1 /* $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */ 2 3 /* 4 * QEMU version: Copy from netbsd, removed debug code, removed some of 5 * the implementations. Left in singly-linked lists, lists, simple 6 * queues, and tail queues. 7 */ 8 9 /* 10 * Copyright (c) 1991, 1993 11 * The Regents of the University of California. All rights reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)queue.h 8.5 (Berkeley) 8/20/94 38 */ 39 40 #ifndef QEMU_SYS_QUEUE_H 41 #define QEMU_SYS_QUEUE_H 42 43 /* 44 * This file defines four types of data structures: singly-linked lists, 45 * lists, simple queues, and tail queues. 46 * 47 * A singly-linked list is headed by a single forward pointer. The 48 * elements are singly linked for minimum space and pointer manipulation 49 * overhead at the expense of O(n) removal for arbitrary elements. New 50 * elements can be added to the list after an existing element or at the 51 * head of the list. Elements being removed from the head of the list 52 * should use the explicit macro for this purpose for optimum 53 * efficiency. A singly-linked list may only be traversed in the forward 54 * direction. Singly-linked lists are ideal for applications with large 55 * datasets and few or no removals or for implementing a LIFO queue. 56 * 57 * A list is headed by a single forward pointer (or an array of forward 58 * pointers for a hash table header). The elements are doubly linked 59 * so that an arbitrary element can be removed without a need to 60 * traverse the list. New elements can be added to the list before 61 * or after an existing element or at the head of the list. A list 62 * may only be traversed in the forward direction. 63 * 64 * A simple queue is headed by a pair of pointers, one the head of the 65 * list and the other to the tail of the list. The elements are singly 66 * linked to save space, so elements can only be removed from the 67 * head of the list. New elements can be added to the list after 68 * an existing element, at the head of the list, or at the end of the 69 * list. A simple queue 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 #include "qemu/atomic.h" /* for smp_wmb() */ 82 83 /* 84 * List definitions. 85 */ 86 #define QLIST_HEAD(name, type) \ 87 struct name { \ 88 struct type *lh_first; /* first element */ \ 89 } 90 91 #define QLIST_HEAD_INITIALIZER(head) \ 92 { NULL } 93 94 #define QLIST_ENTRY(type) \ 95 struct { \ 96 struct type *le_next; /* next element */ \ 97 struct type **le_prev; /* address of previous next element */ \ 98 } 99 100 /* 101 * List functions. 102 */ 103 #define QLIST_INIT(head) do { \ 104 (head)->lh_first = NULL; \ 105 } while (/*CONSTCOND*/0) 106 107 #define QLIST_SWAP(dstlist, srclist, field) do { \ 108 void *tmplist; \ 109 tmplist = (srclist)->lh_first; \ 110 (srclist)->lh_first = (dstlist)->lh_first; \ 111 if ((srclist)->lh_first != NULL) { \ 112 (srclist)->lh_first->field.le_prev = &(srclist)->lh_first; \ 113 } \ 114 (dstlist)->lh_first = tmplist; \ 115 if ((dstlist)->lh_first != NULL) { \ 116 (dstlist)->lh_first->field.le_prev = &(dstlist)->lh_first; \ 117 } \ 118 } while (/*CONSTCOND*/0) 119 120 #define QLIST_INSERT_AFTER(listelm, elm, field) do { \ 121 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 122 (listelm)->field.le_next->field.le_prev = \ 123 &(elm)->field.le_next; \ 124 (listelm)->field.le_next = (elm); \ 125 (elm)->field.le_prev = &(listelm)->field.le_next; \ 126 } while (/*CONSTCOND*/0) 127 128 #define QLIST_INSERT_BEFORE(listelm, elm, field) do { \ 129 (elm)->field.le_prev = (listelm)->field.le_prev; \ 130 (elm)->field.le_next = (listelm); \ 131 *(listelm)->field.le_prev = (elm); \ 132 (listelm)->field.le_prev = &(elm)->field.le_next; \ 133 } while (/*CONSTCOND*/0) 134 135 #define QLIST_INSERT_HEAD(head, elm, field) do { \ 136 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 137 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 138 (head)->lh_first = (elm); \ 139 (elm)->field.le_prev = &(head)->lh_first; \ 140 } while (/*CONSTCOND*/0) 141 142 #define QLIST_REMOVE(elm, field) do { \ 143 if ((elm)->field.le_next != NULL) \ 144 (elm)->field.le_next->field.le_prev = \ 145 (elm)->field.le_prev; \ 146 *(elm)->field.le_prev = (elm)->field.le_next; \ 147 } while (/*CONSTCOND*/0) 148 149 #define QLIST_FOREACH(var, head, field) \ 150 for ((var) = ((head)->lh_first); \ 151 (var); \ 152 (var) = ((var)->field.le_next)) 153 154 #define QLIST_FOREACH_SAFE(var, head, field, next_var) \ 155 for ((var) = ((head)->lh_first); \ 156 (var) && ((next_var) = ((var)->field.le_next), 1); \ 157 (var) = (next_var)) 158 159 /* 160 * List access methods. 161 */ 162 #define QLIST_EMPTY(head) ((head)->lh_first == NULL) 163 #define QLIST_FIRST(head) ((head)->lh_first) 164 #define QLIST_NEXT(elm, field) ((elm)->field.le_next) 165 166 167 /* 168 * Singly-linked List definitions. 169 */ 170 #define QSLIST_HEAD(name, type) \ 171 struct name { \ 172 struct type *slh_first; /* first element */ \ 173 } 174 175 #define QSLIST_HEAD_INITIALIZER(head) \ 176 { NULL } 177 178 #define QSLIST_ENTRY(type) \ 179 struct { \ 180 struct type *sle_next; /* next element */ \ 181 } 182 183 /* 184 * Singly-linked List functions. 185 */ 186 #define QSLIST_INIT(head) do { \ 187 (head)->slh_first = NULL; \ 188 } while (/*CONSTCOND*/0) 189 190 #define QSLIST_INSERT_AFTER(slistelm, elm, field) do { \ 191 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 192 (slistelm)->field.sle_next = (elm); \ 193 } while (/*CONSTCOND*/0) 194 195 #define QSLIST_INSERT_HEAD(head, elm, field) do { \ 196 (elm)->field.sle_next = (head)->slh_first; \ 197 (head)->slh_first = (elm); \ 198 } while (/*CONSTCOND*/0) 199 200 #define QSLIST_INSERT_HEAD_ATOMIC(head, elm, field) do { \ 201 typeof(elm) save_sle_next; \ 202 do { \ 203 save_sle_next = (elm)->field.sle_next = (head)->slh_first; \ 204 } while (atomic_cmpxchg(&(head)->slh_first, save_sle_next, (elm)) != \ 205 save_sle_next); \ 206 } while (/*CONSTCOND*/0) 207 208 #define QSLIST_MOVE_ATOMIC(dest, src) do { \ 209 (dest)->slh_first = atomic_xchg(&(src)->slh_first, NULL); \ 210 } while (/*CONSTCOND*/0) 211 212 #define QSLIST_REMOVE_HEAD(head, field) do { \ 213 (head)->slh_first = (head)->slh_first->field.sle_next; \ 214 } while (/*CONSTCOND*/0) 215 216 #define QSLIST_REMOVE_AFTER(slistelm, field) do { \ 217 (slistelm)->field.sle_next = \ 218 QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \ 219 } while (/*CONSTCOND*/0) 220 221 #define QSLIST_FOREACH(var, head, field) \ 222 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 223 224 #define QSLIST_FOREACH_SAFE(var, head, field, tvar) \ 225 for ((var) = QSLIST_FIRST((head)); \ 226 (var) && ((tvar) = QSLIST_NEXT((var), field), 1); \ 227 (var) = (tvar)) 228 229 /* 230 * Singly-linked List access methods. 231 */ 232 #define QSLIST_EMPTY(head) ((head)->slh_first == NULL) 233 #define QSLIST_FIRST(head) ((head)->slh_first) 234 #define QSLIST_NEXT(elm, field) ((elm)->field.sle_next) 235 236 237 /* 238 * Simple queue definitions. 239 */ 240 #define QSIMPLEQ_HEAD(name, type) \ 241 struct name { \ 242 struct type *sqh_first; /* first element */ \ 243 struct type **sqh_last; /* addr of last next element */ \ 244 } 245 246 #define QSIMPLEQ_HEAD_INITIALIZER(head) \ 247 { NULL, &(head).sqh_first } 248 249 #define QSIMPLEQ_ENTRY(type) \ 250 struct { \ 251 struct type *sqe_next; /* next element */ \ 252 } 253 254 /* 255 * Simple queue functions. 256 */ 257 #define QSIMPLEQ_INIT(head) do { \ 258 (head)->sqh_first = NULL; \ 259 (head)->sqh_last = &(head)->sqh_first; \ 260 } while (/*CONSTCOND*/0) 261 262 #define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 263 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 264 (head)->sqh_last = &(elm)->field.sqe_next; \ 265 (head)->sqh_first = (elm); \ 266 } while (/*CONSTCOND*/0) 267 268 #define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 269 (elm)->field.sqe_next = NULL; \ 270 *(head)->sqh_last = (elm); \ 271 (head)->sqh_last = &(elm)->field.sqe_next; \ 272 } while (/*CONSTCOND*/0) 273 274 #define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 275 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 276 (head)->sqh_last = &(elm)->field.sqe_next; \ 277 (listelm)->field.sqe_next = (elm); \ 278 } while (/*CONSTCOND*/0) 279 280 #define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ 281 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ 282 (head)->sqh_last = &(head)->sqh_first; \ 283 } while (/*CONSTCOND*/0) 284 285 #define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do { \ 286 QSIMPLEQ_INIT(removed); \ 287 if (((removed)->sqh_first = (head)->sqh_first) != NULL) { \ 288 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) { \ 289 (head)->sqh_last = &(head)->sqh_first; \ 290 } \ 291 (removed)->sqh_last = &(elm)->field.sqe_next; \ 292 (elm)->field.sqe_next = NULL; \ 293 } \ 294 } while (/*CONSTCOND*/0) 295 296 #define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ 297 if ((head)->sqh_first == (elm)) { \ 298 QSIMPLEQ_REMOVE_HEAD((head), field); \ 299 } else { \ 300 struct type *curelm = (head)->sqh_first; \ 301 while (curelm->field.sqe_next != (elm)) \ 302 curelm = curelm->field.sqe_next; \ 303 if ((curelm->field.sqe_next = \ 304 curelm->field.sqe_next->field.sqe_next) == NULL) \ 305 (head)->sqh_last = &(curelm)->field.sqe_next; \ 306 } \ 307 } while (/*CONSTCOND*/0) 308 309 #define QSIMPLEQ_FOREACH(var, head, field) \ 310 for ((var) = ((head)->sqh_first); \ 311 (var); \ 312 (var) = ((var)->field.sqe_next)) 313 314 #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 315 for ((var) = ((head)->sqh_first); \ 316 (var) && ((next = ((var)->field.sqe_next)), 1); \ 317 (var) = (next)) 318 319 #define QSIMPLEQ_CONCAT(head1, head2) do { \ 320 if (!QSIMPLEQ_EMPTY((head2))) { \ 321 *(head1)->sqh_last = (head2)->sqh_first; \ 322 (head1)->sqh_last = (head2)->sqh_last; \ 323 QSIMPLEQ_INIT((head2)); \ 324 } \ 325 } while (/*CONSTCOND*/0) 326 327 #define QSIMPLEQ_PREPEND(head1, head2) do { \ 328 if (!QSIMPLEQ_EMPTY((head2))) { \ 329 *(head2)->sqh_last = (head1)->sqh_first; \ 330 (head1)->sqh_first = (head2)->sqh_first; \ 331 QSIMPLEQ_INIT((head2)); \ 332 } \ 333 } while (/*CONSTCOND*/0) 334 335 #define QSIMPLEQ_LAST(head, type, field) \ 336 (QSIMPLEQ_EMPTY((head)) ? \ 337 NULL : \ 338 ((struct type *)(void *) \ 339 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 340 341 /* 342 * Simple queue access methods. 343 */ 344 #define QSIMPLEQ_EMPTY_ATOMIC(head) (atomic_read(&((head)->sqh_first)) == NULL) 345 #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 346 #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 347 #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 348 349 350 /* 351 * Tail queue definitions. 352 */ 353 #define Q_TAILQ_HEAD(name, type, qual) \ 354 struct name { \ 355 qual type *tqh_first; /* first element */ \ 356 qual type *qual *tqh_last; /* addr of last next element */ \ 357 } 358 #define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,) 359 360 #define QTAILQ_HEAD_INITIALIZER(head) \ 361 { NULL, &(head).tqh_first } 362 363 #define Q_TAILQ_ENTRY(type, qual) \ 364 struct { \ 365 qual type *tqe_next; /* next element */ \ 366 qual type *qual *tqe_prev; /* address of previous next element */\ 367 } 368 #define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,) 369 370 /* 371 * Tail queue functions. 372 */ 373 #define QTAILQ_INIT(head) do { \ 374 (head)->tqh_first = NULL; \ 375 (head)->tqh_last = &(head)->tqh_first; \ 376 } while (/*CONSTCOND*/0) 377 378 #define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 379 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 380 (head)->tqh_first->field.tqe_prev = \ 381 &(elm)->field.tqe_next; \ 382 else \ 383 (head)->tqh_last = &(elm)->field.tqe_next; \ 384 (head)->tqh_first = (elm); \ 385 (elm)->field.tqe_prev = &(head)->tqh_first; \ 386 } while (/*CONSTCOND*/0) 387 388 #define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 389 (elm)->field.tqe_next = NULL; \ 390 (elm)->field.tqe_prev = (head)->tqh_last; \ 391 *(head)->tqh_last = (elm); \ 392 (head)->tqh_last = &(elm)->field.tqe_next; \ 393 } while (/*CONSTCOND*/0) 394 395 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 396 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 397 (elm)->field.tqe_next->field.tqe_prev = \ 398 &(elm)->field.tqe_next; \ 399 else \ 400 (head)->tqh_last = &(elm)->field.tqe_next; \ 401 (listelm)->field.tqe_next = (elm); \ 402 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 403 } while (/*CONSTCOND*/0) 404 405 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 406 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 407 (elm)->field.tqe_next = (listelm); \ 408 *(listelm)->field.tqe_prev = (elm); \ 409 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 410 } while (/*CONSTCOND*/0) 411 412 #define QTAILQ_REMOVE(head, elm, field) do { \ 413 if (((elm)->field.tqe_next) != NULL) \ 414 (elm)->field.tqe_next->field.tqe_prev = \ 415 (elm)->field.tqe_prev; \ 416 else \ 417 (head)->tqh_last = (elm)->field.tqe_prev; \ 418 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 419 (elm)->field.tqe_prev = NULL; \ 420 } while (/*CONSTCOND*/0) 421 422 #define QTAILQ_FOREACH(var, head, field) \ 423 for ((var) = ((head)->tqh_first); \ 424 (var); \ 425 (var) = ((var)->field.tqe_next)) 426 427 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 428 for ((var) = ((head)->tqh_first); \ 429 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 430 (var) = (next_var)) 431 432 #define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \ 433 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 434 (var); \ 435 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 436 437 #define QTAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, prev_var) \ 438 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 439 (var) && ((prev_var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)), 1); \ 440 (var) = (prev_var)) 441 442 /* 443 * Tail queue access methods. 444 */ 445 #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 446 #define QTAILQ_FIRST(head) ((head)->tqh_first) 447 #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 448 #define QTAILQ_IN_USE(elm, field) ((elm)->field.tqe_prev != NULL) 449 450 #define QTAILQ_LAST(head, headname) \ 451 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 452 #define QTAILQ_PREV(elm, headname, field) \ 453 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 454 455 #define field_at_offset(base, offset, type) \ 456 ((type) (((char *) (base)) + (offset))) 457 458 typedef struct DUMMY_Q_ENTRY DUMMY_Q_ENTRY; 459 typedef struct DUMMY_Q DUMMY_Q; 460 461 struct DUMMY_Q_ENTRY { 462 QTAILQ_ENTRY(DUMMY_Q_ENTRY) next; 463 }; 464 465 struct DUMMY_Q { 466 QTAILQ_HEAD(DUMMY_Q_HEAD, DUMMY_Q_ENTRY) head; 467 }; 468 469 #define dummy_q ((DUMMY_Q *) 0) 470 #define dummy_qe ((DUMMY_Q_ENTRY *) 0) 471 472 /* 473 * Offsets of layout of a tail queue head. 474 */ 475 #define QTAILQ_FIRST_OFFSET (offsetof(typeof(dummy_q->head), tqh_first)) 476 #define QTAILQ_LAST_OFFSET (offsetof(typeof(dummy_q->head), tqh_last)) 477 /* 478 * Raw access of elements of a tail queue 479 */ 480 #define QTAILQ_RAW_FIRST(head) \ 481 (*field_at_offset(head, QTAILQ_FIRST_OFFSET, void **)) 482 #define QTAILQ_RAW_TQH_LAST(head) \ 483 (*field_at_offset(head, QTAILQ_LAST_OFFSET, void ***)) 484 485 /* 486 * Offsets of layout of a tail queue element. 487 */ 488 #define QTAILQ_NEXT_OFFSET (offsetof(typeof(dummy_qe->next), tqe_next)) 489 #define QTAILQ_PREV_OFFSET (offsetof(typeof(dummy_qe->next), tqe_prev)) 490 491 /* 492 * Raw access of elements of a tail entry 493 */ 494 #define QTAILQ_RAW_NEXT(elm, entry) \ 495 (*field_at_offset(elm, entry + QTAILQ_NEXT_OFFSET, void **)) 496 #define QTAILQ_RAW_TQE_PREV(elm, entry) \ 497 (*field_at_offset(elm, entry + QTAILQ_PREV_OFFSET, void ***)) 498 /* 499 * Tail queue tranversal using pointer arithmetic. 500 */ 501 #define QTAILQ_RAW_FOREACH(elm, head, entry) \ 502 for ((elm) = QTAILQ_RAW_FIRST(head); \ 503 (elm); \ 504 (elm) = QTAILQ_RAW_NEXT(elm, entry)) 505 /* 506 * Tail queue insertion using pointer arithmetic. 507 */ 508 #define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do { \ 509 QTAILQ_RAW_NEXT(elm, entry) = NULL; \ 510 QTAILQ_RAW_TQE_PREV(elm, entry) = QTAILQ_RAW_TQH_LAST(head); \ 511 *QTAILQ_RAW_TQH_LAST(head) = (elm); \ 512 QTAILQ_RAW_TQH_LAST(head) = &QTAILQ_RAW_NEXT(elm, entry); \ 513 } while (/*CONSTCOND*/0) 514 515 #endif /* QEMU_SYS_QUEUE_H */ 516