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: src/sys/sys/queue.h,v 1.69 2008/05/22 14:40:03 ed Exp $ 31 * $DragonFly: src/sys/sys/queue.h,v 1.11 2008/08/28 08:42:29 hasso Exp $ 32 */ 33 34 #ifndef _SYS_QUEUE_H_ 35 #define _SYS_QUEUE_H_ 36 37 #include <sys/cdefs.h> 38 39 /* 40 * This file defines four types of data structures: singly-linked lists, 41 * singly-linked tail queues, lists and tail queues. 42 * 43 * A singly-linked list is headed by a single forward pointer. The elements 44 * are singly linked for minimum space and pointer manipulation overhead at 45 * the expense of O(n) removal for arbitrary elements. New elements can be 46 * added to the list after an existing element or at the head of the list. 47 * Elements being removed from the head of the list should use the explicit 48 * macro for this purpose for optimum efficiency. A singly-linked list may 49 * only be traversed in the forward direction. Singly-linked lists are ideal 50 * for applications with large datasets and few or no removals or for 51 * implementing a LIFO queue. 52 * 53 * A singly-linked tail queue is headed by a pair of pointers, one to the 54 * head of the list and the other to the tail of the list. The elements are 55 * singly linked for minimum space and pointer manipulation overhead at the 56 * expense of O(n) removal for arbitrary elements. New elements can be added 57 * to the list after an existing element, at the head of the list, or at the 58 * end of the list. Elements being removed from the head of the tail queue 59 * should use the explicit macro for this purpose for optimum efficiency. 60 * A singly-linked tail queue may only be traversed in the forward direction. 61 * Singly-linked tail queues are ideal for applications with large datasets 62 * and few or no removals or for implementing a FIFO queue. 63 * 64 * A list is headed by a single forward pointer (or an array of forward 65 * pointers for a hash table header). The elements are doubly linked 66 * so that an arbitrary element can be removed without a need to 67 * traverse the list. New elements can be added to the list before 68 * or after an existing element or at the head of the list. A list 69 * may only be traversed in the forward direction. 70 * 71 * A tail queue is headed by a pair of pointers, one to the head of the 72 * list and the other to the tail of the list. The elements are doubly 73 * linked so that an arbitrary element can be removed without a need to 74 * traverse the list. New elements can be added to the list before or 75 * after an existing element, at the head of the list, or at the end of 76 * the list. A tail queue may be traversed in either direction. 77 * 78 * For details on the use of these macros, see the queue(3) manual page. 79 * 80 * 81 * SLIST LIST STAILQ TAILQ 82 * _HEAD + + + + 83 * _HEAD_INITIALIZER + + + + 84 * _ENTRY + + + + 85 * _INIT + + + + 86 * _EMPTY + + + + 87 * _FIRST + + + + 88 * _NEXT + + + + 89 * _PREV - - - + 90 * _LAST - - + + 91 * _FOREACH + + + + 92 * _FOREACH_MUTABLE + + + + 93 * _FOREACH_REVERSE - - - + 94 * _FOREACH_REVERSE_MUTABLE - - - + 95 * _INSERT_HEAD + + + + 96 * _INSERT_BEFORE - + - + 97 * _INSERT_AFTER + + + + 98 * _INSERT_TAIL - - + + 99 * _CONCAT - - + + 100 * _REMOVE_HEAD + - + - 101 * _REMOVE_NEXT + - + - 102 * _REMOVE + + + + 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 char *lastfile; 109 int lastline; 110 char *prevfile; 111 int prevline; 112 }; 113 114 #define TRACEBUF struct qm_trace trace; 115 #define TRASHIT(x) do {(x) = (void *)-1;} while (0) 116 117 #define QMD_TRACE_HEAD(head) do { \ 118 (head)->trace.prevline = (head)->trace.lastline; \ 119 (head)->trace.prevfile = (head)->trace.lastfile; \ 120 (head)->trace.lastline = __LINE__; \ 121 (head)->trace.lastfile = __FILE__; \ 122 } while (0) 123 124 #define QMD_TRACE_ELEM(elem) do { \ 125 (elem)->trace.prevline = (elem)->trace.lastline; \ 126 (elem)->trace.prevfile = (elem)->trace.lastfile; \ 127 (elem)->trace.lastline = __LINE__; \ 128 (elem)->trace.lastfile = __FILE__; \ 129 } while (0) 130 131 #else 132 #define QMD_TRACE_ELEM(elem) 133 #define QMD_TRACE_HEAD(head) 134 #define TRACEBUF 135 #define TRASHIT(x) 136 #endif /* QUEUE_MACRO_DEBUG */ 137 138 /* 139 * Singly-linked List declarations. 140 */ 141 #define SLIST_HEAD(name, type) \ 142 struct name { \ 143 struct type *slh_first; /* first element */ \ 144 } 145 146 #define SLIST_HEAD_INITIALIZER(head) \ 147 { NULL } 148 149 #define SLIST_ENTRY(type) \ 150 struct { \ 151 struct type *sle_next; /* next element */ \ 152 } 153 154 #define SLIST_ENTRY_INITIALIZER { NULL } 155 156 /* 157 * Singly-linked List functions. 158 */ 159 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 160 161 #define SLIST_FIRST(head) ((head)->slh_first) 162 163 #define SLIST_FOREACH(var, head, field) \ 164 for ((var) = SLIST_FIRST((head)); \ 165 (var); \ 166 (var) = SLIST_NEXT((var), field)) 167 168 #define SLIST_FOREACH_MUTABLE(var, head, field, tvar) \ 169 for ((var) = SLIST_FIRST((head)); \ 170 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 171 (var) = (tvar)) 172 173 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \ 174 for ((varp) = &SLIST_FIRST((head)); \ 175 ((var) = *(varp)) != NULL; \ 176 (varp) = &SLIST_NEXT((var), field)) 177 178 #define SLIST_INIT(head) do { \ 179 SLIST_FIRST((head)) = NULL; \ 180 } while (0) 181 182 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 183 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 184 SLIST_NEXT((slistelm), field) = (elm); \ 185 } while (0) 186 187 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 188 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 189 SLIST_FIRST((head)) = (elm); \ 190 } while (0) 191 192 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 193 194 #define SLIST_REMOVE(head, elm, type, field) do { \ 195 if (SLIST_FIRST((head)) == (elm)) { \ 196 SLIST_REMOVE_HEAD((head), field); \ 197 } \ 198 else { \ 199 struct type *curelm = SLIST_FIRST((head)); \ 200 while (SLIST_NEXT(curelm, field) != (elm)) \ 201 curelm = SLIST_NEXT(curelm, field); \ 202 SLIST_REMOVE_NEXT(head, curelm, field); \ 203 } \ 204 TRASHIT((elm)->field.sle_next); \ 205 } while (0) 206 207 #define SLIST_REMOVE_NEXT(head, elm, field) do { \ 208 SLIST_NEXT(elm, field) = \ 209 SLIST_NEXT(SLIST_NEXT(elm, field), field); \ 210 } while (0) 211 212 #define SLIST_REMOVE_HEAD(head, field) do { \ 213 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 214 } while (0) 215 216 /* 217 * Singly-linked Tail queue declarations. 218 */ 219 #define STAILQ_HEAD(name, type) \ 220 struct name { \ 221 struct type *stqh_first;/* first element */ \ 222 struct type **stqh_last;/* addr of last next element */ \ 223 } 224 225 #define STAILQ_HEAD_INITIALIZER(head) \ 226 { NULL, &(head).stqh_first } 227 228 #define STAILQ_ENTRY(type) \ 229 struct { \ 230 struct type *stqe_next; /* next element */ \ 231 } 232 233 /* 234 * Singly-linked Tail queue functions. 235 */ 236 #define STAILQ_CONCAT(head1, head2) do { \ 237 if (!STAILQ_EMPTY((head2))) { \ 238 *(head1)->stqh_last = (head2)->stqh_first; \ 239 (head1)->stqh_last = (head2)->stqh_last; \ 240 STAILQ_INIT((head2)); \ 241 } \ 242 } while (0) 243 244 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 245 246 #define STAILQ_FIRST(head) ((head)->stqh_first) 247 248 #define STAILQ_FOREACH(var, head, field) \ 249 for((var) = STAILQ_FIRST((head)); \ 250 (var); \ 251 (var) = STAILQ_NEXT((var), field)) 252 253 254 #define STAILQ_FOREACH_MUTABLE(var, head, field, tvar) \ 255 for ((var) = STAILQ_FIRST((head)); \ 256 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 257 (var) = (tvar)) 258 259 #define STAILQ_INIT(head) do { \ 260 STAILQ_FIRST((head)) = NULL; \ 261 (head)->stqh_last = &STAILQ_FIRST((head)); \ 262 } while (0) 263 264 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 265 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 266 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 267 STAILQ_NEXT((tqelm), field) = (elm); \ 268 } while (0) 269 270 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 271 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 272 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 273 STAILQ_FIRST((head)) = (elm); \ 274 } while (0) 275 276 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 277 STAILQ_NEXT((elm), field) = NULL; \ 278 *(head)->stqh_last = (elm); \ 279 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 280 } while (0) 281 282 #define STAILQ_LAST(head, type, field) \ 283 (STAILQ_EMPTY((head)) ? \ 284 NULL : \ 285 ((struct type *)(void *) \ 286 ((char *)((head)->stqh_last) - __offsetof(struct type, field)))) 287 288 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 289 290 #define STAILQ_REMOVE(head, elm, type, field) do { \ 291 if (STAILQ_FIRST((head)) == (elm)) { \ 292 STAILQ_REMOVE_HEAD((head), field); \ 293 } \ 294 else { \ 295 struct type *curelm = STAILQ_FIRST((head)); \ 296 while (STAILQ_NEXT(curelm, field) != (elm)) \ 297 curelm = STAILQ_NEXT(curelm, field); \ 298 STAILQ_REMOVE_NEXT(head, curelm, field); \ 299 } \ 300 TRASHIT((elm)->field.stqe_next); \ 301 } while (0) 302 303 #define STAILQ_REMOVE_HEAD(head, field) do { \ 304 if ((STAILQ_FIRST((head)) = \ 305 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 306 (head)->stqh_last = &STAILQ_FIRST((head)); \ 307 } while (0) 308 309 #define STAILQ_REMOVE_NEXT(head, elm, field) do { \ 310 if ((STAILQ_NEXT(elm, field) = \ 311 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \ 312 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 313 } while (0) 314 315 /* 316 * List declarations. 317 */ 318 #define LIST_HEAD(name, type) \ 319 struct name { \ 320 struct type *lh_first; /* first element */ \ 321 } 322 323 #define LIST_HEAD_INITIALIZER(head) \ 324 { NULL } 325 326 #define LIST_ENTRY(type) \ 327 struct { \ 328 struct type *le_next; /* next element */ \ 329 struct type **le_prev; /* address of previous next element */ \ 330 } 331 332 /* 333 * List functions. 334 */ 335 336 #if (defined(_KERNEL) && defined(INVARIANTS)) 337 #define QMD_LIST_CHECK_HEAD(head, field) do { \ 338 if (LIST_FIRST((head)) != NULL && \ 339 LIST_FIRST((head))->field.le_prev != \ 340 &LIST_FIRST((head))) \ 341 panic("Bad list head %p first->prev != head", (head)); \ 342 } while (0) 343 344 #define QMD_LIST_CHECK_NEXT(elm, field) do { \ 345 if (LIST_NEXT((elm), field) != NULL && \ 346 LIST_NEXT((elm), field)->field.le_prev != \ 347 &((elm)->field.le_next)) \ 348 panic("Bad link elm %p next->prev != elm", (elm)); \ 349 } while (0) 350 351 #define QMD_LIST_CHECK_PREV(elm, field) do { \ 352 if (*(elm)->field.le_prev != (elm)) \ 353 panic("Bad link elm %p prev->next != elm", (elm)); \ 354 } while (0) 355 #else 356 #define QMD_LIST_CHECK_HEAD(head, field) 357 #define QMD_LIST_CHECK_NEXT(elm, field) 358 #define QMD_LIST_CHECK_PREV(elm, field) 359 #endif /* (_KERNEL && INVARIANTS) */ 360 361 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 362 363 #define LIST_FIRST(head) ((head)->lh_first) 364 365 #define LIST_FOREACH(var, head, field) \ 366 for ((var) = LIST_FIRST((head)); \ 367 (var); \ 368 (var) = LIST_NEXT((var), field)) 369 370 #define LIST_FOREACH_MUTABLE(var, head, field, tvar) \ 371 for ((var) = LIST_FIRST((head)); \ 372 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 373 (var) = (tvar)) 374 375 #define LIST_INIT(head) do { \ 376 LIST_FIRST((head)) = NULL; \ 377 } while (0) 378 379 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 380 QMD_LIST_CHECK_NEXT(listelm, field); \ 381 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 382 LIST_NEXT((listelm), field)->field.le_prev = \ 383 &LIST_NEXT((elm), field); \ 384 LIST_NEXT((listelm), field) = (elm); \ 385 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 386 } while (0) 387 388 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 389 QMD_LIST_CHECK_PREV(listelm, field); \ 390 (elm)->field.le_prev = (listelm)->field.le_prev; \ 391 LIST_NEXT((elm), field) = (listelm); \ 392 *(listelm)->field.le_prev = (elm); \ 393 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 394 } while (0) 395 396 #define LIST_INSERT_HEAD(head, elm, field) do { \ 397 QMD_LIST_CHECK_HEAD((head), field); \ 398 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 399 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 400 LIST_FIRST((head)) = (elm); \ 401 (elm)->field.le_prev = &LIST_FIRST((head)); \ 402 } while (0) 403 404 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 405 406 #define LIST_REMOVE(elm, field) do { \ 407 QMD_LIST_CHECK_NEXT(elm, field); \ 408 QMD_LIST_CHECK_PREV(elm, field); \ 409 if (LIST_NEXT((elm), field) != NULL) \ 410 LIST_NEXT((elm), field)->field.le_prev = \ 411 (elm)->field.le_prev; \ 412 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 413 TRASHIT((elm)->field.le_next); \ 414 TRASHIT((elm)->field.le_prev); \ 415 } while (0) 416 417 /* 418 * Tail queue declarations. 419 */ 420 #define TAILQ_HEAD(name, type) \ 421 struct name { \ 422 struct type *tqh_first; /* first element */ \ 423 struct type **tqh_last; /* addr of last next element */ \ 424 TRACEBUF \ 425 } 426 427 #define TAILQ_HEAD_INITIALIZER(head) \ 428 { NULL, &(head).tqh_first } 429 430 #define TAILQ_ENTRY(type) \ 431 struct { \ 432 struct type *tqe_next; /* next element */ \ 433 struct type **tqe_prev; /* address of previous next element */ \ 434 TRACEBUF \ 435 } 436 437 /* 438 * Tail queue functions. 439 */ 440 #if (defined(_KERNEL) && defined(INVARIANTS)) 441 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \ 442 if (!TAILQ_EMPTY(head) && \ 443 TAILQ_FIRST((head))->field.tqe_prev != \ 444 &TAILQ_FIRST((head))) \ 445 panic("Bad tailq head %p first->prev != head", (head)); \ 446 } while (0) 447 448 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \ 449 if (*(head)->tqh_last != NULL) \ 450 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \ 451 } while (0) 452 453 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \ 454 if (TAILQ_NEXT((elm), field) != NULL && \ 455 TAILQ_NEXT((elm), field)->field.tqe_prev != \ 456 &((elm)->field.tqe_next)) \ 457 panic("Bad link elm %p next->prev != elm", (elm)); \ 458 } while (0) 459 460 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \ 461 if (*(elm)->field.tqe_prev != (elm)) \ 462 panic("Bad link elm %p prev->next != elm", (elm)); \ 463 } while (0) 464 #else 465 #define QMD_TAILQ_CHECK_HEAD(head, field) 466 #define QMD_TAILQ_CHECK_TAIL(head, headname) 467 #define QMD_TAILQ_CHECK_NEXT(elm, field) 468 #define QMD_TAILQ_CHECK_PREV(elm, field) 469 #endif /* (_KERNEL && INVARIANTS) */ 470 471 #define TAILQ_CONCAT(head1, head2, field) do { \ 472 if (!TAILQ_EMPTY(head2)) { \ 473 *(head1)->tqh_last = (head2)->tqh_first; \ 474 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 475 (head1)->tqh_last = (head2)->tqh_last; \ 476 TAILQ_INIT((head2)); \ 477 QMD_TRACE_HEAD(head1); \ 478 QMD_TRACE_HEAD(head2); \ 479 } \ 480 } while (0) 481 482 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 483 484 #define TAILQ_FIRST(head) ((head)->tqh_first) 485 486 #define TAILQ_FOREACH(var, head, field) \ 487 for ((var) = TAILQ_FIRST((head)); \ 488 (var); \ 489 (var) = TAILQ_NEXT((var), field)) 490 491 #define TAILQ_FOREACH_MUTABLE(var, head, field, tvar) \ 492 for ((var) = TAILQ_FIRST((head)); \ 493 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 494 (var) = (tvar)) 495 496 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 497 for ((var) = TAILQ_LAST((head), headname); \ 498 (var); \ 499 (var) = TAILQ_PREV((var), headname, field)) 500 501 #define TAILQ_FOREACH_REVERSE_MUTABLE(var, head, headname, field, tvar) \ 502 for ((var) = TAILQ_LAST((head), headname); \ 503 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 504 (var) = (tvar)) 505 506 #define TAILQ_INIT(head) do { \ 507 TAILQ_FIRST((head)) = NULL; \ 508 (head)->tqh_last = &TAILQ_FIRST((head)); \ 509 QMD_TRACE_HEAD(head); \ 510 } while (0) 511 512 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 513 QMD_TAILQ_CHECK_NEXT(listelm, field); \ 514 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 515 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 516 &TAILQ_NEXT((elm), field); \ 517 else { \ 518 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 519 QMD_TRACE_HEAD(head); \ 520 } \ 521 TAILQ_NEXT((listelm), field) = (elm); \ 522 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 523 QMD_TRACE_ELEM(&(elm)->field); \ 524 QMD_TRACE_ELEM(&listelm->field); \ 525 } while (0) 526 527 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 528 QMD_TAILQ_CHECK_PREV(listelm, field); \ 529 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 530 TAILQ_NEXT((elm), field) = (listelm); \ 531 *(listelm)->field.tqe_prev = (elm); \ 532 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 533 QMD_TRACE_ELEM(&(elm)->field); \ 534 QMD_TRACE_ELEM(&listelm->field); \ 535 } while (0) 536 537 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 538 QMD_TAILQ_CHECK_HEAD(head, field); \ 539 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 540 TAILQ_FIRST((head))->field.tqe_prev = \ 541 &TAILQ_NEXT((elm), field); \ 542 else \ 543 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 544 TAILQ_FIRST((head)) = (elm); \ 545 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 546 QMD_TRACE_HEAD(head); \ 547 QMD_TRACE_ELEM(&(elm)->field); \ 548 } while (0) 549 550 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 551 QMD_TAILQ_CHECK_TAIL(head, field); \ 552 TAILQ_NEXT((elm), field) = NULL; \ 553 (elm)->field.tqe_prev = (head)->tqh_last; \ 554 *(head)->tqh_last = (elm); \ 555 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 556 QMD_TRACE_HEAD(head); \ 557 QMD_TRACE_ELEM(&(elm)->field); \ 558 } while (0) 559 560 #define TAILQ_LAST(head, headname) \ 561 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 562 563 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 564 565 #define TAILQ_PREV(elm, headname, field) \ 566 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 567 568 #define TAILQ_REMOVE(head, elm, field) do { \ 569 QMD_TAILQ_CHECK_NEXT(elm, field); \ 570 QMD_TAILQ_CHECK_PREV(elm, field); \ 571 if ((TAILQ_NEXT((elm), field)) != NULL) \ 572 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 573 (elm)->field.tqe_prev; \ 574 else { \ 575 (head)->tqh_last = (elm)->field.tqe_prev; \ 576 QMD_TRACE_HEAD(head); \ 577 } \ 578 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 579 TRASHIT((elm)->field.tqe_next); \ 580 TRASHIT((elm)->field.tqe_prev); \ 581 QMD_TRACE_ELEM(&(elm)->field); \ 582 } while (0) 583 584 585 #ifdef _KERNEL 586 587 /* 588 * XXX insque() and remque() are an old way of handling certain queues. 589 * They bogusly assumes that all queue heads look alike. 590 */ 591 592 struct quehead { 593 struct quehead *qh_link; 594 struct quehead *qh_rlink; 595 }; 596 597 #ifdef __GNUC__ 598 599 static __inline void 600 insque(void *a, void *b) 601 { 602 struct quehead *element = (struct quehead *)a, 603 *head = (struct quehead *)b; 604 605 element->qh_link = head->qh_link; 606 element->qh_rlink = head; 607 head->qh_link = element; 608 element->qh_link->qh_rlink = element; 609 } 610 611 static __inline void 612 remque(void *a) 613 { 614 struct quehead *element = (struct quehead *)a; 615 616 element->qh_link->qh_rlink = element->qh_rlink; 617 element->qh_rlink->qh_link = element->qh_link; 618 element->qh_rlink = 0; 619 } 620 621 #else /* !__GNUC__ */ 622 623 void insque(void *a, void *b); 624 void remque(void *a); 625 626 #endif /* __GNUC__ */ 627 628 #endif /* _KERNEL */ 629 630 #endif /* !_SYS_QUEUE_H_ */ 631