1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)queue.h 8.5 (Berkeley) 8/20/94 32 * $FreeBSD: stable/12/sys/sys/queue.h 371459 2021-12-29 08:24:15Z avg $ 33 */ 34 35 #ifndef _SYS_QUEUE_H_ 36 #define _SYS_QUEUE_H_ 37 38 #include <sys/cdefs.h> 39 40 /* 41 * This file defines four types of data structures: singly-linked lists, 42 * singly-linked tail queues, lists and tail queues. 43 * 44 * A singly-linked list is headed by a single forward pointer. The elements 45 * are singly linked for minimum space and pointer manipulation overhead at 46 * the expense of O(n) removal for arbitrary elements. New elements can be 47 * added to the list after an existing element or at the head of the list. 48 * Elements being removed from the head of the list should use the explicit 49 * macro for this purpose for optimum efficiency. A singly-linked list may 50 * only be traversed in the forward direction. Singly-linked lists are ideal 51 * for applications with large datasets and few or no removals or for 52 * implementing a LIFO queue. 53 * 54 * A singly-linked tail queue is headed by a pair of pointers, one to the 55 * head of the list and the other to the tail of the list. The elements are 56 * singly linked for minimum space and pointer manipulation overhead at the 57 * expense of O(n) removal for arbitrary elements. New elements can be added 58 * to the list after an existing element, at the head of the list, or at the 59 * end of the list. Elements being removed from the head of the tail queue 60 * should use the explicit macro for this purpose for optimum efficiency. 61 * A singly-linked tail queue may only be traversed in the forward direction. 62 * Singly-linked tail queues are ideal for applications with large datasets 63 * and few or no removals or for implementing a FIFO queue. 64 * 65 * A list is headed by a single forward pointer (or an array of forward 66 * pointers for a hash table header). The elements are doubly linked 67 * so that an arbitrary element can be removed without a need to 68 * traverse the list. New elements can be added to the list before 69 * or after an existing element or at the head of the list. A list 70 * may be traversed in either direction. 71 * 72 * A tail queue is headed by a pair of pointers, one to the head of the 73 * list and the other to the tail of the list. The elements are doubly 74 * linked so that an arbitrary element can be removed without a need to 75 * traverse the list. New elements can be added to the list before or 76 * after an existing element, at the head of the list, or at the end of 77 * the list. A tail queue may be traversed in either direction. 78 * 79 * For details on the use of these macros, see the queue(3) manual page. 80 * 81 * Below is a summary of implemented functions where: 82 * + means the macro is available 83 * - means the macro is not available 84 * s means the macro is available but is slow (runs in O(n) time) 85 * 86 * SLIST LIST STAILQ TAILQ 87 * _HEAD + + + + 88 * _CLASS_HEAD + + + + 89 * _HEAD_INITIALIZER + + + + 90 * _ENTRY + + + + 91 * _CLASS_ENTRY + + + + 92 * _INIT + + + + 93 * _EMPTY + + + + 94 * _FIRST + + + + 95 * _NEXT + + + + 96 * _PREV - + - + 97 * _LAST - - + + 98 * _LAST_FAST - - - + 99 * _FOREACH + + + + 100 * _FOREACH_FROM + + + + 101 * _FOREACH_SAFE + + + + 102 * _FOREACH_FROM_SAFE + + + + 103 * _FOREACH_REVERSE - - - + 104 * _FOREACH_REVERSE_FROM - - - + 105 * _FOREACH_REVERSE_SAFE - - - + 106 * _FOREACH_REVERSE_FROM_SAFE - - - + 107 * _INSERT_HEAD + + + + 108 * _INSERT_BEFORE - + - + 109 * _INSERT_AFTER + + + + 110 * _INSERT_TAIL - - + + 111 * _CONCAT s s + + 112 * _REMOVE_AFTER + - + - 113 * _REMOVE_HEAD + - + - 114 * _REMOVE s + s + 115 * _SWAP + + + + 116 * 117 */ 118 #ifdef QUEUE_MACRO_DEBUG 119 #warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH 120 #define QUEUE_MACRO_DEBUG_TRACE 121 #define QUEUE_MACRO_DEBUG_TRASH 122 #endif 123 124 #ifdef QUEUE_MACRO_DEBUG_TRACE 125 /* Store the last 2 places the queue element or head was altered */ 126 struct qm_trace { 127 unsigned long lastline; 128 unsigned long prevline; 129 const char *lastfile; 130 const char *prevfile; 131 }; 132 133 #define TRACEBUF struct qm_trace trace; 134 #define TRACEBUF_INITIALIZER { __LINE__, 0, __FILE__, NULL } , 135 136 #define QMD_TRACE_HEAD(head) do { \ 137 (head)->trace.prevline = (head)->trace.lastline; \ 138 (head)->trace.prevfile = (head)->trace.lastfile; \ 139 (head)->trace.lastline = __LINE__; \ 140 (head)->trace.lastfile = __FILE__; \ 141 } while (0) 142 143 #define QMD_TRACE_ELEM(elem) do { \ 144 (elem)->trace.prevline = (elem)->trace.lastline; \ 145 (elem)->trace.prevfile = (elem)->trace.lastfile; \ 146 (elem)->trace.lastline = __LINE__; \ 147 (elem)->trace.lastfile = __FILE__; \ 148 } while (0) 149 150 #else /* !QUEUE_MACRO_DEBUG_TRACE */ 151 #define QMD_TRACE_ELEM(elem) 152 #define QMD_TRACE_HEAD(head) 153 #define TRACEBUF 154 #define TRACEBUF_INITIALIZER 155 #endif /* QUEUE_MACRO_DEBUG_TRACE */ 156 157 #ifdef QUEUE_MACRO_DEBUG_TRASH 158 #define TRASHIT(x) do {(x) = (void *)-1;} while (0) 159 #define QMD_IS_TRASHED(x) ((x) == (void *)(intptr_t)-1) 160 #else /* !QUEUE_MACRO_DEBUG_TRASH */ 161 #define TRASHIT(x) 162 #define QMD_IS_TRASHED(x) 0 163 #endif /* QUEUE_MACRO_DEBUG_TRASH */ 164 165 #if defined(QUEUE_MACRO_DEBUG_TRACE) || defined(QUEUE_MACRO_DEBUG_TRASH) 166 #define QMD_SAVELINK(name, link) void **name = (void *)&(link) 167 #else /* !QUEUE_MACRO_DEBUG_TRACE && !QUEUE_MACRO_DEBUG_TRASH */ 168 #define QMD_SAVELINK(name, link) 169 #endif /* QUEUE_MACRO_DEBUG_TRACE || QUEUE_MACRO_DEBUG_TRASH */ 170 171 #ifdef __cplusplus 172 /* 173 * In C++ there can be structure lists and class lists: 174 */ 175 #define QUEUE_TYPEOF(type) type 176 #else 177 #define QUEUE_TYPEOF(type) struct type 178 #endif 179 180 /* 181 * Singly-linked List declarations. 182 */ 183 #define SLIST_HEAD(name, type) \ 184 struct name { \ 185 struct type *slh_first; /* first element */ \ 186 } 187 188 #define SLIST_CLASS_HEAD(name, type) \ 189 struct name { \ 190 class type *slh_first; /* first element */ \ 191 } 192 193 #define SLIST_HEAD_INITIALIZER(head) \ 194 { NULL } 195 196 #define SLIST_ENTRY(type) \ 197 struct { \ 198 struct type *sle_next; /* next element */ \ 199 } 200 201 #define SLIST_CLASS_ENTRY(type) \ 202 struct { \ 203 class type *sle_next; /* next element */ \ 204 } 205 206 /* 207 * Singly-linked List functions. 208 */ 209 #if (defined(_KERNEL) && defined(INVARIANTS)) 210 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do { \ 211 if (*(prevp) != (elm)) \ 212 panic("Bad prevptr *(%p) == %p != %p", \ 213 (prevp), *(prevp), (elm)); \ 214 } while (0) 215 #else 216 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) 217 #endif 218 219 #define SLIST_CONCAT(head1, head2, type, field) do { \ 220 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \ 221 if (curelm == NULL) { \ 222 if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \ 223 SLIST_INIT(head2); \ 224 } else if (SLIST_FIRST(head2) != NULL) { \ 225 while (SLIST_NEXT(curelm, field) != NULL) \ 226 curelm = SLIST_NEXT(curelm, field); \ 227 SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \ 228 SLIST_INIT(head2); \ 229 } \ 230 } while (0) 231 232 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 233 234 #define SLIST_FIRST(head) ((head)->slh_first) 235 236 #define SLIST_FOREACH(var, head, field) \ 237 for ((var) = SLIST_FIRST((head)); \ 238 (var); \ 239 (var) = SLIST_NEXT((var), field)) 240 241 #define SLIST_FOREACH_FROM(var, head, field) \ 242 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \ 243 (var); \ 244 (var) = SLIST_NEXT((var), field)) 245 246 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 247 for ((var) = SLIST_FIRST((head)); \ 248 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 249 (var) = (tvar)) 250 251 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \ 252 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \ 253 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 254 (var) = (tvar)) 255 256 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \ 257 for ((varp) = &SLIST_FIRST((head)); \ 258 ((var) = *(varp)) != NULL; \ 259 (varp) = &SLIST_NEXT((var), field)) 260 261 #define SLIST_INIT(head) do { \ 262 SLIST_FIRST((head)) = NULL; \ 263 } while (0) 264 265 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 266 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 267 SLIST_NEXT((slistelm), field) = (elm); \ 268 } while (0) 269 270 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 271 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 272 SLIST_FIRST((head)) = (elm); \ 273 } while (0) 274 275 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 276 277 #define SLIST_REMOVE(head, elm, type, field) do { \ 278 if (SLIST_FIRST((head)) == (elm)) { \ 279 SLIST_REMOVE_HEAD((head), field); \ 280 } \ 281 else { \ 282 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \ 283 while (SLIST_NEXT(curelm, field) != (elm)) \ 284 curelm = SLIST_NEXT(curelm, field); \ 285 SLIST_REMOVE_AFTER(curelm, field); \ 286 } \ 287 } while (0) 288 289 #define SLIST_REMOVE_AFTER(elm, field) do { \ 290 QMD_SAVELINK(oldnext, SLIST_NEXT(elm, field)->field.sle_next); \ 291 SLIST_NEXT(elm, field) = \ 292 SLIST_NEXT(SLIST_NEXT(elm, field), field); \ 293 TRASHIT(*oldnext); \ 294 } while (0) 295 296 #define SLIST_REMOVE_HEAD(head, field) do { \ 297 QMD_SAVELINK(oldnext, SLIST_FIRST(head)->field.sle_next); \ 298 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 299 TRASHIT(*oldnext); \ 300 } while (0) 301 302 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \ 303 QMD_SLIST_CHECK_PREVPTR(prevp, elm); \ 304 *(prevp) = SLIST_NEXT(elm, field); \ 305 TRASHIT((elm)->field.sle_next); \ 306 } while (0) 307 308 #define SLIST_SWAP(head1, head2, type) do { \ 309 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \ 310 SLIST_FIRST(head1) = SLIST_FIRST(head2); \ 311 SLIST_FIRST(head2) = swap_first; \ 312 } while (0) 313 314 /* 315 * Singly-linked Tail queue declarations. 316 */ 317 #define STAILQ_HEAD(name, type) \ 318 struct name { \ 319 struct type *stqh_first;/* first element */ \ 320 struct type **stqh_last;/* addr of last next element */ \ 321 } 322 323 #define STAILQ_CLASS_HEAD(name, type) \ 324 struct name { \ 325 class type *stqh_first; /* first element */ \ 326 class type **stqh_last; /* addr of last next element */ \ 327 } 328 329 #define STAILQ_HEAD_INITIALIZER(head) \ 330 { NULL, &(head).stqh_first } 331 332 #define STAILQ_ENTRY(type) \ 333 struct { \ 334 struct type *stqe_next; /* next element */ \ 335 } 336 337 #define STAILQ_CLASS_ENTRY(type) \ 338 struct { \ 339 class type *stqe_next; /* next element */ \ 340 } 341 342 /* 343 * Singly-linked Tail queue functions. 344 */ 345 #define STAILQ_CONCAT(head1, head2) do { \ 346 if (!STAILQ_EMPTY((head2))) { \ 347 *(head1)->stqh_last = (head2)->stqh_first; \ 348 (head1)->stqh_last = (head2)->stqh_last; \ 349 STAILQ_INIT((head2)); \ 350 } \ 351 } while (0) 352 353 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 354 355 #define STAILQ_FIRST(head) ((head)->stqh_first) 356 357 #define STAILQ_FOREACH(var, head, field) \ 358 for((var) = STAILQ_FIRST((head)); \ 359 (var); \ 360 (var) = STAILQ_NEXT((var), field)) 361 362 #define STAILQ_FOREACH_FROM(var, head, field) \ 363 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \ 364 (var); \ 365 (var) = STAILQ_NEXT((var), field)) 366 367 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \ 368 for ((var) = STAILQ_FIRST((head)); \ 369 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 370 (var) = (tvar)) 371 372 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \ 373 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \ 374 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 375 (var) = (tvar)) 376 377 #define STAILQ_INIT(head) do { \ 378 STAILQ_FIRST((head)) = NULL; \ 379 (head)->stqh_last = &STAILQ_FIRST((head)); \ 380 } while (0) 381 382 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 383 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 384 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 385 STAILQ_NEXT((tqelm), field) = (elm); \ 386 } while (0) 387 388 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 389 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 390 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 391 STAILQ_FIRST((head)) = (elm); \ 392 } while (0) 393 394 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 395 STAILQ_NEXT((elm), field) = NULL; \ 396 *(head)->stqh_last = (elm); \ 397 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 398 } while (0) 399 400 #define STAILQ_LAST(head, type, field) \ 401 (STAILQ_EMPTY((head)) ? NULL : \ 402 __containerof((head)->stqh_last, \ 403 QUEUE_TYPEOF(type), field.stqe_next)) 404 405 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 406 407 #define STAILQ_REMOVE(head, elm, type, field) do { \ 408 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \ 409 if (STAILQ_FIRST((head)) == (elm)) { \ 410 STAILQ_REMOVE_HEAD((head), field); \ 411 } \ 412 else { \ 413 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \ 414 while (STAILQ_NEXT(curelm, field) != (elm)) \ 415 curelm = STAILQ_NEXT(curelm, field); \ 416 STAILQ_REMOVE_AFTER(head, curelm, field); \ 417 } \ 418 TRASHIT(*oldnext); \ 419 } while (0) 420 421 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \ 422 if ((STAILQ_NEXT(elm, field) = \ 423 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \ 424 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 425 } while (0) 426 427 #define STAILQ_REMOVE_HEAD(head, field) do { \ 428 if ((STAILQ_FIRST((head)) = \ 429 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 430 (head)->stqh_last = &STAILQ_FIRST((head)); \ 431 } while (0) 432 433 #define STAILQ_SWAP(head1, head2, type) do { \ 434 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \ 435 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \ 436 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \ 437 (head1)->stqh_last = (head2)->stqh_last; \ 438 STAILQ_FIRST(head2) = swap_first; \ 439 (head2)->stqh_last = swap_last; \ 440 if (STAILQ_EMPTY(head1)) \ 441 (head1)->stqh_last = &STAILQ_FIRST(head1); \ 442 if (STAILQ_EMPTY(head2)) \ 443 (head2)->stqh_last = &STAILQ_FIRST(head2); \ 444 } while (0) 445 446 447 /* 448 * List declarations. 449 */ 450 #define LIST_HEAD(name, type) \ 451 struct name { \ 452 struct type *lh_first; /* first element */ \ 453 } 454 455 #define LIST_CLASS_HEAD(name, type) \ 456 struct name { \ 457 class type *lh_first; /* first element */ \ 458 } 459 460 #define LIST_HEAD_INITIALIZER(head) \ 461 { NULL } 462 463 #define LIST_ENTRY(type) \ 464 struct { \ 465 struct type *le_next; /* next element */ \ 466 struct type **le_prev; /* address of previous next element */ \ 467 } 468 469 #define LIST_CLASS_ENTRY(type) \ 470 struct { \ 471 class type *le_next; /* next element */ \ 472 class type **le_prev; /* address of previous next element */ \ 473 } 474 475 /* 476 * List functions. 477 */ 478 479 #if (defined(_KERNEL) && defined(INVARIANTS)) 480 /* 481 * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME) 482 * 483 * If the list is non-empty, validates that the first element of the list 484 * points back at 'head.' 485 */ 486 #define QMD_LIST_CHECK_HEAD(head, field) do { \ 487 if (LIST_FIRST((head)) != NULL && \ 488 LIST_FIRST((head))->field.le_prev != \ 489 &LIST_FIRST((head))) \ 490 panic("Bad list head %p first->prev != head", (head)); \ 491 } while (0) 492 493 /* 494 * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME) 495 * 496 * If an element follows 'elm' in the list, validates that the next element 497 * points back at 'elm.' 498 */ 499 #define QMD_LIST_CHECK_NEXT(elm, field) do { \ 500 if (LIST_NEXT((elm), field) != NULL && \ 501 LIST_NEXT((elm), field)->field.le_prev != \ 502 &((elm)->field.le_next)) \ 503 panic("Bad link elm %p next->prev != elm", (elm)); \ 504 } while (0) 505 506 /* 507 * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME) 508 * 509 * Validates that the previous element (or head of the list) points to 'elm.' 510 */ 511 #define QMD_LIST_CHECK_PREV(elm, field) do { \ 512 if (*(elm)->field.le_prev != (elm)) \ 513 panic("Bad link elm %p prev->next != elm", (elm)); \ 514 } while (0) 515 #else 516 #define QMD_LIST_CHECK_HEAD(head, field) 517 #define QMD_LIST_CHECK_NEXT(elm, field) 518 #define QMD_LIST_CHECK_PREV(elm, field) 519 #endif /* (_KERNEL && INVARIANTS) */ 520 521 #define LIST_CONCAT(head1, head2, type, field) do { \ 522 QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \ 523 if (curelm == NULL) { \ 524 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \ 525 LIST_FIRST(head2)->field.le_prev = \ 526 &LIST_FIRST((head1)); \ 527 LIST_INIT(head2); \ 528 } \ 529 } else if (LIST_FIRST(head2) != NULL) { \ 530 while (LIST_NEXT(curelm, field) != NULL) \ 531 curelm = LIST_NEXT(curelm, field); \ 532 LIST_NEXT(curelm, field) = LIST_FIRST(head2); \ 533 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \ 534 LIST_INIT(head2); \ 535 } \ 536 } while (0) 537 538 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 539 540 #define LIST_FIRST(head) ((head)->lh_first) 541 542 #define LIST_FOREACH(var, head, field) \ 543 for ((var) = LIST_FIRST((head)); \ 544 (var); \ 545 (var) = LIST_NEXT((var), field)) 546 547 #define LIST_FOREACH_FROM(var, head, field) \ 548 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \ 549 (var); \ 550 (var) = LIST_NEXT((var), field)) 551 552 #define LIST_FOREACH_SAFE(var, head, field, tvar) \ 553 for ((var) = LIST_FIRST((head)); \ 554 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 555 (var) = (tvar)) 556 557 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \ 558 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \ 559 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 560 (var) = (tvar)) 561 562 #define LIST_INIT(head) do { \ 563 LIST_FIRST((head)) = NULL; \ 564 } while (0) 565 566 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 567 QMD_LIST_CHECK_NEXT(listelm, field); \ 568 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 569 LIST_NEXT((listelm), field)->field.le_prev = \ 570 &LIST_NEXT((elm), field); \ 571 LIST_NEXT((listelm), field) = (elm); \ 572 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 573 } while (0) 574 575 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 576 QMD_LIST_CHECK_PREV(listelm, field); \ 577 (elm)->field.le_prev = (listelm)->field.le_prev; \ 578 LIST_NEXT((elm), field) = (listelm); \ 579 *(listelm)->field.le_prev = (elm); \ 580 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 581 } while (0) 582 583 #define LIST_INSERT_HEAD(head, elm, field) do { \ 584 QMD_LIST_CHECK_HEAD((head), field); \ 585 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 586 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 587 LIST_FIRST((head)) = (elm); \ 588 (elm)->field.le_prev = &LIST_FIRST((head)); \ 589 } while (0) 590 591 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 592 593 #define LIST_PREV(elm, head, type, field) \ 594 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \ 595 __containerof((elm)->field.le_prev, \ 596 QUEUE_TYPEOF(type), field.le_next)) 597 598 #define LIST_REMOVE(elm, field) do { \ 599 QMD_SAVELINK(oldnext, (elm)->field.le_next); \ 600 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \ 601 QMD_LIST_CHECK_NEXT(elm, field); \ 602 QMD_LIST_CHECK_PREV(elm, field); \ 603 if (LIST_NEXT((elm), field) != NULL) \ 604 LIST_NEXT((elm), field)->field.le_prev = \ 605 (elm)->field.le_prev; \ 606 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 607 TRASHIT(*oldnext); \ 608 TRASHIT(*oldprev); \ 609 } while (0) 610 611 #define LIST_SWAP(head1, head2, type, field) do { \ 612 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \ 613 LIST_FIRST((head1)) = LIST_FIRST((head2)); \ 614 LIST_FIRST((head2)) = swap_tmp; \ 615 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \ 616 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \ 617 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \ 618 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \ 619 } while (0) 620 621 /* 622 * Tail queue declarations. 623 */ 624 #define TAILQ_HEAD(name, type) \ 625 struct name { \ 626 struct type *tqh_first; /* first element */ \ 627 struct type **tqh_last; /* addr of last next element */ \ 628 TRACEBUF \ 629 } 630 631 #define TAILQ_CLASS_HEAD(name, type) \ 632 struct name { \ 633 class type *tqh_first; /* first element */ \ 634 class type **tqh_last; /* addr of last next element */ \ 635 TRACEBUF \ 636 } 637 638 #define TAILQ_HEAD_INITIALIZER(head) \ 639 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER } 640 641 #define TAILQ_ENTRY(type) \ 642 struct { \ 643 struct type *tqe_next; /* next element */ \ 644 struct type **tqe_prev; /* address of previous next element */ \ 645 TRACEBUF \ 646 } 647 648 #define TAILQ_CLASS_ENTRY(type) \ 649 struct { \ 650 class type *tqe_next; /* next element */ \ 651 class type **tqe_prev; /* address of previous next element */ \ 652 TRACEBUF \ 653 } 654 655 /* 656 * Tail queue functions. 657 */ 658 #if (defined(_KERNEL) && defined(INVARIANTS)) 659 /* 660 * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME) 661 * 662 * If the tailq is non-empty, validates that the first element of the tailq 663 * points back at 'head.' 664 */ 665 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \ 666 if (!TAILQ_EMPTY(head) && \ 667 TAILQ_FIRST((head))->field.tqe_prev != \ 668 &TAILQ_FIRST((head))) \ 669 panic("Bad tailq head %p first->prev != head", (head)); \ 670 } while (0) 671 672 /* 673 * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME) 674 * 675 * Validates that the tail of the tailq is a pointer to pointer to NULL. 676 */ 677 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \ 678 if (*(head)->tqh_last != NULL) \ 679 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \ 680 } while (0) 681 682 /* 683 * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME) 684 * 685 * If an element follows 'elm' in the tailq, validates that the next element 686 * points back at 'elm.' 687 */ 688 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \ 689 if (TAILQ_NEXT((elm), field) != NULL && \ 690 TAILQ_NEXT((elm), field)->field.tqe_prev != \ 691 &((elm)->field.tqe_next)) \ 692 panic("Bad link elm %p next->prev != elm", (elm)); \ 693 } while (0) 694 695 /* 696 * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME) 697 * 698 * Validates that the previous element (or head of the tailq) points to 'elm.' 699 */ 700 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \ 701 if (*(elm)->field.tqe_prev != (elm)) \ 702 panic("Bad link elm %p prev->next != elm", (elm)); \ 703 } while (0) 704 #else 705 #define QMD_TAILQ_CHECK_HEAD(head, field) 706 #define QMD_TAILQ_CHECK_TAIL(head, headname) 707 #define QMD_TAILQ_CHECK_NEXT(elm, field) 708 #define QMD_TAILQ_CHECK_PREV(elm, field) 709 #endif /* (_KERNEL && INVARIANTS) */ 710 711 #define TAILQ_CONCAT(head1, head2, field) do { \ 712 if (!TAILQ_EMPTY(head2)) { \ 713 *(head1)->tqh_last = (head2)->tqh_first; \ 714 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 715 (head1)->tqh_last = (head2)->tqh_last; \ 716 TAILQ_INIT((head2)); \ 717 QMD_TRACE_HEAD(head1); \ 718 QMD_TRACE_HEAD(head2); \ 719 } \ 720 } while (0) 721 722 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 723 724 #define TAILQ_FIRST(head) ((head)->tqh_first) 725 726 #define TAILQ_FOREACH(var, head, field) \ 727 for ((var) = TAILQ_FIRST((head)); \ 728 (var); \ 729 (var) = TAILQ_NEXT((var), field)) 730 731 #define TAILQ_FOREACH_FROM(var, head, field) \ 732 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \ 733 (var); \ 734 (var) = TAILQ_NEXT((var), field)) 735 736 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 737 for ((var) = TAILQ_FIRST((head)); \ 738 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 739 (var) = (tvar)) 740 741 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \ 742 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \ 743 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 744 (var) = (tvar)) 745 746 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 747 for ((var) = TAILQ_LAST((head), headname); \ 748 (var); \ 749 (var) = TAILQ_PREV((var), headname, field)) 750 751 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \ 752 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \ 753 (var); \ 754 (var) = TAILQ_PREV((var), headname, field)) 755 756 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 757 for ((var) = TAILQ_LAST((head), headname); \ 758 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 759 (var) = (tvar)) 760 761 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \ 762 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \ 763 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 764 (var) = (tvar)) 765 766 #define TAILQ_INIT(head) do { \ 767 TAILQ_FIRST((head)) = NULL; \ 768 (head)->tqh_last = &TAILQ_FIRST((head)); \ 769 QMD_TRACE_HEAD(head); \ 770 } while (0) 771 772 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 773 QMD_TAILQ_CHECK_NEXT(listelm, field); \ 774 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 775 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 776 &TAILQ_NEXT((elm), field); \ 777 else { \ 778 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 779 QMD_TRACE_HEAD(head); \ 780 } \ 781 TAILQ_NEXT((listelm), field) = (elm); \ 782 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 783 QMD_TRACE_ELEM(&(elm)->field); \ 784 QMD_TRACE_ELEM(&(listelm)->field); \ 785 } while (0) 786 787 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 788 QMD_TAILQ_CHECK_PREV(listelm, field); \ 789 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 790 TAILQ_NEXT((elm), field) = (listelm); \ 791 *(listelm)->field.tqe_prev = (elm); \ 792 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 793 QMD_TRACE_ELEM(&(elm)->field); \ 794 QMD_TRACE_ELEM(&(listelm)->field); \ 795 } while (0) 796 797 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 798 QMD_TAILQ_CHECK_HEAD(head, field); \ 799 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 800 TAILQ_FIRST((head))->field.tqe_prev = \ 801 &TAILQ_NEXT((elm), field); \ 802 else \ 803 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 804 TAILQ_FIRST((head)) = (elm); \ 805 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 806 QMD_TRACE_HEAD(head); \ 807 QMD_TRACE_ELEM(&(elm)->field); \ 808 } while (0) 809 810 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 811 QMD_TAILQ_CHECK_TAIL(head, field); \ 812 TAILQ_NEXT((elm), field) = NULL; \ 813 (elm)->field.tqe_prev = (head)->tqh_last; \ 814 *(head)->tqh_last = (elm); \ 815 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 816 QMD_TRACE_HEAD(head); \ 817 QMD_TRACE_ELEM(&(elm)->field); \ 818 } while (0) 819 820 #define TAILQ_LAST(head, headname) \ 821 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 822 823 /* 824 * The FAST function is fast in that it causes no data access other 825 * then the access to the head. The standard LAST function above 826 * will cause a data access of both the element you want and 827 * the previous element. FAST is very useful for instances when 828 * you may want to prefetch the last data element. 829 */ 830 #define TAILQ_LAST_FAST(head, type, field) \ 831 (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next)) 832 833 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 834 835 #define TAILQ_PREV(elm, headname, field) \ 836 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 837 838 #define TAILQ_PREV_FAST(elm, head, type, field) \ 839 ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL : \ 840 __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next)) 841 842 #define TAILQ_REMOVE(head, elm, field) do { \ 843 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \ 844 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \ 845 QMD_TAILQ_CHECK_NEXT(elm, field); \ 846 QMD_TAILQ_CHECK_PREV(elm, field); \ 847 if ((TAILQ_NEXT((elm), field)) != NULL) \ 848 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 849 (elm)->field.tqe_prev; \ 850 else { \ 851 (head)->tqh_last = (elm)->field.tqe_prev; \ 852 QMD_TRACE_HEAD(head); \ 853 } \ 854 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 855 TRASHIT(*oldnext); \ 856 TRASHIT(*oldprev); \ 857 QMD_TRACE_ELEM(&(elm)->field); \ 858 } while (0) 859 860 #define TAILQ_SWAP(head1, head2, type, field) do { \ 861 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \ 862 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \ 863 (head1)->tqh_first = (head2)->tqh_first; \ 864 (head1)->tqh_last = (head2)->tqh_last; \ 865 (head2)->tqh_first = swap_first; \ 866 (head2)->tqh_last = swap_last; \ 867 if ((swap_first = (head1)->tqh_first) != NULL) \ 868 swap_first->field.tqe_prev = &(head1)->tqh_first; \ 869 else \ 870 (head1)->tqh_last = &(head1)->tqh_first; \ 871 if ((swap_first = (head2)->tqh_first) != NULL) \ 872 swap_first->field.tqe_prev = &(head2)->tqh_first; \ 873 else \ 874 (head2)->tqh_last = &(head2)->tqh_first; \ 875 } while (0) 876 877 #endif /* !_SYS_QUEUE_H_ */ 878