TRACE_HEAD(head)
154 #define TRACEBUF_INITIALIZER
155 #endif /* QUEUE_MACRO_DEBUG_TRACE */
157 #ifdef QUEUE_MACRO_DEBUG_TRASH
158 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
159 #define QMD_IS_TRASHED(x) ((x) == (void *)(intptr_t)-1)
160 #else /* !QUEUE_MACRO_DEBUG_TRASH */
162 #define QMD_IS_TRASHED(x) 0
163 #endif /* QUEUE_MACRO_DEBUG_TRASH */
165 #if defined(QUEUE_MACRO_DEBUG_TRACE) || defined(QUEUE_MACRO_DEBUG_TRASH)
166 #define QMD_SAVELINK(name, link) void **name = (void *)&(link)
167 #else /* !QUEUE_MACRO_DEBUG_TRACE && !QUEUE_MACRO_DEBUG_TRASH */
168 #define QMD_SAVELINK(name, link)
169 #endif /* QUEUE_MACRO_DEBUG_TRACE || QUEUE_MACRO_DEBUG_TRASH */
173 * In C++ there can be structure lists and class lists:
175 #define QUEUE_TYPEOF(type) type
177 #define QUEUE_TYPEOF(type) struct type
181 * Singly-linked List declarations.
183 #define SLIST_HEAD(name, type) \
185 struct type *slh_first; /* first element */ \
188 #define SLIST_CLASS_HEAD(name, type) \
190 class type *slh_first; /* first element */ \
193 #define SLIST_HEAD_INITIALIZER(head) \
196 #define SLIST_ENTRY(type) \
198 struct type *sle_next; /* next element */ \
201 #define SLIST_CLASS_ENTRY(type) \
203 class type *sle_next; /* next element */ \
207 * Singly-linked List functions.
209 #if (defined(_KERNEL) && defined(INVARIANTS))
210 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do { \
211 if (*(prevp) != (elm)) \
212 panic("Bad prevptr *(%p) == %p != %p", \
213 (prevp), *(prevp), (elm)); \
216 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm)
219 #define SLIST_CONCAT(head1, head2, type, field) do { \
220 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \
221 if (curelm == NULL) { \
222 if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \
224 } else if (SLIST_FIRST(head2) != NULL) { \
225 while (SLIST_NEXT(curelm, field) != NULL) \
226 curelm = SLIST_NEXT(curelm, field); \
227 SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \
232 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
234 #define SLIST_FIRST(head) ((head)->slh_first)
236 #define SLIST_FOREACH(var, head, field) \
237 for ((var) = SLIST_FIRST((head)); \
239 (var) = SLIST_NEXT((var), field))
241 #define SLIST_FOREACH_FROM(var, head, field) \
242 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
244 (var) = SLIST_NEXT((var), field))
246 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
247 for ((var) = SLIST_FIRST((head)); \
248 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
251 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
252 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
253 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
256 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
257 for ((varp) = &SLIST_FIRST((head)); \
258 ((var) = *(varp)) != NULL; \
259 (varp) = &SLIST_NEXT((var), field))
261 #define SLIST_INIT(head) do { \
262 SLIST_FIRST((head)) = NULL; \
265 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
266 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
267 SLIST_NEXT((slistelm), field) = (elm); \
270 #define SLIST_INSERT_HEAD(head, elm, field) do { \
271 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
272 SLIST_FIRST((head)) = (elm); \
275 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
277 #define SLIST_REMOVE(head, elm, type, field) do { \
278 QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
279 if (SLIST_FIRST((head)) == (elm)) { \
280 SLIST_REMOVE_HEAD((head), field); \
283 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \
284 while (SLIST_NEXT(curelm, field) != (elm)) \
285 curelm = SLIST_NEXT(curelm, field); \
286 SLIST_REMOVE_AFTER(curelm, field); \
291 #define SLIST_REMOVE_AFTER(elm, field) do { \
292 SLIST_NEXT(elm, field) = \
293 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
296 #define SLIST_REMOVE_HEAD(head, field) do { \
297 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
300 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \
301 QMD_SLIST_CHECK_PREVPTR(prevp, elm); \
302 *(prevp) = SLIST_NEXT(elm, field); \
303 TRASHIT((elm)->field.sle_next); \
306 #define SLIST_SWAP(head1, head2, type) do { \
307 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \
308 SLIST_FIRST(head1) = SLIST_FIRST(head2); \
309 SLIST_FIRST(head2) = swap_first; \
313 * Singly-linked Tail queue declarations.
315 #define STAILQ_HEAD(name, type) \
317 struct type *stqh_first;/* first element */ \
318 struct type **stqh_last;/* addr of last next element */ \
321 #define STAILQ_CLASS_HEAD(name, type) \
323 class type *stqh_first; /* first element */ \
324 class type **stqh_last; /* addr of last next element */ \
327 #define STAILQ_HEAD_INITIALIZER(head) \
328 { NULL, &(head).stqh_first }
330 #define STAILQ_ENTRY(type) \
332 struct type *stqe_next; /* next element */ \
335 #define STAILQ_CLASS_ENTRY(type) \
337 class type *stqe_next; /* next element */ \
341 * Singly-linked Tail queue functions.
343 #define STAILQ_CONCAT(head1, head2) do { \
344 if (!STAILQ_EMPTY((head2))) { \
345 *(head1)->stqh_last = (head2)->stqh_first; \
346 (head1)->stqh_last = (head2)->stqh_last; \
347 STAILQ_INIT((head2)); \
351 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
353 #define STAILQ_FIRST(head) ((head)->stqh_first)
355 #define STAILQ_FOREACH(var, head, field) \
356 for((var) = STAILQ_FIRST((head)); \
358 (var) = STAILQ_NEXT((var), field))
360 #define STAILQ_FOREACH_FROM(var, head, field) \
361 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
363 (var) = STAILQ_NEXT((var), field))
365 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
366 for ((var) = STAILQ_FIRST((head)); \
367 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
370 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
371 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
372 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
375 #define STAILQ_INIT(head) do { \
376 STAILQ_FIRST((head)) = NULL; \
377 (head)->stqh_last = &STAILQ_FIRST((head)); \
380 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
381 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
382 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
383 STAILQ_NEXT((tqelm), field) = (elm); \
386 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
387 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
388 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
389 STAILQ_FIRST((head)) = (elm); \
392 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
393 STAILQ_NEXT((elm), field) = NULL; \
394 *(head)->stqh_last = (elm); \
395 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
398 #define STAILQ_LAST(head, type, field) \
399 (STAILQ_EMPTY((head)) ? NULL : \
400 __containerof((head)->stqh_last, \
401 QUEUE_TYPEOF(type), field.stqe_next))
403 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
405 #define STAILQ_REMOVE(head, elm, type, field) do { \
406 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
407 if (STAILQ_FIRST((head)) == (elm)) { \
408 STAILQ_REMOVE_HEAD((head), field); \
411 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \
412 while (STAILQ_NEXT(curelm, field) != (elm)) \
413 curelm = STAILQ_NEXT(curelm, field); \
414 STAILQ_REMOVE_AFTER(head, curelm, field); \
419 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \
420 if ((STAILQ_NEXT(elm, field) = \
421 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
422 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
425 #define STAILQ_REMOVE_HEAD(head, field) do { \
426 if ((STAILQ_FIRST((head)) = \
427 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
428 (head)->stqh_last = &STAILQ_FIRST((head)); \
431 #define STAILQ_SWAP(head1, head2, type) do { \
432 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \
433 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \
434 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
435 (head1)->stqh_last = (head2)->stqh_last; \
436 STAILQ_FIRST(head2) = swap_first; \
437 (head2)->stqh_last = swap_last; \
438 if (STAILQ_EMPTY(head1)) \
439 (head1)->stqh_last = &STAILQ_FIRST(head1); \
440 if (STAILQ_EMPTY(head2)) \
441 (head2)->stqh_last = &STAILQ_FIRST(head2); \
448 #define LIST_HEAD(name, type) \
450 struct type *lh_first; /* first element */ \
453 #define LIST_CLASS_HEAD(name, type) \
455 class type *lh_first; /* first element */ \
458 #define LIST_HEAD_INITIALIZER(head) \
461 #define LIST_ENTRY(type) \
463 struct type *le_next; /* next element */ \
464 struct type **le_prev; /* address of previous next element */ \
467 #define LIST_CLASS_ENTRY(type) \
469 class type *le_next; /* next element */ \
470 class type **le_prev; /* address of previous next element */ \
477 #if (defined(_KERNEL) && defined(INVARIANTS))
479 * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
481 * If the list is non-empty, validates that the first element of the list
482 * points back at 'head.'
484 #define QMD_LIST_CHECK_HEAD(head, field) do { \
485 if (LIST_FIRST((head)) != NULL && \
486 LIST_FIRST((head))->field.le_prev != \
487 &LIST_FIRST((head))) \
488 panic("Bad list head %p first->prev != head", (head)); \
492 * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
494 * If an element follows 'elm' in the list, validates that the next element
495 * points back at 'elm.'
497 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
498 if (LIST_NEXT((elm), field) != NULL && \
499 LIST_NEXT((elm), field)->field.le_prev != \
500 &((elm)->field.le_next)) \
501 panic("Bad link elm %p next->prev != elm", (elm)); \
505 * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
507 * Validates that the previous element (or head of the list) points to 'elm.'
509 #define QMD_LIST_CHECK_PREV(elm, field) do { \
510 if (*(elm)->field.le_prev != (elm)) \
511 panic("Bad link elm %p prev->next != elm", (elm)); \
514 #define QMD_LIST_CHECK_HEAD(head, field)
515 #define QMD_LIST_CHECK_NEXT(elm, field)
516 #define QMD_LIST_CHECK_PREV(elm, field)
517 #endif /* (_KERNEL && INVARIANTS) */
519 #define LIST_CONCAT(head1, head2, type, field) do { \
520 QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \
521 if (curelm == NULL) { \
522 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \
523 LIST_FIRST(head2)->field.le_prev = \
524 &LIST_FIRST((head1)); \
527 } else if (LIST_FIRST(head2) != NULL) { \
528 while (LIST_NEXT(curelm, field) != NULL) \
529 curelm = LIST_NEXT(curelm, field); \
530 LIST_NEXT(curelm, field) = LIST_FIRST(head2); \
531 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
536 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
538 #define LIST_FIRST(head) ((head)->lh_first)
540 #define LIST_FOREACH(var, head, field) \
541 for ((var) = LIST_FIRST((head)); \
543 (var) = LIST_NEXT((var), field))
545 #define LIST_FOREACH_FROM(var, head, field) \
546 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
548 (var) = LIST_NEXT((var), field))
550 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
551 for ((var) = LIST_FIRST((head)); \
552 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
555 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
556 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
557 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
560 #define LIST_INIT(head) do { \
561 LIST_FIRST((head)) = NULL; \
564 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
565 QMD_LIST_CHECK_NEXT(listelm, field); \
566 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
567 LIST_NEXT((listelm), field)->field.le_prev = \
568 &LIST_NEXT((elm), field); \
569 LIST_NEXT((listelm), field) = (elm); \
570 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
573 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
574 QMD_LIST_CHECK_PREV(listelm, field); \
575 (elm)->field.le_prev = (listelm)->field.le_prev; \
576 LIST_NEXT((elm), field) = (listelm); \
577 *(listelm)->field.le_prev = (elm); \
578 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
581 #define LIST_INSERT_HEAD(head, elm, field) do { \
582 QMD_LIST_CHECK_HEAD((head), field); \
583 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
584 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
585 LIST_FIRST((head)) = (elm); \
586 (elm)->field.le_prev = &LIST_FIRST((head)); \
589 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
591 #define LIST_PREV(elm, head, type, field) \
592 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
593 __containerof((elm)->field.le_prev, \
594 QUEUE_TYPEOF(type), field.le_next))
596 #define LIST_REMOVE(elm, field) do { \
597 QMD_SAVELINK(oldnext, (elm)->field.le_next); \
598 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
599 QMD_LIST_CHECK_NEXT(elm, field); \
600 QMD_LIST_CHECK_PREV(elm, field); \
601 if (LIST_NEXT((elm), field) != NULL) \
602 LIST_NEXT((elm), field)->field.le_prev = \
603 (elm)->field.le_prev; \
604 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
609 #define LIST_SWAP(head1, head2, type, field) do { \
610 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \
611 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
612 LIST_FIRST((head2)) = swap_tmp; \
613 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
614 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
615 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
616 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
620 * Tail queue declarations.
622 #define TAILQ_HEAD(name, type) \
624 struct type *tqh_first; /* first element */ \
625 struct type **tqh_last; /* addr of last next element */ \
629 #define TAILQ_CLASS_HEAD(name, type) \
631 class type *tqh_first; /* first element */ \
632 class type **tqh_last; /* addr of last next element */ \
636 #define TAILQ_HEAD_INITIALIZER(head) \
637 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
639 #define TAILQ_ENTRY(type) \
641 struct type *tqe_next; /* next element */ \
642 struct type **tqe_prev; /* address of previous next element */ \
646 #define TAILQ_CLASS_ENTRY(type) \
648 class type *tqe_next; /* next element */ \
649 class type **tqe_prev; /* address of previous next element */ \
654 * Tail queue functions.
656 #if (defined(_KERNEL) && defined(INVARIANTS))
658 * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
660 * If the tailq is non-empty, validates that the first element of the tailq
661 * points back at 'head.'
663 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \
664 if (!TAILQ_EMPTY(head) && \
665 TAILQ_FIRST((head))->field.tqe_prev != \
666 &TAILQ_FIRST((head))) \
667 panic("Bad tailq head %p first->prev != head", (head)); \
671 * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
673 * Validates that the tail of the tailq is a pointer to pointer to NULL.
675 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \
676 if (*(head)->tqh_last != NULL) \
677 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
681 * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
683 * If an element follows 'elm' in the tailq, validates that the next element
684 * points back at 'elm.'
686 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
687 if (TAILQ_NEXT((elm), field) != NULL && \
688 TAILQ_NEXT((elm), field)->field.tqe_prev != \
689 &((elm)->field.tqe_next)) \
690 panic("Bad link elm %p next->prev != elm", (elm)); \
694 * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
696 * Validates that the previous element (or head of the tailq) points to 'elm.'
698 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \
699 if (*(elm)->field.tqe_prev != (elm)) \
700 panic("Bad link elm %p prev->next != elm", (elm)); \
703 #define QMD_TAILQ_CHECK_HEAD(head, field)
704 #define QMD_TAILQ_CHECK_TAIL(head, headname)
705 #define QMD_TAILQ_CHECK_NEXT(elm, field)
706 #define QMD_TAILQ_CHECK_PREV(elm, field)
707 #endif /* (_KERNEL && INVARIANTS) */
709 #define TAILQ_CONCAT(head1, head2, field) do { \
710 if (!TAILQ_EMPTY(head2)) { \
711 *(head1)->tqh_last = (head2)->tqh_first; \
712 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
713 (head1)->tqh_last = (head2)->tqh_last; \
714 TAILQ_INIT((head2)); \
715 QMD_TRACE_HEAD(head1); \
716 QMD_TRACE_HEAD(head2); \
720 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
722 #define TAILQ_FIRST(head) ((head)->tqh_first)
724 #define TAILQ_FOREACH(var, head, field) \
725 for ((var) = TAILQ_FIRST((head)); \
727 (var) = TAILQ_NEXT((var), field))
729 #define TAILQ_FOREACH_FROM(var, head, field) \
730 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
732 (var) = TAILQ_NEXT((var), field))
734 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
735 for ((var) = TAILQ_FIRST((head)); \
736 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
739 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
740 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
741 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
744 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
745 for ((var) = TAILQ_LAST((head), headname); \
747 (var) = TAILQ_PREV((var), headname, field))
749 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \
750 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
752 (var) = TAILQ_PREV((var), headname, field))
754 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
755 for ((var) = TAILQ_LAST((head), headname); \
756 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
759 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
760 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
761 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
764 #define TAILQ_INIT(head) do { \
765 TAILQ_FIRST((head)) = NULL; \
766 (head)->tqh_last = &TAILQ_FIRST((head)); \
767 QMD_TRACE_HEAD(head); \
770 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
771 QMD_TAILQ_CHECK_NEXT(listelm, field); \
772 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
773 TAILQ_NEXT((elm), field)->field.tqe_prev = \
774 &TAILQ_NEXT((elm), field); \
776 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
777 QMD_TRACE_HEAD(head); \
779 TAILQ_NEXT((listelm), field) = (elm); \
780 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
781 QMD_TRACE_ELEM(&(elm)->field); \
782 QMD_TRACE_ELEM(&(listelm)->field); \
785 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
786 QMD_TAILQ_CHECK_PREV(listelm, field); \
787 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
788 TAILQ_NEXT((elm), field) = (listelm); \
789 *(listelm)->field.tqe_prev = (elm); \
790 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
791 QMD_TRACE_ELEM(&(elm)->field); \
792 QMD_TRACE_ELEM(&(listelm)->field); \
795 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
796 QMD_TAILQ_CHECK_HEAD(head, field); \
797 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
798 TAILQ_FIRST((head))->field.tqe_prev = \
799 &TAILQ_NEXT((elm), field); \
801 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
802 TAILQ_FIRST((head)) = (elm); \
803 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
804 QMD_TRACE_HEAD(head); \
805 QMD_TRACE_ELEM(&(elm)->field); \
808 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
809 QMD_TAILQ_CHECK_TAIL(head, field); \
810 TAILQ_NEXT((elm), field) = NULL; \
811 (elm)->field.tqe_prev = (head)->tqh_last; \
812 *(head)->tqh_last = (elm); \
813 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
814 QMD_TRACE_HEAD(head); \
815 QMD_TRACE_ELEM(&(elm)->field); \
818 #define TAILQ_LAST(head, headname) \
819 (*(((struct headname *)((head)->tqh_last))->tqh_last))
822 * The FAST function is fast in that it causes no data access other
823 * then the access to the head. The standard LAST function above
824 * will cause a data access of both the element you want and
825 * the previous element. FAST is very useful for instances when
826 * you may want to prefetch the last data element.
828 #define TAILQ_LAST_FAST(head, type, field) \
829 (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
831 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
833 #define TAILQ_PREV(elm, headname, field) \
834 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
836 #define TAILQ_PREV_FAST(elm, head, type, field) \
837 ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL : \
838 __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next))
840 #define TAILQ_REMOVE(head, elm, field) do { \
841 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
842 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
843 QMD_TAILQ_CHECK_NEXT(elm, field); \
844 QMD_TAILQ_CHECK_PREV(elm, field); \
845 if ((TAILQ_NEXT((elm), field)) != NULL) \
846 TAILQ_NEXT((elm), field)->field.tqe_prev = \
847 (elm)->field.tqe_prev; \
849 (head)->tqh_last = (elm)->field.tqe_prev; \
850 QMD_TRACE_HEAD(head); \
852 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
855 QMD_TRACE_ELEM(&(elm)->field); \
858 #define TAILQ_SWAP(head1, head2, type, field) do { \
859 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \
860 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \
861 (head1)->tqh_first = (head2)->tqh_first; \
862 (head1)->tqh_last = (head2)->tqh_last; \
863 (head2)->tqh_first = swap_first; \
864 (head2)->tqh_last = swap_last; \
865 if ((swap_first = (head1)->tqh_first) != NULL) \
866 swap_first->field.tqe_prev = &(head1)->tqh_first; \
868 (head1)->tqh_last = &(head1)->tqh_first; \
869 if ((swap_first = (head2)->tqh_first) != NULL) \
870 swap_first->field.tqe_prev = &(head2)->tqh_first; \
872 (head2)->tqh_last = &(head2)->tqh_first; \
875 #endif /* !_SYS_QUEUE_H_ */