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_LAST(head, type, field) \ 328 (QSIMPLEQ_EMPTY((head)) ? \ 329 NULL : \ 330 ((struct type *)(void *) \ 331 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 332 333 /* 334 * Simple queue access methods. 335 */ 336 #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 337 #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 338 #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 339 340 341 /* 342 * Tail queue definitions. 343 */ 344 #define Q_TAILQ_HEAD(name, type, qual) \ 345 struct name { \ 346 qual type *tqh_first; /* first element */ \ 347 qual type *qual *tqh_last; /* addr of last next element */ \ 348 } 349 #define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,) 350 351 #define QTAILQ_HEAD_INITIALIZER(head) \ 352 { NULL, &(head).tqh_first } 353 354 #define Q_TAILQ_ENTRY(type, qual) \ 355 struct { \ 356 qual type *tqe_next; /* next element */ \ 357 qual type *qual *tqe_prev; /* address of previous next element */\ 358 } 359 #define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,) 360 361 /* 362 * Tail queue functions. 363 */ 364 #define QTAILQ_INIT(head) do { \ 365 (head)->tqh_first = NULL; \ 366 (head)->tqh_last = &(head)->tqh_first; \ 367 } while (/*CONSTCOND*/0) 368 369 #define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 370 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 371 (head)->tqh_first->field.tqe_prev = \ 372 &(elm)->field.tqe_next; \ 373 else \ 374 (head)->tqh_last = &(elm)->field.tqe_next; \ 375 (head)->tqh_first = (elm); \ 376 (elm)->field.tqe_prev = &(head)->tqh_first; \ 377 } while (/*CONSTCOND*/0) 378 379 #define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 380 (elm)->field.tqe_next = NULL; \ 381 (elm)->field.tqe_prev = (head)->tqh_last; \ 382 *(head)->tqh_last = (elm); \ 383 (head)->tqh_last = &(elm)->field.tqe_next; \ 384 } while (/*CONSTCOND*/0) 385 386 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 387 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 388 (elm)->field.tqe_next->field.tqe_prev = \ 389 &(elm)->field.tqe_next; \ 390 else \ 391 (head)->tqh_last = &(elm)->field.tqe_next; \ 392 (listelm)->field.tqe_next = (elm); \ 393 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 394 } while (/*CONSTCOND*/0) 395 396 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 397 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 398 (elm)->field.tqe_next = (listelm); \ 399 *(listelm)->field.tqe_prev = (elm); \ 400 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 401 } while (/*CONSTCOND*/0) 402 403 #define QTAILQ_REMOVE(head, elm, field) do { \ 404 if (((elm)->field.tqe_next) != NULL) \ 405 (elm)->field.tqe_next->field.tqe_prev = \ 406 (elm)->field.tqe_prev; \ 407 else \ 408 (head)->tqh_last = (elm)->field.tqe_prev; \ 409 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 410 (elm)->field.tqe_prev = NULL; \ 411 } while (/*CONSTCOND*/0) 412 413 #define QTAILQ_FOREACH(var, head, field) \ 414 for ((var) = ((head)->tqh_first); \ 415 (var); \ 416 (var) = ((var)->field.tqe_next)) 417 418 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 419 for ((var) = ((head)->tqh_first); \ 420 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 421 (var) = (next_var)) 422 423 #define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \ 424 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 425 (var); \ 426 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 427 428 /* 429 * Tail queue access methods. 430 */ 431 #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 432 #define QTAILQ_FIRST(head) ((head)->tqh_first) 433 #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 434 #define QTAILQ_IN_USE(elm, field) ((elm)->field.tqe_prev != NULL) 435 436 #define QTAILQ_LAST(head, headname) \ 437 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 438 #define QTAILQ_PREV(elm, headname, field) \ 439 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 440 441 #define field_at_offset(base, offset, type) \ 442 ((type) (((char *) (base)) + (offset))) 443 444 typedef struct DUMMY_Q_ENTRY DUMMY_Q_ENTRY; 445 typedef struct DUMMY_Q DUMMY_Q; 446 447 struct DUMMY_Q_ENTRY { 448 QTAILQ_ENTRY(DUMMY_Q_ENTRY) next; 449 }; 450 451 struct DUMMY_Q { 452 QTAILQ_HEAD(DUMMY_Q_HEAD, DUMMY_Q_ENTRY) head; 453 }; 454 455 #define dummy_q ((DUMMY_Q *) 0) 456 #define dummy_qe ((DUMMY_Q_ENTRY *) 0) 457 458 /* 459 * Offsets of layout of a tail queue head. 460 */ 461 #define QTAILQ_FIRST_OFFSET (offsetof(typeof(dummy_q->head), tqh_first)) 462 #define QTAILQ_LAST_OFFSET (offsetof(typeof(dummy_q->head), tqh_last)) 463 /* 464 * Raw access of elements of a tail queue 465 */ 466 #define QTAILQ_RAW_FIRST(head) \ 467 (*field_at_offset(head, QTAILQ_FIRST_OFFSET, void **)) 468 #define QTAILQ_RAW_TQH_LAST(head) \ 469 (*field_at_offset(head, QTAILQ_LAST_OFFSET, void ***)) 470 471 /* 472 * Offsets of layout of a tail queue element. 473 */ 474 #define QTAILQ_NEXT_OFFSET (offsetof(typeof(dummy_qe->next), tqe_next)) 475 #define QTAILQ_PREV_OFFSET (offsetof(typeof(dummy_qe->next), tqe_prev)) 476 477 /* 478 * Raw access of elements of a tail entry 479 */ 480 #define QTAILQ_RAW_NEXT(elm, entry) \ 481 (*field_at_offset(elm, entry + QTAILQ_NEXT_OFFSET, void **)) 482 #define QTAILQ_RAW_TQE_PREV(elm, entry) \ 483 (*field_at_offset(elm, entry + QTAILQ_PREV_OFFSET, void ***)) 484 /* 485 * Tail queue tranversal using pointer arithmetic. 486 */ 487 #define QTAILQ_RAW_FOREACH(elm, head, entry) \ 488 for ((elm) = QTAILQ_RAW_FIRST(head); \ 489 (elm); \ 490 (elm) = QTAILQ_RAW_NEXT(elm, entry)) 491 /* 492 * Tail queue insertion using pointer arithmetic. 493 */ 494 #define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do { \ 495 QTAILQ_RAW_NEXT(elm, entry) = NULL; \ 496 QTAILQ_RAW_TQE_PREV(elm, entry) = QTAILQ_RAW_TQH_LAST(head); \ 497 *QTAILQ_RAW_TQH_LAST(head) = (elm); \ 498 QTAILQ_RAW_TQH_LAST(head) = &QTAILQ_RAW_NEXT(elm, entry); \ 499 } while (/*CONSTCOND*/0) 500 501 #endif /* QEMU_SYS_QUEUE_H */ 502