xnu-7195.81.3.tar.gz

[apple/xnu.git] / bsd / sys / queue.h

diff --git a/bsd/sys/queue.h b/bsd/sys/queue.h
index 1894436fb2828d1ea2408c5e9abcac8e5a03a084..46b382ed77f9ac928e464b1c64c87f7aecd1064e 100644 (file)
--- a/bsd/sys/queue.h
+++ b/bsd/sys/queue.h
@@ -2,7 +2,7 @@
  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

- * 
+ *

  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in


@@ -11,10 +11,10 @@
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.

- * 
+ *

  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.

- * 
+ *

  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,


@@ -22,10 +22,10 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.

- * 
+ *

  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */

-/*
+/*-

  * Copyright (c) 1991, 1993
  *     The Regents of the University of California.  All rights reserved.
  *
  * Copyright (c) 1991, 1993
  *     The Regents of the University of California.  All rights reserved.
  *


@@ -37,10 +37,6 @@
  * 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.
  * 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.

- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *     This product includes software developed by the University of
- *     California, Berkeley and its contributors.

  * 4. 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.
  * 4. 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.


@@ -61,11 +57,20 @@
  */
 
 #ifndef _SYS_QUEUE_H_
  */
 
 #ifndef _SYS_QUEUE_H_

-#define        _SYS_QUEUE_H_
+#define _SYS_QUEUE_H_
+
+#ifdef KERNEL_PRIVATE
+#include <kern/debug.h> /* panic function call */
+#include <sys/cdefs.h>  /* __improbable in kernelspace */
+#else
+#ifndef __improbable
+#define __improbable(x) (x)             /* noop in userspace */
+#endif /* __improbable */
+#endif /* KERNEL_PRIVATE */

 
 /*
  * This file defines five types of data structures: singly-linked lists,
 
 /*
  * This file defines five types of data structures: singly-linked lists,

- * slingly-linked tail queues, lists, tail queues, and circular queues.
+ * singly-linked tail queues, lists, 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
  *
  * A singly-linked list is headed by a single forward pointer. The elements
  * are singly linked for minimum space and pointer manipulation overhead at


@@ -100,7 +105,7 @@
  * 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
  * 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 only be traversed in the forward direction.
+ * the list. A tail queue may be traversed in either direction.

  *
  * 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
  *
  * 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


@@ -109,404 +114,837 @@
  * 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.
  * 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.

+ * Note that circle queues are deprecated, because, as the removal log
+ * in FreeBSD states, "CIRCLEQs are a disgrace to everything Knuth taught
+ * us in Volume 1 Chapter 2. [...] Use TAILQ instead, it provides the same
+ * functionality." Code using them will continue to compile, but they
+ * are no longer documented on the man page.

  *
  * For details on the use of these macros, see the queue(3) manual page.
  *
  *
  *
  * For details on the use of these macros, see the queue(3) manual page.
  *
  *

- *                     SLIST   LIST    STAILQ  TAILQ   CIRCLEQ
- * _HEAD               +       +       +       +       +
- * _ENTRY              +       +       +       +       +
- * _INIT               +       +       +       +       +
- * _EMPTY              +       +       +       +       +
- * _FIRST              +       +       +       +       +
- * _NEXT               +       +       +       +       +
- * _PREV               -       -       -       +       +
- * _LAST               -       -       +       +       +
- * _FOREACH            +       +       -       +       +
- * _INSERT_HEAD                +       +       +       +       +
- * _INSERT_BEFORE      -       +       -       +       +
- * _INSERT_AFTER       +       +       +       +       +
- * _INSERT_TAIL                -       -       +       +       +
- * _REMOVE_HEAD                +       -       +       -       -
- * _REMOVE             +       +       +       +       +
+ *                             SLIST   LIST    STAILQ  TAILQ   CIRCLEQ
+ * _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_HEAD_UNTIL          -       -       +       -       -
+ * _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_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 TRACEBUF
+#define TRASHIT(x)
+#endif  /* QUEUE_MACRO_DEBUG */

 
 /*
 
 /*

- * Singly-linked List definitions.
+ * Horrible macros to enable use of code that was meant to be C-specific
+ *   (and which push struct onto type) in C++; without these, C++ code
+ *   that uses these macros in the context of a class will blow up
+ *   due to "struct" being preprended to "type" by the macros, causing
+ *   inconsistent use of tags.
+ *
+ * This approach is necessary because these are macros; we have to use
+ *   these on a per-macro basis (because the queues are implemented as
+ *   macros, disabling this warning in the scope of the header file is
+ *   insufficient), whuch means we can't use #pragma, and have to use
+ *   _Pragma.  We only need to use these for the queue macros that
+ *   prepend "struct" to "type" and will cause C++ to blow up.

  */
  */

-#define SLIST_HEAD(name, type)                                         \
-struct name {                                                          \
-       struct type *slh_first; /* first element */                     \
-}
- 
-#define SLIST_ENTRY(type)                                              \
-struct {                                                               \
-       struct type *sle_next;  /* next element */                      \
-}
- 
+#if defined(__clang__) && defined(__cplusplus)
+#define __MISMATCH_TAGS_PUSH                                            \
+       _Pragma("clang diagnostic push")                                \
+       _Pragma("clang diagnostic ignored \"-Wmismatched-tags\"")
+#define __MISMATCH_TAGS_POP                                             \
+       _Pragma("clang diagnostic pop")
+#else
+#define __MISMATCH_TAGS_PUSH
+#define __MISMATCH_TAGS_POP
+#endif
+
+/*!
+ * Ensures that these macros can safely be used in structs when compiling with
+ * clang. The macros do not allow for nullability attributes to be specified due
+ * to how they are expanded. For example:
+ *
+ *     SLIST_HEAD(, foo _Nullable) bar;
+ *
+ * expands to
+ *
+ *     struct {
+ *         struct foo _Nullable *slh_first;
+ *     }
+ *
+ * which is not valid because the nullability specifier has to apply to the
+ * pointer. So just ignore nullability completeness in all the places where this
+ * is an issue.
+ */
+#if defined(__clang__)
+#define __NULLABILITY_COMPLETENESS_PUSH \
+       _Pragma("clang diagnostic push") \
+       _Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
+#define __NULLABILITY_COMPLETENESS_POP \
+       _Pragma("clang diagnostic pop")
+#else
+#define __NULLABILITY_COMPLETENESS_PUSH
+#define __NULLABILITY_COMPLETENESS_POP
+#endif
+
+/*
+ * Singly-linked List declarations.
+ */
+#define SLIST_HEAD(name, type)                                          \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct name {                                                           \
+       struct type *slh_first; /* first element */                     \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define SLIST_HEAD_INITIALIZER(head)                                    \
+       { NULL }
+
+#define SLIST_ENTRY(type)                                               \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct {                                                                \
+       struct type *sle_next;  /* next element */                      \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+

 /*
  * Singly-linked List functions.
  */
 /*
  * Singly-linked List functions.
  */

-#define        SLIST_EMPTY(head)       ((head)->slh_first == NULL)
+#define SLIST_EMPTY(head)       ((head)->slh_first == NULL)

 
 

-#define        SLIST_FIRST(head)       ((head)->slh_first)
+#define SLIST_FIRST(head)       ((head)->slh_first)

 
 

-#define SLIST_FOREACH(var, head, field)                                        \
-       for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
+#define SLIST_FOREACH(var, head, field)                                 \
+       for ((var) = SLIST_FIRST((head));                               \
+           (var);                                                      \
+           (var) = SLIST_NEXT((var), field))

 
 

-#define SLIST_INIT(head) {                                             \
-       (head)->slh_first = NULL;                                       \
-}
+#define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
+       for ((var) = SLIST_FIRST((head));                               \
+           (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
+           (var) = (tvar))

 
 

-#define SLIST_INSERT_AFTER(slistelm, elm, field) do {                  \
-       (elm)->field.sle_next = (slistelm)->field.sle_next;             \
-       (slistelm)->field.sle_next = (elm);                             \
+#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)
 
 } while (0)
 

-#define SLIST_INSERT_HEAD(head, elm, field) do {                       \
-       (elm)->field.sle_next = (head)->slh_first;                      \
-       (head)->slh_first = (elm);                                      \
+#define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
+       SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);       \
+       SLIST_NEXT((slistelm), field) = (elm);                          \

 } while (0)
 
 } while (0)
 

-#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
+#define SLIST_INSERT_HEAD(head, elm, field) do {                        \
+       SLIST_NEXT((elm), field) = SLIST_FIRST((head));                 \
+       SLIST_FIRST((head)) = (elm);                                    \
+} while (0)

 
 

-#define SLIST_REMOVE_HEAD(head, field) do {                            \
-       (head)->slh_first = (head)->slh_first->field.sle_next;          \
+#define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
+
+#define SLIST_REMOVE(head, elm, type, field)                            \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+do {                                                                    \
+       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((elm)->field.sle_next);                                 \
+} while (0)                                                             \
+__NULLABILITY_COMPLETENESS_POP                                      \
+__MISMATCH_TAGS_POP
+
+#define SLIST_REMOVE_AFTER(elm, field) do {                             \
+       SLIST_NEXT(elm, field) =                                        \
+           SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \

 } while (0)
 
 } while (0)
 

-#define SLIST_REMOVE(head, elm, type, field) do {                      \
-       if ((head)->slh_first == (elm)) {                               \
-               SLIST_REMOVE_HEAD((head), field);                       \
-       }                                                               \
-       else {                                                          \
-               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;             \
-       }                                                               \
+#define SLIST_REMOVE_HEAD(head, field) do {                             \
+       SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \

 } while (0)
 
 /*
 } while (0)
 
 /*

- * Singly-linked Tail queue definitions.
+ * 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)                                  \
+#define STAILQ_HEAD(name, type)                                         \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct name {                                                           \
+       struct type *stqh_first;/* first element */                     \
+       struct type **stqh_last;/* addr of last next element */         \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define STAILQ_HEAD_INITIALIZER(head)                                   \

        { NULL, &(head).stqh_first }
 
        { NULL, &(head).stqh_first }
 

-#define STAILQ_ENTRY(type)                                             \
-struct {                                                               \
-       struct type *stqe_next; /* next element */                      \
-}
+#define STAILQ_ENTRY(type)                                              \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct {                                                                \
+       struct type *stqe_next; /* next element */                      \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                         \
+__MISMATCH_TAGS_POP

 
 /*
  * Singly-linked Tail queue functions.
  */
 
 /*
  * Singly-linked Tail queue functions.
  */

-#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
-
-#define        STAILQ_INIT(head) do {                                          \
-       (head)->stqh_first = NULL;                                      \
-       (head)->stqh_last = &(head)->stqh_first;                        \
+#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)
 
 } while (0)
 

-#define STAILQ_FIRST(head)     ((head)->stqh_first)
-#define STAILQ_LAST(head)      (*(head)->stqh_last)
+#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 (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;                    \
+#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)
 
 } while (0)
 

-#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {              \
-       if (((elm)->field.stqe_next = (tqelm)->field.stqe_next) == NULL)\
-               (head)->stqh_last = &(elm)->field.stqe_next;            \
-       (tqelm)->field.stqe_next = (elm);                               \
+#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)
 
 } while (0)
 

-#define STAILQ_NEXT(elm, field)        ((elm)->field.stqe_next)
+#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_REMOVE_HEAD(head, field) do {                           \
-       if (((head)->stqh_first =                                       \
-            (head)->stqh_first->field.stqe_next) == NULL)              \
-               (head)->stqh_last = &(head)->stqh_first;                \
+#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)
 
 } while (0)
 

-#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {                        \
-       if (((head)->stqh_first = (elm)->field.stqe_next) == NULL)      \
-               (head)->stqh_last = &(head)->stqh_first;                \
+#define STAILQ_LAST(head, type, field)                                  \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+       (STAILQ_EMPTY((head)) ?                                         \
+               NULL :                                                  \
+               ((struct type *)(void *)                                \
+               ((char *)((head)->stqh_last) - __offsetof(struct type, field))))\
+__NULLABILITY_COMPLETENESS_POP                                         \
+__MISMATCH_TAGS_POP
+
+#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
+
+#define STAILQ_REMOVE(head, elm, type, field)                           \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+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_AFTER(head, curelm, field);               \
+       }                                                               \
+       TRASHIT((elm)->field.stqe_next);                                \
+} while (0)                                                             \
+__NULLABILITY_COMPLETENESS_POP                                      \
+__MISMATCH_TAGS_POP
+
+#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)
 
 } while (0)
 

+#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {                 \
+       if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
+              (head)->stqh_last = &STAILQ_FIRST((head));              \
+} while (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; \
-       }                                                               \
+#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)
 
 } while (0)
 

+#define STAILQ_SWAP(head1, head2, type)                                 \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+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)                                                             \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+

 /*
 /*

- * List definitions.
+ * List declarations.

  */
  */

-#define LIST_HEAD(name, type)                                          \
-struct name {                                                          \
-       struct type *lh_first;  /* first element */                     \
-}
-
-#define LIST_HEAD_INITIALIZER(head)                                    \
+#define LIST_HEAD(name, type)                                           \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct name {                                                           \
+       struct type *lh_first;  /* first element */                     \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define LIST_HEAD_INITIALIZER(head)                                     \

        { NULL }
 
        { NULL }
 

-#define LIST_ENTRY(type)                                               \
-struct {                                                               \
-       struct type *le_next;   /* next element */                      \
-       struct type **le_prev;  /* address of previous next element */  \
-}
+#define LIST_ENTRY(type)                                                \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct {                                                                \
+       struct type *le_next;   /* next element */                      \
+       struct type **le_prev;  /* address of previous next element */  \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP

 
 /*
  * List functions.
  */
 
 
 /*
  * List functions.
  */
 

-#define        LIST_EMPTY(head) ((head)->lh_first == NULL)
-
-#define LIST_FIRST(head)       ((head)->lh_first)
+#ifdef KERNEL_PRIVATE
+#define LIST_CHECK_HEAD(head, field) do {                               \
+       if (__improbable(                                               \
+             LIST_FIRST((head)) != NULL &&                             \
+             LIST_FIRST((head))->field.le_prev !=                      \
+             &LIST_FIRST((head))))                                     \
+                    panic("Bad list head %p first->prev != head @%u",  \
+                        (head), __LINE__);                             \
+} while (0)

 
 

-#define LIST_FOREACH(var, head, field)                                 \
-       for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)
+#define LIST_CHECK_NEXT(elm, field) do {                                \
+       if (__improbable(                                               \
+             LIST_NEXT((elm), field) != NULL &&                        \
+             LIST_NEXT((elm), field)->field.le_prev !=                 \
+             &((elm)->field.le_next)))                                 \
+                    panic("Bad link elm %p next->prev != elm @%u",     \
+                        (elm), __LINE__);                              \
+} while (0)

 
 

-#define        LIST_INIT(head) do {                                            \
-       (head)->lh_first = NULL;                                        \
+#define LIST_CHECK_PREV(elm, field) do {                                \
+       if (__improbable(*(elm)->field.le_prev != (elm)))               \
+               panic("Bad link elm %p prev->next != elm @%u",          \
+                   (elm), __LINE__);                                   \

 } while (0)
 } while (0)

+#else
+#define LIST_CHECK_HEAD(head, field)
+#define LIST_CHECK_NEXT(elm, field)
+#define LIST_CHECK_PREV(elm, field)
+#endif /* KERNEL_PRIVATE */
+
+#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_INSERT_AFTER(listelm, elm, field) do {                    \
-       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;               \
+#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)
 
 } while (0)
 

-#define LIST_INSERT_BEFORE(listelm, elm, field) do {                   \
-       (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;               \
+#define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
+       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)
 
 } while (0)
 

-#define LIST_INSERT_HEAD(head, elm, field) do {                                \
-       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;                       \
+#define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
+       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)
 
 } while (0)
 

-#define LIST_NEXT(elm, field)  ((elm)->field.le_next)
+#define LIST_INSERT_HEAD(head, elm, field) do {                         \
+       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_REMOVE(elm, field) do {                                   \
-       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;                   \
+#define LIST_NEXT(elm, field)   ((elm)->field.le_next)
+
+#define LIST_REMOVE(elm, field) do {                                    \
+       LIST_CHECK_NEXT(elm, field);                            \
+       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)
 
 } while (0)
 

+#define LIST_SWAP(head1, head2, type, field)                            \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+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)                                                             \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+

 /*
 /*

- * Tail queue definitions.
+ * 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 */         \
-}
-
-#define TAILQ_HEAD_INITIALIZER(head)                                   \
+#define TAILQ_HEAD(name, type)                                          \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct name {                                                           \
+       struct type *tqh_first; /* first element */                     \
+       struct type **tqh_last; /* addr of last next element */         \
+       TRACEBUF                                                        \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define TAILQ_HEAD_INITIALIZER(head)                                    \

        { NULL, &(head).tqh_first }
 
        { NULL, &(head).tqh_first }
 

-#define TAILQ_ENTRY(type)                                              \
-struct {                                                               \
-       struct type *tqe_next;  /* next element */                      \
-       struct type **tqe_prev; /* address of previous next element */  \
-}
+#define TAILQ_ENTRY(type)                                               \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct {                                                                \
+       struct type *tqe_next;  /* next element */                      \
+       struct type **tqe_prev; /* address of previous next element */  \
+       TRACEBUF                                                        \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP

 
 /*
  * Tail queue functions.
  */
 
 /*
  * Tail queue functions.
  */

-#define        TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
+#ifdef KERNEL_PRIVATE
+#define TAILQ_CHECK_HEAD(head, field) do {                              \
+       if (__improbable(                                                \
+             TAILQ_FIRST((head)) != NULL &&                            \
+             TAILQ_FIRST((head))->field.tqe_prev !=                    \
+             &TAILQ_FIRST((head))))                                    \
+                    panic("Bad tailq head %p first->prev != head @%u", \
+                        (head), __LINE__);                             \
+} while (0)
+
+#define TAILQ_CHECK_NEXT(elm, field) do {                               \
+       if (__improbable(                                                \
+             TAILQ_NEXT((elm), field) != NULL &&                       \
+             TAILQ_NEXT((elm), field)->field.tqe_prev !=               \
+             &((elm)->field.tqe_next)))                                \
+                    panic("Bad tailq elm %p next->prev != elm @%u",    \
+                        (elm), __LINE__);                              \
+} while(0)
+
+#define TAILQ_CHECK_PREV(elm, field) do {                               \
+       if (__improbable(*(elm)->field.tqe_prev != (elm)))               \
+             panic("Bad tailq elm %p prev->next != elm @%u",           \
+                 (elm), __LINE__);                                     \
+} while(0)
+#else
+#define TAILQ_CHECK_HEAD(head, field)
+#define TAILQ_CHECK_NEXT(elm, field)
+#define TAILQ_CHECK_PREV(elm, field)
+#endif /* KERNEL_PRIVATE */
+
+#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_FOREACH(var, head, field)                                        \
-       for (var = TAILQ_FIRST(head); var; var = TAILQ_NEXT(var, field))
+#define TAILQ_FIRST(head)       ((head)->tqh_first)

 
 

-#define TAILQ_FOREACH_REVERSE(var, head, field, headname)                                      \
-       for (var = TAILQ_LAST(head, headname);                 \
-              var; var = TAILQ_PREV(var, headname, field))
+#define TAILQ_FOREACH(var, head, field)                                 \
+       for ((var) = TAILQ_FIRST((head));                               \
+           (var);                                                      \
+           (var) = TAILQ_NEXT((var), field))

 
 

-#define        TAILQ_FIRST(head) ((head)->tqh_first)
+#define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
+       for ((var) = TAILQ_FIRST((head));                               \
+           (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
+           (var) = (tvar))

 
 

-#define        TAILQ_LAST(head, headname) \
-       (*(((struct headname *)((head)->tqh_last))->tqh_last))
+#define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
+       for ((var) = TAILQ_LAST((head), headname);                      \
+           (var);                                                      \
+           (var) = TAILQ_PREV((var), headname, field))

 
 

-#define        TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
+#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_PREV(elm, headname, field) \
-       (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
+#if XNU_KERNEL_PRIVATE
+/*
+ * Can be used when the initialized HEAD was just bzeroed
+ * Works around deficiencies in clang analysis of initialization patterns.
+ * See: <rdar://problem/47939050>
+ */
+#define TAILQ_INIT_AFTER_BZERO(head) do {                               \
+       (head)->tqh_last = &TAILQ_FIRST((head));                        \
+} while (0)
+#endif /* XNU_KERNEL_PRIVATE */

 
 

-#define        TAILQ_INIT(head) do {                                           \
-       (head)->tqh_first = NULL;                                       \
-       (head)->tqh_last = &(head)->tqh_first;                          \
+#define TAILQ_INIT(head) do {                                           \
+       TAILQ_FIRST((head)) = NULL;                                     \
+       (head)->tqh_last = &TAILQ_FIRST((head));                        \
+       QMD_TRACE_HEAD(head);                                           \

 } while (0)
 
 } while (0)
 

-#define TAILQ_INSERT_HEAD(head, elm, field) do {                       \
-       if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
-               (head)->tqh_first->field.tqe_prev =                     \
-                   &(elm)->field.tqe_next;                             \
-       else                                                            \
-               (head)->tqh_last = &(elm)->field.tqe_next;              \
-       (head)->tqh_first = (elm);                                      \
-       (elm)->field.tqe_prev = &(head)->tqh_first;                     \
+
+#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
+       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)
 
 } while (0)
 

-#define TAILQ_INSERT_TAIL(head, elm, field) do {                       \
-       (elm)->field.tqe_next = NULL;                                   \
-       (elm)->field.tqe_prev = (head)->tqh_last;                       \
-       *(head)->tqh_last = (elm);                                      \
-       (head)->tqh_last = &(elm)->field.tqe_next;                      \
+#define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
+       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)
 
 } while (0)
 

-#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
-       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;             \
+#define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
+       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)
 
 } while (0)
 

-#define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                  \
-       (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;             \
+#define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
+       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)
 
 } while (0)
 

-#define TAILQ_REMOVE(head, elm, field) do {                            \
-       if (((elm)->field.tqe_next) != NULL)                            \
-               (elm)->field.tqe_next->field.tqe_prev =                 \
-                   (elm)->field.tqe_prev;                              \
-       else                                                            \
-               (head)->tqh_last = (elm)->field.tqe_prev;               \
-       *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
+#define TAILQ_LAST(head, headname)                                      \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+       (*(((struct headname *)((head)->tqh_last))->tqh_last))          \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
+
+#define TAILQ_PREV(elm, headname, field)                                \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+       (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))     \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define TAILQ_REMOVE(head, elm, field) do {                             \
+       TAILQ_CHECK_NEXT(elm, field);                                   \
+       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((elm)->field.tqe_next);                                 \
+       TRASHIT((elm)->field.tqe_prev);                                 \
+       QMD_TRACE_ELEM(&(elm)->field);                                  \

 } while (0)
 
 /*
 } while (0)
 
 /*

- * Circular queue definitions.
+ * Why did they switch to spaces for this one macro?

  */
  */

-#define CIRCLEQ_HEAD(name, type)                                       \
-struct name {                                                          \
-       struct type *cqh_first;         /* first element */             \
-       struct type *cqh_last;          /* last element */              \
-}
+#define TAILQ_SWAP(head1, head2, type, field)                           \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+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)                                                             \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP

 
 

-#define CIRCLEQ_ENTRY(type)                                            \
-struct {                                                               \
-       struct type *cqe_next;          /* next element */              \
-       struct type *cqe_prev;          /* previous element */          \
-}
+/*
+ * Circular queue definitions.
+ */
+#define CIRCLEQ_HEAD(name, type)                                        \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct name {                                                           \
+       struct type *cqh_first;         /* first element */             \
+       struct type *cqh_last;          /* last element */              \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                          \
+__MISMATCH_TAGS_POP
+
+#define CIRCLEQ_ENTRY(type)                                             \
+__MISMATCH_TAGS_PUSH                                                    \
+__NULLABILITY_COMPLETENESS_PUSH                                         \
+struct {                                                                \
+       struct type *cqe_next;          /* next element */              \
+       struct type *cqe_prev;          /* previous element */          \
+}                                                                       \
+__NULLABILITY_COMPLETENESS_POP                                         \
+__MISMATCH_TAGS_POP

 
 /*
  * Circular queue functions.
  */
 
 /*
  * Circular queue functions.
  */

+#ifdef KERNEL_PRIVATE
+#define CIRCLEQ_CHECK_HEAD(head, field) do {                            \
+       if (__improbable(                                                \
+             CIRCLEQ_FIRST((head)) != ((void*)(head)) &&               \
+             CIRCLEQ_FIRST((head))->field.cqe_prev != ((void*)(head))))\
+                    panic("Bad circleq head %p first->prev != head @%u", \
+                        (head), __LINE__);                             \
+} while(0)
+#define CIRCLEQ_CHECK_NEXT(head, elm, field) do {                       \
+       if (__improbable(                                                \
+             CIRCLEQ_NEXT((elm), field) != ((void*)(head)) &&          \
+             CIRCLEQ_NEXT((elm), field)->field.cqe_prev != (elm)))     \
+                    panic("Bad circleq elm %p next->prev != elm @%u",  \
+                        (elm), __LINE__);                              \
+} while(0)
+#define CIRCLEQ_CHECK_PREV(head, elm, field) do {                       \
+       if (__improbable(                                                \
+             CIRCLEQ_PREV((elm), field) != ((void*)(head)) &&          \
+             CIRCLEQ_PREV((elm), field)->field.cqe_next != (elm)))     \
+                    panic("Bad circleq elm %p prev->next != elm @%u",  \
+                        (elm), __LINE__);                              \
+} while(0)
+#else
+#define CIRCLEQ_CHECK_HEAD(head, field)
+#define CIRCLEQ_CHECK_NEXT(head, elm, field)
+#define CIRCLEQ_CHECK_PREV(head, elm, field)
+#endif /* KERNEL_PRIVATE */
+

 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
 
 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
 
 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
 
 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
 

-#define CIRCLEQ_FOREACH(var, head, field)                              \
-       for((var) = (head)->cqh_first;                                  \
-           (var) != (void *)(head);                                    \
+#define CIRCLEQ_FOREACH(var, head, field)                               \
+       for((var) = (head)->cqh_first;                                  \
+           (var) != (void *)(head);                                    \

            (var) = (var)->field.cqe_next)
 
            (var) = (var)->field.cqe_next)
 

-#define        CIRCLEQ_INIT(head) do {                                         \
-       (head)->cqh_first = (void *)(head);                             \
-       (head)->cqh_last = (void *)(head);                              \
+#define CIRCLEQ_INIT(head) do {                                         \
+       (head)->cqh_first = (void *)(head);                             \
+       (head)->cqh_last = (void *)(head);                              \

 } while (0)
 
 } while (0)
 

-#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
-       (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);                              \
+#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
+       CIRCLEQ_CHECK_NEXT(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 (0)
 
 } while (0)
 

-#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {          \
-       (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);                              \
+#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
+       CIRCLEQ_CHECK_PREV(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 (0)
 
 } while (0)
 

-#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                     \
-       (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);                                      \
+#define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
+       CIRCLEQ_CHECK_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 (0)
 
 } while (0)
 

-#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                     \
-       (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);                                       \
+#define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
+       (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 (0)
 
 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
 
 } while (0)
 
 #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_REMOVE(head, elm, field) do {                           \
-       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;                              \
+#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
+
+#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
+
+#define CIRCLEQ_REMOVE(head, elm, field) do {                           \
+       CIRCLEQ_CHECK_NEXT(head, elm, field);                           \
+       CIRCLEQ_CHECK_PREV(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;                              \

 } while (0)
 
 } while (0)
 

-#ifdef KERNEL
+#ifdef _KERNEL

 
 #if NOTFB31
 
 
 #if NOTFB31
 


@@ -520,12 +958,38 @@ struct quehead {
        struct quehead *qh_rlink;
 };
 
        struct quehead *qh_rlink;
 };
 

-#ifdef __GNUC__
+#ifdef __GNUC__
+#ifdef KERNEL_PRIVATE
+static __inline void
+chkquenext(void *a)
+{
+       struct quehead *element = (struct quehead *)a;
+       if (__improbable(element->qh_link != NULL &&
+           element->qh_link->qh_rlink != element)) {
+               panic("Bad que elm %p next->prev != elm", a);
+       }
+}
+
+static __inline void
+chkqueprev(void *a)
+{
+       struct quehead *element = (struct quehead *)a;
+       if (__improbable(element->qh_rlink != NULL &&
+           element->qh_rlink->qh_link != element)) {
+               panic("Bad que elm %p prev->next != elm", a);
+       }
+}
+#else /* !KERNEL_PRIVATE */
+#define chkquenext(a)
+#define chkqueprev(a)
+#endif /* KERNEL_PRIVATE */

 
 static __inline void
 insque(void *a, void *b)
 {
 
 static __inline void
 insque(void *a, void *b)
 {

-       struct quehead *element = a, *head = b;
+       struct quehead *element = (struct quehead *)a,
+           *head = (struct quehead *)b;
+       chkquenext(head);

 
        element->qh_link = head->qh_link;
        element->qh_rlink = head;
 
        element->qh_link = head->qh_link;
        element->qh_rlink = head;


@@ -536,7 +1000,9 @@ insque(void *a, void *b)
 static __inline void
 remque(void *a)
 {
 static __inline void
 remque(void *a)
 {

-       struct quehead *element = a;
+       struct quehead *element = (struct quehead *)a;
+       chkquenext(element);
+       chkqueprev(element);

 
        element->qh_link->qh_rlink = element->qh_rlink;
        element->qh_rlink->qh_link = element->qh_link;
 
        element->qh_link->qh_rlink = element->qh_rlink;
        element->qh_rlink->qh_link = element->qh_link;


@@ -545,12 +1011,12 @@ remque(void *a)
 
 #else /* !__GNUC__ */
 
 
 #else /* !__GNUC__ */
 

-void   insque(void *a, void *b);
-void   remque(void *a);
+void    insque(void *a, void *b);
+void    remque(void *a);

 
 #endif /* __GNUC__ */
 
 
 #endif /* __GNUC__ */
 

-#endif
-#endif /* KERNEL */
+#endif /* NOTFB31 */
+#endif /* _KERNEL */

 
 #endif /* !_SYS_QUEUE_H_ */
 
 #endif /* !_SYS_QUEUE_H_ */