FreeBSD/Linux Kernel Cross Reference
sys/sys/queue.h
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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)queue.h 8.5 (Berkeley) 8/20/94
30 * $FreeBSD: head/sys/sys/queue.h 246387 2013-02-06 07:27:25Z glebius $
31 */
32
33 #ifndef _SYS_QUEUE_H_
34 #define _SYS_QUEUE_H_
35
36 #include <sys/cdefs.h>
37
38 /*
39 * This file defines four types of data structures: singly-linked lists,
40 * singly-linked tail queues, lists and tail queues.
41 *
42 * A singly-linked list is headed by a single forward pointer. The elements
43 * are singly linked for minimum space and pointer manipulation overhead at
44 * the expense of O(n) removal for arbitrary elements. New elements can be
45 * added to the list after an existing element or at the head of the list.
46 * Elements being removed from the head of the list should use the explicit
47 * macro for this purpose for optimum efficiency. A singly-linked list may
48 * only be traversed in the forward direction. Singly-linked lists are ideal
49 * for applications with large datasets and few or no removals or for
50 * implementing a LIFO queue.
51 *
52 * A singly-linked tail queue is headed by a pair of pointers, one to the
53 * head of the list and the other to the tail of the list. The elements are
54 * singly linked for minimum space and pointer manipulation overhead at the
55 * expense of O(n) removal for arbitrary elements. New elements can be added
56 * to the list after an existing element, at the head of the list, or at the
57 * end of the list. Elements being removed from the head of the tail queue
58 * should use the explicit macro for this purpose for optimum efficiency.
59 * A singly-linked tail queue may only be traversed in the forward direction.
60 * Singly-linked tail queues are ideal for applications with large datasets
61 * and few or no removals or for implementing a FIFO queue.
62 *
63 * A list is headed by a single forward pointer (or an array of forward
64 * pointers for a hash table header). The elements are doubly linked
65 * so that an arbitrary element can be removed without a need to
66 * traverse the list. New elements can be added to the list before
67 * or after an existing element or at the head of the list. A list
68 * may be traversed in either direction.
69 *
70 * A tail queue is headed by a pair of pointers, one to the head of the
71 * list and the other to the tail of the list. The elements are doubly
72 * linked 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 or
74 * after an existing element, at the head of the list, or at the end of
75 * the list. A tail queue may be traversed in either direction.
76 *
77 * For details on the use of these macros, see the queue(3) manual page.
78 *
79 *
80 * SLIST LIST STAILQ TAILQ
81 * _HEAD + + + +
82 * _HEAD_INITIALIZER + + + +
83 * _ENTRY + + + +
84 * _INIT + + + +
85 * _EMPTY + + + +
86 * _FIRST + + + +
87 * _NEXT + + + +
88 * _PREV - + - +
89 * _LAST - - + +
90 * _FOREACH + + + +
91 * _FOREACH_SAFE + + + +
92 * _FOREACH_REVERSE - - - +
93 * _FOREACH_REVERSE_SAFE - - - +
94 * _INSERT_HEAD + + + +
95 * _INSERT_BEFORE - + - +
96 * _INSERT_AFTER + + + +
97 * _INSERT_TAIL - - + +
98 * _CONCAT - - + +
99 * _REMOVE_AFTER + - + -
100 * _REMOVE_HEAD + - + -
101 * _REMOVE + + + +
102 * _SWAP + + + +
103 *
104 */
105 #ifdef QUEUE_MACRO_DEBUG
106 /* Store the last 2 places the queue element or head was altered */
107 struct qm_trace {
108 unsigned long lastline;
109 unsigned long prevline;
110 const char *lastfile;
111 const char *prevfile;
112 };
113
114 #define TRACEBUF struct qm_trace trace;
115 #define TRACEBUF_INITIALIZER { __FILE__, __LINE__, NULL, 0 } ,
116 #define TRASHIT(x) do {(x) = (void *)-1;} while (0)
117 #define QMD_SAVELINK(name, link) void **name = (void *)&(link)
118
119 #define QMD_TRACE_HEAD(head) do { \
120 (head)->trace.prevline = (head)->trace.lastline; \
121 (head)->trace.prevfile = (head)->trace.lastfile; \
122 (head)->trace.lastline = __LINE__; \
123 (head)->trace.lastfile = __FILE__; \
124 } while (0)
125
126 #define QMD_TRACE_ELEM(elem) do { \
127 (elem)->trace.prevline = (elem)->trace.lastline; \
128 (elem)->trace.prevfile = (elem)->trace.lastfile; \
129 (elem)->trace.lastline = __LINE__; \
130 (elem)->trace.lastfile = __FILE__; \
131 } while (0)
132
133 #else
134 #define QMD_TRACE_ELEM(elem)
135 #define QMD_TRACE_HEAD(head)
136 #define QMD_SAVELINK(name, link)
137 #define TRACEBUF
138 #define TRACEBUF_INITIALIZER
139 #define TRASHIT(x)
140 #endif /* QUEUE_MACRO_DEBUG */
141
142 /*
143 * Singly-linked List declarations.
144 */
145 #define SLIST_HEAD(name, type) \
146 struct name { \
147 struct type *slh_first; /* first element */ \
148 }
149
150 #define SLIST_HEAD_INITIALIZER(head) \
151 { NULL }
152
153 #define SLIST_ENTRY(type) \
154 struct { \
155 struct type *sle_next; /* next element */ \
156 }
157
158 /*
159 * Singly-linked List functions.
160 */
161 #define SLIST_EMPTY(head) ((head)->slh_first == NULL)
162
163 #define SLIST_FIRST(head) ((head)->slh_first)
164
165 #define SLIST_FOREACH(var, head, field) \
166 for ((var) = SLIST_FIRST((head)); \
167 (var); \
168 (var) = SLIST_NEXT((var), field))
169
170 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \
171 for ((var) = SLIST_FIRST((head)); \
172 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \
173 (var) = (tvar))
174
175 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
176 for ((varp) = &SLIST_FIRST((head)); \
177 ((var) = *(varp)) != NULL; \
178 (varp) = &SLIST_NEXT((var), field))
179
180 #define SLIST_INIT(head) do { \
181 SLIST_FIRST((head)) = NULL; \
182 } while (0)
183
184 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
185 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
186 SLIST_NEXT((slistelm), field) = (elm); \
187 } while (0)
188
189 #define SLIST_INSERT_HEAD(head, elm, field) do { \
190 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
191 SLIST_FIRST((head)) = (elm); \
192 } while (0)
193
194 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
195
196 #define SLIST_REMOVE(head, elm, type, field) do { \
197 QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
198 if (SLIST_FIRST((head)) == (elm)) { \
199 SLIST_REMOVE_HEAD((head), field); \
200 } \
201 else { \
202 struct type *curelm = SLIST_FIRST((head)); \
203 while (SLIST_NEXT(curelm, field) != (elm)) \
204 curelm = SLIST_NEXT(curelm, field); \
205 SLIST_REMOVE_AFTER(curelm, field); \
206 } \
207 TRASHIT(*oldnext); \
208 } while (0)
209
210 #define SLIST_REMOVE_AFTER(elm, field) do { \
211 SLIST_NEXT(elm, field) = \
212 SLIST_NEXT(SLIST_NEXT(elm, field), field); \
213 } while (0)
214
215 #define SLIST_REMOVE_HEAD(head, field) do { \
216 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
217 } while (0)
218
219 #define SLIST_SWAP(head1, head2, type) do { \
220 struct type *swap_first = SLIST_FIRST(head1); \
221 SLIST_FIRST(head1) = SLIST_FIRST(head2); \
222 SLIST_FIRST(head2) = swap_first; \
223 } while (0)
224
225 /*
226 * Singly-linked Tail queue declarations.
227 */
228 #define STAILQ_HEAD(name, type) \
229 struct name { \
230 struct type *stqh_first;/* first element */ \
231 struct type **stqh_last;/* addr of last next element */ \
232 }
233
234 #define STAILQ_HEAD_INITIALIZER(head) \
235 { NULL, &(head).stqh_first }
236
237 #define STAILQ_ENTRY(type) \
238 struct { \
239 struct type *stqe_next; /* next element */ \
240 }
241
242 /*
243 * Singly-linked Tail queue functions.
244 */
245 #define STAILQ_CONCAT(head1, head2) do { \
246 if (!STAILQ_EMPTY((head2))) { \
247 *(head1)->stqh_last = (head2)->stqh_first; \
248 (head1)->stqh_last = (head2)->stqh_last; \
249 STAILQ_INIT((head2)); \
250 } \
251 } while (0)
252
253 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
254
255 #define STAILQ_FIRST(head) ((head)->stqh_first)
256
257 #define STAILQ_FOREACH(var, head, field) \
258 for((var) = STAILQ_FIRST((head)); \
259 (var); \
260 (var) = STAILQ_NEXT((var), field))
261
262
263 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
264 for ((var) = STAILQ_FIRST((head)); \
265 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
266 (var) = (tvar))
267
268 #define STAILQ_INIT(head) do { \
269 STAILQ_FIRST((head)) = NULL; \
270 (head)->stqh_last = &STAILQ_FIRST((head)); \
271 } while (0)
272
273 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
274 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
275 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
276 STAILQ_NEXT((tqelm), field) = (elm); \
277 } while (0)
278
279 #define STAILQ_INSERT_HEAD(head, elm, field) do { \
280 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
281 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
282 STAILQ_FIRST((head)) = (elm); \
283 } while (0)
284
285 #define STAILQ_INSERT_TAIL(head, elm, field) do { \
286 STAILQ_NEXT((elm), field) = NULL; \
287 *(head)->stqh_last = (elm); \
288 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
289 } while (0)
290
291 #define STAILQ_LAST(head, type, field) \
292 (STAILQ_EMPTY((head)) ? NULL : \
293 __containerof((head)->stqh_last, struct type, field.stqe_next))
294
295 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
296
297 #define STAILQ_REMOVE(head, elm, type, field) do { \
298 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
299 if (STAILQ_FIRST((head)) == (elm)) { \
300 STAILQ_REMOVE_HEAD((head), field); \
301 } \
302 else { \
303 struct type *curelm = STAILQ_FIRST((head)); \
304 while (STAILQ_NEXT(curelm, field) != (elm)) \
305 curelm = STAILQ_NEXT(curelm, field); \
306 STAILQ_REMOVE_AFTER(head, curelm, field); \
307 } \
308 TRASHIT(*oldnext); \
309 } while (0)
310
311 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \
312 if ((STAILQ_NEXT(elm, field) = \
313 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
314 (head)->stqh_last = &STAILQ_NEXT((elm), field); \
315 } while (0)
316
317 #define STAILQ_REMOVE_HEAD(head, field) do { \
318 if ((STAILQ_FIRST((head)) = \
319 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
320 (head)->stqh_last = &STAILQ_FIRST((head)); \
321 } while (0)
322
323 #define STAILQ_SWAP(head1, head2, type) do { \
324 struct type *swap_first = STAILQ_FIRST(head1); \
325 struct type **swap_last = (head1)->stqh_last; \
326 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
327 (head1)->stqh_last = (head2)->stqh_last; \
328 STAILQ_FIRST(head2) = swap_first; \
329 (head2)->stqh_last = swap_last; \
330 if (STAILQ_EMPTY(head1)) \
331 (head1)->stqh_last = &STAILQ_FIRST(head1); \
332 if (STAILQ_EMPTY(head2)) \
333 (head2)->stqh_last = &STAILQ_FIRST(head2); \
334 } while (0)
335
336
337 /*
338 * List declarations.
339 */
340 #define LIST_HEAD(name, type) \
341 struct name { \
342 struct type *lh_first; /* first element */ \
343 }
344
345 #define LIST_HEAD_INITIALIZER(head) \
346 { NULL }
347
348 #define LIST_ENTRY(type) \
349 struct { \
350 struct type *le_next; /* next element */ \
351 struct type **le_prev; /* address of previous next element */ \
352 }
353
354 /*
355 * List functions.
356 */
357
358 #if (defined(_KERNEL) && defined(INVARIANTS))
359 #define QMD_LIST_CHECK_HEAD(head, field) do { \
360 if (LIST_FIRST((head)) != NULL && \
361 LIST_FIRST((head))->field.le_prev != \
362 &LIST_FIRST((head))) \
363 panic("Bad list head %p first->prev != head", (head)); \
364 } while (0)
365
366 #define QMD_LIST_CHECK_NEXT(elm, field) do { \
367 if (LIST_NEXT((elm), field) != NULL && \
368 LIST_NEXT((elm), field)->field.le_prev != \
369 &((elm)->field.le_next)) \
370 panic("Bad link elm %p next->prev != elm", (elm)); \
371 } while (0)
372
373 #define QMD_LIST_CHECK_PREV(elm, field) do { \
374 if (*(elm)->field.le_prev != (elm)) \
375 panic("Bad link elm %p prev->next != elm", (elm)); \
376 } while (0)
377 #else
378 #define QMD_LIST_CHECK_HEAD(head, field)
379 #define QMD_LIST_CHECK_NEXT(elm, field)
380 #define QMD_LIST_CHECK_PREV(elm, field)
381 #endif /* (_KERNEL && INVARIANTS) */
382
383 #define LIST_EMPTY(head) ((head)->lh_first == NULL)
384
385 #define LIST_FIRST(head) ((head)->lh_first)
386
387 #define LIST_FOREACH(var, head, field) \
388 for ((var) = LIST_FIRST((head)); \
389 (var); \
390 (var) = LIST_NEXT((var), field))
391
392 #define LIST_FOREACH_SAFE(var, head, field, tvar) \
393 for ((var) = LIST_FIRST((head)); \
394 (var) && ((tvar) = LIST_NEXT((var), field), 1); \
395 (var) = (tvar))
396
397 #define LIST_INIT(head) do { \
398 LIST_FIRST((head)) = NULL; \
399 } while (0)
400
401 #define LIST_INSERT_AFTER(listelm, elm, field) do { \
402 QMD_LIST_CHECK_NEXT(listelm, field); \
403 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
404 LIST_NEXT((listelm), field)->field.le_prev = \
405 &LIST_NEXT((elm), field); \
406 LIST_NEXT((listelm), field) = (elm); \
407 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \
408 } while (0)
409
410 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \
411 QMD_LIST_CHECK_PREV(listelm, field); \
412 (elm)->field.le_prev = (listelm)->field.le_prev; \
413 LIST_NEXT((elm), field) = (listelm); \
414 *(listelm)->field.le_prev = (elm); \
415 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \
416 } while (0)
417
418 #define LIST_INSERT_HEAD(head, elm, field) do { \
419 QMD_LIST_CHECK_HEAD((head), field); \
420 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
421 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
422 LIST_FIRST((head)) = (elm); \
423 (elm)->field.le_prev = &LIST_FIRST((head)); \
424 } while (0)
425
426 #define LIST_NEXT(elm, field) ((elm)->field.le_next)
427
428 #define LIST_PREV(elm, head, type, field) \
429 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
430 __containerof((elm)->field.le_prev, struct type, field.le_next))
431
432 #define LIST_REMOVE(elm, field) do { \
433 QMD_SAVELINK(oldnext, (elm)->field.le_next); \
434 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
435 QMD_LIST_CHECK_NEXT(elm, field); \
436 QMD_LIST_CHECK_PREV(elm, field); \
437 if (LIST_NEXT((elm), field) != NULL) \
438 LIST_NEXT((elm), field)->field.le_prev = \
439 (elm)->field.le_prev; \
440 *(elm)->field.le_prev = LIST_NEXT((elm), field); \
441 TRASHIT(*oldnext); \
442 TRASHIT(*oldprev); \
443 } while (0)
444
445 #define LIST_SWAP(head1, head2, type, field) do { \
446 struct type *swap_tmp = LIST_FIRST((head1)); \
447 LIST_FIRST((head1)) = LIST_FIRST((head2)); \
448 LIST_FIRST((head2)) = swap_tmp; \
449 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
450 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
451 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
452 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
453 } while (0)
454
455 /*
456 * Tail queue declarations.
457 */
458 #define TAILQ_HEAD(name, type) \
459 struct name { \
460 struct type *tqh_first; /* first element */ \
461 struct type **tqh_last; /* addr of last next element */ \
462 TRACEBUF \
463 }
464
465 #define TAILQ_HEAD_INITIALIZER(head) \
466 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
467
468 #define TAILQ_ENTRY(type) \
469 struct { \
470 struct type *tqe_next; /* next element */ \
471 struct type **tqe_prev; /* address of previous next element */ \
472 TRACEBUF \
473 }
474
475 /*
476 * Tail queue functions.
477 */
478 #if (defined(_KERNEL) && defined(INVARIANTS))
479 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \
480 if (!TAILQ_EMPTY(head) && \
481 TAILQ_FIRST((head))->field.tqe_prev != \
482 &TAILQ_FIRST((head))) \
483 panic("Bad tailq head %p first->prev != head", (head)); \
484 } while (0)
485
486 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \
487 if (*(head)->tqh_last != NULL) \
488 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \
489 } while (0)
490
491 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
492 if (TAILQ_NEXT((elm), field) != NULL && \
493 TAILQ_NEXT((elm), field)->field.tqe_prev != \
494 &((elm)->field.tqe_next)) \
495 panic("Bad link elm %p next->prev != elm", (elm)); \
496 } while (0)
497
498 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \
499 if (*(elm)->field.tqe_prev != (elm)) \
500 panic("Bad link elm %p prev->next != elm", (elm)); \
501 } while (0)
502 #else
503 #define QMD_TAILQ_CHECK_HEAD(head, field)
504 #define QMD_TAILQ_CHECK_TAIL(head, headname)
505 #define QMD_TAILQ_CHECK_NEXT(elm, field)
506 #define QMD_TAILQ_CHECK_PREV(elm, field)
507 #endif /* (_KERNEL && INVARIANTS) */
508
509 #define TAILQ_CONCAT(head1, head2, field) do { \
510 if (!TAILQ_EMPTY(head2)) { \
511 *(head1)->tqh_last = (head2)->tqh_first; \
512 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
513 (head1)->tqh_last = (head2)->tqh_last; \
514 TAILQ_INIT((head2)); \
515 QMD_TRACE_HEAD(head1); \
516 QMD_TRACE_HEAD(head2); \
517 } \
518 } while (0)
519
520 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
521
522 #define TAILQ_FIRST(head) ((head)->tqh_first)
523
524 #define TAILQ_FOREACH(var, head, field) \
525 for ((var) = TAILQ_FIRST((head)); \
526 (var); \
527 (var) = TAILQ_NEXT((var), field))
528
529 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
530 for ((var) = TAILQ_FIRST((head)); \
531 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
532 (var) = (tvar))
533
534 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
535 for ((var) = TAILQ_LAST((head), headname); \
536 (var); \
537 (var) = TAILQ_PREV((var), headname, field))
538
539 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
540 for ((var) = TAILQ_LAST((head), headname); \
541 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
542 (var) = (tvar))
543
544 #define TAILQ_INIT(head) do { \
545 TAILQ_FIRST((head)) = NULL; \
546 (head)->tqh_last = &TAILQ_FIRST((head)); \
547 QMD_TRACE_HEAD(head); \
548 } while (0)
549
550 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
551 QMD_TAILQ_CHECK_NEXT(listelm, field); \
552 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
553 TAILQ_NEXT((elm), field)->field.tqe_prev = \
554 &TAILQ_NEXT((elm), field); \
555 else { \
556 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
557 QMD_TRACE_HEAD(head); \
558 } \
559 TAILQ_NEXT((listelm), field) = (elm); \
560 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
561 QMD_TRACE_ELEM(&(elm)->field); \
562 QMD_TRACE_ELEM(&listelm->field); \
563 } while (0)
564
565 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
566 QMD_TAILQ_CHECK_PREV(listelm, field); \
567 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
568 TAILQ_NEXT((elm), field) = (listelm); \
569 *(listelm)->field.tqe_prev = (elm); \
570 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
571 QMD_TRACE_ELEM(&(elm)->field); \
572 QMD_TRACE_ELEM(&listelm->field); \
573 } while (0)
574
575 #define TAILQ_INSERT_HEAD(head, elm, field) do { \
576 QMD_TAILQ_CHECK_HEAD(head, field); \
577 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
578 TAILQ_FIRST((head))->field.tqe_prev = \
579 &TAILQ_NEXT((elm), field); \
580 else \
581 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
582 TAILQ_FIRST((head)) = (elm); \
583 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
584 QMD_TRACE_HEAD(head); \
585 QMD_TRACE_ELEM(&(elm)->field); \
586 } while (0)
587
588 #define TAILQ_INSERT_TAIL(head, elm, field) do { \
589 QMD_TAILQ_CHECK_TAIL(head, field); \
590 TAILQ_NEXT((elm), field) = NULL; \
591 (elm)->field.tqe_prev = (head)->tqh_last; \
592 *(head)->tqh_last = (elm); \
593 (head)->tqh_last = &TAILQ_NEXT((elm), field); \
594 QMD_TRACE_HEAD(head); \
595 QMD_TRACE_ELEM(&(elm)->field); \
596 } while (0)
597
598 #define TAILQ_LAST(head, headname) \
599 (*(((struct headname *)((head)->tqh_last))->tqh_last))
600
601 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
602
603 #define TAILQ_PREV(elm, headname, field) \
604 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
605
606 #define TAILQ_REMOVE(head, elm, field) do { \
607 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
608 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
609 QMD_TAILQ_CHECK_NEXT(elm, field); \
610 QMD_TAILQ_CHECK_PREV(elm, field); \
611 if ((TAILQ_NEXT((elm), field)) != NULL) \
612 TAILQ_NEXT((elm), field)->field.tqe_prev = \
613 (elm)->field.tqe_prev; \
614 else { \
615 (head)->tqh_last = (elm)->field.tqe_prev; \
616 QMD_TRACE_HEAD(head); \
617 } \
618 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
619 TRASHIT(*oldnext); \
620 TRASHIT(*oldprev); \
621 QMD_TRACE_ELEM(&(elm)->field); \
622 } while (0)
623
624 #define TAILQ_SWAP(head1, head2, type, field) do { \
625 struct type *swap_first = (head1)->tqh_first; \
626 struct type **swap_last = (head1)->tqh_last; \
627 (head1)->tqh_first = (head2)->tqh_first; \
628 (head1)->tqh_last = (head2)->tqh_last; \
629 (head2)->tqh_first = swap_first; \
630 (head2)->tqh_last = swap_last; \
631 if ((swap_first = (head1)->tqh_first) != NULL) \
632 swap_first->field.tqe_prev = &(head1)->tqh_first; \
633 else \
634 (head1)->tqh_last = &(head1)->tqh_first; \
635 if ((swap_first = (head2)->tqh_first) != NULL) \
636 swap_first->field.tqe_prev = &(head2)->tqh_first; \
637 else \
638 (head2)->tqh_last = &(head2)->tqh_first; \
639 } while (0)
640
641 #endif /* !_SYS_QUEUE_H_ */
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