1 /*
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)queue.h 8.5 (Berkeley) 8/20/94
34 * $FreeBSD: src/sys/sys/queue.h,v 1.54 2002/08/05 05:18:43 alfred Exp $
35 */
36
37 #ifndef _SYS_QUEUE_H_
38 #define _SYS_QUEUE_H_
39
40 #include <sys/cdefs.h>
41
42 /*
43 * This file defines four types of data structures: singly-linked lists,
44 * singly-linked tail queues, lists and tail queues.
45 *
46 * A singly-linked list is headed by a single forward pointer. The elements
47 * are singly linked for minimum space and pointer manipulation overhead at
48 * the expense of O(n) removal for arbitrary elements. New elements can be
49 * added to the list after an existing element or at the head of the list.
50 * Elements being removed from the head of the list should use the explicit
51 * macro for this purpose for optimum efficiency. A singly-linked list may
52 * only be traversed in the forward direction. Singly-linked lists are ideal
53 * for applications with large datasets and few or no removals or for
54 * implementing a LIFO queue.
55 *
56 * A singly-linked tail queue is headed by a pair of pointers, one to the
57 * head of the list and the other to the tail of the list. The elements are
58 * singly linked for minimum space and pointer manipulation overhead at the
59 * expense of O(n) removal for arbitrary elements. New elements can be added
60 * to the list after an existing element, at the head of the list, or at the
61 * end of the list. Elements being removed from the head of the tail queue
62 * should use the explicit macro for this purpose for optimum efficiency.
63 * A singly-linked tail queue may only be traversed in the forward direction.
64 * Singly-linked tail queues are ideal for applications with large datasets
65 * and few or no removals or for implementing a FIFO queue.
66 *
67 * A list is headed by a single forward pointer (or an array of forward
68 * pointers for a hash table header). The elements are doubly linked
69 * so that an arbitrary element can be removed without a need to
70 * traverse the list. New elements can be added to the list before
71 * or after an existing element or at the head of the list. A list
72 * may only be traversed in the forward direction.
73 *
74 * A tail queue is headed by a pair of pointers, one to the head of the
75 * list and the other to the tail of the list. The elements are doubly
76 * linked so that an arbitrary element can be removed without a need to
77 * traverse the list. New elements can be added to the list before or
78 * after an existing element, at the head of the list, or at the end of
79 * the list. A tail queue may be traversed in either direction.
80 *
81 * For details on the use of these macros, see the queue(3) manual page.
82 *
83 *
84 * SLIST LIST STAILQ TAILQ
85 * _HEAD + + + +
86 * _HEAD_INITIALIZER + + + +
87 * _ENTRY + + + +
88 * _INIT + + + +
89 * _EMPTY + + + +
90 * _FIRST + + + +
91 * _NEXT + + + +
92 * _PREV - - - +
93 * _LAST - - + +
94 * _FOREACH + + + +
95 * _FOREACH_REVERSE - - - +
96 * _INSERT_HEAD + + + +
97 * _INSERT_BEFORE - + - +
98 * _INSERT_AFTER + + + +
99 * _INSERT_TAIL - - + +
100 * _CONCAT - - + +
101 * _REMOVE_HEAD + - + -
102 * _REMOVE + + + +
103 *
104 */
105 #define QUEUE_MACRO_DEBUG 0
106 #if QUEUE_MACRO_DEBUG
107 /* Store the last 2 places the queue element or head was altered */
108 struct qm_trace {
109 char * lastfile;
110 int lastline;
111 char * prevfile;
112 int prevline;
113 };
114
115 #define TRACEBUF struct qm_trace trace;
116 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
117
118 #define QMD_TRACE_HEAD(head) do { \
119 (head)->trace.prevline = (head)->trace.lastline; \
120 (head)->trace.prevfile = (head)->trace.lastfile; \
121 (head)->trace.lastline = __LINE__; \
122 (head)->trace.lastfile = __FILE__; \
123 } while (0)
124
125 #define QMD_TRACE_ELEM(elem) do { \
126 (elem)->trace.prevline = (elem)->trace.lastline; \
127 (elem)->trace.prevfile = (elem)->trace.lastfile; \
128 (elem)->trace.lastline = __LINE__; \
129 (elem)->trace.lastfile = __FILE__; \
130 } while (0)
131
132 #else
133 #define QMD_TRACE_ELEM(elem)
134 #define QMD_TRACE_HEAD(head)
135 #define TRACEBUF
136 #define TRASHIT(x)
137 #endif /* QUEUE_MACRO_DEBUG */
138
139 /*
140 * Singly-linked List declarations.
141 */
142 #define SLIST_HEAD(name, type) \
143 struct name { \
144 struct type *slh_first; /* first element */ \
145 }
146
147 #define SLIST_HEAD_INITIALIZER(head) \
148 { NULL }
149
150 #define SLIST_ENTRY(type) \
151 struct { \
152 struct type *sle_next; /* next element */ \
153 }
154
155 /*
156 * Singly-linked List functions.
157 */
158 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
159
160 #define SLIST_FIRST(head) ((head)->slh_first)
161
162 #define SLIST_FOREACH(var, head, field) \
163 for ((var) = SLIST_FIRST((head)); \
164 (var); \
165 (var) = SLIST_NEXT((var), field))
166
167 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
168 for ((varp) = &SLIST_FIRST((head)); \
169 ((var) = *(varp)) != NULL; \
170 (varp) = &SLIST_NEXT((var), field))
171
172 #define SLIST_INIT(head) do { \
173 SLIST_FIRST((head)) = NULL; \
174 } while (0)
175
176 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
177 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
178 SLIST_NEXT((slistelm), field) = (elm); \
179 } while (0)
180
181 #define SLIST_INSERT_HEAD(head, elm, field) do { \
182 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
183 SLIST_FIRST((head)) = (elm); \
184 } while (0)
185
186 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
187
188 #define SLIST_REMOVE(head, elm, type, field) do { \
189 if (SLIST_FIRST((head)) == (elm)) { \
190 SLIST_REMOVE_HEAD((head), field); \
191 } \
192 else { \
193 struct type *curelm = SLIST_FIRST((head)); \
194 while (SLIST_NEXT(curelm, field) != (elm)) \
195 curelm = SLIST_NEXT(curelm, field); \
196 SLIST_NEXT(curelm, field) = \
197 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
198 } \
199 } while (0)
200
201 #define SLIST_REMOVE_HEAD(head, field) do { \
202 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
203 } while (0)
204
205 /*
206 * Singly-linked Tail queue declarations.
207 */
208 #define STAILQ_HEAD(name, type) \
209 struct name { \
210 struct type *stqh_first;/* first element */ \
211 struct type **stqh_last;/* addr of last next element */ \
212 }
213
214 #define STAILQ_HEAD_INITIALIZER(head) \
215 { NULL, &(head).stqh_first }
216
217 #define STAILQ_ENTRY(type) \
218 struct { \
219 struct type *stqe_next; /* next element */ \
220 }
221
222 /*
223 * Singly-linked Tail queue functions.
224 */
225 #define STAILQ_CONCAT(head1, head2) do { \
226 if (!STAILQ_EMPTY((head2))) { \
227 *(head1)->stqh_last = (head2)->stqh_first; \
228 (head1)->stqh_last = (head2)->stqh_last; \
229 STAILQ_INIT((head2)); \
230 } \
231 } while (0)
232
233 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
234
235 #define STAILQ_FIRST(head) ((head)->stqh_first)
236
237 #define STAILQ_FOREACH(var, head, field) \
238 for((var) = STAILQ_FIRST((head)); \
239 (var); \
240 (var) = STAILQ_NEXT((var), field))
241
242 #define STAILQ_INIT(head) do { \
243 STAILQ_FIRST((head)) = NULL; \
244 (head)->stqh_last = &STAILQ_FIRST((head)); \
245 } while (0)
246
247 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
248 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
249 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
250 STAILQ_NEXT((tqelm), field) = (elm); \
251 } while (0)
252
253 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
254 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
255 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
256 STAILQ_FIRST((head)) = (elm); \
257 } while (0)
258
259 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
260 STAILQ_NEXT((elm), field) = NULL; \
261 *(head)->stqh_last = (elm); \
262 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
263 } while (0)
264
265 #define STAILQ_LAST(head, type, field) \
266 (STAILQ_EMPTY((head)) ? \
267 NULL : \
268 ((struct type *) \
269 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
270
271 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
272
273 #define STAILQ_REMOVE(head, elm, type, field) do { \
274 if (STAILQ_FIRST((head)) == (elm)) { \
275 STAILQ_REMOVE_HEAD((head), field); \
276 } \
277 else { \
278 struct type *curelm = STAILQ_FIRST((head)); \
279 while (STAILQ_NEXT(curelm, field) != (elm)) \
280 curelm = STAILQ_NEXT(curelm, field); \
281 if ((STAILQ_NEXT(curelm, field) = \
282 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
283 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\
284 } \
285 } while (0)
286
287 #define STAILQ_REMOVE_HEAD(head, field) do { \
288 if ((STAILQ_FIRST((head)) = \
289 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
290 (head)->stqh_last = &STAILQ_FIRST((head)); \
291 } while (0)
292
293 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
294 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
295 (head)->stqh_last = &STAILQ_FIRST((head)); \
296 } while (0)
297
298 /*
299 * List declarations.
300 */
301 #define LIST_HEAD(name, type) \
302 struct name { \
303 struct type *lh_first; /* first element */ \
304 }
305
306 #define LIST_HEAD_INITIALIZER(head) \
307 { NULL }
308
309 #define LIST_ENTRY(type) \
310 struct { \
311 struct type *le_next; /* next element */ \
312 struct type **le_prev; /* address of previous next element */ \
313 }
314
315 /*
316 * List functions.
317 */
318
319 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
320
321 #define LIST_FIRST(head) ((head)->lh_first)
322
323 #define LIST_FOREACH(var, head, field) \
324 for ((var) = LIST_FIRST((head)); \
325 (var); \
326 (var) = LIST_NEXT((var), field))
327
328 #define LIST_INIT(head) do { \
329 LIST_FIRST((head)) = NULL; \
330 } while (0)
331
332 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
333 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
334 LIST_NEXT((listelm), field)->field.le_prev = \
335 &LIST_NEXT((elm), field); \
336 LIST_NEXT((listelm), field) = (elm); \
337 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
338 } while (0)
339
340 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
341 (elm)->field.le_prev = (listelm)->field.le_prev; \
342 LIST_NEXT((elm), field) = (listelm); \
343 *(listelm)->field.le_prev = (elm); \
344 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
345 } while (0)
346
347 #define LIST_INSERT_HEAD(head, elm, field) do { \
348 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
349 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
350 LIST_FIRST((head)) = (elm); \
351 (elm)->field.le_prev = &LIST_FIRST((head)); \
352 } while (0)
353
354 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
355
356 #define LIST_REMOVE(elm, field) do { \
357 if (LIST_NEXT((elm), field) != NULL) \
358 LIST_NEXT((elm), field)->field.le_prev = \
359 (elm)->field.le_prev; \
360 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
361 } while (0)
362
363 /*
364 * Tail queue declarations.
365 */
366 #define TAILQ_HEAD(name, type) \
367 struct name { \
368 struct type *tqh_first; /* first element */ \
369 struct type **tqh_last; /* addr of last next element */ \
370 TRACEBUF \
371 }
372
373 #define TAILQ_HEAD_INITIALIZER(head) \
374 { NULL, &(head).tqh_first }
375
376 #define TAILQ_ENTRY(type) \
377 struct { \
378 struct type *tqe_next; /* next element */ \
379 struct type **tqe_prev; /* address of previous next element */ \
380 TRACEBUF \
381 }
382
383 /*
384 * Tail queue functions.
385 */
386 #define TAILQ_CONCAT(head1, head2, field) do { \
387 if (!TAILQ_EMPTY(head2)) { \
388 *(head1)->tqh_last = (head2)->tqh_first; \
389 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
390 (head1)->tqh_last = (head2)->tqh_last; \
391 TAILQ_INIT((head2)); \
392 QMD_TRACE_HEAD(head); \
393 QMD_TRACE_HEAD(head2); \
394 } \
395 } while (0)
396
397 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
398
399 #define TAILQ_FIRST(head) ((head)->tqh_first)
400
401 #define TAILQ_FOREACH(var, head, field) \
402 for ((var) = TAILQ_FIRST((head)); \
403 (var); \
404 (var) = TAILQ_NEXT((var), field))
405
406 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
407 for ((var) = TAILQ_LAST((head), headname); \
408 (var); \
409 (var) = TAILQ_PREV((var), headname, field))
410
411 #define TAILQ_INIT(head) do { \
412 TAILQ_FIRST((head)) = NULL; \
413 (head)->tqh_last = &TAILQ_FIRST((head)); \
414 QMD_TRACE_HEAD(head); \
415 } while (0)
416
417 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
418 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
419 TAILQ_NEXT((elm), field)->field.tqe_prev = \
420 &TAILQ_NEXT((elm), field); \
421 else { \
422 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
423 QMD_TRACE_HEAD(head); \
424 } \
425 TAILQ_NEXT((listelm), field) = (elm); \
426 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
427 QMD_TRACE_ELEM(&(elm)->field); \
428 QMD_TRACE_ELEM(&listelm->field); \
429 } while (0)
430
431 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
432 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
433 TAILQ_NEXT((elm), field) = (listelm); \
434 *(listelm)->field.tqe_prev = (elm); \
435 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
436 QMD_TRACE_ELEM(&(elm)->field); \
437 QMD_TRACE_ELEM(&listelm->field); \
438 } while (0)
439
440 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
441 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
442 TAILQ_FIRST((head))->field.tqe_prev = \
443 &TAILQ_NEXT((elm), field); \
444 else \
445 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
446 TAILQ_FIRST((head)) = (elm); \
447 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
448 QMD_TRACE_HEAD(head); \
449 QMD_TRACE_ELEM(&(elm)->field); \
450 } while (0)
451
452 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
453 TAILQ_NEXT((elm), field) = NULL; \
454 (elm)->field.tqe_prev = (head)->tqh_last; \
455 *(head)->tqh_last = (elm); \
456 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
457 QMD_TRACE_HEAD(head); \
458 QMD_TRACE_ELEM(&(elm)->field); \
459 } while (0)
460
461 #define TAILQ_LAST(head, headname) \
462 (*(((struct headname *)((head)->tqh_last))->tqh_last))
463
464 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
465
466 #define TAILQ_PREV(elm, headname, field) \
467 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
468
469 #define TAILQ_REMOVE(head, elm, field) do { \
470 if ((TAILQ_NEXT((elm), field)) != NULL) \
471 TAILQ_NEXT((elm), field)->field.tqe_prev = \
472 (elm)->field.tqe_prev; \
473 else { \
474 (head)->tqh_last = (elm)->field.tqe_prev; \
475 QMD_TRACE_HEAD(head); \
476 } \
477 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
478 TRASHIT((elm)->field.tqe_next); \
479 TRASHIT((elm)->field.tqe_prev); \
480 QMD_TRACE_ELEM(&(elm)->field); \
481 } while (0)
482
483
484 /*
485 * Circular queue definitions.
486 */
487 #define CIRCLEQ_HEAD(name, type) \
488 struct name { \
489 struct type *cqh_first; /* first element */ \
490 struct type *cqh_last; /* last element */ \
491 }
492
493 #define CIRCLEQ_ENTRY(type) \
494 struct { \
495 struct type *cqe_next; /* next element */ \
496 struct type *cqe_prev; /* previous element */ \
497 }
498
499 /*
500 * Circular queue functions.
501 */
502 #define CIRCLEQ_INIT(head) { \
503 (head)->cqh_first = (void *)(head); \
504 (head)->cqh_last = (void *)(head); \
505 }
506
507 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \
508 (elm)->field.cqe_next = (listelm)->field.cqe_next; \
509 (elm)->field.cqe_prev = (listelm); \
510 if ((listelm)->field.cqe_next == (void *)(head)) \
511 (head)->cqh_last = (elm); \
512 else \
513 (listelm)->field.cqe_next->field.cqe_prev = (elm); \
514 (listelm)->field.cqe_next = (elm); \
515 }
516
517 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \
518 (elm)->field.cqe_next = (listelm); \
519 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
520 if ((listelm)->field.cqe_prev == (void *)(head)) \
521 (head)->cqh_first = (elm); \
522 else \
523 (listelm)->field.cqe_prev->field.cqe_next = (elm); \
524 (listelm)->field.cqe_prev = (elm); \
525 }
526
527 #define CIRCLEQ_INSERT_HEAD(head, elm, field) { \
528 (elm)->field.cqe_next = (head)->cqh_first; \
529 (elm)->field.cqe_prev = (void *)(head); \
530 if ((head)->cqh_last == (void *)(head)) \
531 (head)->cqh_last = (elm); \
532 else \
533 (head)->cqh_first->field.cqe_prev = (elm); \
534 (head)->cqh_first = (elm); \
535 }
536
537 #define CIRCLEQ_INSERT_TAIL(head, elm, field) { \
538 (elm)->field.cqe_next = (void *)(head); \
539 (elm)->field.cqe_prev = (head)->cqh_last; \
540 if ((head)->cqh_first == (void *)(head)) \
541 (head)->cqh_first = (elm); \
542 else \
543 (head)->cqh_last->field.cqe_next = (elm); \
544 (head)->cqh_last = (elm); \
545 }
546
547 #define CIRCLEQ_REMOVE(head, elm, field) { \
548 if ((elm)->field.cqe_next == (void *)(head)) \
549 (head)->cqh_last = (elm)->field.cqe_prev; \
550 else \
551 (elm)->field.cqe_next->field.cqe_prev = \
552 (elm)->field.cqe_prev; \
553 if ((elm)->field.cqe_prev == (void *)(head)) \
554 (head)->cqh_first = (elm)->field.cqe_next; \
555 else \
556 (elm)->field.cqe_prev->field.cqe_next = \
557 (elm)->field.cqe_next; \
558 }
559
560 #ifdef KERNEL
561
562 /*
563 * XXX insque() and remque() are an old way of handling certain queues.
564 * They bogusly assumes that all queue heads look alike.
565 */
566
567
568 #ifdef __GNUC__
569
570 struct quehead {
571 #if defined(__arm__)
572 struct quehead *qh_link __attribute__((packed));
573 struct quehead *qh_rlink __attribute__((packed));
574 #else /* !defined(__arm__)) */
575 struct quehead *qh_link;
576 struct quehead *qh_rlink;
577 #endif
578 };
579
580 static __inline void
insque(void * a,void * b)581 insque(void *a, void *b)
582 {
583 struct quehead *element = (struct quehead *)a,
584 *head = (struct quehead *)b;
585
586 element->qh_link = head->qh_link;
587 element->qh_rlink = head;
588 head->qh_link = element;
589 element->qh_link->qh_rlink = element;
590 }
591
592 static __inline void
remque(void * a)593 remque(void *a)
594 {
595 struct quehead *element = (struct quehead *)a;
596
597 element->qh_link->qh_rlink = element->qh_rlink;
598 element->qh_rlink->qh_link = element->qh_link;
599 element->qh_rlink = 0;
600 }
601
602 #else /* !__GNUC__ */
603
604 void insque(void *a, void *b);
605 void remque(void *a);
606
607 #endif /* __GNUC__ */
608
609 #endif /* _KERNEL */
610
611 #endif /* !_SYS_QUEUE_H_ */