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- Test m_pkthdr.fw_flags against DUMMYNET_MBUF_TAGGED before trying to locate
[dragonfly/netmp.git] / sys / sys / queue.h
bloba7b3962b827a145b33c88e45cf4315eec4e55c27
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 1.32.2.7 2002/04/17 14:21:02 des Exp $
35 * $DragonFly: src/sys/sys/queue.h,v 1.10 2008/07/23 17:22:33 dillon Exp $
36 */
37
38 #ifndef _SYS_QUEUE_H_
39 #define _SYS_QUEUE_H_
40
41 #ifndef _MACHINE_STDINT_H_
42 #include <machine/stdint.h> /* for __offsetof */
43 #endif
44
45 /*
46 * This file defines five types of data structures: singly-linked lists,
47 * singly-linked tail queues, lists, tail queues, and circular queues.
48 *
49 * A singly-linked list is headed by a single forward pointer. The elements
50 * are singly linked for minimum space and pointer manipulation overhead at
51 * the expense of O(n) removal for arbitrary elements. New elements can be
52 * added to the list after an existing element or at the head of the list.
53 * Elements being removed from the head of the list should use the explicit
54 * macro for this purpose for optimum efficiency. A singly-linked list may
55 * only be traversed in the forward direction. Singly-linked lists are ideal
56 * for applications with large datasets and few or no removals or for
57 * implementing a LIFO queue.
58 *
59 * A singly-linked tail queue is headed by a pair of pointers, one to the
60 * head of the list and the other to the tail of the list. The elements are
61 * singly linked for minimum space and pointer manipulation overhead at the
62 * expense of O(n) removal for arbitrary elements. New elements can be added
63 * to the list after an existing element, at the head of the list, or at the
64 * end of the list. Elements being removed from the head of the tail queue
65 * should use the explicit macro for this purpose for optimum efficiency.
66 * A singly-linked tail queue may only be traversed in the forward direction.
67 * Singly-linked tail queues are ideal for applications with large datasets
68 * and few or no removals or for implementing a FIFO queue.
69 *
70 * A list is headed by a single forward pointer (or an array of forward
71 * pointers for a hash table header). The elements are doubly linked
72 * so that an arbitrary element can be removed without a need to
73 * traverse the list. New elements can be added to the list before
74 * or after an existing element or at the head of the list. A list
75 * may only be traversed in the forward direction.
76 *
77 * A tail queue is headed by a pair of pointers, one to the head of the
78 * list and the other to the tail of the list. The elements are doubly
79 * linked so that an arbitrary element can be removed without a need to
80 * traverse the list. New elements can be added to the list before or
81 * after an existing element, at the head of the list, or at the end of
82 * the list. A tail queue may be traversed in either direction.
83 *
84 * A circle queue is headed by a pair of pointers, one to the head of the
85 * list and the other to the tail of the list. The elements are doubly
86 * linked so that an arbitrary element can be removed without a need to
87 * traverse the list. New elements can be added to the list before or after
88 * an existing element, at the head of the list, or at the end of the list.
89 * A circle queue may be traversed in either direction, but has a more
90 * complex end of list detection.
91 *
92 * For details on the use of these macros, see the queue(3) manual page.
93 *
94 *
95 * SLIST LIST STAILQ TAILQ CIRCLEQ
96 * _HEAD + + + + +
97 * _HEAD_INITIALIZER + + + + +
98 * _ENTRY + + + + +
99 * _INIT + + + + +
100 * _EMPTY + + + + +
101 * _FIRST + + + + +
102 * _NEXT + + + + +
103 * _PREV - - - + +
104 * _LAST - - + + +
105 * _FOREACH + + + + +
106 * _FOREACH_MUTABLE - + - + -
107 * _FOREACH_REVERSE - - - + +
108 * _INSERT_HEAD + + + + +
109 * _INSERT_BEFORE - + - + +
110 * _INSERT_AFTER + + + + +
111 * _INSERT_TAIL - - + + +
112 * _CONCAT - - + + -
113 * _REMOVE_HEAD + - + - -
114 * _REMOVE + + + + +
115 *
116 */
117
118 /*
119 * Singly-linked List declarations.
120 */
121 #define SLIST_HEAD(name, type) \
122 struct name { \
123 struct type *slh_first; /* first element */ \
124 }
125
126 #define SLIST_HEAD_INITIALIZER(head) \
127 { NULL }
128
129 #define SLIST_ENTRY(type) \
130 struct { \
131 struct type *sle_next; /* next element */ \
132 }
133
134 #define SLIST_ENTRY_INITIALIZER { NULL }
135
136 /*
137 * Singly-linked List functions.
138 */
139 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
140
141 #define SLIST_FIRST(head) ((head)->slh_first)
142
143 #define SLIST_FOREACH(var, head, field) \
144 for ((var) = SLIST_FIRST((head)); \
145 (var); \
146 (var) = SLIST_NEXT((var), field))
147
148 #define SLIST_INIT(head) do { \
149 SLIST_FIRST((head)) = NULL; \
150 } while (0)
151
152 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
153 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
154 SLIST_NEXT((slistelm), field) = (elm); \
155 } while (0)
156
157 #define SLIST_INSERT_HEAD(head, elm, field) do { \
158 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
159 SLIST_FIRST((head)) = (elm); \
160 } while (0)
161
162 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
163
164 #define SLIST_REMOVE(head, elm, type, field) do { \
165 if (SLIST_FIRST((head)) == (elm)) { \
166 SLIST_REMOVE_HEAD((head), field); \
167 } \
168 else { \
169 struct type *curelm = SLIST_FIRST((head)); \
170 while (SLIST_NEXT(curelm, field) != (elm)) \
171 curelm = SLIST_NEXT(curelm, field); \
172 SLIST_NEXT(curelm, field) = \
173 SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
174 } \
175 } while (0)
176
177 #define SLIST_REMOVE_HEAD(head, field) do { \
178 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
179 } while (0)
180
181 /*
182 * Singly-linked Tail queue declarations.
183 */
184 #define STAILQ_HEAD(name, type) \
185 struct name { \
186 struct type *stqh_first;/* first element */ \
187 struct type **stqh_last;/* addr of last next element */ \
188 }
189
190 #define STAILQ_HEAD_INITIALIZER(head) \
191 { NULL, &(head).stqh_first }
192
193 #define STAILQ_ENTRY(type) \
194 struct { \
195 struct type *stqe_next; /* next element */ \
196 }
197
198 /*
199 * Singly-linked Tail queue functions.
200 */
201 #define STAILQ_CONCAT(head1, head2) do { \
202 if (!STAILQ_EMPTY((head2))) { \
203 *(head1)->stqh_last = (head2)->stqh_first; \
204 (head1)->stqh_last = (head2)->stqh_last; \
205 STAILQ_INIT((head2)); \
206 } \
207 } while (0)
208
209 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
210
211 #define STAILQ_FIRST(head) ((head)->stqh_first)
212
213 #define STAILQ_FOREACH(var, head, field) \
214 for((var) = STAILQ_FIRST((head)); \
215 (var); \
216 (var) = STAILQ_NEXT((var), field))
217
218 #define STAILQ_INIT(head) do { \
219 STAILQ_FIRST((head)) = NULL; \
220 (head)->stqh_last = &STAILQ_FIRST((head)); \
221 } while (0)
222
223 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
224 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
225 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
226 STAILQ_NEXT((tqelm), field) = (elm); \
227 } while (0)
228
229 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
230 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
231 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
232 STAILQ_FIRST((head)) = (elm); \
233 } while (0)
234
235 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
236 STAILQ_NEXT((elm), field) = NULL; \
237 *(head)->stqh_last = (elm); \
238 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
239 } while (0)
240
241 #define STAILQ_LAST(head, type, field) \
242 (STAILQ_EMPTY(head) ? \
243 NULL : \
244 ((struct type *) \
245 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
246
247 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
248
249 #define STAILQ_REMOVE(head, elm, type, field) do { \
250 if (STAILQ_FIRST((head)) == (elm)) { \
251 STAILQ_REMOVE_HEAD(head, field); \
252 } \
253 else { \
254 struct type *curelm = STAILQ_FIRST((head)); \
255 while (STAILQ_NEXT(curelm, field) != (elm)) \
256 curelm = STAILQ_NEXT(curelm, field); \
257 if ((STAILQ_NEXT(curelm, field) = \
258 STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
259 (head)->stqh_last = &STAILQ_NEXT((curelm), field);\
260 } \
261 } while (0)
262
263 #define STAILQ_REMOVE_HEAD(head, field) do { \
264 if ((STAILQ_FIRST((head)) = \
265 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
266 (head)->stqh_last = &STAILQ_FIRST((head)); \
267 } while (0)
268
269 #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
270 if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
271 (head)->stqh_last = &STAILQ_FIRST((head)); \
272 } while (0)
273
274 /*
275 * List declarations.
276 */
277 #define LIST_HEAD(name, type) \
278 struct name { \
279 struct type *lh_first; /* first element */ \
280 }
281
282 #define LIST_HEAD_INITIALIZER(head) \
283 { NULL }
284
285 #define LIST_ENTRY(type) \
286 struct { \
287 struct type *le_next; /* next element */ \
288 struct type **le_prev; /* address of previous next element */ \
289 }
290
291 /*
292 * List functions.
293 */
294
295 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
296
297 #define LIST_FIRST(head) ((head)->lh_first)
298
299 #define LIST_FOREACH(var, head, field) \
300 for ((var) = LIST_FIRST((head)); \
301 (var); \
302 (var) = LIST_NEXT((var), field))
303
304 #define LIST_FOREACH_MUTABLE(var, head, field, nvar) \
305 for ((var) = LIST_FIRST((head)); \
306 (var) && ((nvar) = LIST_NEXT((var), field), 1); \
307 (var) = (nvar))
308
309 #define LIST_INIT(head) do { \
310 LIST_FIRST((head)) = NULL; \
311 } while (0)
312
313 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
314 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
315 LIST_NEXT((listelm), field)->field.le_prev = \
316 &LIST_NEXT((elm), field); \
317 LIST_NEXT((listelm), field) = (elm); \
318 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
319 } while (0)
320
321 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
322 (elm)->field.le_prev = (listelm)->field.le_prev; \
323 LIST_NEXT((elm), field) = (listelm); \
324 *(listelm)->field.le_prev = (elm); \
325 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
326 } while (0)
327
328 #define LIST_INSERT_HEAD(head, elm, field) do { \
329 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
330 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
331 LIST_FIRST((head)) = (elm); \
332 (elm)->field.le_prev = &LIST_FIRST((head)); \
333 } while (0)
334
335 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
336
337 #define LIST_REMOVE(elm, field) do { \
338 if (LIST_NEXT((elm), field) != NULL) \
339 LIST_NEXT((elm), field)->field.le_prev = \
340 (elm)->field.le_prev; \
341 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
342 } while (0)
343
344 /*
345 * Tail queue declarations.
346 */
347 #define TAILQ_HEAD(name, type) \
348 struct name { \
349 struct type *tqh_first; /* first element */ \
350 struct type **tqh_last; /* addr of last next element */ \
351 }
352
353 #define TAILQ_HEAD_INITIALIZER(head) \
354 { NULL, &(head).tqh_first }
355
356 #define TAILQ_ENTRY(type) \
357 struct { \
358 struct type *tqe_next; /* next element */ \
359 struct type **tqe_prev; /* address of previous next element */ \
360 }
361
362 /*
363 * Tail queue functions.
364 */
365 #define TAILQ_CONCAT(head1, head2, field) do { \
366 if (!TAILQ_EMPTY(head2)) { \
367 *(head1)->tqh_last = (head2)->tqh_first; \
368 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
369 (head1)->tqh_last = (head2)->tqh_last; \
370 TAILQ_INIT((head2)); \
371 } \
372 } while (0)
373
374 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
375
376 #define TAILQ_FIRST(head) ((head)->tqh_first)
377
378 #define TAILQ_FOREACH(var, head, field) \
379 for ((var) = TAILQ_FIRST((head)); \
380 (var); \
381 (var) = TAILQ_NEXT((var), field))
382
383 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
384 for ((var) = TAILQ_FIRST((head)); \
385 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
386 (var) = (tvar))
387
388
389 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
390 for ((var) = TAILQ_LAST((head), headname); \
391 (var); \
392 (var) = TAILQ_PREV((var), headname, field))
393
394 #define TAILQ_FOREACH_MUTABLE(var, head, field, nvar) \
395 for ((var) = TAILQ_FIRST((head)); \
396 (var) && ((nvar) = TAILQ_NEXT((var), field), (var)); \
397 (var) = (nvar))
398
399 #define TAILQ_INIT(head) do { \
400 TAILQ_FIRST((head)) = NULL; \
401 (head)->tqh_last = &TAILQ_FIRST((head)); \
402 } while (0)
403
404 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
405 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
406 TAILQ_NEXT((elm), field)->field.tqe_prev = \
407 &TAILQ_NEXT((elm), field); \
408 else \
409 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
410 TAILQ_NEXT((listelm), field) = (elm); \
411 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
412 } while (0)
413
414 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
415 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
416 TAILQ_NEXT((elm), field) = (listelm); \
417 *(listelm)->field.tqe_prev = (elm); \
418 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
419 } while (0)
420
421 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
422 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
423 TAILQ_FIRST((head))->field.tqe_prev = \
424 &TAILQ_NEXT((elm), field); \
425 else \
426 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
427 TAILQ_FIRST((head)) = (elm); \
428 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
429 } while (0)
430
431 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
432 TAILQ_NEXT((elm), field) = NULL; \
433 (elm)->field.tqe_prev = (head)->tqh_last; \
434 *(head)->tqh_last = (elm); \
435 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
436 } while (0)
437
438 #define TAILQ_LAST(head, headname) \
439 (*(((struct headname *)((head)->tqh_last))->tqh_last))
440
441 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
442
443 #define TAILQ_PREV(elm, headname, field) \
444 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
445
446 #define TAILQ_REMOVE(head, elm, field) do { \
447 if ((TAILQ_NEXT((elm), field)) != NULL) \
448 TAILQ_NEXT((elm), field)->field.tqe_prev = \
449 (elm)->field.tqe_prev; \
450 else \
451 (head)->tqh_last = (elm)->field.tqe_prev; \
452 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
453 } while (0)
454
455 /*
456 * Circular queue declarations.
457 */
458 #define CIRCLEQ_HEAD(name, type) \
459 struct name { \
460 struct type *cqh_first; /* first element */ \
461 struct type *cqh_last; /* last element */ \
462 }
463
464 #define CIRCLEQ_HEAD_INITIALIZER(head) \
465 { (void *)&(head), (void *)&(head) }
466
467 #define CIRCLEQ_ENTRY(type) \
468 struct { \
469 struct type *cqe_next; /* next element */ \
470 struct type *cqe_prev; /* previous element */ \
471 }
472
473 /*
474 * Circular queue functions.
475 */
476 #define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
477
478 #define CIRCLEQ_FIRST(head) ((head)->cqh_first)
479
480 #define CIRCLEQ_FOREACH(var, head, field) \
481 for ((var) = CIRCLEQ_FIRST((head)); \
482 (var) != (void *)(head) || ((var) = NULL); \
483 (var) = CIRCLEQ_NEXT((var), field))
484
485 #define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
486 for ((var) = CIRCLEQ_LAST((head)); \
487 (var) != (void *)(head) || ((var) = NULL); \
488 (var) = CIRCLEQ_PREV((var), field))
489
490 #define CIRCLEQ_INIT(head) do { \
491 CIRCLEQ_FIRST((head)) = (void *)(head); \
492 CIRCLEQ_LAST((head)) = (void *)(head); \
493 } while (0)
494
495 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
496 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field); \
497 CIRCLEQ_PREV((elm), field) = (listelm); \
498 if (CIRCLEQ_NEXT((listelm), field) == (void *)(head)) \
499 CIRCLEQ_LAST((head)) = (elm); \
500 else \
501 CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\
502 CIRCLEQ_NEXT((listelm), field) = (elm); \
503 } while (0)
504
505 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
506 CIRCLEQ_NEXT((elm), field) = (listelm); \
507 CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field); \
508 if (CIRCLEQ_PREV((listelm), field) == (void *)(head)) \
509 CIRCLEQ_FIRST((head)) = (elm); \
510 else \
511 CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\
512 CIRCLEQ_PREV((listelm), field) = (elm); \
513 } while (0)
514
515 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
516 CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head)); \
517 CIRCLEQ_PREV((elm), field) = (void *)(head); \
518 if (CIRCLEQ_LAST((head)) == (void *)(head)) \
519 CIRCLEQ_LAST((head)) = (elm); \
520 else \
521 CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm); \
522 CIRCLEQ_FIRST((head)) = (elm); \
523 } while (0)
524
525 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
526 CIRCLEQ_NEXT((elm), field) = (void *)(head); \
527 CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head)); \
528 if (CIRCLEQ_FIRST((head)) == (void *)(head)) \
529 CIRCLEQ_FIRST((head)) = (elm); \
530 else \
531 CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm); \
532 CIRCLEQ_LAST((head)) = (elm); \
533 } while (0)
534
535 #define CIRCLEQ_LAST(head) ((head)->cqh_last)
536
537 #define CIRCLEQ_NEXT(elm,field) ((elm)->field.cqe_next)
538
539 #define CIRCLEQ_PREV(elm,field) ((elm)->field.cqe_prev)
540
541 #define CIRCLEQ_REMOVE(head, elm, field) do { \
542 if (CIRCLEQ_NEXT((elm), field) == (void *)(head)) \
543 CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field); \
544 else \
545 CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) = \
546 CIRCLEQ_PREV((elm), field); \
547 if (CIRCLEQ_PREV((elm), field) == (void *)(head)) \
548 CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field); \
549 else \
550 CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) = \
551 CIRCLEQ_NEXT((elm), field); \
552 } while (0)
553
554 #ifdef _KERNEL
555
556 /*
557 * XXX insque() and remque() are an old way of handling certain queues.
558 * They bogusly assumes that all queue heads look alike.
559 */
560
561 struct quehead {
562 struct quehead *qh_link;
563 struct quehead *qh_rlink;
564 };
565
566 #ifdef __GNUC__
567
568 static __inline void
569 insque(void *a, void *b)
570 {
571 struct quehead *element = (struct quehead *)a,
572 *head = (struct quehead *)b;
573
574 element->qh_link = head->qh_link;
575 element->qh_rlink = head;
576 head->qh_link = element;
577 element->qh_link->qh_rlink = element;
578 }
579
580 static __inline void
581 remque(void *a)
582 {
583 struct quehead *element = (struct quehead *)a;
584
585 element->qh_link->qh_rlink = element->qh_rlink;
586 element->qh_rlink->qh_link = element->qh_link;
587 element->qh_rlink = 0;
588 }
589
590 #else /* !__GNUC__ */
591
592 void insque (void *a, void *b);
593 void remque (void *a);
594
595 #endif /* __GNUC__ */
596
597 #endif /* _KERNEL */
598
599 #endif /* !_SYS_QUEUE_H_ */
MP support for (parts of) the network stack