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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 QMD_SAVELINK(name, link) void **name = (void *)&(link)
159 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
160 #define QMD_IS_TRASHED(x) ((x) == (void *)(intptr_t)-1)
161 #else /* !QUEUE_MACRO_DEBUG_TRASH */
162 #define QMD_SAVELINK(name, link)
164 #define QMD_IS_TRASHED(x) 0
165 #endif /* QUEUE_MACRO_DEBUG_TRASH */
169 * In C++ there can be structure lists and class lists:
171 #define QUEUE_TYPEOF(type) type
173 #define QUEUE_TYPEOF(type) struct type
177 * Singly-linked List declarations.
179 #define SLIST_HEAD(name, type) \
181 struct type *slh_first; /* first element */ \
184 #define SLIST_CLASS_HEAD(name, type) \
186 class type *slh_first; /* first element */ \
189 #define SLIST_HEAD_INITIALIZER(head) \
192 #define SLIST_ENTRY(type) \
194 struct type *sle_next; /* next element */ \
197 #define SLIST_CLASS_ENTRY(type) \
199 class type *sle_next; /* next element */ \
203 * Singly-linked List functions.
205 #if (defined(_KERNEL) && defined(INVARIANTS))
206 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do { \
207 if (*(prevp) != (elm)) \
208 panic("Bad prevptr *(%p) == %p != %p", \
209 (prevp), *(prevp), (elm)); \
212 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm)
215 #define SLIST_CONCAT(head1, head2, type, field) do { \
216 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \
217 if (curelm == NULL) { \
218 if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \
220 } else if (SLIST_FIRST(head2) != NULL) { \
221 while (SLIST_NEXT(curelm, field) != NULL) \
222 curelm = SLIST_NEXT(curelm, field); \
223 SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \
228 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
230 #define SLIST_FIRST(head) ((head)->slh_first)
232 #define SLIST_FOREACH(var, head, field) \
233 for ((var) = SLIST_FIRST((head)); \
235 (var) = SLIST_NEXT((var), field))
237 #define SLIST_FOREACH_FROM(var, head, field) \
238 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
240 (var) = SLIST_NEXT((var), field))
242 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
243 for ((var) = SLIST_FIRST((head)); \
244 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
247 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
248 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
249 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
252 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
253 for ((varp) = &SLIST_FIRST((head)); \
254 ((var) = *(varp)) != NULL; \
255 (varp) = &SLIST_NEXT((var), field))
257 #define SLIST_INIT(head) do { \
258 SLIST_FIRST((head)) = NULL; \
261 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
262 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
263 SLIST_NEXT((slistelm), field) = (elm); \
266 #define SLIST_INSERT_HEAD(head, elm, field) do { \
267 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
268 SLIST_FIRST((head)) = (elm); \
271 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
273 #define SLIST_REMOVE(head, elm, type, field) do { \
274 QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
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); \
287 #define SLIST_REMOVE_AFTER(elm, field) do { \
288 SLIST_NEXT(elm, field) = \
289 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
292 #define SLIST_REMOVE_HEAD(head, field) do { \
293 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
296 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \
297 QMD_SLIST_CHECK_PREVPTR(prevp, elm); \
298 *(prevp) = SLIST_NEXT(elm, field); \
299 TRASHIT((elm)->field.sle_next); \
302 #define SLIST_SWAP(head1, head2, type) do { \
303 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \
304 SLIST_FIRST(head1) = SLIST_FIRST(head2); \
305 SLIST_FIRST(head2) = swap_first; \
309 * Singly-linked Tail queue declarations.
311 #define STAILQ_HEAD(name, type) \
313 struct type *stqh_first;/* first element */ \
314 struct type **stqh_last;/* addr of last next element */ \
317 #define STAILQ_CLASS_HEAD(name, type) \
319 class type *stqh_first; /* first element */ \
320 class type **stqh_last; /* addr of last next element */ \
323 #define STAILQ_HEAD_INITIALIZER(head) \
324 { NULL, &(head).stqh_first }
326 #define STAILQ_ENTRY(type) \
328 struct type *stqe_next; /* next element */ \
331 #define STAILQ_CLASS_ENTRY(type) \
333 class type *stqe_next; /* next element */ \
337 * Singly-linked Tail queue functions.
339 #define STAILQ_CONCAT(head1, head2) do { \
340 if (!STAILQ_EMPTY((head2))) { \
341 *(head1)->stqh_last = (head2)->stqh_first; \
342 (head1)->stqh_last = (head2)->stqh_last; \
343 STAILQ_INIT((head2)); \
347 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
349 #define STAILQ_FIRST(head) ((head)->stqh_first)
351 #define STAILQ_FOREACH(var, head, field) \
352 for((var) = STAILQ_FIRST((head)); \
354 (var) = STAILQ_NEXT((var), field))
356 #define STAILQ_FOREACH_FROM(var, head, field) \
357 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
359 (var) = STAILQ_NEXT((var), field))
361 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
362 for ((var) = STAILQ_FIRST((head)); \
363 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
366 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
367 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
368 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
371 #define STAILQ_INIT(head) do { \
372 STAILQ_FIRST((head)) = NULL; \
373 (head)->stqh_last = &STAILQ_FIRST((head)); \
376 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
377 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
378 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
379 STAILQ_NEXT((tqelm), field) = (elm); \
382 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
383 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
384 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
385 STAILQ_FIRST((head)) = (elm); \
388 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
389 STAILQ_NEXT((elm), field) = NULL; \
390 *(head)->stqh_last = (elm); \
391 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
394 #define STAILQ_LAST(head, type, field) \
395 (STAILQ_EMPTY((head)) ? NULL : \
396 __containerof((head)->stqh_last, \
397 QUEUE_TYPEOF(type), field.stqe_next))
399 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
401 #define STAILQ_REMOVE(head, elm, type, field) do { \
402 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
403 if (STAILQ_FIRST((head)) == (elm)) { \
404 STAILQ_REMOVE_HEAD((head), field); \
407 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \
408 while (STAILQ_NEXT(curelm, field) != (elm)) \
409 curelm = STAILQ_NEXT(curelm, field); \
410 STAILQ_REMOVE_AFTER(head, curelm, field); \
415 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \
416 if ((STAILQ_NEXT(elm, field) = \
417 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
418 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
421 #define STAILQ_REMOVE_HEAD(head, field) do { \
422 if ((STAILQ_FIRST((head)) = \
423 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
424 (head)->stqh_last = &STAILQ_FIRST((head)); \
427 #define STAILQ_SWAP(head1, head2, type) do { \
428 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \
429 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \
430 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
431 (head1)->stqh_last = (head2)->stqh_last; \
432 STAILQ_FIRST(head2) = swap_first; \
433 (head2)->stqh_last = swap_last; \
434 if (STAILQ_EMPTY(head1)) \
435 (head1)->stqh_last = &STAILQ_FIRST(head1); \
436 if (STAILQ_EMPTY(head2)) \
437 (head2)->stqh_last = &STAILQ_FIRST(head2); \
444 #define LIST_HEAD(name, type) \
446 struct type *lh_first; /* first element */ \
449 #define LIST_CLASS_HEAD(name, type) \
451 class type *lh_first; /* first element */ \
454 #define LIST_HEAD_INITIALIZER(head) \
457 #define LIST_ENTRY(type) \
459 struct type *le_next; /* next element */ \
460 struct type **le_prev; /* address of previous next element */ \
463 #define LIST_CLASS_ENTRY(type) \
465 class type *le_next; /* next element */ \
466 class type **le_prev; /* address of previous next element */ \
473 #if (defined(_KERNEL) && defined(INVARIANTS))
475 * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
477 * If the list is non-empty, validates that the first element of the list
478 * points back at 'head.'
480 #define QMD_LIST_CHECK_HEAD(head, field) do { \
481 if (LIST_FIRST((head)) != NULL && \
482 LIST_FIRST((head))->field.le_prev != \
483 &LIST_FIRST((head))) \
484 panic("Bad list head %p first->prev != head", (head)); \
488 * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
490 * If an element follows 'elm' in the list, validates that the next element
491 * points back at 'elm.'
493 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
494 if (LIST_NEXT((elm), field) != NULL && \
495 LIST_NEXT((elm), field)->field.le_prev != \
496 &((elm)->field.le_next)) \
497 panic("Bad link elm %p next->prev != elm", (elm)); \
501 * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
503 * Validates that the previous element (or head of the list) points to 'elm.'
505 #define QMD_LIST_CHECK_PREV(elm, field) do { \
506 if (*(elm)->field.le_prev != (elm)) \
507 panic("Bad link elm %p prev->next != elm", (elm)); \
510 #define QMD_LIST_CHECK_HEAD(head, field)
511 #define QMD_LIST_CHECK_NEXT(elm, field)
512 #define QMD_LIST_CHECK_PREV(elm, field)
513 #endif /* (_KERNEL && INVARIANTS) */
515 #define LIST_CONCAT(head1, head2, type, field) do { \
516 QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \
517 if (curelm == NULL) { \
518 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \
519 LIST_FIRST(head2)->field.le_prev = \
520 &LIST_FIRST((head1)); \
523 } else if (LIST_FIRST(head2) != NULL) { \
524 while (LIST_NEXT(curelm, field) != NULL) \
525 curelm = LIST_NEXT(curelm, field); \
526 LIST_NEXT(curelm, field) = LIST_FIRST(head2); \
527 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
532 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
534 #define LIST_FIRST(head) ((head)->lh_first)
536 #define LIST_FOREACH(var, head, field) \
537 for ((var) = LIST_FIRST((head)); \
539 (var) = LIST_NEXT((var), field))
541 #define LIST_FOREACH_FROM(var, head, field) \
542 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
544 (var) = LIST_NEXT((var), field))
546 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
547 for ((var) = LIST_FIRST((head)); \
548 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
551 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
552 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
553 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
556 #define LIST_INIT(head) do { \
557 LIST_FIRST((head)) = NULL; \
560 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
561 QMD_LIST_CHECK_NEXT(listelm, field); \
562 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
563 LIST_NEXT((listelm), field)->field.le_prev = \
564 &LIST_NEXT((elm), field); \
565 LIST_NEXT((listelm), field) = (elm); \
566 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
569 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
570 QMD_LIST_CHECK_PREV(listelm, field); \
571 (elm)->field.le_prev = (listelm)->field.le_prev; \
572 LIST_NEXT((elm), field) = (listelm); \
573 *(listelm)->field.le_prev = (elm); \
574 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
577 #define LIST_INSERT_HEAD(head, elm, field) do { \
578 QMD_LIST_CHECK_HEAD((head), field); \
579 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
580 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
581 LIST_FIRST((head)) = (elm); \
582 (elm)->field.le_prev = &LIST_FIRST((head)); \
585 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
587 #define LIST_PREV(elm, head, type, field) \
588 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
589 __containerof((elm)->field.le_prev, \
590 QUEUE_TYPEOF(type), field.le_next))
592 #define LIST_REMOVE(elm, field) do { \
593 QMD_SAVELINK(oldnext, (elm)->field.le_next); \
594 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
595 QMD_LIST_CHECK_NEXT(elm, field); \
596 QMD_LIST_CHECK_PREV(elm, field); \
597 if (LIST_NEXT((elm), field) != NULL) \
598 LIST_NEXT((elm), field)->field.le_prev = \
599 (elm)->field.le_prev; \
600 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
605 #define LIST_SWAP(head1, head2, type, field) do { \
606 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \
607 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
608 LIST_FIRST((head2)) = swap_tmp; \
609 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
610 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
611 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
612 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
616 * Tail queue declarations.
618 #define TAILQ_HEAD(name, type) \
620 struct type *tqh_first; /* first element */ \
621 struct type **tqh_last; /* addr of last next element */ \
625 #define TAILQ_CLASS_HEAD(name, type) \
627 class type *tqh_first; /* first element */ \
628 class type **tqh_last; /* addr of last next element */ \
632 #define TAILQ_HEAD_INITIALIZER(head) \
633 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
635 #define TAILQ_ENTRY(type) \
637 struct type *tqe_next; /* next element */ \
638 struct type **tqe_prev; /* address of previous next element */ \
642 #define TAILQ_CLASS_ENTRY(type) \
644 class type *tqe_next; /* next element */ \
645 class type **tqe_prev; /* address of previous next element */ \
650 * Tail queue functions.
652 #if (defined(_KERNEL) && defined(INVARIANTS))
654 * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
656 * If the tailq is non-empty, validates that the first element of the tailq
657 * points back at 'head.'
659 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \
660 if (!TAILQ_EMPTY(head) && \
661 TAILQ_FIRST((head))->field.tqe_prev != \
662 &TAILQ_FIRST((head))) \
663 panic("Bad tailq head %p first->prev != head", (head)); \
667 * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
669 * Validates that the tail of the tailq is a pointer to pointer to NULL.
671 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \
672 if (*(head)->tqh_last != NULL) \
673 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
677 * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
679 * If an element follows 'elm' in the tailq, validates that the next element
680 * points back at 'elm.'
682 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
683 if (TAILQ_NEXT((elm), field) != NULL && \
684 TAILQ_NEXT((elm), field)->field.tqe_prev != \
685 &((elm)->field.tqe_next)) \
686 panic("Bad link elm %p next->prev != elm", (elm)); \
690 * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
692 * Validates that the previous element (or head of the tailq) points to 'elm.'
694 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \
695 if (*(elm)->field.tqe_prev != (elm)) \
696 panic("Bad link elm %p prev->next != elm", (elm)); \
699 #define QMD_TAILQ_CHECK_HEAD(head, field)
700 #define QMD_TAILQ_CHECK_TAIL(head, headname)
701 #define QMD_TAILQ_CHECK_NEXT(elm, field)
702 #define QMD_TAILQ_CHECK_PREV(elm, field)
703 #endif /* (_KERNEL && INVARIANTS) */
705 #define TAILQ_CONCAT(head1, head2, field) do { \
706 if (!TAILQ_EMPTY(head2)) { \
707 *(head1)->tqh_last = (head2)->tqh_first; \
708 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
709 (head1)->tqh_last = (head2)->tqh_last; \
710 TAILQ_INIT((head2)); \
711 QMD_TRACE_HEAD(head1); \
712 QMD_TRACE_HEAD(head2); \
716 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
718 #define TAILQ_FIRST(head) ((head)->tqh_first)
720 #define TAILQ_FOREACH(var, head, field) \
721 for ((var) = TAILQ_FIRST((head)); \
723 (var) = TAILQ_NEXT((var), field))
725 #define TAILQ_FOREACH_FROM(var, head, field) \
726 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
728 (var) = TAILQ_NEXT((var), field))
730 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
731 for ((var) = TAILQ_FIRST((head)); \
732 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
735 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
736 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
737 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
740 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
741 for ((var) = TAILQ_LAST((head), headname); \
743 (var) = TAILQ_PREV((var), headname, field))
745 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \
746 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
748 (var) = TAILQ_PREV((var), headname, field))
750 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
751 for ((var) = TAILQ_LAST((head), headname); \
752 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
755 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
756 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
757 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
760 #define TAILQ_INIT(head) do { \
761 TAILQ_FIRST((head)) = NULL; \
762 (head)->tqh_last = &TAILQ_FIRST((head)); \
763 QMD_TRACE_HEAD(head); \
766 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
767 QMD_TAILQ_CHECK_NEXT(listelm, field); \
768 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
769 TAILQ_NEXT((elm), field)->field.tqe_prev = \
770 &TAILQ_NEXT((elm), field); \
772 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
773 QMD_TRACE_HEAD(head); \
775 TAILQ_NEXT((listelm), field) = (elm); \
776 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
777 QMD_TRACE_ELEM(&(elm)->field); \
778 QMD_TRACE_ELEM(&(listelm)->field); \
781 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
782 QMD_TAILQ_CHECK_PREV(listelm, field); \
783 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
784 TAILQ_NEXT((elm), field) = (listelm); \
785 *(listelm)->field.tqe_prev = (elm); \
786 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
787 QMD_TRACE_ELEM(&(elm)->field); \
788 QMD_TRACE_ELEM(&(listelm)->field); \
791 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
792 QMD_TAILQ_CHECK_HEAD(head, field); \
793 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
794 TAILQ_FIRST((head))->field.tqe_prev = \
795 &TAILQ_NEXT((elm), field); \
797 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
798 TAILQ_FIRST((head)) = (elm); \
799 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
800 QMD_TRACE_HEAD(head); \
801 QMD_TRACE_ELEM(&(elm)->field); \
804 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
805 QMD_TAILQ_CHECK_TAIL(head, field); \
806 TAILQ_NEXT((elm), field) = NULL; \
807 (elm)->field.tqe_prev = (head)->tqh_last; \
808 *(head)->tqh_last = (elm); \
809 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
810 QMD_TRACE_HEAD(head); \
811 QMD_TRACE_ELEM(&(elm)->field); \
814 #define TAILQ_LAST(head, headname) \
815 (*(((struct headname *)((head)->tqh_last))->tqh_last))
818 * The FAST function is fast in that it causes no data access other
819 * then the access to the head. The standard LAST function above
820 * will cause a data access of both the element you want and
821 * the previous element. FAST is very useful for instances when
822 * you may want to prefetch the last data element.
824 #define TAILQ_LAST_FAST(head, type, field) \
825 (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
827 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
829 #define TAILQ_PREV(elm, headname, field) \
830 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
832 #define TAILQ_REMOVE(head, elm, field) do { \
833 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
834 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
835 QMD_TAILQ_CHECK_NEXT(elm, field); \
836 QMD_TAILQ_CHECK_PREV(elm, field); \
837 if ((TAILQ_NEXT((elm), field)) != NULL) \
838 TAILQ_NEXT((elm), field)->field.tqe_prev = \
839 (elm)->field.tqe_prev; \
841 (head)->tqh_last = (elm)->field.tqe_prev; \
842 QMD_TRACE_HEAD(head); \
844 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
847 QMD_TRACE_ELEM(&(elm)->field); \
850 #define TAILQ_SWAP(head1, head2, type, field) do { \
851 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \
852 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \
853 (head1)->tqh_first = (head2)->tqh_first; \
854 (head1)->tqh_last = (head2)->tqh_last; \
855 (head2)->tqh_first = swap_first; \
856 (head2)->tqh_last = swap_last; \
857 if ((swap_first = (head1)->tqh_first) != NULL) \
858 swap_first->field.tqe_prev = &(head1)->tqh_first; \
860 (head1)->tqh_last = &(head1)->tqh_first; \
861 if ((swap_first = (head2)->tqh_first) != NULL) \
862 swap_first->field.tqe_prev = &(head2)->tqh_first; \
864 (head2)->tqh_last = &(head2)->tqh_first; \
867 #endif /* !_SYS_QUEUE_H_ */