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) \ 87struct name { \ 88 struct type *lh_first; /* first element */ \ 89} 90 91#define QLIST_HEAD_INITIALIZER(head) \ 92 { NULL } 93 94#define QLIST_ENTRY(type) \ 95struct { \ 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_INSERT_AFTER(listelm, elm, field) do { \ 108 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 109 (listelm)->field.le_next->field.le_prev = \ 110 &(elm)->field.le_next; \ 111 (listelm)->field.le_next = (elm); \ 112 (elm)->field.le_prev = &(listelm)->field.le_next; \ 113} while (/*CONSTCOND*/0) 114 115#define QLIST_INSERT_BEFORE(listelm, elm, field) do { \ 116 (elm)->field.le_prev = (listelm)->field.le_prev; \ 117 (elm)->field.le_next = (listelm); \ 118 *(listelm)->field.le_prev = (elm); \ 119 (listelm)->field.le_prev = &(elm)->field.le_next; \ 120} while (/*CONSTCOND*/0) 121 122#define QLIST_INSERT_HEAD(head, elm, field) do { \ 123 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 124 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 125 (head)->lh_first = (elm); \ 126 (elm)->field.le_prev = &(head)->lh_first; \ 127} while (/*CONSTCOND*/0) 128 129#define QLIST_INSERT_HEAD_RCU(head, elm, field) do { \ 130 (elm)->field.le_prev = &(head)->lh_first; \ 131 (elm)->field.le_next = (head)->lh_first; \ 132 smp_wmb(); /* fill elm before linking it */ \ 133 if ((head)->lh_first != NULL) { \ 134 (head)->lh_first->field.le_prev = &(elm)->field.le_next; \ 135 } \ 136 (head)->lh_first = (elm); \ 137 smp_wmb(); \ 138} while (/* CONSTCOND*/0) 139 140#define QLIST_REMOVE(elm, field) do { \ 141 if ((elm)->field.le_next != NULL) \ 142 (elm)->field.le_next->field.le_prev = \ 143 (elm)->field.le_prev; \ 144 *(elm)->field.le_prev = (elm)->field.le_next; \ 145} while (/*CONSTCOND*/0) 146 147#define QLIST_FOREACH(var, head, field) \ 148 for ((var) = ((head)->lh_first); \ 149 (var); \ 150 (var) = ((var)->field.le_next)) 151 152#define QLIST_FOREACH_SAFE(var, head, field, next_var) \ 153 for ((var) = ((head)->lh_first); \ 154 (var) && ((next_var) = ((var)->field.le_next), 1); \ 155 (var) = (next_var)) 156 157/* 158 * List access methods. 159 */ 160#define QLIST_EMPTY(head) ((head)->lh_first == NULL) 161#define QLIST_FIRST(head) ((head)->lh_first) 162#define QLIST_NEXT(elm, field) ((elm)->field.le_next) 163 164 165/* 166 * Singly-linked List definitions. 167 */ 168#define QSLIST_HEAD(name, type) \ 169struct name { \ 170 struct type *slh_first; /* first element */ \ 171} 172 173#define QSLIST_HEAD_INITIALIZER(head) \ 174 { NULL } 175 176#define QSLIST_ENTRY(type) \ 177struct { \ 178 struct type *sle_next; /* next element */ \ 179} 180 181/* 182 * Singly-linked List functions. 183 */ 184#define QSLIST_INIT(head) do { \ 185 (head)->slh_first = NULL; \ 186} while (/*CONSTCOND*/0) 187 188#define QSLIST_INSERT_AFTER(slistelm, elm, field) do { \ 189 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 190 (slistelm)->field.sle_next = (elm); \ 191} while (/*CONSTCOND*/0) 192 193#define QSLIST_INSERT_HEAD(head, elm, field) do { \ 194 (elm)->field.sle_next = (head)->slh_first; \ 195 (head)->slh_first = (elm); \ 196} while (/*CONSTCOND*/0) 197 198#define QSLIST_REMOVE_HEAD(head, field) do { \ 199 (head)->slh_first = (head)->slh_first->field.sle_next; \ 200} while (/*CONSTCOND*/0) 201 202#define QSLIST_REMOVE_AFTER(slistelm, field) do { \ 203 (slistelm)->field.sle_next = \ 204 QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \ 205} while (/*CONSTCOND*/0) 206 207#define QSLIST_FOREACH(var, head, field) \ 208 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 209 210#define QSLIST_FOREACH_SAFE(var, head, field, tvar) \ 211 for ((var) = QSLIST_FIRST((head)); \ 212 (var) && ((tvar) = QSLIST_NEXT((var), field), 1); \ 213 (var) = (tvar)) 214 215/* 216 * Singly-linked List access methods. 217 */ 218#define QSLIST_EMPTY(head) ((head)->slh_first == NULL) 219#define QSLIST_FIRST(head) ((head)->slh_first) 220#define QSLIST_NEXT(elm, field) ((elm)->field.sle_next) 221 222 223/* 224 * Simple queue definitions. 225 */ 226#define QSIMPLEQ_HEAD(name, type) \ 227struct name { \ 228 struct type *sqh_first; /* first element */ \ 229 struct type **sqh_last; /* addr of last next element */ \ 230} 231 232#define QSIMPLEQ_HEAD_INITIALIZER(head) \ 233 { NULL, &(head).sqh_first } 234 235#define QSIMPLEQ_ENTRY(type) \ 236struct { \ 237 struct type *sqe_next; /* next element */ \ 238} 239 240/* 241 * Simple queue functions. 242 */ 243#define QSIMPLEQ_INIT(head) do { \ 244 (head)->sqh_first = NULL; \ 245 (head)->sqh_last = &(head)->sqh_first; \ 246} while (/*CONSTCOND*/0) 247 248#define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 249 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 250 (head)->sqh_last = &(elm)->field.sqe_next; \ 251 (head)->sqh_first = (elm); \ 252} while (/*CONSTCOND*/0) 253 254#define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 255 (elm)->field.sqe_next = NULL; \ 256 *(head)->sqh_last = (elm); \ 257 (head)->sqh_last = &(elm)->field.sqe_next; \ 258} while (/*CONSTCOND*/0) 259 260#define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 261 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 262 (head)->sqh_last = &(elm)->field.sqe_next; \ 263 (listelm)->field.sqe_next = (elm); \ 264} while (/*CONSTCOND*/0) 265 266#define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ 267 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ 268 (head)->sqh_last = &(head)->sqh_first; \ 269} while (/*CONSTCOND*/0) 270 271#define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ 272 if ((head)->sqh_first == (elm)) { \ 273 QSIMPLEQ_REMOVE_HEAD((head), field); \ 274 } else { \ 275 struct type *curelm = (head)->sqh_first; \ 276 while (curelm->field.sqe_next != (elm)) \ 277 curelm = curelm->field.sqe_next; \ 278 if ((curelm->field.sqe_next = \ 279 curelm->field.sqe_next->field.sqe_next) == NULL) \ 280 (head)->sqh_last = &(curelm)->field.sqe_next; \ 281 } \ 282} while (/*CONSTCOND*/0) 283 284#define QSIMPLEQ_FOREACH(var, head, field) \ 285 for ((var) = ((head)->sqh_first); \ 286 (var); \ 287 (var) = ((var)->field.sqe_next)) 288 289#define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 290 for ((var) = ((head)->sqh_first); \ 291 (var) && ((next = ((var)->field.sqe_next)), 1); \ 292 (var) = (next)) 293 294#define QSIMPLEQ_CONCAT(head1, head2) do { \ 295 if (!QSIMPLEQ_EMPTY((head2))) { \ 296 *(head1)->sqh_last = (head2)->sqh_first; \ 297 (head1)->sqh_last = (head2)->sqh_last; \ 298 QSIMPLEQ_INIT((head2)); \ 299 } \ 300} while (/*CONSTCOND*/0) 301 302#define QSIMPLEQ_LAST(head, type, field) \ 303 (QSIMPLEQ_EMPTY((head)) ? \ 304 NULL : \ 305 ((struct type *)(void *) \ 306 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 307 308/* 309 * Simple queue access methods. 310 */ 311#define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 312#define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 313#define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 314 315 316/* 317 * Tail queue definitions. 318 */ 319#define Q_TAILQ_HEAD(name, type, qual) \ 320struct name { \ 321 qual type *tqh_first; /* first element */ \ 322 qual type *qual *tqh_last; /* addr of last next element */ \ 323} 324#define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,) 325 326#define QTAILQ_HEAD_INITIALIZER(head) \ 327 { NULL, &(head).tqh_first } 328 329#define Q_TAILQ_ENTRY(type, qual) \ 330struct { \ 331 qual type *tqe_next; /* next element */ \ 332 qual type *qual *tqe_prev; /* address of previous next element */\ 333} 334#define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,) 335 336/* 337 * Tail queue functions. 338 */ 339#define QTAILQ_INIT(head) do { \ 340 (head)->tqh_first = NULL; \ 341 (head)->tqh_last = &(head)->tqh_first; \ 342} while (/*CONSTCOND*/0) 343 344#define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 345 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 346 (head)->tqh_first->field.tqe_prev = \ 347 &(elm)->field.tqe_next; \ 348 else \ 349 (head)->tqh_last = &(elm)->field.tqe_next; \ 350 (head)->tqh_first = (elm); \ 351 (elm)->field.tqe_prev = &(head)->tqh_first; \ 352} while (/*CONSTCOND*/0) 353 354#define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 355 (elm)->field.tqe_next = NULL; \ 356 (elm)->field.tqe_prev = (head)->tqh_last; \ 357 *(head)->tqh_last = (elm); \ 358 (head)->tqh_last = &(elm)->field.tqe_next; \ 359} while (/*CONSTCOND*/0) 360 361#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 362 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 363 (elm)->field.tqe_next->field.tqe_prev = \ 364 &(elm)->field.tqe_next; \ 365 else \ 366 (head)->tqh_last = &(elm)->field.tqe_next; \ 367 (listelm)->field.tqe_next = (elm); \ 368 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 369} while (/*CONSTCOND*/0) 370 371#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 372 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 373 (elm)->field.tqe_next = (listelm); \ 374 *(listelm)->field.tqe_prev = (elm); \ 375 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 376} while (/*CONSTCOND*/0) 377 378#define QTAILQ_REMOVE(head, elm, field) do { \ 379 if (((elm)->field.tqe_next) != NULL) \ 380 (elm)->field.tqe_next->field.tqe_prev = \ 381 (elm)->field.tqe_prev; \ 382 else \ 383 (head)->tqh_last = (elm)->field.tqe_prev; \ 384 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 385} while (/*CONSTCOND*/0) 386 387#define QTAILQ_FOREACH(var, head, field) \ 388 for ((var) = ((head)->tqh_first); \ 389 (var); \ 390 (var) = ((var)->field.tqe_next)) 391 392#define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 393 for ((var) = ((head)->tqh_first); \ 394 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 395 (var) = (next_var)) 396 397#define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \ 398 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 399 (var); \ 400 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 401 402/* 403 * Tail queue access methods. 404 */ 405#define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 406#define QTAILQ_FIRST(head) ((head)->tqh_first) 407#define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 408 409#define QTAILQ_LAST(head, headname) \ 410 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 411#define QTAILQ_PREV(elm, headname, field) \ 412 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 413 414#endif /* !QEMU_SYS_QUEUE_H_ */ 415