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 do { \ 202 (elm)->field.sle_next = (head)->slh_first; \ 203 } while (atomic_cmpxchg(&(head)->slh_first, (elm)->field.sle_next, \ 204 (elm)) != (elm)->field.sle_next); \ 205 } while (/*CONSTCOND*/0) 206 207 #define QSLIST_MOVE_ATOMIC(dest, src) do { \ 208 (dest)->slh_first = atomic_xchg(&(src)->slh_first, NULL); \ 209 } while (/*CONSTCOND*/0) 210 211 #define QSLIST_REMOVE_HEAD(head, field) do { \ 212 (head)->slh_first = (head)->slh_first->field.sle_next; \ 213 } while (/*CONSTCOND*/0) 214 215 #define QSLIST_REMOVE_AFTER(slistelm, field) do { \ 216 (slistelm)->field.sle_next = \ 217 QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \ 218 } while (/*CONSTCOND*/0) 219 220 #define QSLIST_FOREACH(var, head, field) \ 221 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 222 223 #define QSLIST_FOREACH_SAFE(var, head, field, tvar) \ 224 for ((var) = QSLIST_FIRST((head)); \ 225 (var) && ((tvar) = QSLIST_NEXT((var), field), 1); \ 226 (var) = (tvar)) 227 228 /* 229 * Singly-linked List access methods. 230 */ 231 #define QSLIST_EMPTY(head) ((head)->slh_first == NULL) 232 #define QSLIST_FIRST(head) ((head)->slh_first) 233 #define QSLIST_NEXT(elm, field) ((elm)->field.sle_next) 234 235 236 /* 237 * Simple queue definitions. 238 */ 239 #define QSIMPLEQ_HEAD(name, type) \ 240 struct name { \ 241 struct type *sqh_first; /* first element */ \ 242 struct type **sqh_last; /* addr of last next element */ \ 243 } 244 245 #define QSIMPLEQ_HEAD_INITIALIZER(head) \ 246 { NULL, &(head).sqh_first } 247 248 #define QSIMPLEQ_ENTRY(type) \ 249 struct { \ 250 struct type *sqe_next; /* next element */ \ 251 } 252 253 /* 254 * Simple queue functions. 255 */ 256 #define QSIMPLEQ_INIT(head) do { \ 257 (head)->sqh_first = NULL; \ 258 (head)->sqh_last = &(head)->sqh_first; \ 259 } while (/*CONSTCOND*/0) 260 261 #define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 262 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 263 (head)->sqh_last = &(elm)->field.sqe_next; \ 264 (head)->sqh_first = (elm); \ 265 } while (/*CONSTCOND*/0) 266 267 #define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 268 (elm)->field.sqe_next = NULL; \ 269 *(head)->sqh_last = (elm); \ 270 (head)->sqh_last = &(elm)->field.sqe_next; \ 271 } while (/*CONSTCOND*/0) 272 273 #define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 274 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 275 (head)->sqh_last = &(elm)->field.sqe_next; \ 276 (listelm)->field.sqe_next = (elm); \ 277 } while (/*CONSTCOND*/0) 278 279 #define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ 280 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ 281 (head)->sqh_last = &(head)->sqh_first; \ 282 } while (/*CONSTCOND*/0) 283 284 #define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do { \ 285 QSIMPLEQ_INIT(removed); \ 286 if (((removed)->sqh_first = (head)->sqh_first) != NULL) { \ 287 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) { \ 288 (head)->sqh_last = &(head)->sqh_first; \ 289 } \ 290 (removed)->sqh_last = &(elm)->field.sqe_next; \ 291 (elm)->field.sqe_next = NULL; \ 292 } \ 293 } while (/*CONSTCOND*/0) 294 295 #define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ 296 if ((head)->sqh_first == (elm)) { \ 297 QSIMPLEQ_REMOVE_HEAD((head), field); \ 298 } else { \ 299 struct type *curelm = (head)->sqh_first; \ 300 while (curelm->field.sqe_next != (elm)) \ 301 curelm = curelm->field.sqe_next; \ 302 if ((curelm->field.sqe_next = \ 303 curelm->field.sqe_next->field.sqe_next) == NULL) \ 304 (head)->sqh_last = &(curelm)->field.sqe_next; \ 305 } \ 306 } while (/*CONSTCOND*/0) 307 308 #define QSIMPLEQ_FOREACH(var, head, field) \ 309 for ((var) = ((head)->sqh_first); \ 310 (var); \ 311 (var) = ((var)->field.sqe_next)) 312 313 #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 314 for ((var) = ((head)->sqh_first); \ 315 (var) && ((next = ((var)->field.sqe_next)), 1); \ 316 (var) = (next)) 317 318 #define QSIMPLEQ_CONCAT(head1, head2) do { \ 319 if (!QSIMPLEQ_EMPTY((head2))) { \ 320 *(head1)->sqh_last = (head2)->sqh_first; \ 321 (head1)->sqh_last = (head2)->sqh_last; \ 322 QSIMPLEQ_INIT((head2)); \ 323 } \ 324 } while (/*CONSTCOND*/0) 325 326 #define QSIMPLEQ_LAST(head, type, field) \ 327 (QSIMPLEQ_EMPTY((head)) ? \ 328 NULL : \ 329 ((struct type *)(void *) \ 330 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 331 332 /* 333 * Simple queue access methods. 334 */ 335 #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 336 #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 337 #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 338 339 340 /* 341 * Tail queue definitions. 342 */ 343 #define Q_TAILQ_HEAD(name, type, qual) \ 344 struct name { \ 345 qual type *tqh_first; /* first element */ \ 346 qual type *qual *tqh_last; /* addr of last next element */ \ 347 } 348 #define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,) 349 350 #define QTAILQ_HEAD_INITIALIZER(head) \ 351 { NULL, &(head).tqh_first } 352 353 #define Q_TAILQ_ENTRY(type, qual) \ 354 struct { \ 355 qual type *tqe_next; /* next element */ \ 356 qual type *qual *tqe_prev; /* address of previous next element */\ 357 } 358 #define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,) 359 360 /* 361 * Tail queue functions. 362 */ 363 #define QTAILQ_INIT(head) do { \ 364 (head)->tqh_first = NULL; \ 365 (head)->tqh_last = &(head)->tqh_first; \ 366 } while (/*CONSTCOND*/0) 367 368 #define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 369 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 370 (head)->tqh_first->field.tqe_prev = \ 371 &(elm)->field.tqe_next; \ 372 else \ 373 (head)->tqh_last = &(elm)->field.tqe_next; \ 374 (head)->tqh_first = (elm); \ 375 (elm)->field.tqe_prev = &(head)->tqh_first; \ 376 } while (/*CONSTCOND*/0) 377 378 #define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 379 (elm)->field.tqe_next = NULL; \ 380 (elm)->field.tqe_prev = (head)->tqh_last; \ 381 *(head)->tqh_last = (elm); \ 382 (head)->tqh_last = &(elm)->field.tqe_next; \ 383 } while (/*CONSTCOND*/0) 384 385 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 386 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 387 (elm)->field.tqe_next->field.tqe_prev = \ 388 &(elm)->field.tqe_next; \ 389 else \ 390 (head)->tqh_last = &(elm)->field.tqe_next; \ 391 (listelm)->field.tqe_next = (elm); \ 392 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 393 } while (/*CONSTCOND*/0) 394 395 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 396 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 397 (elm)->field.tqe_next = (listelm); \ 398 *(listelm)->field.tqe_prev = (elm); \ 399 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 400 } while (/*CONSTCOND*/0) 401 402 #define QTAILQ_REMOVE(head, elm, field) do { \ 403 if (((elm)->field.tqe_next) != NULL) \ 404 (elm)->field.tqe_next->field.tqe_prev = \ 405 (elm)->field.tqe_prev; \ 406 else \ 407 (head)->tqh_last = (elm)->field.tqe_prev; \ 408 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 409 } while (/*CONSTCOND*/0) 410 411 #define QTAILQ_FOREACH(var, head, field) \ 412 for ((var) = ((head)->tqh_first); \ 413 (var); \ 414 (var) = ((var)->field.tqe_next)) 415 416 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 417 for ((var) = ((head)->tqh_first); \ 418 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 419 (var) = (next_var)) 420 421 #define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \ 422 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 423 (var); \ 424 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 425 426 /* 427 * Tail queue access methods. 428 */ 429 #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 430 #define QTAILQ_FIRST(head) ((head)->tqh_first) 431 #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 432 433 #define QTAILQ_LAST(head, headname) \ 434 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 435 #define QTAILQ_PREV(elm, headname, field) \ 436 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 437 438 #endif /* !QEMU_SYS_QUEUE_H_ */ 439