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+// SPDX-License-Identifier: BSD-3-Clause
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * @(#)queue.h 8.5 (Berkeley) 8/20/94
+ * $FreeBSD$
+ */
+
+#ifndef _SYS_QUEUE_H_
+#define _SYS_QUEUE_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * This file defines four types of data structures: singly-linked lists,
+ * singly-linked tail queues, lists and tail queues.
+ *
+ * A singly-linked list is headed by a single forward pointer. The elements
+ * are singly linked for minimum space and pointer manipulation overhead at
+ * the expense of O(n) removal for arbitrary elements. New elements can be
+ * added to the list after an existing element or at the head of the list.
+ * Elements being removed from the head of the list should use the explicit
+ * macro for this purpose for optimum efficiency. A singly-linked list may
+ * only be traversed in the forward direction. Singly-linked lists are ideal
+ * for applications with large datasets and few or no removals or for
+ * implementing a LIFO queue.
+ *
+ * A singly-linked tail queue is headed by a pair of pointers, one to the
+ * head of the list and the other to the tail of the list. The elements are
+ * singly linked for minimum space and pointer manipulation overhead at the
+ * expense of O(n) removal for arbitrary elements. New elements can be added
+ * to the list after an existing element, at the head of the list, or at the
+ * end of the list. Elements being removed from the head of the tail queue
+ * should use the explicit macro for this purpose for optimum efficiency.
+ * A singly-linked tail queue may only be traversed in the forward direction.
+ * Singly-linked tail queues are ideal for applications with large datasets
+ * and few or no removals or for implementing a FIFO queue.
+ *
+ * A list is headed by a single forward pointer (or an array of forward
+ * pointers for a hash table header). The elements are doubly linked
+ * so that an arbitrary element can be removed without a need to
+ * traverse the list. New elements can be added to the list before
+ * or after an existing element or at the head of the list. A list
+ * may only be traversed in the forward direction.
+ *
+ * A tail queue is headed by a pair of pointers, one to the head of the
+ * list and the other to the tail of the list. The elements are doubly
+ * linked so that an arbitrary element can be removed without a need to
+ * traverse the list. New elements can be added to the list before or
+ * after an existing element, at the head of the list, or at the end of
+ * the list. A tail queue may be traversed in either direction.
+ *
+ * For details on the use of these macros, see the queue(3) manual page.
+ *
+ *
+ * SLIST LIST STAILQ TAILQ
+ * _HEAD + + + +
+ * _HEAD_INITIALIZER + + + +
+ * _ENTRY + + + +
+ * _INIT + + + +
+ * _EMPTY + + + +
+ * _FIRST + + + +
+ * _NEXT + + + +
+ * _PREV - - - +
+ * _LAST - - + +
+ * _FOREACH + + + +
+ * _FOREACH_SAFE + + + +
+ * _FOREACH_REVERSE - - - +
+ * _FOREACH_REVERSE_SAFE - - - +
+ * _INSERT_HEAD + + + +
+ * _INSERT_BEFORE - + - +
+ * _INSERT_AFTER + + + +
+ * _INSERT_TAIL - - + +
+ * _CONCAT - - + +
+ * _REMOVE_AFTER + - + -
+ * _REMOVE_HEAD + - + -
+ * _REMOVE + + + +
+ * _SWAP + + + +
+ *
+ */
+#ifdef QUEUE_MACRO_DEBUG
+/* Store the last 2 places the queue element or head was altered */
+struct qm_trace {
+ char *lastfile;
+ int lastline;
+ char *prevfile;
+ int prevline;
+};
+
+#define TRACEBUF struct qm_trace trace;
+#define TRASHIT(x) do {(x) = (void *)-1;} while (0)
+#define QMD_SAVELINK(name, link) void **name = (void *)&(link)
+
+#define QMD_TRACE_HEAD(head) \
+ do { \
+ (head)->trace.prevline = (head)->trace.lastline; \
+ (head)->trace.prevfile = (head)->trace.lastfile; \
+ (head)->trace.lastline = __LINE__; \
+ (head)->trace.lastfile = __FILE__; \
+ } while (0)
+
+#define QMD_TRACE_ELEM(elem) \
+ do { \
+ (elem)->trace.prevline = (elem)->trace.lastline; \
+ (elem)->trace.prevfile = (elem)->trace.lastfile; \
+ (elem)->trace.lastline = __LINE__; \
+ (elem)->trace.lastfile = __FILE__; \
+ } while (0)
+
+#else
+#define QMD_TRACE_ELEM(elem)
+#define QMD_TRACE_HEAD(head)
+#define QMD_SAVELINK(name, link)
+#define TRACEBUF
+#define TRASHIT(x)
+#endif /* QUEUE_MACRO_DEBUG */
+
+/*
+ * Singly-linked List declarations.
+ */
+#define SLIST_HEAD(name, type) \
+ struct name { \
+ struct type *slh_first; /* first element */ \
+ }
+
+#define SLIST_HEAD_INITIALIZER(head) \
+ { \
+ NULL \
+ }
+
+#define SLIST_ENTRY(type) \
+ struct { \
+ struct type *sle_next; /* next element */ \
+ }
+
+/*
+ * Singly-linked List functions.
+ */
+#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
+
+#define SLIST_FIRST(head) ((head)->slh_first)
+
+#define SLIST_FOREACH(var, head, field) \
+ for ((var) = SLIST_FIRST((head)); (var); \
+ (var) = SLIST_NEXT((var), field))
+
+#define SLIST_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = SLIST_FIRST((head)); \
+ (var) && ((tvar) = SLIST_NEXT((var), field), 1); (var) = (tvar))
+
+#define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
+ for ((varp) = &SLIST_FIRST((head)); ((var) = *(varp)) != NULL; \
+ (varp) = &SLIST_NEXT((var), field))
+
+#define SLIST_INIT(head) \
+ do { \
+ SLIST_FIRST((head)) = NULL; \
+ } while (0)
+
+#define SLIST_INSERT_AFTER(slistelm, elm, field) \
+ do { \
+ SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
+ SLIST_NEXT((slistelm), field) = (elm); \
+ } while (0)
+
+#define SLIST_INSERT_HEAD(head, elm, field) \
+ do { \
+ SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
+ SLIST_FIRST((head)) = (elm); \
+ } while (0)
+
+#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
+
+#define SLIST_REMOVE(head, elm, type, field) \
+ do { \
+ QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
+ if (SLIST_FIRST((head)) == (elm)) { \
+ SLIST_REMOVE_HEAD((head), field); \
+ } else { \
+ struct type *curelm = SLIST_FIRST((head)); \
+ while (SLIST_NEXT(curelm, field) != (elm)) \
+ curelm = SLIST_NEXT(curelm, field); \
+ SLIST_REMOVE_AFTER(curelm, field); \
+ } \
+ TRASHIT(*oldnext); \
+ } while (0)
+
+#define SLIST_REMOVE_AFTER(elm, field) \
+ do { \
+ SLIST_NEXT(elm, field) = \
+ SLIST_NEXT(SLIST_NEXT(elm, field), field); \
+ } while (0)
+
+#define SLIST_REMOVE_HEAD(head, field) \
+ do { \
+ SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
+ } while (0)
+
+#define SLIST_SWAP(head1, head2, type) \
+ do { \
+ struct type *swap_first = SLIST_FIRST(head1); \
+ SLIST_FIRST(head1) = SLIST_FIRST(head2); \
+ SLIST_FIRST(head2) = swap_first; \
+ } while (0)
+
+/*
+ * Singly-linked Tail queue declarations.
+ */
+#define STAILQ_HEAD(name, type) \
+ struct name { \
+ struct type *stqh_first; /* first element */ \
+ struct type **stqh_last; /* addr of last next element */ \
+ }
+
+#define STAILQ_HEAD_INITIALIZER(head) \
+ { \
+ NULL, &(head).stqh_first \
+ }
+
+#define STAILQ_ENTRY(type) \
+ struct { \
+ struct type *stqe_next; /* next element */ \
+ }
+
+/*
+ * Singly-linked Tail queue functions.
+ */
+#define STAILQ_CONCAT(head1, head2) \
+ do { \
+ if (!STAILQ_EMPTY((head2))) { \
+ *(head1)->stqh_last = (head2)->stqh_first; \
+ (head1)->stqh_last = (head2)->stqh_last; \
+ STAILQ_INIT((head2)); \
+ } \
+ } while (0)
+
+#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
+
+#define STAILQ_FIRST(head) ((head)->stqh_first)
+
+#define STAILQ_FOREACH(var, head, field) \
+ for ((var) = STAILQ_FIRST((head)); (var); \
+ (var) = STAILQ_NEXT((var), field))
+
+
+#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = STAILQ_FIRST((head)); \
+ (var) && ((tvar) = STAILQ_NEXT((var), field), 1); (var) = (tvar))
+
+#define STAILQ_INIT(head) \
+ do { \
+ STAILQ_FIRST((head)) = NULL; \
+ (head)->stqh_last = &STAILQ_FIRST((head)); \
+ } while (0)
+
+#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) \
+ do { \
+ if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) \
+ == NULL) \
+ (head)->stqh_last = &STAILQ_NEXT((elm), field); \
+ STAILQ_NEXT((tqelm), field) = (elm); \
+ } while (0)
+
+#define STAILQ_INSERT_HEAD(head, elm, field) \
+ do { \
+ if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) \
+ == NULL) \
+ (head)->stqh_last = &STAILQ_NEXT((elm), field); \
+ STAILQ_FIRST((head)) = (elm); \
+ } while (0)
+
+#define STAILQ_INSERT_TAIL(head, elm, field) \
+ do { \
+ STAILQ_NEXT((elm), field) = NULL; \
+ *(head)->stqh_last = (elm); \
+ (head)->stqh_last = &STAILQ_NEXT((elm), field); \
+ } while (0)
+
+#define STAILQ_LAST(head, type, field) \
+ (STAILQ_EMPTY((head)) \
+ ? NULL \
+ : ((struct type *)(void *)((char *)((head)->stqh_last) \
+ - offsetof(struct type, field))))
+
+#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
+
+#define STAILQ_REMOVE(head, elm, type, field) \
+ do { \
+ QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
+ if (STAILQ_FIRST((head)) == (elm)) { \
+ STAILQ_REMOVE_HEAD((head), field); \
+ } else { \
+ struct type *curelm = STAILQ_FIRST((head)); \
+ while (STAILQ_NEXT(curelm, field) != (elm)) \
+ curelm = STAILQ_NEXT(curelm, field); \
+ STAILQ_REMOVE_AFTER(head, curelm, field); \
+ } \
+ TRASHIT(*oldnext); \
+ } while (0)
+
+#define STAILQ_REMOVE_AFTER(head, elm, field) \
+ do { \
+ if ((STAILQ_NEXT(elm, field) = \
+ STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) \
+ == NULL) \
+ (head)->stqh_last = &STAILQ_NEXT((elm), field); \
+ } while (0)
+
+#define STAILQ_REMOVE_HEAD(head, field) \
+ do { \
+ if ((STAILQ_FIRST((head)) = \
+ STAILQ_NEXT(STAILQ_FIRST((head)), field)) \
+ == NULL) \
+ (head)->stqh_last = &STAILQ_FIRST((head)); \
+ } while (0)
+
+#define STAILQ_SWAP(head1, head2, type) \
+ do { \
+ struct type *swap_first = STAILQ_FIRST(head1); \
+ struct type **swap_last = (head1)->stqh_last; \
+ STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
+ (head1)->stqh_last = (head2)->stqh_last; \
+ STAILQ_FIRST(head2) = swap_first; \
+ (head2)->stqh_last = swap_last; \
+ if (STAILQ_EMPTY(head1)) \
+ (head1)->stqh_last = &STAILQ_FIRST(head1); \
+ if (STAILQ_EMPTY(head2)) \
+ (head2)->stqh_last = &STAILQ_FIRST(head2); \
+ } while (0)
+
+
+/*
+ * List declarations.
+ */
+#define LIST_HEAD(name, type) \
+ struct name { \
+ struct type *lh_first; /* first element */ \
+ }
+
+#define LIST_HEAD_INITIALIZER(head) \
+ { \
+ NULL \
+ }
+
+#define LIST_ENTRY(type) \
+ struct { \
+ struct type *le_next; /* next element */ \
+ struct type **le_prev; /* address of previous next element */ \
+ }
+
+/*
+ * List functions.
+ */
+
+#if (defined(_KERNEL) && defined(INVARIANTS))
+#define QMD_LIST_CHECK_HEAD(head, field) \
+ do { \
+ if (LIST_FIRST((head)) != NULL \
+ && LIST_FIRST((head))->field.le_prev \
+ != &LIST_FIRST((head))) \
+ panic("Bad list head %p first->prev != head", (head)); \
+ } while (0)
+
+#define QMD_LIST_CHECK_NEXT(elm, field) \
+ do { \
+ if (LIST_NEXT((elm), field) != NULL \
+ && LIST_NEXT((elm), field)->field.le_prev \
+ != &((elm)->field.le_next)) \
+ panic("Bad link elm %p next->prev != elm", (elm)); \
+ } while (0)
+
+#define QMD_LIST_CHECK_PREV(elm, field) \
+ do { \
+ if (*(elm)->field.le_prev != (elm)) \
+ panic("Bad link elm %p prev->next != elm", (elm)); \
+ } while (0)
+#else
+#define QMD_LIST_CHECK_HEAD(head, field)
+#define QMD_LIST_CHECK_NEXT(elm, field)
+#define QMD_LIST_CHECK_PREV(elm, field)
+#endif /* (_KERNEL && INVARIANTS) */
+
+#define LIST_EMPTY(head) ((head)->lh_first == NULL)
+
+#define LIST_FIRST(head) ((head)->lh_first)
+
+#define LIST_FOREACH(var, head, field) \
+ for ((var) = LIST_FIRST((head)); (var); (var) = LIST_NEXT((var), field))
+
+#define LIST_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = LIST_FIRST((head)); \
+ (var) && ((tvar) = LIST_NEXT((var), field), 1); (var) = (tvar))
+
+#define LIST_INIT(head) \
+ do { \
+ LIST_FIRST((head)) = NULL; \
+ } while (0)
+
+#define LIST_INSERT_AFTER(listelm, elm, field) \
+ do { \
+ QMD_LIST_CHECK_NEXT(listelm, field); \
+ if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) \
+ != NULL) \
+ LIST_NEXT((listelm), field)->field.le_prev = \
+ &LIST_NEXT((elm), field); \
+ LIST_NEXT((listelm), field) = (elm); \
+ (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
+ } while (0)
+
+#define LIST_INSERT_BEFORE(listelm, elm, field) \
+ do { \
+ QMD_LIST_CHECK_PREV(listelm, field); \
+ (elm)->field.le_prev = (listelm)->field.le_prev; \
+ LIST_NEXT((elm), field) = (listelm); \
+ *(listelm)->field.le_prev = (elm); \
+ (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
+ } while (0)
+
+#define LIST_INSERT_HEAD(head, elm, field) \
+ do { \
+ QMD_LIST_CHECK_HEAD((head), field); \
+ if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
+ LIST_FIRST((head))->field.le_prev = \
+ &LIST_NEXT((elm), field); \
+ LIST_FIRST((head)) = (elm); \
+ (elm)->field.le_prev = &LIST_FIRST((head)); \
+ } while (0)
+
+#define LIST_NEXT(elm, field) ((elm)->field.le_next)
+
+#define LIST_REMOVE(elm, field) \
+ do { \
+ QMD_SAVELINK(oldnext, (elm)->field.le_next); \
+ QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
+ QMD_LIST_CHECK_NEXT(elm, field); \
+ QMD_LIST_CHECK_PREV(elm, field); \
+ if (LIST_NEXT((elm), field) != NULL) \
+ LIST_NEXT((elm), field)->field.le_prev = \
+ (elm)->field.le_prev; \
+ *(elm)->field.le_prev = LIST_NEXT((elm), field); \
+ TRASHIT(*oldnext); \
+ TRASHIT(*oldprev); \
+ } while (0)
+
+#define LIST_SWAP(head1, head2, type, field) \
+ do { \
+ struct type *swap_tmp = LIST_FIRST((head1)); \
+ LIST_FIRST((head1)) = LIST_FIRST((head2)); \
+ LIST_FIRST((head2)) = swap_tmp; \
+ if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
+ swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
+ if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
+ swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
+ } while (0)
+
+/*
+ * Tail queue declarations.
+ */
+#define TAILQ_HEAD(name, type) \
+ struct name { \
+ struct type *tqh_first; /* first element */ \
+ struct type **tqh_last; /* addr of last next element */ \
+ TRACEBUF \
+ }
+
+#define TAILQ_HEAD_INITIALIZER(head) \
+ { \
+ NULL, &(head).tqh_first \
+ }
+
+#define TAILQ_ENTRY(type) \
+ struct { \
+ struct type *tqe_next; /* next element */ \
+ struct type **tqe_prev; /* address of previous next element */ \
+ TRACEBUF \
+ }
+
+/*
+ * Tail queue functions.
+ */
+#if (defined(_KERNEL) && defined(INVARIANTS))
+#define QMD_TAILQ_CHECK_HEAD(head, field) \
+ do { \
+ if (!TAILQ_EMPTY(head) \
+ && TAILQ_FIRST((head))->field.tqe_prev \
+ != &TAILQ_FIRST((head))) \
+ panic("Bad tailq head %p first->prev != head", \
+ (head)); \
+ } while (0)
+
+#define QMD_TAILQ_CHECK_TAIL(head, field) \
+ do { \
+ if (*(head)->tqh_last != NULL) \
+ panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
+ } while (0)
+
+#define QMD_TAILQ_CHECK_NEXT(elm, field) \
+ do { \
+ if (TAILQ_NEXT((elm), field) != NULL \
+ && TAILQ_NEXT((elm), field)->field.tqe_prev \
+ != &((elm)->field.tqe_next)) \
+ panic("Bad link elm %p next->prev != elm", (elm)); \
+ } while (0)
+
+#define QMD_TAILQ_CHECK_PREV(elm, field) \
+ do { \
+ if (*(elm)->field.tqe_prev != (elm)) \
+ panic("Bad link elm %p prev->next != elm", (elm)); \
+ } while (0)
+#else
+#define QMD_TAILQ_CHECK_HEAD(head, field)
+#define QMD_TAILQ_CHECK_TAIL(head, headname)
+#define QMD_TAILQ_CHECK_NEXT(elm, field)
+#define QMD_TAILQ_CHECK_PREV(elm, field)
+#endif /* (_KERNEL && INVARIANTS) */
+
+#define TAILQ_CONCAT(head1, head2, field) \
+ do { \
+ if (!TAILQ_EMPTY(head2)) { \
+ *(head1)->tqh_last = (head2)->tqh_first; \
+ (head2)->tqh_first->field.tqe_prev = \
+ (head1)->tqh_last; \
+ (head1)->tqh_last = (head2)->tqh_last; \
+ TAILQ_INIT((head2)); \
+ QMD_TRACE_HEAD(head1); \
+ QMD_TRACE_HEAD(head2); \
+ } \
+ } while (0)
+
+#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
+
+#define TAILQ_FIRST(head) ((head)->tqh_first)
+
+#define TAILQ_FOREACH(var, head, field) \
+ for ((var) = TAILQ_FIRST((head)); (var); \
+ (var) = TAILQ_NEXT((var), field))
+
+#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
+ for ((var) = TAILQ_FIRST((head)); \
+ (var) && ((tvar) = TAILQ_NEXT((var), field), 1); (var) = (tvar))
+
+#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
+ for ((var) = TAILQ_LAST((head), headname); (var); \
+ (var) = TAILQ_PREV((var), headname, field))
+
+#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
+ for ((var) = TAILQ_LAST((head), headname); \
+ (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
+ (var) = (tvar))
+
+#define TAILQ_INIT(head) \
+ do { \
+ TAILQ_FIRST((head)) = NULL; \
+ (head)->tqh_last = &TAILQ_FIRST((head)); \
+ QMD_TRACE_HEAD(head); \
+ } while (0)
+
+#define TAILQ_INSERT_AFTER(head, listelm, elm, field) \
+ do { \
+ QMD_TAILQ_CHECK_NEXT(listelm, field); \
+ if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) \
+ != NULL) \
+ TAILQ_NEXT((elm), field)->field.tqe_prev = \
+ &TAILQ_NEXT((elm), field); \
+ else { \
+ (head)->tqh_last = &TAILQ_NEXT((elm), field); \
+ QMD_TRACE_HEAD(head); \
+ } \
+ TAILQ_NEXT((listelm), field) = (elm); \
+ (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
+ QMD_TRACE_ELEM(&(elm)->field); \
+ QMD_TRACE_ELEM(&listelm->field); \
+ } while (0)
+
+#define TAILQ_INSERT_BEFORE(listelm, elm, field) \
+ do { \
+ QMD_TAILQ_CHECK_PREV(listelm, field); \
+ (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
+ TAILQ_NEXT((elm), field) = (listelm); \
+ *(listelm)->field.tqe_prev = (elm); \
+ (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
+ QMD_TRACE_ELEM(&(elm)->field); \
+ QMD_TRACE_ELEM(&listelm->field); \
+ } while (0)
+
+#define TAILQ_INSERT_HEAD(head, elm, field) \
+ do { \
+ QMD_TAILQ_CHECK_HEAD(head, field); \
+ if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
+ TAILQ_FIRST((head))->field.tqe_prev = \
+ &TAILQ_NEXT((elm), field); \
+ else \
+ (head)->tqh_last = &TAILQ_NEXT((elm), field); \
+ TAILQ_FIRST((head)) = (elm); \
+ (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
+ QMD_TRACE_HEAD(head); \
+ QMD_TRACE_ELEM(&(elm)->field); \
+ } while (0)
+
+#define TAILQ_INSERT_TAIL(head, elm, field) \
+ do { \
+ QMD_TAILQ_CHECK_TAIL(head, field); \
+ TAILQ_NEXT((elm), field) = NULL; \
+ (elm)->field.tqe_prev = (head)->tqh_last; \
+ *(head)->tqh_last = (elm); \
+ (head)->tqh_last = &TAILQ_NEXT((elm), field); \
+ QMD_TRACE_HEAD(head); \
+ QMD_TRACE_ELEM(&(elm)->field); \
+ } while (0)
+
+#define TAILQ_LAST(head, headname) \
+ (*(((struct headname *)((head)->tqh_last))->tqh_last))
+
+#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
+
+#define TAILQ_PREV(elm, headname, field) \
+ (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+
+#define TAILQ_REMOVE(head, elm, field) \
+ do { \
+ QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
+ QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
+ QMD_TAILQ_CHECK_NEXT(elm, field); \
+ QMD_TAILQ_CHECK_PREV(elm, field); \
+ if ((TAILQ_NEXT((elm), field)) != NULL) \
+ TAILQ_NEXT((elm), field)->field.tqe_prev = \
+ (elm)->field.tqe_prev; \
+ else { \
+ (head)->tqh_last = (elm)->field.tqe_prev; \
+ QMD_TRACE_HEAD(head); \
+ } \
+ *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
+ TRASHIT(*oldnext); \
+ TRASHIT(*oldprev); \
+ QMD_TRACE_ELEM(&(elm)->field); \
+ } while (0)
+
+#define TAILQ_SWAP(head1, head2, type, field) \
+ do { \
+ struct type *swap_first = (head1)->tqh_first; \
+ struct type **swap_last = (head1)->tqh_last; \
+ (head1)->tqh_first = (head2)->tqh_first; \
+ (head1)->tqh_last = (head2)->tqh_last; \
+ (head2)->tqh_first = swap_first; \
+ (head2)->tqh_last = swap_last; \
+ if ((swap_first = (head1)->tqh_first) != NULL) \
+ swap_first->field.tqe_prev = &(head1)->tqh_first; \
+ else \
+ (head1)->tqh_last = &(head1)->tqh_first; \
+ if ((swap_first = (head2)->tqh_first) != NULL) \
+ swap_first->field.tqe_prev = &(head2)->tqh_first; \
+ else \
+ (head2)->tqh_last = &(head2)->tqh_first; \
+ } while (0)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* !_SYS_QUEUE_H_ */