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_FIX_HEAD_PTR(head, field) do { \ 121 if ((head)->lh_first != NULL) { \ 122 (head)->lh_first->field.le_prev = &(head)->lh_first; \ 123 } \ 124 } while (/*CONSTCOND*/0) 125 126 #define QLIST_INSERT_AFTER(listelm, elm, field) do { \ 127 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 128 (listelm)->field.le_next->field.le_prev = \ 129 &(elm)->field.le_next; \ 130 (listelm)->field.le_next = (elm); \ 131 (elm)->field.le_prev = &(listelm)->field.le_next; \ 132 } while (/*CONSTCOND*/0) 133 134 #define QLIST_INSERT_BEFORE(listelm, elm, field) do { \ 135 (elm)->field.le_prev = (listelm)->field.le_prev; \ 136 (elm)->field.le_next = (listelm); \ 137 *(listelm)->field.le_prev = (elm); \ 138 (listelm)->field.le_prev = &(elm)->field.le_next; \ 139 } while (/*CONSTCOND*/0) 140 141 #define QLIST_INSERT_HEAD(head, elm, field) do { \ 142 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 143 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 144 (head)->lh_first = (elm); \ 145 (elm)->field.le_prev = &(head)->lh_first; \ 146 } while (/*CONSTCOND*/0) 147 148 #define QLIST_REMOVE(elm, field) do { \ 149 if ((elm)->field.le_next != NULL) \ 150 (elm)->field.le_next->field.le_prev = \ 151 (elm)->field.le_prev; \ 152 *(elm)->field.le_prev = (elm)->field.le_next; \ 153 } while (/*CONSTCOND*/0) 154 155 #define QLIST_FOREACH(var, head, field) \ 156 for ((var) = ((head)->lh_first); \ 157 (var); \ 158 (var) = ((var)->field.le_next)) 159 160 #define QLIST_FOREACH_SAFE(var, head, field, next_var) \ 161 for ((var) = ((head)->lh_first); \ 162 (var) && ((next_var) = ((var)->field.le_next), 1); \ 163 (var) = (next_var)) 164 165 /* 166 * List access methods. 167 */ 168 #define QLIST_EMPTY(head) ((head)->lh_first == NULL) 169 #define QLIST_FIRST(head) ((head)->lh_first) 170 #define QLIST_NEXT(elm, field) ((elm)->field.le_next) 171 172 173 /* 174 * Singly-linked List definitions. 175 */ 176 #define QSLIST_HEAD(name, type) \ 177 struct name { \ 178 struct type *slh_first; /* first element */ \ 179 } 180 181 #define QSLIST_HEAD_INITIALIZER(head) \ 182 { NULL } 183 184 #define QSLIST_ENTRY(type) \ 185 struct { \ 186 struct type *sle_next; /* next element */ \ 187 } 188 189 /* 190 * Singly-linked List functions. 191 */ 192 #define QSLIST_INIT(head) do { \ 193 (head)->slh_first = NULL; \ 194 } while (/*CONSTCOND*/0) 195 196 #define QSLIST_INSERT_AFTER(slistelm, elm, field) do { \ 197 (elm)->field.sle_next = (slistelm)->field.sle_next; \ 198 (slistelm)->field.sle_next = (elm); \ 199 } while (/*CONSTCOND*/0) 200 201 #define QSLIST_INSERT_HEAD(head, elm, field) do { \ 202 (elm)->field.sle_next = (head)->slh_first; \ 203 (head)->slh_first = (elm); \ 204 } while (/*CONSTCOND*/0) 205 206 #define QSLIST_INSERT_HEAD_ATOMIC(head, elm, field) do { \ 207 typeof(elm) save_sle_next; \ 208 do { \ 209 save_sle_next = (elm)->field.sle_next = (head)->slh_first; \ 210 } while (atomic_cmpxchg(&(head)->slh_first, save_sle_next, (elm)) != \ 211 save_sle_next); \ 212 } while (/*CONSTCOND*/0) 213 214 #define QSLIST_MOVE_ATOMIC(dest, src) do { \ 215 (dest)->slh_first = atomic_xchg(&(src)->slh_first, NULL); \ 216 } while (/*CONSTCOND*/0) 217 218 #define QSLIST_REMOVE_HEAD(head, field) do { \ 219 (head)->slh_first = (head)->slh_first->field.sle_next; \ 220 } while (/*CONSTCOND*/0) 221 222 #define QSLIST_REMOVE_AFTER(slistelm, field) do { \ 223 (slistelm)->field.sle_next = \ 224 QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \ 225 } while (/*CONSTCOND*/0) 226 227 #define QSLIST_FOREACH(var, head, field) \ 228 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 229 230 #define QSLIST_FOREACH_SAFE(var, head, field, tvar) \ 231 for ((var) = QSLIST_FIRST((head)); \ 232 (var) && ((tvar) = QSLIST_NEXT((var), field), 1); \ 233 (var) = (tvar)) 234 235 /* 236 * Singly-linked List access methods. 237 */ 238 #define QSLIST_EMPTY(head) ((head)->slh_first == NULL) 239 #define QSLIST_FIRST(head) ((head)->slh_first) 240 #define QSLIST_NEXT(elm, field) ((elm)->field.sle_next) 241 242 243 /* 244 * Simple queue definitions. 245 */ 246 #define QSIMPLEQ_HEAD(name, type) \ 247 struct name { \ 248 struct type *sqh_first; /* first element */ \ 249 struct type **sqh_last; /* addr of last next element */ \ 250 } 251 252 #define QSIMPLEQ_HEAD_INITIALIZER(head) \ 253 { NULL, &(head).sqh_first } 254 255 #define QSIMPLEQ_ENTRY(type) \ 256 struct { \ 257 struct type *sqe_next; /* next element */ \ 258 } 259 260 /* 261 * Simple queue functions. 262 */ 263 #define QSIMPLEQ_INIT(head) do { \ 264 (head)->sqh_first = NULL; \ 265 (head)->sqh_last = &(head)->sqh_first; \ 266 } while (/*CONSTCOND*/0) 267 268 #define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 269 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 270 (head)->sqh_last = &(elm)->field.sqe_next; \ 271 (head)->sqh_first = (elm); \ 272 } while (/*CONSTCOND*/0) 273 274 #define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 275 (elm)->field.sqe_next = NULL; \ 276 *(head)->sqh_last = (elm); \ 277 (head)->sqh_last = &(elm)->field.sqe_next; \ 278 } while (/*CONSTCOND*/0) 279 280 #define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 281 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 282 (head)->sqh_last = &(elm)->field.sqe_next; \ 283 (listelm)->field.sqe_next = (elm); \ 284 } while (/*CONSTCOND*/0) 285 286 #define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ 287 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ 288 (head)->sqh_last = &(head)->sqh_first; \ 289 } while (/*CONSTCOND*/0) 290 291 #define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do { \ 292 QSIMPLEQ_INIT(removed); \ 293 if (((removed)->sqh_first = (head)->sqh_first) != NULL) { \ 294 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) { \ 295 (head)->sqh_last = &(head)->sqh_first; \ 296 } \ 297 (removed)->sqh_last = &(elm)->field.sqe_next; \ 298 (elm)->field.sqe_next = NULL; \ 299 } \ 300 } while (/*CONSTCOND*/0) 301 302 #define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ 303 if ((head)->sqh_first == (elm)) { \ 304 QSIMPLEQ_REMOVE_HEAD((head), field); \ 305 } else { \ 306 struct type *curelm = (head)->sqh_first; \ 307 while (curelm->field.sqe_next != (elm)) \ 308 curelm = curelm->field.sqe_next; \ 309 if ((curelm->field.sqe_next = \ 310 curelm->field.sqe_next->field.sqe_next) == NULL) \ 311 (head)->sqh_last = &(curelm)->field.sqe_next; \ 312 } \ 313 } while (/*CONSTCOND*/0) 314 315 #define QSIMPLEQ_FOREACH(var, head, field) \ 316 for ((var) = ((head)->sqh_first); \ 317 (var); \ 318 (var) = ((var)->field.sqe_next)) 319 320 #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 321 for ((var) = ((head)->sqh_first); \ 322 (var) && ((next = ((var)->field.sqe_next)), 1); \ 323 (var) = (next)) 324 325 #define QSIMPLEQ_CONCAT(head1, head2) do { \ 326 if (!QSIMPLEQ_EMPTY((head2))) { \ 327 *(head1)->sqh_last = (head2)->sqh_first; \ 328 (head1)->sqh_last = (head2)->sqh_last; \ 329 QSIMPLEQ_INIT((head2)); \ 330 } \ 331 } while (/*CONSTCOND*/0) 332 333 #define QSIMPLEQ_LAST(head, type, field) \ 334 (QSIMPLEQ_EMPTY((head)) ? \ 335 NULL : \ 336 ((struct type *)(void *) \ 337 ((char *)((head)->sqh_last) - offsetof(struct type, field)))) 338 339 /* 340 * Simple queue access methods. 341 */ 342 #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 343 #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 344 #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 345 346 347 /* 348 * Tail queue definitions. 349 */ 350 #define Q_TAILQ_HEAD(name, type, qual) \ 351 struct name { \ 352 qual type *tqh_first; /* first element */ \ 353 qual type *qual *tqh_last; /* addr of last next element */ \ 354 } 355 #define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,) 356 357 #define QTAILQ_HEAD_INITIALIZER(head) \ 358 { NULL, &(head).tqh_first } 359 360 #define Q_TAILQ_ENTRY(type, qual) \ 361 struct { \ 362 qual type *tqe_next; /* next element */ \ 363 qual type *qual *tqe_prev; /* address of previous next element */\ 364 } 365 #define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,) 366 367 /* 368 * Tail queue functions. 369 */ 370 #define QTAILQ_INIT(head) do { \ 371 (head)->tqh_first = NULL; \ 372 (head)->tqh_last = &(head)->tqh_first; \ 373 } while (/*CONSTCOND*/0) 374 375 #define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 376 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 377 (head)->tqh_first->field.tqe_prev = \ 378 &(elm)->field.tqe_next; \ 379 else \ 380 (head)->tqh_last = &(elm)->field.tqe_next; \ 381 (head)->tqh_first = (elm); \ 382 (elm)->field.tqe_prev = &(head)->tqh_first; \ 383 } while (/*CONSTCOND*/0) 384 385 #define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 386 (elm)->field.tqe_next = NULL; \ 387 (elm)->field.tqe_prev = (head)->tqh_last; \ 388 *(head)->tqh_last = (elm); \ 389 (head)->tqh_last = &(elm)->field.tqe_next; \ 390 } while (/*CONSTCOND*/0) 391 392 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 393 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 394 (elm)->field.tqe_next->field.tqe_prev = \ 395 &(elm)->field.tqe_next; \ 396 else \ 397 (head)->tqh_last = &(elm)->field.tqe_next; \ 398 (listelm)->field.tqe_next = (elm); \ 399 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 400 } while (/*CONSTCOND*/0) 401 402 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 403 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 404 (elm)->field.tqe_next = (listelm); \ 405 *(listelm)->field.tqe_prev = (elm); \ 406 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 407 } while (/*CONSTCOND*/0) 408 409 #define QTAILQ_REMOVE(head, elm, field) do { \ 410 if (((elm)->field.tqe_next) != NULL) \ 411 (elm)->field.tqe_next->field.tqe_prev = \ 412 (elm)->field.tqe_prev; \ 413 else \ 414 (head)->tqh_last = (elm)->field.tqe_prev; \ 415 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 416 } while (/*CONSTCOND*/0) 417 418 #define QTAILQ_FOREACH(var, head, field) \ 419 for ((var) = ((head)->tqh_first); \ 420 (var); \ 421 (var) = ((var)->field.tqe_next)) 422 423 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 424 for ((var) = ((head)->tqh_first); \ 425 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 426 (var) = (next_var)) 427 428 #define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \ 429 for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last)); \ 430 (var); \ 431 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last))) 432 433 /* 434 * Tail queue access methods. 435 */ 436 #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 437 #define QTAILQ_FIRST(head) ((head)->tqh_first) 438 #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 439 440 #define QTAILQ_LAST(head, headname) \ 441 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 442 #define QTAILQ_PREV(elm, headname, field) \ 443 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 444 445 #endif /* !QEMU_SYS_QUEUE_H_ */ 446