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1c79356b 1/*
5d5c5d0d
A		 2 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3 *
2d21ac55 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
0a7de745 5 *
2d21ac55
A		 6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
0a7de745 14 *
2d21ac55
A		 15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
0a7de745 17 *
2d21ac55
A		 18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5
A		 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55
A		 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
0a7de745 25 *
2d21ac55 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b 27 */
2d21ac55 28/*-
1c79356b
A		 29 * Copyright (c) 1991, 1993
30 * The Regents of the University of California. All rights reserved.
31 *
32 * Redistribution and use in source and binary forms, with or without
33 * modification, are permitted provided that the following conditions
34 * are met:
35 * 1. Redistributions of source code must retain the above copyright
36 * notice, this list of conditions and the following disclaimer.
37 * 2. Redistributions in binary form must reproduce the above copyright
38 * notice, this list of conditions and the following disclaimer in the
39 * documentation and/or other materials provided with the distribution.
1c79356b
A		 40 * 4. Neither the name of the University nor the names of its contributors
41 * may be used to endorse or promote products derived from this software
42 * without specific prior written permission.
43 *
44 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
45 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
46 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
47 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
48 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
49 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
50 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
51 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
52 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
53 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
54 * SUCH DAMAGE.
55 *
56 * @(#)queue.h 8.5 (Berkeley) 8/20/94
57 */
58
59#ifndef _SYS_QUEUE_H_
0a7de745 60#define _SYS_QUEUE_H_
1c79356b 61
d9a64523
A		 62#ifdef KERNEL_PRIVATE
63#include <kern/debug.h> /* panic function call */
0a7de745 64#include <sys/cdefs.h> /* __improbable in kernelspace */
d9a64523
A		 65#else
66#ifndef __improbable
0a7de745 67#define __improbable(x) (x) /* noop in userspace */
d9a64523
A		 68#endif /* __improbable */
69#endif /* KERNEL_PRIVATE */
70
1c79356b
A		 71/*
72 * This file defines five types of data structures: singly-linked lists,
2d21ac55 73 * singly-linked tail queues, lists, tail queues, and circular queues.
1c79356b
A		 74 *
75 * A singly-linked list is headed by a single forward pointer. The elements
76 * are singly linked for minimum space and pointer manipulation overhead at
77 * the expense of O(n) removal for arbitrary elements. New elements can be
78 * added to the list after an existing element or at the head of the list.
79 * Elements being removed from the head of the list should use the explicit
80 * macro for this purpose for optimum efficiency. A singly-linked list may
81 * only be traversed in the forward direction. Singly-linked lists are ideal
82 * for applications with large datasets and few or no removals or for
83 * implementing a LIFO queue.
84 *
85 * A singly-linked tail queue is headed by a pair of pointers, one to the
86 * head of the list and the other to the tail of the list. The elements are
87 * singly linked for minimum space and pointer manipulation overhead at the
88 * expense of O(n) removal for arbitrary elements. New elements can be added
89 * to the list after an existing element, at the head of the list, or at the
90 * end of the list. Elements being removed from the head of the tail queue
91 * should use the explicit macro for this purpose for optimum efficiency.
92 * A singly-linked tail queue may only be traversed in the forward direction.
93 * Singly-linked tail queues are ideal for applications with large datasets
94 * and few or no removals or for implementing a FIFO queue.
95 *
96 * A list is headed by a single forward pointer (or an array of forward
97 * pointers for a hash table header). The elements are doubly linked
98 * so that an arbitrary element can be removed without a need to
99 * traverse the list. New elements can be added to the list before
100 * or after an existing element or at the head of the list. A list
101 * may only be traversed in the forward direction.
102 *
103 * A tail queue is headed by a pair of pointers, one to the head of the
104 * list and the other to the tail of the list. The elements are doubly
105 * linked so that an arbitrary element can be removed without a need to
106 * traverse the list. New elements can be added to the list before or
107 * after an existing element, at the head of the list, or at the end of
2d21ac55 108 * the list. A tail queue may be traversed in either direction.
1c79356b
A		 109 *
110 * A circle queue is headed by a pair of pointers, one to the head of the
111 * list and the other to the tail of the list. The elements are doubly
112 * linked so that an arbitrary element can be removed without a need to
113 * traverse the list. New elements can be added to the list before or after
114 * an existing element, at the head of the list, or at the end of the list.
115 * A circle queue may be traversed in either direction, but has a more
116 * complex end of list detection.
2d21ac55
A		 117 * Note that circle queues are deprecated, because, as the removal log
118 * in FreeBSD states, "CIRCLEQs are a disgrace to everything Knuth taught
119 * us in Volume 1 Chapter 2. [...] Use TAILQ instead, it provides the same
120 * functionality." Code using them will continue to compile, but they
121 * are no longer documented on the man page.
1c79356b
A		 122 *
123 * For details on the use of these macros, see the queue(3) manual page.
124 *
125 *
2d21ac55
A		 126 * SLIST LIST STAILQ TAILQ CIRCLEQ
127 * _HEAD + + + + +
128 * _HEAD_INITIALIZER + + + + -
129 * _ENTRY + + + + +
130 * _INIT + + + + +
131 * _EMPTY + + + + +
132 * _FIRST + + + + +
133 * _NEXT + + + + +
134 * _PREV - - - + +
135 * _LAST - - + + +
136 * _FOREACH + + + + +
137 * _FOREACH_SAFE + + + + -
138 * _FOREACH_REVERSE - - - + -
139 * _FOREACH_REVERSE_SAFE - - - + -
140 * _INSERT_HEAD + + + + +
141 * _INSERT_BEFORE - + - + +
142 * _INSERT_AFTER + + + + +
143 * _INSERT_TAIL - - + + +
144 * _CONCAT - - + + -
6d2010ae 145 * _REMOVE_AFTER + - + - -
2d21ac55 146 * _REMOVE_HEAD + - + - -
6d2010ae 147 * _REMOVE_HEAD_UNTIL - - + - -
2d21ac55 148 * _REMOVE + + + + +
6d2010ae 149 * _SWAP - + + + -
1c79356b
A		 150 *
151 */
2d21ac55
A		 152#ifdef QUEUE_MACRO_DEBUG
153/* Store the last 2 places the queue element or head was altered */
154struct qm_trace {
155 char * lastfile;
156 int lastline;
157 char * prevfile;
158 int prevline;
159};
160
0a7de745
A		 161#define TRACEBUF struct qm_trace trace;
162#define TRASHIT(x) do {(x) = (void *)-1;} while (0)
2d21ac55 163
0a7de745
A		 164#define QMD_TRACE_HEAD(head) do { \
165 (head)->trace.prevline = (head)->trace.lastline; \
166 (head)->trace.prevfile = (head)->trace.lastfile; \
167 (head)->trace.lastline = __LINE__; \
168 (head)->trace.lastfile = __FILE__; \
2d21ac55
A		 169} while (0)
170
0a7de745
A		 171#define QMD_TRACE_ELEM(elem) do { \
172 (elem)->trace.prevline = (elem)->trace.lastline; \
173 (elem)->trace.prevfile = (elem)->trace.lastfile; \
174 (elem)->trace.lastline = __LINE__; \
175 (elem)->trace.lastfile = __FILE__; \
2d21ac55
A		 176} while (0)
177
178#else
0a7de745
A		 179#define QMD_TRACE_ELEM(elem)
180#define QMD_TRACE_HEAD(head)
181#define TRACEBUF
182#define TRASHIT(x)
183#endif /* QUEUE_MACRO_DEBUG */
1c79356b 184
39236c6e
A		 185/*
186 * Horrible macros to enable use of code that was meant to be C-specific
187 * (and which push struct onto type) in C++; without these, C++ code
188 * that uses these macros in the context of a class will blow up
189 * due to "struct" being preprended to "type" by the macros, causing
190 * inconsistent use of tags.
191 *
192 * This approach is necessary because these are macros; we have to use
193 * these on a per-macro basis (because the queues are implemented as
194 * macros, disabling this warning in the scope of the header file is
195 * insufficient), whuch means we can't use #pragma, and have to use
196 * _Pragma. We only need to use these for the queue macros that
197 * prepend "struct" to "type" and will cause C++ to blow up.
198 */
199#if defined(__clang__) && defined(__cplusplus)
0a7de745
A		 200#define __MISMATCH_TAGS_PUSH \
201 _Pragma("clang diagnostic push") \
39236c6e 202 _Pragma("clang diagnostic ignored \"-Wmismatched-tags\"")
0a7de745 203#define __MISMATCH_TAGS_POP \
39236c6e
A		 204 _Pragma("clang diagnostic pop")
205#else
206#define __MISMATCH_TAGS_PUSH
207#define __MISMATCH_TAGS_POP
208#endif
209
cb323159
A		 210/*!
211 * Ensures that these macros can safely be used in structs when compiling with
212 * clang. The macros do not allow for nullability attributes to be specified due
213 * to how they are expanded. For example:
214 *
215 * SLIST_HEAD(, foo _Nullable) bar;
216 *
217 * expands to
218 *
219 * struct {
220 * struct foo _Nullable *slh_first;
221 * }
222 *
223 * which is not valid because the nullability specifier has to apply to the
224 * pointer. So just ignore nullability completeness in all the places where this
225 * is an issue.
226 */
227#if defined(__clang__)
228#define __NULLABILITY_COMPLETENESS_PUSH \
229 _Pragma("clang diagnostic push") \
230 _Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
231#define __NULLABILITY_COMPLETENESS_POP \
232 _Pragma("clang diagnostic pop")
233#else
234#define __NULLABILITY_COMPLETENESS_PUSH
235#define __NULLABILITY_COMPLETENESS_POP
236#endif
237
1c79356b 238/*
2d21ac55 239 * Singly-linked List declarations.
1c79356b 240 */
0a7de745
A		 241#define SLIST_HEAD(name, type) \
242__MISMATCH_TAGS_PUSH \
cb323159 243__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 244struct name { \
245 struct type *slh_first; /* first element */ \
246} \
cb323159 247__NULLABILITY_COMPLETENESS_POP \
39236c6e 248__MISMATCH_TAGS_POP
2d21ac55 249
0a7de745 250#define SLIST_HEAD_INITIALIZER(head) \
2d21ac55
A		 251 { NULL }
252
0a7de745
A		 253#define SLIST_ENTRY(type) \
254__MISMATCH_TAGS_PUSH \
cb323159 255__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 256struct { \
257 struct type *sle_next; /* next element */ \
258} \
cb323159 259__NULLABILITY_COMPLETENESS_POP \
39236c6e 260__MISMATCH_TAGS_POP
2d21ac55 261
1c79356b
A		 262/*
263 * Singly-linked List functions.
264 */
0a7de745 265#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
1c79356b 266
0a7de745 267#define SLIST_FIRST(head) ((head)->slh_first)
1c79356b 268
0a7de745
A		 269#define SLIST_FOREACH(var, head, field) \
270 for ((var) = SLIST_FIRST((head)); \
271 (var); \
2d21ac55 272 (var) = SLIST_NEXT((var), field))
1c79356b 273
0a7de745
A		 274#define SLIST_FOREACH_SAFE(var, head, field, tvar) \
275 for ((var) = SLIST_FIRST((head)); \
276 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
2d21ac55 277 (var) = (tvar))
1c79356b 278
0a7de745
A		 279#define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
280 for ((varp) = &SLIST_FIRST((head)); \
281 ((var) = *(varp)) != NULL; \
2d21ac55 282 (varp) = &SLIST_NEXT((var), field))
1c79356b 283
0a7de745
A		 284#define SLIST_INIT(head) do { \
285 SLIST_FIRST((head)) = NULL; \
1c79356b
A		 286} while (0)
287
0a7de745
A		 288#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
289 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
290 SLIST_NEXT((slistelm), field) = (elm); \
2d21ac55 291} while (0)
1c79356b 292
0a7de745
A		 293#define SLIST_INSERT_HEAD(head, elm, field) do { \
294 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
295 SLIST_FIRST((head)) = (elm); \
1c79356b
A		 296} while (0)
297
0a7de745 298#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
2d21ac55 299
0a7de745
A		 300#define SLIST_REMOVE(head, elm, type, field) \
301__MISMATCH_TAGS_PUSH \
cb323159 302__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 303do { \
304 if (SLIST_FIRST((head)) == (elm)) { \
305 SLIST_REMOVE_HEAD((head), field); \
306 } \
307 else { \
308 struct type *curelm = SLIST_FIRST((head)); \
309 while (SLIST_NEXT(curelm, field) != (elm)) \
310 curelm = SLIST_NEXT(curelm, field); \
311 SLIST_REMOVE_AFTER(curelm, field); \
312 } \
313 TRASHIT((elm)->field.sle_next); \
314} while (0) \
cb323159 315__NULLABILITY_COMPLETENESS_POP \
39236c6e 316__MISMATCH_TAGS_POP
2d21ac55 317
0a7de745
A		 318#define SLIST_REMOVE_AFTER(elm, field) do { \
319 SLIST_NEXT(elm, field) = \
320 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
6d2010ae
A		 321} while (0)
322
0a7de745
A		 323#define SLIST_REMOVE_HEAD(head, field) do { \
324 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
1c79356b
A		 325} while (0)
326
327/*
2d21ac55 328 * Singly-linked Tail queue declarations.
1c79356b 329 */
0a7de745
A		 330#define STAILQ_HEAD(name, type) \
331__MISMATCH_TAGS_PUSH \
cb323159 332__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 333struct name { \
334 struct type *stqh_first;/* first element */ \
335 struct type **stqh_last;/* addr of last next element */ \
336} \
cb323159 337__NULLABILITY_COMPLETENESS_POP \
39236c6e 338__MISMATCH_TAGS_POP
1c79356b 339
0a7de745 340#define STAILQ_HEAD_INITIALIZER(head) \
1c79356b
A		 341 { NULL, &(head).stqh_first }
342
0a7de745
A		 343#define STAILQ_ENTRY(type) \
344__MISMATCH_TAGS_PUSH \
cb323159 345__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 346struct { \
347 struct type *stqe_next; /* next element */ \
348} \
cb323159 349__NULLABILITY_COMPLETENESS_POP \
39236c6e 350__MISMATCH_TAGS_POP
1c79356b
A		 351
352/*
353 * Singly-linked Tail queue functions.
354 */
0a7de745
A		 355#define STAILQ_CONCAT(head1, head2) do { \
356 if (!STAILQ_EMPTY((head2))) { \
357 *(head1)->stqh_last = (head2)->stqh_first; \
358 (head1)->stqh_last = (head2)->stqh_last; \
359 STAILQ_INIT((head2)); \
360 } \
1c79356b
A		 361} while (0)
362
0a7de745 363#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
1c79356b 364
0a7de745 365#define STAILQ_FIRST(head) ((head)->stqh_first)
2d21ac55 366
0a7de745
A		 367#define STAILQ_FOREACH(var, head, field) \
368 for((var) = STAILQ_FIRST((head)); \
369 (var); \
2d21ac55 370 (var) = STAILQ_NEXT((var), field))
1c79356b 371
1c79356b 372
0a7de745
A		 373#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
374 for ((var) = STAILQ_FIRST((head)); \
375 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
2d21ac55
A		 376 (var) = (tvar))
377
0a7de745
A		 378#define STAILQ_INIT(head) do { \
379 STAILQ_FIRST((head)) = NULL; \
380 (head)->stqh_last = &STAILQ_FIRST((head)); \
1c79356b
A		 381} while (0)
382
0a7de745 383#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
2d21ac55 384 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
0a7de745
A		 385 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
386 STAILQ_NEXT((tqelm), field) = (elm); \
2d21ac55 387} while (0)
1c79356b 388
0a7de745
A		 389#define STAILQ_INSERT_HEAD(head, elm, field) do { \
390 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
391 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
392 STAILQ_FIRST((head)) = (elm); \
1c79356b
A		 393} while (0)
394
0a7de745
A		 395#define STAILQ_INSERT_TAIL(head, elm, field) do { \
396 STAILQ_NEXT((elm), field) = NULL; \
397 *(head)->stqh_last = (elm); \
398 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
1c79356b
A		 399} while (0)
400
0a7de745
A		 401#define STAILQ_LAST(head, type, field) \
402__MISMATCH_TAGS_PUSH \
cb323159 403__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 404 (STAILQ_EMPTY((head)) ? \
405 NULL : \
406 ((struct type *)(void *) \
407 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))\
cb323159 408__NULLABILITY_COMPLETENESS_POP \
39236c6e 409__MISMATCH_TAGS_POP
1c79356b 410
0a7de745
A		 411#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
412
413#define STAILQ_REMOVE(head, elm, type, field) \
414__MISMATCH_TAGS_PUSH \
cb323159 415__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 416do { \
417 if (STAILQ_FIRST((head)) == (elm)) { \
418 STAILQ_REMOVE_HEAD((head), field); \
419 } \
420 else { \
421 struct type *curelm = STAILQ_FIRST((head)); \
422 while (STAILQ_NEXT(curelm, field) != (elm)) \
423 curelm = STAILQ_NEXT(curelm, field); \
424 STAILQ_REMOVE_AFTER(head, curelm, field); \
425 } \
426 TRASHIT((elm)->field.stqe_next); \
427} while (0) \
cb323159 428__NULLABILITY_COMPLETENESS_POP \
39236c6e 429__MISMATCH_TAGS_POP
2d21ac55 430
0a7de745
A		 431#define STAILQ_REMOVE_HEAD(head, field) do { \
432 if ((STAILQ_FIRST((head)) = \
433 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
434 (head)->stqh_last = &STAILQ_FIRST((head)); \
2d21ac55
A		 435} while (0)
436
6d2010ae
A		 437#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
438 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
0a7de745
A		 439 (head)->stqh_last = &STAILQ_FIRST((head)); \
440} while (0)
441
442#define STAILQ_REMOVE_AFTER(head, elm, field) do { \
443 if ((STAILQ_NEXT(elm, field) = \
444 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
445 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
446} while (0)
447
448#define STAILQ_SWAP(head1, head2, type) \
449__MISMATCH_TAGS_PUSH \
cb323159 450__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 451do { \
452 struct type *swap_first = STAILQ_FIRST(head1); \
453 struct type **swap_last = (head1)->stqh_last; \
454 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
455 (head1)->stqh_last = (head2)->stqh_last; \
456 STAILQ_FIRST(head2) = swap_first; \
457 (head2)->stqh_last = swap_last; \
458 if (STAILQ_EMPTY(head1)) \
459 (head1)->stqh_last = &STAILQ_FIRST(head1); \
460 if (STAILQ_EMPTY(head2)) \
461 (head2)->stqh_last = &STAILQ_FIRST(head2); \
462} while (0) \
cb323159 463__NULLABILITY_COMPLETENESS_POP \
39236c6e 464__MISMATCH_TAGS_POP
6d2010ae
A		 465
466
1c79356b 467/*
2d21ac55 468 * List declarations.
1c79356b 469 */
0a7de745
A		 470#define LIST_HEAD(name, type) \
471__MISMATCH_TAGS_PUSH \
cb323159 472__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 473struct name { \
474 struct type *lh_first; /* first element */ \
475} \
cb323159 476__NULLABILITY_COMPLETENESS_POP \
39236c6e 477__MISMATCH_TAGS_POP
1c79356b 478
0a7de745 479#define LIST_HEAD_INITIALIZER(head) \
1c79356b
A		 480 { NULL }
481
0a7de745
A		 482#define LIST_ENTRY(type) \
483__MISMATCH_TAGS_PUSH \
cb323159 484__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 485struct { \
486 struct type *le_next; /* next element */ \
487 struct type **le_prev; /* address of previous next element */ \
488} \
cb323159 489__NULLABILITY_COMPLETENESS_POP \
39236c6e 490__MISMATCH_TAGS_POP
1c79356b
A		 491
492/*
493 * List functions.
494 */
495
d9a64523 496#ifdef KERNEL_PRIVATE
0a7de745
A		 497#define LIST_CHECK_HEAD(head, field) do { \
498 if (__improbable( \
499 LIST_FIRST((head)) != NULL && \
500 LIST_FIRST((head))->field.le_prev != \
501 &LIST_FIRST((head)))) \
502 panic("Bad list head %p first->prev != head", (head)); \
2d21ac55 503} while (0)
1c79356b 504
0a7de745
A		 505#define LIST_CHECK_NEXT(elm, field) do { \
506 if (__improbable( \
507 LIST_NEXT((elm), field) != NULL && \
508 LIST_NEXT((elm), field)->field.le_prev != \
509 &((elm)->field.le_next))) \
510 panic("Bad link elm %p next->prev != elm", (elm)); \
2d21ac55
A		 511} while (0)
512
0a7de745
A		 513#define LIST_CHECK_PREV(elm, field) do { \
514 if (__improbable(*(elm)->field.le_prev != (elm))) \
515 panic("Bad link elm %p prev->next != elm", (elm)); \
2d21ac55
A		 516} while (0)
517#else
0a7de745
A		 518#define LIST_CHECK_HEAD(head, field)
519#define LIST_CHECK_NEXT(elm, field)
520#define LIST_CHECK_PREV(elm, field)
d9a64523 521#endif /* KERNEL_PRIVATE */
1c79356b 522
0a7de745 523#define LIST_EMPTY(head) ((head)->lh_first == NULL)
2d21ac55 524
0a7de745 525#define LIST_FIRST(head) ((head)->lh_first)
2d21ac55 526
0a7de745
A		 527#define LIST_FOREACH(var, head, field) \
528 for ((var) = LIST_FIRST((head)); \
529 (var); \
2d21ac55
A		 530 (var) = LIST_NEXT((var), field))
531
0a7de745
A		 532#define LIST_FOREACH_SAFE(var, head, field, tvar) \
533 for ((var) = LIST_FIRST((head)); \
534 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
2d21ac55 535 (var) = (tvar))
1c79356b 536
0a7de745
A		 537#define LIST_INIT(head) do { \
538 LIST_FIRST((head)) = NULL; \
1c79356b
A		 539} while (0)
540
0a7de745
A		 541#define LIST_INSERT_AFTER(listelm, elm, field) do { \
542 LIST_CHECK_NEXT(listelm, field); \
2d21ac55 543 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
0a7de745
A		 544 LIST_NEXT((listelm), field)->field.le_prev = \
545 &LIST_NEXT((elm), field); \
546 LIST_NEXT((listelm), field) = (elm); \
547 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
548} while (0)
549
550#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
551 LIST_CHECK_PREV(listelm, field); \
552 (elm)->field.le_prev = (listelm)->field.le_prev; \
553 LIST_NEXT((elm), field) = (listelm); \
554 *(listelm)->field.le_prev = (elm); \
555 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
556} while (0)
557
558#define LIST_INSERT_HEAD(head, elm, field) do { \
559 LIST_CHECK_HEAD((head), field); \
560 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
561 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
562 LIST_FIRST((head)) = (elm); \
563 (elm)->field.le_prev = &LIST_FIRST((head)); \
564} while (0)
565
566#define LIST_NEXT(elm, field) ((elm)->field.le_next)
567
568#define LIST_REMOVE(elm, field) do { \
569 LIST_CHECK_NEXT(elm, field); \
570 LIST_CHECK_PREV(elm, field); \
571 if (LIST_NEXT((elm), field) != NULL) \
572 LIST_NEXT((elm), field)->field.le_prev = \
573 (elm)->field.le_prev; \
574 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
575 TRASHIT((elm)->field.le_next); \
576 TRASHIT((elm)->field.le_prev); \
577} while (0)
578
579#define LIST_SWAP(head1, head2, type, field) \
580__MISMATCH_TAGS_PUSH \
cb323159 581__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 582do { \
583 struct type *swap_tmp = LIST_FIRST((head1)); \
584 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
585 LIST_FIRST((head2)) = swap_tmp; \
586 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
587 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
588 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
589 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
590} while (0) \
cb323159 591__NULLABILITY_COMPLETENESS_POP \
39236c6e 592__MISMATCH_TAGS_POP
6d2010ae 593
1c79356b 594/*
2d21ac55 595 * Tail queue declarations.
1c79356b 596 */
0a7de745
A		 597#define TAILQ_HEAD(name, type) \
598__MISMATCH_TAGS_PUSH \
cb323159 599__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 600struct name { \
601 struct type *tqh_first; /* first element */ \
602 struct type **tqh_last; /* addr of last next element */ \
603 TRACEBUF \
604} \
cb323159 605__NULLABILITY_COMPLETENESS_POP \
39236c6e 606__MISMATCH_TAGS_POP
1c79356b 607
0a7de745 608#define TAILQ_HEAD_INITIALIZER(head) \
1c79356b
A		 609 { NULL, &(head).tqh_first }
610
0a7de745
A		 611#define TAILQ_ENTRY(type) \
612__MISMATCH_TAGS_PUSH \
cb323159 613__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 614struct { \
615 struct type *tqe_next; /* next element */ \
616 struct type **tqe_prev; /* address of previous next element */ \
617 TRACEBUF \
618} \
cb323159 619__NULLABILITY_COMPLETENESS_POP \
39236c6e 620__MISMATCH_TAGS_POP
1c79356b
A		 621
622/*
623 * Tail queue functions.
624 */
d9a64523 625#ifdef KERNEL_PRIVATE
0a7de745
A		 626#define TAILQ_CHECK_HEAD(head, field) do { \
627 if (__improbable( \
628 TAILQ_FIRST((head)) != NULL && \
629 TAILQ_FIRST((head))->field.tqe_prev != \
630 &TAILQ_FIRST((head)))) \
631 panic("Bad tailq head %p first->prev != head", (head)); \
632} while (0)
633
634#define TAILQ_CHECK_NEXT(elm, field) do { \
635 if (__improbable( \
636 TAILQ_NEXT((elm), field) != NULL && \
637 TAILQ_NEXT((elm), field)->field.tqe_prev != \
638 &((elm)->field.tqe_next))) \
639 panic("Bad tailq elm %p next->prev != elm", (elm)); \
d9a64523
A		 640} while(0)
641
0a7de745
A		 642#define TAILQ_CHECK_PREV(elm, field) do { \
643 if (__improbable(*(elm)->field.tqe_prev != (elm))) \
644 panic("Bad tailq elm %p prev->next != elm", (elm)); \
d9a64523
A		 645} while(0)
646#else
0a7de745
A		 647#define TAILQ_CHECK_HEAD(head, field)
648#define TAILQ_CHECK_NEXT(elm, field)
649#define TAILQ_CHECK_PREV(elm, field)
d9a64523
A		 650#endif /* KERNEL_PRIVATE */
651
0a7de745
A		 652#define TAILQ_CONCAT(head1, head2, field) do { \
653 if (!TAILQ_EMPTY(head2)) { \
654 *(head1)->tqh_last = (head2)->tqh_first; \
655 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
656 (head1)->tqh_last = (head2)->tqh_last; \
657 TAILQ_INIT((head2)); \
658 QMD_TRACE_HEAD(head1); \
659 QMD_TRACE_HEAD(head2); \
660 } \
2d21ac55 661} while (0)
1c79356b 662
0a7de745 663#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
1c79356b 664
0a7de745 665#define TAILQ_FIRST(head) ((head)->tqh_first)
1c79356b 666
0a7de745
A		 667#define TAILQ_FOREACH(var, head, field) \
668 for ((var) = TAILQ_FIRST((head)); \
669 (var); \
2d21ac55 670 (var) = TAILQ_NEXT((var), field))
1c79356b 671
0a7de745
A		 672#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
673 for ((var) = TAILQ_FIRST((head)); \
674 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
2d21ac55 675 (var) = (tvar))
1c79356b 676
0a7de745
A		 677#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
678 for ((var) = TAILQ_LAST((head), headname); \
679 (var); \
2d21ac55 680 (var) = TAILQ_PREV((var), headname, field))
1c79356b 681
0a7de745
A		 682#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
683 for ((var) = TAILQ_LAST((head), headname); \
684 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
2d21ac55 685 (var) = (tvar))
1c79356b 686
cb323159
A		 687#if XNU_KERNEL_PRIVATE
688/*
689 * Can be used when the initialized HEAD was just bzeroed
690 * Works around deficiencies in clang analysis of initialization patterns.
691 * See: <rdar://problem/47939050>
692 */
693#define TAILQ_INIT_AFTER_BZERO(head) do { \
694 (head)->tqh_last = &TAILQ_FIRST((head)); \
695} while (0)
696#endif /* XNU_KERNEL_PRIVATE */
697
0a7de745
A		 698#define TAILQ_INIT(head) do { \
699 TAILQ_FIRST((head)) = NULL; \
700 (head)->tqh_last = &TAILQ_FIRST((head)); \
701 QMD_TRACE_HEAD(head); \
1c79356b
A		 702} while (0)
703
d9a64523 704
0a7de745
A		 705#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
706 TAILQ_CHECK_NEXT(listelm, field); \
2d21ac55 707 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
0a7de745
A		 708 TAILQ_NEXT((elm), field)->field.tqe_prev = \
709 &TAILQ_NEXT((elm), field); \
710 else { \
711 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
712 QMD_TRACE_HEAD(head); \
713 } \
714 TAILQ_NEXT((listelm), field) = (elm); \
715 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
716 QMD_TRACE_ELEM(&(elm)->field); \
717 QMD_TRACE_ELEM(&listelm->field); \
718} while (0)
719
720#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
721 TAILQ_CHECK_PREV(listelm, field); \
722 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
723 TAILQ_NEXT((elm), field) = (listelm); \
724 *(listelm)->field.tqe_prev = (elm); \
725 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
726 QMD_TRACE_ELEM(&(elm)->field); \
727 QMD_TRACE_ELEM(&listelm->field); \
728} while (0)
729
730#define TAILQ_INSERT_HEAD(head, elm, field) do { \
731 TAILQ_CHECK_HEAD(head, field); \
732 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
733 TAILQ_FIRST((head))->field.tqe_prev = \
734 &TAILQ_NEXT((elm), field); \
735 else \
736 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
737 TAILQ_FIRST((head)) = (elm); \
738 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
739 QMD_TRACE_HEAD(head); \
740 QMD_TRACE_ELEM(&(elm)->field); \
741} while (0)
742
743#define TAILQ_INSERT_TAIL(head, elm, field) do { \
744 TAILQ_NEXT((elm), field) = NULL; \
745 (elm)->field.tqe_prev = (head)->tqh_last; \
746 *(head)->tqh_last = (elm); \
747 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
748 QMD_TRACE_HEAD(head); \
749 QMD_TRACE_ELEM(&(elm)->field); \
750} while (0)
751
752#define TAILQ_LAST(head, headname) \
753__MISMATCH_TAGS_PUSH \
cb323159 754__NULLABILITY_COMPLETENESS_PUSH \
0a7de745 755 (*(((struct headname *)((head)->tqh_last))->tqh_last)) \
cb323159 756__NULLABILITY_COMPLETENESS_POP \
39236c6e 757__MISMATCH_TAGS_POP
2d21ac55 758
0a7de745 759#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
2d21ac55 760
0a7de745
A		 761#define TAILQ_PREV(elm, headname, field) \
762__MISMATCH_TAGS_PUSH \
cb323159 763__NULLABILITY_COMPLETENESS_PUSH \
0a7de745 764 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) \
cb323159 765__NULLABILITY_COMPLETENESS_POP \
39236c6e 766__MISMATCH_TAGS_POP
2d21ac55 767
0a7de745
A		 768#define TAILQ_REMOVE(head, elm, field) do { \
769 TAILQ_CHECK_NEXT(elm, field); \
770 TAILQ_CHECK_PREV(elm, field); \
771 if ((TAILQ_NEXT((elm), field)) != NULL) \
772 TAILQ_NEXT((elm), field)->field.tqe_prev = \
773 (elm)->field.tqe_prev; \
774 else { \
775 (head)->tqh_last = (elm)->field.tqe_prev; \
776 QMD_TRACE_HEAD(head); \
777 } \
778 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
779 TRASHIT((elm)->field.tqe_next); \
780 TRASHIT((elm)->field.tqe_prev); \
781 QMD_TRACE_ELEM(&(elm)->field); \
1c79356b
A		 782} while (0)
783
39236c6e
A		 784/*
785 * Why did they switch to spaces for this one macro?
786 */
787#define TAILQ_SWAP(head1, head2, type, field) \
788__MISMATCH_TAGS_PUSH \
cb323159 789__NULLABILITY_COMPLETENESS_PUSH \
39236c6e 790do { \
6d2010ae
A		 791 struct type *swap_first = (head1)->tqh_first; \
792 struct type **swap_last = (head1)->tqh_last; \
793 (head1)->tqh_first = (head2)->tqh_first; \
794 (head1)->tqh_last = (head2)->tqh_last; \
795 (head2)->tqh_first = swap_first; \
796 (head2)->tqh_last = swap_last; \
797 if ((swap_first = (head1)->tqh_first) != NULL) \
0a7de745 798 swap_first->field.tqe_prev = &(head1)->tqh_first; \
6d2010ae 799 else \
0a7de745 800 (head1)->tqh_last = &(head1)->tqh_first; \
6d2010ae 801 if ((swap_first = (head2)->tqh_first) != NULL) \
0a7de745 802 swap_first->field.tqe_prev = &(head2)->tqh_first; \
6d2010ae 803 else \
0a7de745 804 (head2)->tqh_last = &(head2)->tqh_first; \
39236c6e 805} while (0) \
cb323159 806__NULLABILITY_COMPLETENESS_POP \
39236c6e 807__MISMATCH_TAGS_POP
6d2010ae 808
1c79356b
A		 809/*
810 * Circular queue definitions.
811 */
0a7de745
A		 812#define CIRCLEQ_HEAD(name, type) \
813__MISMATCH_TAGS_PUSH \
cb323159 814__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 815struct name { \
816 struct type *cqh_first; /* first element */ \
817 struct type *cqh_last; /* last element */ \
818} \
cb323159 819__NULLABILITY_COMPLETENESS_POP \
39236c6e 820__MISMATCH_TAGS_POP
1c79356b 821
0a7de745
A		 822#define CIRCLEQ_ENTRY(type) \
823__MISMATCH_TAGS_PUSH \
cb323159 824__NULLABILITY_COMPLETENESS_PUSH \
0a7de745
A		 825struct { \
826 struct type *cqe_next; /* next element */ \
827 struct type *cqe_prev; /* previous element */ \
828} \
cb323159 829__NULLABILITY_COMPLETENESS_POP \
39236c6e 830__MISMATCH_TAGS_POP
1c79356b
A		 831
832/*
833 * Circular queue functions.
834 */
d9a64523 835#ifdef KERNEL_PRIVATE
0a7de745
A		 836#define CIRCLEQ_CHECK_HEAD(head, field) do { \
837 if (__improbable( \
838 CIRCLEQ_FIRST((head)) != ((void*)(head)) && \
d9a64523 839 CIRCLEQ_FIRST((head))->field.cqe_prev != ((void*)(head))))\
0a7de745 840 panic("Bad circleq head %p first->prev != head", (head)); \
d9a64523 841} while(0)
0a7de745
A		 842#define CIRCLEQ_CHECK_NEXT(head, elm, field) do { \
843 if (__improbable( \
844 CIRCLEQ_NEXT((elm), field) != ((void*)(head)) && \
845 CIRCLEQ_NEXT((elm), field)->field.cqe_prev != (elm))) \
846 panic("Bad circleq elm %p next->prev != elm", (elm)); \
d9a64523 847} while(0)
0a7de745
A		 848#define CIRCLEQ_CHECK_PREV(head, elm, field) do { \
849 if (__improbable( \
850 CIRCLEQ_PREV((elm), field) != ((void*)(head)) && \
851 CIRCLEQ_PREV((elm), field)->field.cqe_next != (elm))) \
852 panic("Bad circleq elm %p prev->next != elm", (elm)); \
d9a64523
A		 853} while(0)
854#else
0a7de745
A		 855#define CIRCLEQ_CHECK_HEAD(head, field)
856#define CIRCLEQ_CHECK_NEXT(head, elm, field)
857#define CIRCLEQ_CHECK_PREV(head, elm, field)
d9a64523
A		 858#endif /* KERNEL_PRIVATE */
859
1c79356b
A		 860#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
861
862#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
863
0a7de745
A		 864#define CIRCLEQ_FOREACH(var, head, field) \
865 for((var) = (head)->cqh_first; \
866 (var) != (void *)(head); \
1c79356b
A		 867 (var) = (var)->field.cqe_next)
868
0a7de745
A		 869#define CIRCLEQ_INIT(head) do { \
870 (head)->cqh_first = (void *)(head); \
871 (head)->cqh_last = (void *)(head); \
872} while (0)
873
874#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
875 CIRCLEQ_CHECK_NEXT(head, listelm, field); \
876 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
877 (elm)->field.cqe_prev = (listelm); \
878 if ((listelm)->field.cqe_next == (void *)(head)) \
879 (head)->cqh_last = (elm); \
880 else \
881 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
882 (listelm)->field.cqe_next = (elm); \
883} while (0)
884
885#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
886 CIRCLEQ_CHECK_PREV(head, listelm, field); \
887 (elm)->field.cqe_next = (listelm); \
888 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
889 if ((listelm)->field.cqe_prev == (void *)(head)) \
890 (head)->cqh_first = (elm); \
891 else \
892 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
893 (listelm)->field.cqe_prev = (elm); \
894} while (0)
895
896#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
897 CIRCLEQ_CHECK_HEAD(head, field); \
898 (elm)->field.cqe_next = (head)->cqh_first; \
899 (elm)->field.cqe_prev = (void *)(head); \
900 if ((head)->cqh_last == (void *)(head)) \
901 (head)->cqh_last = (elm); \
902 else \
903 (head)->cqh_first->field.cqe_prev = (elm); \
904 (head)->cqh_first = (elm); \
905} while (0)
906
907#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
908 (elm)->field.cqe_next = (void *)(head); \
909 (elm)->field.cqe_prev = (head)->cqh_last; \
910 if ((head)->cqh_first == (void *)(head)) \
911 (head)->cqh_first = (elm); \
912 else \
913 (head)->cqh_last->field.cqe_next = (elm); \
914 (head)->cqh_last = (elm); \
1c79356b
A		 915} while (0)
916
917#define CIRCLEQ_LAST(head) ((head)->cqh_last)
918
0a7de745 919#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
1c79356b 920
0a7de745 921#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
1c79356b 922
0a7de745
A		 923#define CIRCLEQ_REMOVE(head, elm, field) do { \
924 CIRCLEQ_CHECK_NEXT(head, elm, field); \
925 CIRCLEQ_CHECK_PREV(head, elm, field); \
926 if ((elm)->field.cqe_next == (void *)(head)) \
927 (head)->cqh_last = (elm)->field.cqe_prev; \
928 else \
929 (elm)->field.cqe_next->field.cqe_prev = \
930 (elm)->field.cqe_prev; \
931 if ((elm)->field.cqe_prev == (void *)(head)) \
932 (head)->cqh_first = (elm)->field.cqe_next; \
933 else \
934 (elm)->field.cqe_prev->field.cqe_next = \
935 (elm)->field.cqe_next; \
1c79356b
A		 936} while (0)
937
2d21ac55 938#ifdef _KERNEL
1c79356b
A		 939
940#if NOTFB31
941
942/*
943 * XXX insque() and remque() are an old way of handling certain queues.
944 * They bogusly assumes that all queue heads look alike.
945 */
946
947struct quehead {
948 struct quehead *qh_link;
949 struct quehead *qh_rlink;
950};
951
2d21ac55 952#ifdef __GNUC__
d9a64523
A		 953#ifdef KERNEL_PRIVATE
954static __inline void
955chkquenext(void *a)
956{
0a7de745
A		 957 struct quehead *element = (struct quehead *)a;
958 if (__improbable(element->qh_link != NULL &&
959 element->qh_link->qh_rlink != element)) {
960 panic("Bad que elm %p next->prev != elm", a);
961 }
d9a64523
A		 962}
963
964static __inline void
965chkqueprev(void *a)
966{
0a7de745
A		 967 struct quehead *element = (struct quehead *)a;
968 if (__improbable(element->qh_rlink != NULL &&
969 element->qh_rlink->qh_link != element)) {
970 panic("Bad que elm %p prev->next != elm", a);
971 }
d9a64523
A		 972}
973#else /* !KERNEL_PRIVATE */
974#define chkquenext(a)
975#define chkqueprev(a)
976#endif /* KERNEL_PRIVATE */
1c79356b
A		 977
978static __inline void
979insque(void *a, void *b)
980{
2d21ac55 981 struct quehead *element = (struct quehead *)a,
0a7de745 982 *head = (struct quehead *)b;
d9a64523 983 chkquenext(head);
1c79356b
A		 984
985 element->qh_link = head->qh_link;
986 element->qh_rlink = head;
987 head->qh_link = element;
988 element->qh_link->qh_rlink = element;
989}
990
991static __inline void
992remque(void *a)
993{
2d21ac55 994 struct quehead *element = (struct quehead *)a;
d9a64523
A		 995 chkquenext(element);
996 chkqueprev(element);
1c79356b
A		 997
998 element->qh_link->qh_rlink = element->qh_rlink;
999 element->qh_rlink->qh_link = element->qh_link;
1000 element->qh_rlink = 0;
1001}
1002
1003#else /* !__GNUC__ */
1004
0a7de745
A		 1005void insque(void *a, void *b);
1006void remque(void *a);
1c79356b
A		 1007
1008#endif /* __GNUC__ */
1009
d9a64523 1010#endif /* NOTFB31 */
2d21ac55 1011#endif /* _KERNEL */
1c79356b
A		 1012
1013#endif /* !_SYS_QUEUE_H_ */
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