]> Zhao Yanbai Git Server - minix.git/commitdiff
Pull in NetBSD's queue.h (for pkgsrc)
authorArun Thomas <arun@minix3.org>
Wed, 7 Jul 2010 14:17:25 +0000 (14:17 +0000)
committerArun Thomas <arun@minix3.org>
Wed, 7 Jul 2010 14:17:25 +0000 (14:17 +0000)
include/sys/Makefile
include/sys/null.h [new file with mode: 0644]
include/sys/queue.h

index 6cc8f8bb267827f88efb1f98c672fbc39247cd20..37623982e0a58bb2da92c84cb1b3fa9174e3f7fa 100644 (file)
@@ -9,6 +9,6 @@ INCS=   asynchio.h dir.h file.h ioc_cmos.h ioc_disk.h \
        select.h sem.h shm.h sigcontext.h signal.h socket.h \
        soundcard.h statfs.h statvfs.h stat.h svrctl.h timeb.h \
        time.h times.h types.h ucontext.h uio.h un.h utsname.h video.h vm.h \
-       wait.h cdefs.h 
+       wait.h cdefs.h null.h
 
 .include <bsd.kinc.mk>
diff --git a/include/sys/null.h b/include/sys/null.h
new file mode 100644 (file)
index 0000000..18836fc
--- /dev/null
@@ -0,0 +1,16 @@
+/*     $NetBSD: null.h,v 1.8 2009/10/13 17:19:00 dsl Exp $     */
+
+#ifndef _SYS_NULL_H_
+#define _SYS_NULL_H_
+#ifndef        NULL
+#if !defined(__GNUG__) || __GNUG__ < 2 || (__GNUG__ == 2 && __GNUC_MINOR__ < 90)
+#if !defined(__cplusplus)
+#define        NULL    ((void *)0)
+#else
+#define        NULL    0
+#endif /* !__cplusplus */
+#else
+#define        NULL    __null
+#endif
+#endif
+#endif /* _SYS_NULL_H_ */
index 3a0a354c36786105cbab2c318b4c54da865390fb..4c72a39dd2ac0c0ff6095202cd8a5a7ff68ebd86 100644 (file)
@@ -1,4 +1,6 @@
-/*-
+/*     $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $      */
+
+/*
  * Copyright (c) 1991, 1993
  *     The Regents of the University of California.  All rights reserved.
  *
@@ -10,7 +12,7 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
+ * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * SUCH DAMAGE.
  *
  *     @(#)queue.h     8.5 (Berkeley) 8/20/94
- * $FreeBSD$
  */
 
-#ifndef _SYS_QUEUE_H_
+#ifndef        _SYS_QUEUE_H_
 #define        _SYS_QUEUE_H_
 
-#include <sys/cdefs.h>
+#include <sys/null.h>
 
 /*
- * This file defines four types of data structures: singly-linked lists,
- * singly-linked tail queues, lists and tail queues.
+ * This file defines five types of data structures: singly-linked lists,
+ * lists, simple queues, tail queues, and circular 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 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 list is headed by a single forward pointer (or an array of forward
  * pointers for a hash table header). The elements are doubly linked
  * or after an existing element or at the head of the list. A list
  * may only be traversed in the forward direction.
  *
+ * A simple queue is headed by a pair of pointers, one the head of the
+ * list and the other to the tail of the list. The elements are singly
+ * linked to save space, so elements can only be removed from the
+ * head of the list. 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. A simple queue 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
  * 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_HEAD                        +       -       +       -
- * _REMOVE_NEXT                        +       -       +       -
- * _REMOVE                     +       +       +       +
+ * A circle 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 circle queue may be traversed in either direction, but has a more
+ * complex end of list detection.
  *
+ * For details on the use of these macros, see the queue(3) manual page.
  */
-#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_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)
 
+/*
+ * List definitions.
+ */
+#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(QUEUEDEBUG)
+#define        QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)                   \
+       if ((head)->lh_first &&                                         \
+           (head)->lh_first->field.le_prev != &(head)->lh_first)       \
+               panic("LIST_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__);
+#define        QUEUEDEBUG_LIST_OP(elm, field)                                  \
+       if ((elm)->field.le_next &&                                     \
+           (elm)->field.le_next->field.le_prev !=                      \
+           &(elm)->field.le_next)                                      \
+               panic("LIST_* forw %p %s:%d", (elm), __FILE__, __LINE__);\
+       if (*(elm)->field.le_prev != (elm))                             \
+               panic("LIST_* back %p %s:%d", (elm), __FILE__, __LINE__);
+#define        QUEUEDEBUG_LIST_POSTREMOVE(elm, field)                          \
+       (elm)->field.le_next = (void *)1L;                              \
+       (elm)->field.le_prev = (void *)1L;
 #else
-#define        QMD_TRACE_ELEM(elem)
-#define        QMD_TRACE_HEAD(head)
-#define        TRACEBUF
-#define        TRASHIT(x)
-#endif /* QUEUE_MACRO_DEBUG */
+#define        QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)
+#define        QUEUEDEBUG_LIST_OP(elm, field)
+#define        QUEUEDEBUG_LIST_POSTREMOVE(elm, field)
+#endif
+
+#define        LIST_INIT(head) do {                                            \
+       (head)->lh_first = NULL;                                        \
+} while (/*CONSTCOND*/0)
+
+#define        LIST_INSERT_AFTER(listelm, elm, field) do {                     \
+       QUEUEDEBUG_LIST_OP((listelm), field)                            \
+       if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
+               (listelm)->field.le_next->field.le_prev =               \
+                   &(elm)->field.le_next;                              \
+       (listelm)->field.le_next = (elm);                               \
+       (elm)->field.le_prev = &(listelm)->field.le_next;               \
+} while (/*CONSTCOND*/0)
+
+#define        LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
+       QUEUEDEBUG_LIST_OP((listelm), field)                            \
+       (elm)->field.le_prev = (listelm)->field.le_prev;                \
+       (elm)->field.le_next = (listelm);                               \
+       *(listelm)->field.le_prev = (elm);                              \
+       (listelm)->field.le_prev = &(elm)->field.le_next;               \
+} while (/*CONSTCOND*/0)
+
+#define        LIST_INSERT_HEAD(head, elm, field) do {                         \
+       QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field)               \
+       if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
+               (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
+       (head)->lh_first = (elm);                                       \
+       (elm)->field.le_prev = &(head)->lh_first;                       \
+} while (/*CONSTCOND*/0)
+
+#define        LIST_REMOVE(elm, field) do {                                    \
+       QUEUEDEBUG_LIST_OP((elm), field)                                \
+       if ((elm)->field.le_next != NULL)                               \
+               (elm)->field.le_next->field.le_prev =                   \
+                   (elm)->field.le_prev;                               \
+       *(elm)->field.le_prev = (elm)->field.le_next;                   \
+       QUEUEDEBUG_LIST_POSTREMOVE((elm), field)                        \
+} while (/*CONSTCOND*/0)
+
+#define        LIST_FOREACH(var, head, field)                                  \
+       for ((var) = ((head)->lh_first);                                \
+               (var);                                                  \
+               (var) = ((var)->field.le_next))
 
 /*
- * Singly-linked List declarations.
+ * List access methods.
+ */
+#define        LIST_EMPTY(head)                ((head)->lh_first == NULL)
+#define        LIST_FIRST(head)                ((head)->lh_first)
+#define        LIST_NEXT(elm, field)           ((elm)->field.le_next)
+
+
+/*
+ * Singly-linked List definitions.
  */
 #define        SLIST_HEAD(name, type)                                          \
 struct name {                                                          \
@@ -153,70 +193,65 @@ struct {                                                          \
 /*
  * 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)
+       (head)->slh_first = NULL;                                       \
+} while (/*CONSTCOND*/0)
 
 #define        SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
-       SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);       \
-       SLIST_NEXT((slistelm), field) = (elm);                          \
-} while (0)
+       (elm)->field.sle_next = (slistelm)->field.sle_next;             \
+       (slistelm)->field.sle_next = (elm);                             \
+} while (/*CONSTCOND*/0)
 
 #define        SLIST_INSERT_HEAD(head, elm, field) do {                        \
-       SLIST_NEXT((elm), field) = SLIST_FIRST((head));                 \
-       SLIST_FIRST((head)) = (elm);                                    \
-} while (0)
+       (elm)->field.sle_next = (head)->slh_first;                      \
+       (head)->slh_first = (elm);                                      \
+} while (/*CONSTCOND*/0)
 
-#define        SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
+#define        SLIST_REMOVE_HEAD(head, field) do {                             \
+       (head)->slh_first = (head)->slh_first->field.sle_next;          \
+} while (/*CONSTCOND*/0)
 
 #define        SLIST_REMOVE(head, elm, type, field) do {                       \
-       if (SLIST_FIRST((head)) == (elm)) {                             \
+       if ((head)->slh_first == (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_NEXT(head, curelm, field);                 \
+               struct type *curelm = (head)->slh_first;                \
+               while(curelm->field.sle_next != (elm))                  \
+                       curelm = curelm->field.sle_next;                \
+               curelm->field.sle_next =                                \
+                   curelm->field.sle_next->field.sle_next;             \
        }                                                               \
-       TRASHIT((elm)->field.sle_next);                                 \
-} while (0)
+} while (/*CONSTCOND*/0)
 
-#define SLIST_REMOVE_NEXT(head, elm, field) do {                               \
-       SLIST_NEXT(elm, field) =                                        \
-           SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
-} while (0)
+#define        SLIST_REMOVE_AFTER(slistelm, field) do {                        \
+       (slistelm)->field.sle_next =                                    \
+           SLIST_NEXT(SLIST_NEXT((slistelm), field), field);           \
+} while (/*CONSTCOND*/0)
+
+#define        SLIST_FOREACH(var, head, field)                                 \
+       for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
+
+#define        SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
+       for ((var) = SLIST_FIRST((head));                               \
+           (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
+           (var) = (tvar))
+
+/*
+ * Singly-linked List access methods.
+ */
+#define        SLIST_EMPTY(head)       ((head)->slh_first == NULL)
+#define        SLIST_FIRST(head)       ((head)->slh_first)
+#define        SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 
-#define        SLIST_REMOVE_HEAD(head, field) do {                             \
-       SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
-} while (0)
 
 /*
  * Singly-linked Tail queue declarations.
  */
-#define        STAILQ_HEAD(name, type)                                         \
+#define        STAILQ_HEAD(name, type)                                 \
 struct name {                                                          \
-       struct type *stqh_first;/* first element */                     \
-       struct type **stqh_last;/* addr of last next element */         \
+       struct type *stqh_first;        /* first element */                     \
+       struct type **stqh_last;        /* addr of last next element */         \
 }
 
 #define        STAILQ_HEAD_INITIALIZER(head)                                   \
@@ -230,398 +265,475 @@ struct {                                                                \
 /*
  * 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_INIT(head) do {                                          \
+       (head)->stqh_first = NULL;                                      \
+       (head)->stqh_last = &(head)->stqh_first;                                \
+} while (/*CONSTCOND*/0)
 
-#define        STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
+#define        STAILQ_INSERT_HEAD(head, elm, field) do {                       \
+       if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
+               (head)->stqh_last = &(elm)->field.stqe_next;            \
+       (head)->stqh_first = (elm);                                     \
+} while (/*CONSTCOND*/0)
 
-#define        STAILQ_FIRST(head)      ((head)->stqh_first)
+#define        STAILQ_INSERT_TAIL(head, elm, field) do {                       \
+       (elm)->field.stqe_next = NULL;                                  \
+       *(head)->stqh_last = (elm);                                     \
+       (head)->stqh_last = &(elm)->field.stqe_next;                    \
+} while (/*CONSTCOND*/0)
 
-#define        STAILQ_FOREACH(var, head, field)                                \
-       for((var) = STAILQ_FIRST((head));                               \
-          (var);                                                       \
-          (var) = STAILQ_NEXT((var), field))
+#define        STAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
+       if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
+               (head)->stqh_last = &(elm)->field.stqe_next;            \
+       (listelm)->field.stqe_next = (elm);                             \
+} while (/*CONSTCOND*/0)
+
+#define        STAILQ_REMOVE_HEAD(head, field) do {                            \
+       if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
+               (head)->stqh_last = &(head)->stqh_first;                        \
+} while (/*CONSTCOND*/0)
+
+#define        STAILQ_REMOVE(head, elm, type, field) do {                      \
+       if ((head)->stqh_first == (elm)) {                              \
+               STAILQ_REMOVE_HEAD((head), field);                      \
+       } else {                                                        \
+               struct type *curelm = (head)->stqh_first;               \
+               while (curelm->field.stqe_next != (elm))                        \
+                       curelm = curelm->field.stqe_next;               \
+               if ((curelm->field.stqe_next =                          \
+                       curelm->field.stqe_next->field.stqe_next) == NULL) \
+                           (head)->stqh_last = &(curelm)->field.stqe_next; \
+       }                                                               \
+} while (/*CONSTCOND*/0)
 
+#define        STAILQ_FOREACH(var, head, field)                                \
+       for ((var) = ((head)->stqh_first);                              \
+               (var);                                                  \
+               (var) = ((var)->field.stqe_next))
 
 #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_CONCAT(head1, head2) do {                                \
+       if (!STAILQ_EMPTY((head2))) {                                   \
+               *(head1)->stqh_last = (head2)->stqh_first;              \
+               (head1)->stqh_last = (head2)->stqh_last;                \
+               STAILQ_INIT((head2));                                   \
+       }                                                               \
+} while (/*CONSTCOND*/0)
 
 #define        STAILQ_LAST(head, type, field)                                  \
        (STAILQ_EMPTY((head)) ?                                         \
                NULL :                                                  \
                ((struct type *)(void *)                                \
-               ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
+               ((char *)((head)->stqh_last) - offsetof(struct type, field))))
 
+/*
+ * Singly-linked Tail queue access methods.
+ */
+#define        STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
+#define        STAILQ_FIRST(head)      ((head)->stqh_first)
 #define        STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 
-#define        STAILQ_REMOVE(head, elm, type, field) do {                      \
-       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_NEXT(head, curelm, field);                \
-       }                                                               \
-       TRASHIT((elm)->field.stqe_next);                                \
-} 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_REMOVE_NEXT(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)
 
 /*
- * List declarations.
+ * Simple queue definitions.
  */
-#define        LIST_HEAD(name, type)                                           \
+#define        SIMPLEQ_HEAD(name, type)                                        \
 struct name {                                                          \
-       struct type *lh_first;  /* first element */                     \
+       struct type *sqh_first; /* first element */                     \
+       struct type **sqh_last; /* addr of last next element */         \
 }
 
-#define        LIST_HEAD_INITIALIZER(head)                                     \
-       { NULL }
+#define        SIMPLEQ_HEAD_INITIALIZER(head)                                  \
+       { NULL, &(head).sqh_first }
 
-#define        LIST_ENTRY(type)                                                \
+#define        SIMPLEQ_ENTRY(type)                                             \
 struct {                                                               \
-       struct type *le_next;   /* next element */                      \
-       struct type **le_prev;  /* address of previous next element */  \
+       struct type *sqe_next;  /* next element */                      \
 }
 
 /*
- * List functions.
+ * Simple queue functions.
  */
+#define        SIMPLEQ_INIT(head) do {                                         \
+       (head)->sqh_first = NULL;                                       \
+       (head)->sqh_last = &(head)->sqh_first;                          \
+} while (/*CONSTCOND*/0)
+
+#define        SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
+       if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
+               (head)->sqh_last = &(elm)->field.sqe_next;              \
+       (head)->sqh_first = (elm);                                      \
+} while (/*CONSTCOND*/0)
+
+#define        SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
+       (elm)->field.sqe_next = NULL;                                   \
+       *(head)->sqh_last = (elm);                                      \
+       (head)->sqh_last = &(elm)->field.sqe_next;                      \
+} while (/*CONSTCOND*/0)
+
+#define        SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
+       if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
+               (head)->sqh_last = &(elm)->field.sqe_next;              \
+       (listelm)->field.sqe_next = (elm);                              \
+} while (/*CONSTCOND*/0)
+
+#define        SIMPLEQ_REMOVE_HEAD(head, field) do {                           \
+       if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
+               (head)->sqh_last = &(head)->sqh_first;                  \
+} while (/*CONSTCOND*/0)
+
+#define        SIMPLEQ_REMOVE(head, elm, type, field) do {                     \
+       if ((head)->sqh_first == (elm)) {                               \
+               SIMPLEQ_REMOVE_HEAD((head), field);                     \
+       } else {                                                        \
+               struct type *curelm = (head)->sqh_first;                \
+               while (curelm->field.sqe_next != (elm))                 \
+                       curelm = curelm->field.sqe_next;                \
+               if ((curelm->field.sqe_next =                           \
+                       curelm->field.sqe_next->field.sqe_next) == NULL) \
+                           (head)->sqh_last = &(curelm)->field.sqe_next; \
+       }                                                               \
+} while (/*CONSTCOND*/0)
+
+#define        SIMPLEQ_FOREACH(var, head, field)                               \
+       for ((var) = ((head)->sqh_first);                               \
+               (var);                                                  \
+               (var) = ((var)->field.sqe_next))
+
+#define        SIMPLEQ_FOREACH_SAFE(var, head, field, next)                    \
+       for ((var) = ((head)->sqh_first);                               \
+               (var) && ((next = ((var)->field.sqe_next)), 1);         \
+               (var) = (next))
+
+#define        SIMPLEQ_CONCAT(head1, head2) do {                               \
+       if (!SIMPLEQ_EMPTY((head2))) {                                  \
+               *(head1)->sqh_last = (head2)->sqh_first;                \
+               (head1)->sqh_last = (head2)->sqh_last;          \
+               SIMPLEQ_INIT((head2));                                  \
+       }                                                               \
+} while (/*CONSTCOND*/0)
 
-#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        SIMPLEQ_LAST(head, type, field)                                 \
+       (SIMPLEQ_EMPTY((head)) ?                                                \
+               NULL :                                                  \
+               ((struct type *)(void *)                                \
+               ((char *)((head)->sqh_last) - offsetof(struct type, field))))
 
-#define        LIST_NEXT(elm, field)   ((elm)->field.le_next)
+/*
+ * Simple queue access methods.
+ */
+#define        SIMPLEQ_EMPTY(head)             ((head)->sqh_first == NULL)
+#define        SIMPLEQ_FIRST(head)             ((head)->sqh_first)
+#define        SIMPLEQ_NEXT(elm, field)        ((elm)->field.sqe_next)
 
-#define        LIST_REMOVE(elm, field) do {                                    \
-       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((elm)->field.le_next);                                  \
-       TRASHIT((elm)->field.le_prev);                                  \
-} while (0)
 
 /*
- * Tail queue declarations.
+ * Tail queue definitions.
  */
-#define        TAILQ_HEAD(name, type)                                          \
+#define        _TAILQ_HEAD(name, type, qual)                                   \
 struct name {                                                          \
-       struct type *tqh_first; /* first element */                     \
-       struct type **tqh_last; /* addr of last next element */         \
-       TRACEBUF                                                        \
+       qual type *tqh_first;           /* first element */             \
+       qual type *qual *tqh_last;      /* addr of last next element */ \
 }
+#define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type,)
 
 #define        TAILQ_HEAD_INITIALIZER(head)                                    \
        { NULL, &(head).tqh_first }
 
-#define        TAILQ_ENTRY(type)                                               \
+#define        _TAILQ_ENTRY(type, qual)                                        \
 struct {                                                               \
-       struct type *tqe_next;  /* next element */                      \
-       struct type **tqe_prev; /* address of previous next element */  \
-       TRACEBUF                                                        \
+       qual type *tqe_next;            /* next element */              \
+       qual type *qual *tqe_prev;      /* address of previous next element */\
 }
+#define TAILQ_ENTRY(type)      _TAILQ_ENTRY(struct type,)
 
 /*
  * 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 defined(_KERNEL) && defined(QUEUEDEBUG)
+#define        QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)                  \
+       if ((head)->tqh_first &&                                        \
+           (head)->tqh_first->field.tqe_prev != &(head)->tqh_first)    \
+               panic("TAILQ_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__);
+#define        QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)                  \
        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 {                           \
+               panic("TAILQ_INSERT_TAIL %p %s:%d", (head), __FILE__, __LINE__);
+#define        QUEUEDEBUG_TAILQ_OP(elm, field)                                 \
+       if ((elm)->field.tqe_next &&                                    \
+           (elm)->field.tqe_next->field.tqe_prev !=                    \
+           &(elm)->field.tqe_next)                                     \
+               panic("TAILQ_* forw %p %s:%d", (elm), __FILE__, __LINE__);\
        if (*(elm)->field.tqe_prev != (elm))                            \
-               panic("Bad link elm %p prev->next != elm", (elm));      \
-} while (0)
+               panic("TAILQ_* back %p %s:%d", (elm), __FILE__, __LINE__);
+#define        QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)                    \
+       if ((elm)->field.tqe_next == NULL &&                            \
+           (head)->tqh_last != &(elm)->field.tqe_next)                 \
+               panic("TAILQ_PREREMOVE head %p elm %p %s:%d",           \
+                     (head), (elm), __FILE__, __LINE__);
+#define        QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)                         \
+       (elm)->field.tqe_next = (void *)1L;                             \
+       (elm)->field.tqe_prev = (void *)1L;
 #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        QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)
+#define        QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)
+#define        QUEUEDEBUG_TAILQ_OP(elm, field)
+#define        QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)
+#define        QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)
+#endif
 
 #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)
+       (head)->tqh_first = NULL;                                       \
+       (head)->tqh_last = &(head)->tqh_first;                          \
+} while (/*CONSTCOND*/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);                          \
+       QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field)              \
+       if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
+               (head)->tqh_first->field.tqe_prev =                     \
+                   &(elm)->field.tqe_next;                             \
        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)
+               (head)->tqh_last = &(elm)->field.tqe_next;              \
+       (head)->tqh_first = (elm);                                      \
+       (elm)->field.tqe_prev = &(head)->tqh_first;                     \
+} while (/*CONSTCOND*/0)
 
 #define        TAILQ_INSERT_TAIL(head, elm, field) do {                        \
-       QMD_TAILQ_CHECK_TAIL(head, field);                              \
-       TAILQ_NEXT((elm), field) = NULL;                                \
+       QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field)              \
+       (elm)->field.tqe_next = 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)
+       (head)->tqh_last = &(elm)->field.tqe_next;                      \
+} while (/*CONSTCOND*/0)
 
-#define        TAILQ_LAST(head, headname)                                      \
-       (*(((struct headname *)((head)->tqh_last))->tqh_last))
-
-#define        TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
+#define        TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
+       QUEUEDEBUG_TAILQ_OP((listelm), field)                           \
+       if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
+               (elm)->field.tqe_next->field.tqe_prev =                 \
+                   &(elm)->field.tqe_next;                             \
+       else                                                            \
+               (head)->tqh_last = &(elm)->field.tqe_next;              \
+       (listelm)->field.tqe_next = (elm);                              \
+       (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
+} while (/*CONSTCOND*/0)
 
-#define        TAILQ_PREV(elm, headname, field)                                \
-       (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+#define        TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
+       QUEUEDEBUG_TAILQ_OP((listelm), field)                           \
+       (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
+       (elm)->field.tqe_next = (listelm);                              \
+       *(listelm)->field.tqe_prev = (elm);                             \
+       (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
+} while (/*CONSTCOND*/0)
 
 #define        TAILQ_REMOVE(head, elm, field) do {                             \
-       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 =              \
+       QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field)                \
+       QUEUEDEBUG_TAILQ_OP((elm), field)                               \
+       if (((elm)->field.tqe_next) != NULL)                            \
+               (elm)->field.tqe_next->field.tqe_prev =                 \
                    (elm)->field.tqe_prev;                              \
-       else {                                                          \
+       else                                                            \
                (head)->tqh_last = (elm)->field.tqe_prev;               \
-               QMD_TRACE_HEAD(head);                                   \
-       }                                                               \
-       *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);              \
-       TRASHIT((elm)->field.tqe_next);                                 \
-       TRASHIT((elm)->field.tqe_prev);                                 \
-       QMD_TRACE_ELEM(&(elm)->field);                                  \
-} while (0)
+       *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
+       QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field);                      \
+} while (/*CONSTCOND*/0)
 
+#define        TAILQ_FOREACH(var, head, field)                                 \
+       for ((var) = ((head)->tqh_first);                               \
+               (var);                                                  \
+               (var) = ((var)->field.tqe_next))
 
-#ifdef _KERNEL
+#define        TAILQ_FOREACH_SAFE(var, head, field, next)                      \
+       for ((var) = ((head)->tqh_first);                               \
+               (var) != NULL && ((next) = TAILQ_NEXT(var, field), 1);  \
+               (var) = (next))
+
+#define        TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
+       for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \
+               (var);                                                  \
+               (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
+
+#define        TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, prev)    \
+       for ((var) = TAILQ_LAST((head), headname);                      \
+               (var) && ((prev) = TAILQ_PREV((var), headname, field), 1);\
+               (var) = (prev))
+
+#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));                                    \
+       }                                                               \
+} while (/*CONSTCOND*/0)
 
 /*
- * XXX insque() and remque() are an old way of handling certain queues.
- * They bogusly assumes that all queue heads look alike.
+ * Tail queue access methods.
  */
+#define        TAILQ_EMPTY(head)               ((head)->tqh_first == NULL)
+#define        TAILQ_FIRST(head)               ((head)->tqh_first)
+#define        TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 
-struct quehead {
-       struct quehead *qh_link;
-       struct quehead *qh_rlink;
-};
+#define        TAILQ_LAST(head, headname) \
+       (*(((struct headname *)((head)->tqh_last))->tqh_last))
+#define        TAILQ_PREV(elm, headname, field) \
+       (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 
-#ifdef __CC_SUPPORTS___INLINE
 
-static __inline void
-insque(void *a, void *b)
-{
-       struct quehead *element = (struct quehead *)a,
-                *head = (struct quehead *)b;
+/*
+ * Circular queue definitions.
+ */
+#if defined(_KERNEL) && defined(QUEUEDEBUG)
+#define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)                           \
+       if ((head)->cqh_first != (void *)(head) &&                      \
+           (head)->cqh_first->field.cqe_prev != (void *)(head))        \
+               panic("CIRCLEQ head forw %p %s:%d", (head),             \
+                     __FILE__, __LINE__);                              \
+       if ((head)->cqh_last != (void *)(head) &&                       \
+           (head)->cqh_last->field.cqe_next != (void *)(head))         \
+               panic("CIRCLEQ head back %p %s:%d", (head),             \
+                     __FILE__, __LINE__);
+#define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)                       \
+       if ((elm)->field.cqe_next == (void *)(head)) {                  \
+               if ((head)->cqh_last != (elm))                          \
+                       panic("CIRCLEQ elm last %p %s:%d", (elm),       \
+                             __FILE__, __LINE__);                      \
+       } else {                                                        \
+               if ((elm)->field.cqe_next->field.cqe_prev != (elm))     \
+                       panic("CIRCLEQ elm forw %p %s:%d", (elm),       \
+                             __FILE__, __LINE__);                      \
+       }                                                               \
+       if ((elm)->field.cqe_prev == (void *)(head)) {                  \
+               if ((head)->cqh_first != (elm))                         \
+                       panic("CIRCLEQ elm first %p %s:%d", (elm),      \
+                             __FILE__, __LINE__);                      \
+       } else {                                                        \
+               if ((elm)->field.cqe_prev->field.cqe_next != (elm))     \
+                       panic("CIRCLEQ elm prev %p %s:%d", (elm),       \
+                             __FILE__, __LINE__);                      \
+       }
+#define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)                      \
+       (elm)->field.cqe_next = (void *)1L;                             \
+       (elm)->field.cqe_prev = (void *)1L;
+#else
+#define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)
+#define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)
+#define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)
+#endif
 
-       element->qh_link = head->qh_link;
-       element->qh_rlink = head;
-       head->qh_link = element;
-       element->qh_link->qh_rlink = element;
+#define        CIRCLEQ_HEAD(name, type)                                        \
+struct name {                                                          \
+       struct type *cqh_first;         /* first element */             \
+       struct type *cqh_last;          /* last element */              \
 }
 
-static __inline void
-remque(void *a)
-{
-       struct quehead *element = (struct quehead *)a;
+#define        CIRCLEQ_HEAD_INITIALIZER(head)                                  \
+       { (void *)&head, (void *)&head }
 
-       element->qh_link->qh_rlink = element->qh_rlink;
-       element->qh_rlink->qh_link = element->qh_link;
-       element->qh_rlink = 0;
+#define        CIRCLEQ_ENTRY(type)                                             \
+struct {                                                               \
+       struct type *cqe_next;          /* next element */              \
+       struct type *cqe_prev;          /* previous element */          \
 }
 
-#else /* !__CC_SUPPORTS___INLINE */
-
-void   insque(void *a, void *b);
-void   remque(void *a);
+/*
+ * Circular queue functions.
+ */
+#define        CIRCLEQ_INIT(head) do {                                         \
+       (head)->cqh_first = (void *)(head);                             \
+       (head)->cqh_last = (void *)(head);                              \
+} while (/*CONSTCOND*/0)
+
+#define        CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
+       QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
+       QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)                \
+       (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
+       (elm)->field.cqe_prev = (listelm);                              \
+       if ((listelm)->field.cqe_next == (void *)(head))                \
+               (head)->cqh_last = (elm);                               \
+       else                                                            \
+               (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
+       (listelm)->field.cqe_next = (elm);                              \
+} while (/*CONSTCOND*/0)
+
+#define        CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
+       QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
+       QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)                \
+       (elm)->field.cqe_next = (listelm);                              \
+       (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
+       if ((listelm)->field.cqe_prev == (void *)(head))                \
+               (head)->cqh_first = (elm);                              \
+       else                                                            \
+               (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
+       (listelm)->field.cqe_prev = (elm);                              \
+} while (/*CONSTCOND*/0)
+
+#define        CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
+       QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
+       (elm)->field.cqe_next = (head)->cqh_first;                      \
+       (elm)->field.cqe_prev = (void *)(head);                         \
+       if ((head)->cqh_last == (void *)(head))                         \
+               (head)->cqh_last = (elm);                               \
+       else                                                            \
+               (head)->cqh_first->field.cqe_prev = (elm);              \
+       (head)->cqh_first = (elm);                                      \
+} while (/*CONSTCOND*/0)
+
+#define        CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
+       QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
+       (elm)->field.cqe_next = (void *)(head);                         \
+       (elm)->field.cqe_prev = (head)->cqh_last;                       \
+       if ((head)->cqh_first == (void *)(head))                        \
+               (head)->cqh_first = (elm);                              \
+       else                                                            \
+               (head)->cqh_last->field.cqe_next = (elm);               \
+       (head)->cqh_last = (elm);                                       \
+} while (/*CONSTCOND*/0)
+
+#define        CIRCLEQ_REMOVE(head, elm, field) do {                           \
+       QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
+       QUEUEDEBUG_CIRCLEQ_ELM((head), (elm), field)                    \
+       if ((elm)->field.cqe_next == (void *)(head))                    \
+               (head)->cqh_last = (elm)->field.cqe_prev;               \
+       else                                                            \
+               (elm)->field.cqe_next->field.cqe_prev =                 \
+                   (elm)->field.cqe_prev;                              \
+       if ((elm)->field.cqe_prev == (void *)(head))                    \
+               (head)->cqh_first = (elm)->field.cqe_next;              \
+       else                                                            \
+               (elm)->field.cqe_prev->field.cqe_next =                 \
+                   (elm)->field.cqe_next;                              \
+       QUEUEDEBUG_CIRCLEQ_POSTREMOVE((elm), field)                     \
+} while (/*CONSTCOND*/0)
 
-#endif /* __CC_SUPPORTS___INLINE */
+#define        CIRCLEQ_FOREACH(var, head, field)                               \
+       for ((var) = ((head)->cqh_first);                               \
+               (var) != (const void *)(head);                          \
+               (var) = ((var)->field.cqe_next))
 
-#endif /* _KERNEL */
+#define        CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
+       for ((var) = ((head)->cqh_last);                                \
+               (var) != (const void *)(head);                          \
+               (var) = ((var)->field.cqe_prev))
 
-#endif /* !_SYS_QUEUE_H_ */
+/*
+ * Circular queue access methods.
+ */
+#define        CIRCLEQ_EMPTY(head)             ((head)->cqh_first == (void *)(head))
+#define        CIRCLEQ_FIRST(head)             ((head)->cqh_first)
+#define        CIRCLEQ_LAST(head)              ((head)->cqh_last)
+#define        CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
+#define        CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
+
+#define CIRCLEQ_LOOP_NEXT(head, elm, field)                            \
+       (((elm)->field.cqe_next == (void *)(head))                      \
+           ? ((head)->cqh_first)                                       \
+           : (elm->field.cqe_next))
+#define CIRCLEQ_LOOP_PREV(head, elm, field)                            \
+       (((elm)->field.cqe_prev == (void *)(head))                      \
+           ? ((head)->cqh_last)                                        \
+           : (elm->field.cqe_prev))
+
+#endif /* !_SYS_QUEUE_H_ */