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 * $FreeBSD$ 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 QMD_SAVELINK(name, link) void **name = (void *)&(link) 159 #define TRASHIT(x) do {(x) = (void *)-1;} while (0) 160 #define QMD_IS_TRASHED(x) ((x) == (void *)(intptr_t)-1) 161 #else /* !QUEUE_MACRO_DEBUG_TRASH */ 162 #define QMD_SAVELINK(name, link) 163 #define TRASHIT(x) 164 #define QMD_IS_TRASHED(x) 0 165 #endif /* QUEUE_MACRO_DEBUG_TRASH */ 166 167 #ifdef __cplusplus 168 /* 169 * In C++ there can be structure lists and class lists: 170 */ 171 #define QUEUE_TYPEOF(type) type 172 #else 173 #define QUEUE_TYPEOF(type) struct type 174 #endif 175 176 /* 177 * Singly-linked List declarations. 178 */ 179 #define SLIST_HEAD(name, type) \ 180 struct name { \ 181 struct type *slh_first; /* first element */ \ 182 } 183 184 #define SLIST_CLASS_HEAD(name, type) \ 185 struct name { \ 186 class type *slh_first; /* first element */ \ 187 } 188 189 #define SLIST_HEAD_INITIALIZER(head) \ 190 { NULL } 191 192 #define SLIST_ENTRY(type) \ 193 struct { \ 194 struct type *sle_next; /* next element */ \ 195 } 196 197 #define SLIST_CLASS_ENTRY(type) \ 198 struct { \ 199 class type *sle_next; /* next element */ \ 200 } 201 202 /* 203 * Singly-linked List functions. 204 */ 205 #if (defined(_KERNEL) && defined(INVARIANTS)) 206 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do { \ 207 if (*(prevp) != (elm)) \ 208 panic("Bad prevptr *(%p) == %p != %p", \ 209 (prevp), *(prevp), (elm)); \ 210 } while (0) 211 #else 212 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) 213 #endif 214 215 #define SLIST_CONCAT(head1, head2, type, field) do { \ 216 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \ 217 if (curelm == NULL) { \ 218 if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \ 219 SLIST_INIT(head2); \ 220 } else if (SLIST_FIRST(head2) != NULL) { \ 221 while (SLIST_NEXT(curelm, field) != NULL) \ 222 curelm = SLIST_NEXT(curelm, field); \ 223 SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \ 224 SLIST_INIT(head2); \ 225 } \ 226 } while (0) 227 228 #define SLIST_EMPTY(head) ((head)->slh_first == NULL) 229 230 #define SLIST_FIRST(head) ((head)->slh_first) 231 232 #define SLIST_FOREACH(var, head, field) \ 233 for ((var) = SLIST_FIRST((head)); \ 234 (var); \ 235 (var) = SLIST_NEXT((var), field)) 236 237 #define SLIST_FOREACH_FROM(var, head, field) \ 238 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \ 239 (var); \ 240 (var) = SLIST_NEXT((var), field)) 241 242 #define SLIST_FOREACH_SAFE(var, head, field, tvar) \ 243 for ((var) = SLIST_FIRST((head)); \ 244 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 245 (var) = (tvar)) 246 247 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \ 248 for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \ 249 (var) && ((tvar) = SLIST_NEXT((var), field), 1); \ 250 (var) = (tvar)) 251 252 #define SLIST_FOREACH_PREVPTR(var, varp, head, field) \ 253 for ((varp) = &SLIST_FIRST((head)); \ 254 ((var) = *(varp)) != NULL; \ 255 (varp) = &SLIST_NEXT((var), field)) 256 257 #define SLIST_INIT(head) do { \ 258 SLIST_FIRST((head)) = NULL; \ 259 } while (0) 260 261 #define SLIST_INSERT_AFTER(slistelm, elm, field) do { \ 262 SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \ 263 SLIST_NEXT((slistelm), field) = (elm); \ 264 } while (0) 265 266 #define SLIST_INSERT_HEAD(head, elm, field) do { \ 267 SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \ 268 SLIST_FIRST((head)) = (elm); \ 269 } while (0) 270 271 #define SLIST_NEXT(elm, field) ((elm)->field.sle_next) 272 273 #define SLIST_REMOVE(head, elm, type, field) do { \ 274 QMD_SAVELINK(oldnext, (elm)->field.sle_next); \ 275 if (SLIST_FIRST((head)) == (elm)) { \ 276 SLIST_REMOVE_HEAD((head), field); \ 277 } \ 278 else { \ 279 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \ 280 while (SLIST_NEXT(curelm, field) != (elm)) \ 281 curelm = SLIST_NEXT(curelm, field); \ 282 SLIST_REMOVE_AFTER(curelm, field); \ 283 } \ 284 TRASHIT(*oldnext); \ 285 } while (0) 286 287 #define SLIST_REMOVE_AFTER(elm, field) do { \ 288 SLIST_NEXT(elm, field) = \ 289 SLIST_NEXT(SLIST_NEXT(elm, field), field); \ 290 } while (0) 291 292 #define SLIST_REMOVE_HEAD(head, field) do { \ 293 SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \ 294 } while (0) 295 296 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \ 297 QMD_SLIST_CHECK_PREVPTR(prevp, elm); \ 298 *(prevp) = SLIST_NEXT(elm, field); \ 299 TRASHIT((elm)->field.sle_next); \ 300 } while (0) 301 302 #define SLIST_SWAP(head1, head2, type) do { \ 303 QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \ 304 SLIST_FIRST(head1) = SLIST_FIRST(head2); \ 305 SLIST_FIRST(head2) = swap_first; \ 306 } while (0) 307 308 /* 309 * Singly-linked Tail queue declarations. 310 */ 311 #define STAILQ_HEAD(name, type) \ 312 struct name { \ 313 struct type *stqh_first;/* first element */ \ 314 struct type **stqh_last;/* addr of last next element */ \ 315 } 316 317 #define STAILQ_CLASS_HEAD(name, type) \ 318 struct name { \ 319 class type *stqh_first; /* first element */ \ 320 class type **stqh_last; /* addr of last next element */ \ 321 } 322 323 #define STAILQ_HEAD_INITIALIZER(head) \ 324 { NULL, &(head).stqh_first } 325 326 #define STAILQ_ENTRY(type) \ 327 struct { \ 328 struct type *stqe_next; /* next element */ \ 329 } 330 331 #define STAILQ_CLASS_ENTRY(type) \ 332 struct { \ 333 class type *stqe_next; /* next element */ \ 334 } 335 336 /* 337 * Singly-linked Tail queue functions. 338 */ 339 #define STAILQ_CONCAT(head1, head2) do { \ 340 if (!STAILQ_EMPTY((head2))) { \ 341 *(head1)->stqh_last = (head2)->stqh_first; \ 342 (head1)->stqh_last = (head2)->stqh_last; \ 343 STAILQ_INIT((head2)); \ 344 } \ 345 } while (0) 346 347 #define STAILQ_EMPTY(head) ((head)->stqh_first == NULL) 348 349 #define STAILQ_FIRST(head) ((head)->stqh_first) 350 351 #define STAILQ_FOREACH(var, head, field) \ 352 for((var) = STAILQ_FIRST((head)); \ 353 (var); \ 354 (var) = STAILQ_NEXT((var), field)) 355 356 #define STAILQ_FOREACH_FROM(var, head, field) \ 357 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \ 358 (var); \ 359 (var) = STAILQ_NEXT((var), field)) 360 361 #define STAILQ_FOREACH_SAFE(var, head, field, tvar) \ 362 for ((var) = STAILQ_FIRST((head)); \ 363 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 364 (var) = (tvar)) 365 366 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \ 367 for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \ 368 (var) && ((tvar) = STAILQ_NEXT((var), field), 1); \ 369 (var) = (tvar)) 370 371 #define STAILQ_INIT(head) do { \ 372 STAILQ_FIRST((head)) = NULL; \ 373 (head)->stqh_last = &STAILQ_FIRST((head)); \ 374 } while (0) 375 376 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \ 377 if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\ 378 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 379 STAILQ_NEXT((tqelm), field) = (elm); \ 380 } while (0) 381 382 #define STAILQ_INSERT_HEAD(head, elm, field) do { \ 383 if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \ 384 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 385 STAILQ_FIRST((head)) = (elm); \ 386 } while (0) 387 388 #define STAILQ_INSERT_TAIL(head, elm, field) do { \ 389 STAILQ_NEXT((elm), field) = NULL; \ 390 *(head)->stqh_last = (elm); \ 391 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 392 } while (0) 393 394 #define STAILQ_LAST(head, type, field) \ 395 (STAILQ_EMPTY((head)) ? NULL : \ 396 __containerof((head)->stqh_last, \ 397 QUEUE_TYPEOF(type), field.stqe_next)) 398 399 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next) 400 401 #define STAILQ_REMOVE(head, elm, type, field) do { \ 402 QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \ 403 if (STAILQ_FIRST((head)) == (elm)) { \ 404 STAILQ_REMOVE_HEAD((head), field); \ 405 } \ 406 else { \ 407 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \ 408 while (STAILQ_NEXT(curelm, field) != (elm)) \ 409 curelm = STAILQ_NEXT(curelm, field); \ 410 STAILQ_REMOVE_AFTER(head, curelm, field); \ 411 } \ 412 TRASHIT(*oldnext); \ 413 } while (0) 414 415 #define STAILQ_REMOVE_AFTER(head, elm, field) do { \ 416 if ((STAILQ_NEXT(elm, field) = \ 417 STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \ 418 (head)->stqh_last = &STAILQ_NEXT((elm), field); \ 419 } while (0) 420 421 #define STAILQ_REMOVE_HEAD(head, field) do { \ 422 if ((STAILQ_FIRST((head)) = \ 423 STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \ 424 (head)->stqh_last = &STAILQ_FIRST((head)); \ 425 } while (0) 426 427 #define STAILQ_SWAP(head1, head2, type) do { \ 428 QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \ 429 QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \ 430 STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \ 431 (head1)->stqh_last = (head2)->stqh_last; \ 432 STAILQ_FIRST(head2) = swap_first; \ 433 (head2)->stqh_last = swap_last; \ 434 if (STAILQ_EMPTY(head1)) \ 435 (head1)->stqh_last = &STAILQ_FIRST(head1); \ 436 if (STAILQ_EMPTY(head2)) \ 437 (head2)->stqh_last = &STAILQ_FIRST(head2); \ 438 } while (0) 439 440 441 /* 442 * List declarations. 443 */ 444 #define LIST_HEAD(name, type) \ 445 struct name { \ 446 struct type *lh_first; /* first element */ \ 447 } 448 449 #define LIST_CLASS_HEAD(name, type) \ 450 struct name { \ 451 class type *lh_first; /* first element */ \ 452 } 453 454 #define LIST_HEAD_INITIALIZER(head) \ 455 { NULL } 456 457 #define LIST_ENTRY(type) \ 458 struct { \ 459 struct type *le_next; /* next element */ \ 460 struct type **le_prev; /* address of previous next element */ \ 461 } 462 463 #define LIST_CLASS_ENTRY(type) \ 464 struct { \ 465 class type *le_next; /* next element */ \ 466 class type **le_prev; /* address of previous next element */ \ 467 } 468 469 /* 470 * List functions. 471 */ 472 473 #if (defined(_KERNEL) && defined(INVARIANTS)) 474 /* 475 * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME) 476 * 477 * If the list is non-empty, validates that the first element of the list 478 * points back at 'head.' 479 */ 480 #define QMD_LIST_CHECK_HEAD(head, field) do { \ 481 if (LIST_FIRST((head)) != NULL && \ 482 LIST_FIRST((head))->field.le_prev != \ 483 &LIST_FIRST((head))) \ 484 panic("Bad list head %p first->prev != head", (head)); \ 485 } while (0) 486 487 /* 488 * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME) 489 * 490 * If an element follows 'elm' in the list, validates that the next element 491 * points back at 'elm.' 492 */ 493 #define QMD_LIST_CHECK_NEXT(elm, field) do { \ 494 if (LIST_NEXT((elm), field) != NULL && \ 495 LIST_NEXT((elm), field)->field.le_prev != \ 496 &((elm)->field.le_next)) \ 497 panic("Bad link elm %p next->prev != elm", (elm)); \ 498 } while (0) 499 500 /* 501 * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME) 502 * 503 * Validates that the previous element (or head of the list) points to 'elm.' 504 */ 505 #define QMD_LIST_CHECK_PREV(elm, field) do { \ 506 if (*(elm)->field.le_prev != (elm)) \ 507 panic("Bad link elm %p prev->next != elm", (elm)); \ 508 } while (0) 509 #else 510 #define QMD_LIST_CHECK_HEAD(head, field) 511 #define QMD_LIST_CHECK_NEXT(elm, field) 512 #define QMD_LIST_CHECK_PREV(elm, field) 513 #endif /* (_KERNEL && INVARIANTS) */ 514 515 #define LIST_CONCAT(head1, head2, type, field) do { \ 516 QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \ 517 if (curelm == NULL) { \ 518 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \ 519 LIST_FIRST(head2)->field.le_prev = \ 520 &LIST_FIRST((head1)); \ 521 LIST_INIT(head2); \ 522 } \ 523 } else if (LIST_FIRST(head2) != NULL) { \ 524 while (LIST_NEXT(curelm, field) != NULL) \ 525 curelm = LIST_NEXT(curelm, field); \ 526 LIST_NEXT(curelm, field) = LIST_FIRST(head2); \ 527 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \ 528 LIST_INIT(head2); \ 529 } \ 530 } while (0) 531 532 #define LIST_EMPTY(head) ((head)->lh_first == NULL) 533 534 #define LIST_FIRST(head) ((head)->lh_first) 535 536 #define LIST_FOREACH(var, head, field) \ 537 for ((var) = LIST_FIRST((head)); \ 538 (var); \ 539 (var) = LIST_NEXT((var), field)) 540 541 #define LIST_FOREACH_FROM(var, head, field) \ 542 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \ 543 (var); \ 544 (var) = LIST_NEXT((var), field)) 545 546 #define LIST_FOREACH_SAFE(var, head, field, tvar) \ 547 for ((var) = LIST_FIRST((head)); \ 548 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 549 (var) = (tvar)) 550 551 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \ 552 for ((var) = ((var) ? (var) : LIST_FIRST((head))); \ 553 (var) && ((tvar) = LIST_NEXT((var), field), 1); \ 554 (var) = (tvar)) 555 556 #define LIST_INIT(head) do { \ 557 LIST_FIRST((head)) = NULL; \ 558 } while (0) 559 560 #define LIST_INSERT_AFTER(listelm, elm, field) do { \ 561 QMD_LIST_CHECK_NEXT(listelm, field); \ 562 if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\ 563 LIST_NEXT((listelm), field)->field.le_prev = \ 564 &LIST_NEXT((elm), field); \ 565 LIST_NEXT((listelm), field) = (elm); \ 566 (elm)->field.le_prev = &LIST_NEXT((listelm), field); \ 567 } while (0) 568 569 #define LIST_INSERT_BEFORE(listelm, elm, field) do { \ 570 QMD_LIST_CHECK_PREV(listelm, field); \ 571 (elm)->field.le_prev = (listelm)->field.le_prev; \ 572 LIST_NEXT((elm), field) = (listelm); \ 573 *(listelm)->field.le_prev = (elm); \ 574 (listelm)->field.le_prev = &LIST_NEXT((elm), field); \ 575 } while (0) 576 577 #define LIST_INSERT_HEAD(head, elm, field) do { \ 578 QMD_LIST_CHECK_HEAD((head), field); \ 579 if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \ 580 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\ 581 LIST_FIRST((head)) = (elm); \ 582 (elm)->field.le_prev = &LIST_FIRST((head)); \ 583 } while (0) 584 585 #define LIST_NEXT(elm, field) ((elm)->field.le_next) 586 587 #define LIST_PREV(elm, head, type, field) \ 588 ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \ 589 __containerof((elm)->field.le_prev, \ 590 QUEUE_TYPEOF(type), field.le_next)) 591 592 #define LIST_REMOVE(elm, field) do { \ 593 QMD_SAVELINK(oldnext, (elm)->field.le_next); \ 594 QMD_SAVELINK(oldprev, (elm)->field.le_prev); \ 595 QMD_LIST_CHECK_NEXT(elm, field); \ 596 QMD_LIST_CHECK_PREV(elm, field); \ 597 if (LIST_NEXT((elm), field) != NULL) \ 598 LIST_NEXT((elm), field)->field.le_prev = \ 599 (elm)->field.le_prev; \ 600 *(elm)->field.le_prev = LIST_NEXT((elm), field); \ 601 TRASHIT(*oldnext); \ 602 TRASHIT(*oldprev); \ 603 } while (0) 604 605 #define LIST_SWAP(head1, head2, type, field) do { \ 606 QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \ 607 LIST_FIRST((head1)) = LIST_FIRST((head2)); \ 608 LIST_FIRST((head2)) = swap_tmp; \ 609 if ((swap_tmp = LIST_FIRST((head1))) != NULL) \ 610 swap_tmp->field.le_prev = &LIST_FIRST((head1)); \ 611 if ((swap_tmp = LIST_FIRST((head2))) != NULL) \ 612 swap_tmp->field.le_prev = &LIST_FIRST((head2)); \ 613 } while (0) 614 615 /* 616 * Tail queue declarations. 617 */ 618 #define TAILQ_HEAD(name, type) \ 619 struct name { \ 620 struct type *tqh_first; /* first element */ \ 621 struct type **tqh_last; /* addr of last next element */ \ 622 TRACEBUF \ 623 } 624 625 #define TAILQ_CLASS_HEAD(name, type) \ 626 struct name { \ 627 class type *tqh_first; /* first element */ \ 628 class type **tqh_last; /* addr of last next element */ \ 629 TRACEBUF \ 630 } 631 632 #define TAILQ_HEAD_INITIALIZER(head) \ 633 { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER } 634 635 #define TAILQ_ENTRY(type) \ 636 struct { \ 637 struct type *tqe_next; /* next element */ \ 638 struct type **tqe_prev; /* address of previous next element */ \ 639 TRACEBUF \ 640 } 641 642 #define TAILQ_CLASS_ENTRY(type) \ 643 struct { \ 644 class type *tqe_next; /* next element */ \ 645 class type **tqe_prev; /* address of previous next element */ \ 646 TRACEBUF \ 647 } 648 649 /* 650 * Tail queue functions. 651 */ 652 #if (defined(_KERNEL) && defined(INVARIANTS)) 653 /* 654 * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME) 655 * 656 * If the tailq is non-empty, validates that the first element of the tailq 657 * points back at 'head.' 658 */ 659 #define QMD_TAILQ_CHECK_HEAD(head, field) do { \ 660 if (!TAILQ_EMPTY(head) && \ 661 TAILQ_FIRST((head))->field.tqe_prev != \ 662 &TAILQ_FIRST((head))) \ 663 panic("Bad tailq head %p first->prev != head", (head)); \ 664 } while (0) 665 666 /* 667 * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME) 668 * 669 * Validates that the tail of the tailq is a pointer to pointer to NULL. 670 */ 671 #define QMD_TAILQ_CHECK_TAIL(head, field) do { \ 672 if (*(head)->tqh_last != NULL) \ 673 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head)); \ 674 } while (0) 675 676 /* 677 * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME) 678 * 679 * If an element follows 'elm' in the tailq, validates that the next element 680 * points back at 'elm.' 681 */ 682 #define QMD_TAILQ_CHECK_NEXT(elm, field) do { \ 683 if (TAILQ_NEXT((elm), field) != NULL && \ 684 TAILQ_NEXT((elm), field)->field.tqe_prev != \ 685 &((elm)->field.tqe_next)) \ 686 panic("Bad link elm %p next->prev != elm", (elm)); \ 687 } while (0) 688 689 /* 690 * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME) 691 * 692 * Validates that the previous element (or head of the tailq) points to 'elm.' 693 */ 694 #define QMD_TAILQ_CHECK_PREV(elm, field) do { \ 695 if (*(elm)->field.tqe_prev != (elm)) \ 696 panic("Bad link elm %p prev->next != elm", (elm)); \ 697 } while (0) 698 #else 699 #define QMD_TAILQ_CHECK_HEAD(head, field) 700 #define QMD_TAILQ_CHECK_TAIL(head, headname) 701 #define QMD_TAILQ_CHECK_NEXT(elm, field) 702 #define QMD_TAILQ_CHECK_PREV(elm, field) 703 #endif /* (_KERNEL && INVARIANTS) */ 704 705 #define TAILQ_CONCAT(head1, head2, field) do { \ 706 if (!TAILQ_EMPTY(head2)) { \ 707 *(head1)->tqh_last = (head2)->tqh_first; \ 708 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \ 709 (head1)->tqh_last = (head2)->tqh_last; \ 710 TAILQ_INIT((head2)); \ 711 QMD_TRACE_HEAD(head1); \ 712 QMD_TRACE_HEAD(head2); \ 713 } \ 714 } while (0) 715 716 #define TAILQ_EMPTY(head) ((head)->tqh_first == NULL) 717 718 #define TAILQ_FIRST(head) ((head)->tqh_first) 719 720 #define TAILQ_FOREACH(var, head, field) \ 721 for ((var) = TAILQ_FIRST((head)); \ 722 (var); \ 723 (var) = TAILQ_NEXT((var), field)) 724 725 #define TAILQ_FOREACH_FROM(var, head, field) \ 726 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \ 727 (var); \ 728 (var) = TAILQ_NEXT((var), field)) 729 730 #define TAILQ_FOREACH_SAFE(var, head, field, tvar) \ 731 for ((var) = TAILQ_FIRST((head)); \ 732 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 733 (var) = (tvar)) 734 735 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \ 736 for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \ 737 (var) && ((tvar) = TAILQ_NEXT((var), field), 1); \ 738 (var) = (tvar)) 739 740 #define TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 741 for ((var) = TAILQ_LAST((head), headname); \ 742 (var); \ 743 (var) = TAILQ_PREV((var), headname, field)) 744 745 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \ 746 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \ 747 (var); \ 748 (var) = TAILQ_PREV((var), headname, field)) 749 750 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \ 751 for ((var) = TAILQ_LAST((head), headname); \ 752 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 753 (var) = (tvar)) 754 755 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \ 756 for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \ 757 (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \ 758 (var) = (tvar)) 759 760 #define TAILQ_INIT(head) do { \ 761 TAILQ_FIRST((head)) = NULL; \ 762 (head)->tqh_last = &TAILQ_FIRST((head)); \ 763 QMD_TRACE_HEAD(head); \ 764 } while (0) 765 766 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 767 QMD_TAILQ_CHECK_NEXT(listelm, field); \ 768 if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\ 769 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 770 &TAILQ_NEXT((elm), field); \ 771 else { \ 772 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 773 QMD_TRACE_HEAD(head); \ 774 } \ 775 TAILQ_NEXT((listelm), field) = (elm); \ 776 (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \ 777 QMD_TRACE_ELEM(&(elm)->field); \ 778 QMD_TRACE_ELEM(&(listelm)->field); \ 779 } while (0) 780 781 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 782 QMD_TAILQ_CHECK_PREV(listelm, field); \ 783 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 784 TAILQ_NEXT((elm), field) = (listelm); \ 785 *(listelm)->field.tqe_prev = (elm); \ 786 (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \ 787 QMD_TRACE_ELEM(&(elm)->field); \ 788 QMD_TRACE_ELEM(&(listelm)->field); \ 789 } while (0) 790 791 #define TAILQ_INSERT_HEAD(head, elm, field) do { \ 792 QMD_TAILQ_CHECK_HEAD(head, field); \ 793 if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \ 794 TAILQ_FIRST((head))->field.tqe_prev = \ 795 &TAILQ_NEXT((elm), field); \ 796 else \ 797 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 798 TAILQ_FIRST((head)) = (elm); \ 799 (elm)->field.tqe_prev = &TAILQ_FIRST((head)); \ 800 QMD_TRACE_HEAD(head); \ 801 QMD_TRACE_ELEM(&(elm)->field); \ 802 } while (0) 803 804 #define TAILQ_INSERT_TAIL(head, elm, field) do { \ 805 QMD_TAILQ_CHECK_TAIL(head, field); \ 806 TAILQ_NEXT((elm), field) = NULL; \ 807 (elm)->field.tqe_prev = (head)->tqh_last; \ 808 *(head)->tqh_last = (elm); \ 809 (head)->tqh_last = &TAILQ_NEXT((elm), field); \ 810 QMD_TRACE_HEAD(head); \ 811 QMD_TRACE_ELEM(&(elm)->field); \ 812 } while (0) 813 814 #define TAILQ_LAST(head, headname) \ 815 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 816 817 /* 818 * The FAST function is fast in that it causes no data access other 819 * then the access to the head. The standard LAST function above 820 * will cause a data access of both the element you want and 821 * the previous element. FAST is very useful for instances when 822 * you may want to prefetch the last data element. 823 */ 824 #define TAILQ_LAST_FAST(head, type, field) \ 825 (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next)) 826 827 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 828 829 #define TAILQ_PREV(elm, headname, field) \ 830 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 831 832 #define TAILQ_PREV_FAST(elm, head, type, field) \ 833 ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL : \ 834 __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next)) 835 836 #define TAILQ_REMOVE(head, elm, field) do { \ 837 QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \ 838 QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \ 839 QMD_TAILQ_CHECK_NEXT(elm, field); \ 840 QMD_TAILQ_CHECK_PREV(elm, field); \ 841 if ((TAILQ_NEXT((elm), field)) != NULL) \ 842 TAILQ_NEXT((elm), field)->field.tqe_prev = \ 843 (elm)->field.tqe_prev; \ 844 else { \ 845 (head)->tqh_last = (elm)->field.tqe_prev; \ 846 QMD_TRACE_HEAD(head); \ 847 } \ 848 *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \ 849 TRASHIT(*oldnext); \ 850 TRASHIT(*oldprev); \ 851 QMD_TRACE_ELEM(&(elm)->field); \ 852 } while (0) 853 854 #define TAILQ_SWAP(head1, head2, type, field) do { \ 855 QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \ 856 QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \ 857 (head1)->tqh_first = (head2)->tqh_first; \ 858 (head1)->tqh_last = (head2)->tqh_last; \ 859 (head2)->tqh_first = swap_first; \ 860 (head2)->tqh_last = swap_last; \ 861 if ((swap_first = (head1)->tqh_first) != NULL) \ 862 swap_first->field.tqe_prev = &(head1)->tqh_first; \ 863 else \ 864 (head1)->tqh_last = &(head1)->tqh_first; \ 865 if ((swap_first = (head2)->tqh_first) != NULL) \ 866 swap_first->field.tqe_prev = &(head2)->tqh_first; \ 867 else \ 868 (head2)->tqh_last = &(head2)->tqh_first; \ 869 } while (0) 870 871 #endif /* !_SYS_QUEUE_H_ */ 872