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 /* 82 * List definitions. 83 */ 84 #define QLIST_HEAD(name, type) \ 85 struct name { \ 86 struct type *lh_first; /* first element */ \ 87 } 88 89 #define QLIST_HEAD_INITIALIZER(head) \ 90 { NULL } 91 92 #define QLIST_ENTRY(type) \ 93 struct { \ 94 struct type *le_next; /* next element */ \ 95 struct type **le_prev; /* address of previous next element */ \ 96 } 97 98 /* 99 * List functions. 100 */ 101 #define QLIST_INIT(head) do { \ 102 (head)->lh_first = NULL; \ 103 } while (/*CONSTCOND*/0) 104 105 #define QLIST_SWAP(dstlist, srclist, field) do { \ 106 void *tmplist; \ 107 tmplist = (srclist)->lh_first; \ 108 (srclist)->lh_first = (dstlist)->lh_first; \ 109 if ((srclist)->lh_first != NULL) { \ 110 (srclist)->lh_first->field.le_prev = &(srclist)->lh_first; \ 111 } \ 112 (dstlist)->lh_first = tmplist; \ 113 if ((dstlist)->lh_first != NULL) { \ 114 (dstlist)->lh_first->field.le_prev = &(dstlist)->lh_first; \ 115 } \ 116 } while (/*CONSTCOND*/0) 117 118 #define QLIST_INSERT_AFTER(listelm, elm, field) do { \ 119 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 120 (listelm)->field.le_next->field.le_prev = \ 121 &(elm)->field.le_next; \ 122 (listelm)->field.le_next = (elm); \ 123 (elm)->field.le_prev = &(listelm)->field.le_next; \ 124 } while (/*CONSTCOND*/0) 125 126 #define QLIST_INSERT_BEFORE(listelm, elm, field) do { \ 127 (elm)->field.le_prev = (listelm)->field.le_prev; \ 128 (elm)->field.le_next = (listelm); \ 129 *(listelm)->field.le_prev = (elm); \ 130 (listelm)->field.le_prev = &(elm)->field.le_next; \ 131 } while (/*CONSTCOND*/0) 132 133 #define QLIST_INSERT_HEAD(head, elm, field) do { \ 134 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 135 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 136 (head)->lh_first = (elm); \ 137 (elm)->field.le_prev = &(head)->lh_first; \ 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) \ 169 struct name { \ 170 struct type *slh_first; /* first element */ \ 171 } 172 173 #define QSLIST_HEAD_INITIALIZER(head) \ 174 { NULL } 175 176 #define QSLIST_ENTRY(type) \ 177 struct { \ 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_INSERT_HEAD_ATOMIC(head, elm, field) do { \ 199 typeof(elm) save_sle_next; \ 200 do { \ 201 save_sle_next = (elm)->field.sle_next = (head)->slh_first; \ 202 } while (atomic_cmpxchg(&(head)->slh_first, save_sle_next, (elm)) != \ 203 save_sle_next); \ 204 } while (/*CONSTCOND*/0) 205 206 #define QSLIST_MOVE_ATOMIC(dest, src) do { \ 207 (dest)->slh_first = atomic_xchg(&(src)->slh_first, NULL); \ 208 } while (/*CONSTCOND*/0) 209 210 #define QSLIST_REMOVE_HEAD(head, field) do { \ 211 (head)->slh_first = (head)->slh_first->field.sle_next; \ 212 } while (/*CONSTCOND*/0) 213 214 #define QSLIST_REMOVE_AFTER(slistelm, field) do { \ 215 (slistelm)->field.sle_next = \ 216 QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \ 217 } while (/*CONSTCOND*/0) 218 219 #define QSLIST_FOREACH(var, head, field) \ 220 for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next) 221 222 #define QSLIST_FOREACH_SAFE(var, head, field, tvar) \ 223 for ((var) = QSLIST_FIRST((head)); \ 224 (var) && ((tvar) = QSLIST_NEXT((var), field), 1); \ 225 (var) = (tvar)) 226 227 /* 228 * Singly-linked List access methods. 229 */ 230 #define QSLIST_EMPTY(head) ((head)->slh_first == NULL) 231 #define QSLIST_FIRST(head) ((head)->slh_first) 232 #define QSLIST_NEXT(elm, field) ((elm)->field.sle_next) 233 234 235 /* 236 * Simple queue definitions. 237 */ 238 #define QSIMPLEQ_HEAD(name, type) \ 239 struct name { \ 240 struct type *sqh_first; /* first element */ \ 241 struct type **sqh_last; /* addr of last next element */ \ 242 } 243 244 #define QSIMPLEQ_HEAD_INITIALIZER(head) \ 245 { NULL, &(head).sqh_first } 246 247 #define QSIMPLEQ_ENTRY(type) \ 248 struct { \ 249 struct type *sqe_next; /* next element */ \ 250 } 251 252 /* 253 * Simple queue functions. 254 */ 255 #define QSIMPLEQ_INIT(head) do { \ 256 (head)->sqh_first = NULL; \ 257 (head)->sqh_last = &(head)->sqh_first; \ 258 } while (/*CONSTCOND*/0) 259 260 #define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \ 261 if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \ 262 (head)->sqh_last = &(elm)->field.sqe_next; \ 263 (head)->sqh_first = (elm); \ 264 } while (/*CONSTCOND*/0) 265 266 #define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \ 267 (elm)->field.sqe_next = NULL; \ 268 *(head)->sqh_last = (elm); \ 269 (head)->sqh_last = &(elm)->field.sqe_next; \ 270 } while (/*CONSTCOND*/0) 271 272 #define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \ 273 if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \ 274 (head)->sqh_last = &(elm)->field.sqe_next; \ 275 (listelm)->field.sqe_next = (elm); \ 276 } while (/*CONSTCOND*/0) 277 278 #define QSIMPLEQ_REMOVE_HEAD(head, field) do { \ 279 if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\ 280 (head)->sqh_last = &(head)->sqh_first; \ 281 } while (/*CONSTCOND*/0) 282 283 #define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do { \ 284 QSIMPLEQ_INIT(removed); \ 285 if (((removed)->sqh_first = (head)->sqh_first) != NULL) { \ 286 if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) { \ 287 (head)->sqh_last = &(head)->sqh_first; \ 288 } \ 289 (removed)->sqh_last = &(elm)->field.sqe_next; \ 290 (elm)->field.sqe_next = NULL; \ 291 } \ 292 } while (/*CONSTCOND*/0) 293 294 #define QSIMPLEQ_REMOVE(head, elm, type, field) do { \ 295 if ((head)->sqh_first == (elm)) { \ 296 QSIMPLEQ_REMOVE_HEAD((head), field); \ 297 } else { \ 298 struct type *curelm = (head)->sqh_first; \ 299 while (curelm->field.sqe_next != (elm)) \ 300 curelm = curelm->field.sqe_next; \ 301 if ((curelm->field.sqe_next = \ 302 curelm->field.sqe_next->field.sqe_next) == NULL) \ 303 (head)->sqh_last = &(curelm)->field.sqe_next; \ 304 } \ 305 } while (/*CONSTCOND*/0) 306 307 #define QSIMPLEQ_FOREACH(var, head, field) \ 308 for ((var) = ((head)->sqh_first); \ 309 (var); \ 310 (var) = ((var)->field.sqe_next)) 311 312 #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \ 313 for ((var) = ((head)->sqh_first); \ 314 (var) && ((next = ((var)->field.sqe_next)), 1); \ 315 (var) = (next)) 316 317 #define QSIMPLEQ_CONCAT(head1, head2) do { \ 318 if (!QSIMPLEQ_EMPTY((head2))) { \ 319 *(head1)->sqh_last = (head2)->sqh_first; \ 320 (head1)->sqh_last = (head2)->sqh_last; \ 321 QSIMPLEQ_INIT((head2)); \ 322 } \ 323 } while (/*CONSTCOND*/0) 324 325 #define QSIMPLEQ_PREPEND(head1, head2) do { \ 326 if (!QSIMPLEQ_EMPTY((head2))) { \ 327 *(head2)->sqh_last = (head1)->sqh_first; \ 328 (head1)->sqh_first = (head2)->sqh_first; \ 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_ATOMIC(head) (atomic_read(&((head)->sqh_first)) == NULL) 343 #define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL) 344 #define QSIMPLEQ_FIRST(head) ((head)->sqh_first) 345 #define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next) 346 347 typedef struct QTailQLink { 348 void *tql_next; 349 struct QTailQLink *tql_prev; 350 } QTailQLink; 351 352 /* 353 * Tail queue definitions. The union acts as a poor man template, as if 354 * it were QTailQLink<type>. 355 */ 356 #define QTAILQ_HEAD(name, type) \ 357 union name { \ 358 struct type *tqh_first; /* first element */ \ 359 QTailQLink tqh_circ; /* link for circular backwards list */ \ 360 } 361 362 #define QTAILQ_HEAD_INITIALIZER(head) \ 363 { .tqh_circ = { NULL, &(head).tqh_circ } } 364 365 #define QTAILQ_ENTRY(type) \ 366 union { \ 367 struct type *tqe_next; /* next element */ \ 368 QTailQLink tqe_circ; /* link for circular backwards list */ \ 369 } 370 371 /* 372 * Tail queue functions. 373 */ 374 #define QTAILQ_INIT(head) do { \ 375 (head)->tqh_first = NULL; \ 376 (head)->tqh_circ.tql_prev = &(head)->tqh_circ; \ 377 } while (/*CONSTCOND*/0) 378 379 #define QTAILQ_INSERT_HEAD(head, elm, field) do { \ 380 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 381 (head)->tqh_first->field.tqe_circ.tql_prev = \ 382 &(elm)->field.tqe_circ; \ 383 else \ 384 (head)->tqh_circ.tql_prev = &(elm)->field.tqe_circ; \ 385 (head)->tqh_first = (elm); \ 386 (elm)->field.tqe_circ.tql_prev = &(head)->tqh_circ; \ 387 } while (/*CONSTCOND*/0) 388 389 #define QTAILQ_INSERT_TAIL(head, elm, field) do { \ 390 (elm)->field.tqe_next = NULL; \ 391 (elm)->field.tqe_circ.tql_prev = (head)->tqh_circ.tql_prev; \ 392 (head)->tqh_circ.tql_prev->tql_next = (elm); \ 393 (head)->tqh_circ.tql_prev = &(elm)->field.tqe_circ; \ 394 } while (/*CONSTCOND*/0) 395 396 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 397 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 398 (elm)->field.tqe_next->field.tqe_circ.tql_prev = \ 399 &(elm)->field.tqe_circ; \ 400 else \ 401 (head)->tqh_circ.tql_prev = &(elm)->field.tqe_circ; \ 402 (listelm)->field.tqe_next = (elm); \ 403 (elm)->field.tqe_circ.tql_prev = &(listelm)->field.tqe_circ; \ 404 } while (/*CONSTCOND*/0) 405 406 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 407 (elm)->field.tqe_circ.tql_prev = (listelm)->field.tqe_circ.tql_prev; \ 408 (elm)->field.tqe_next = (listelm); \ 409 (listelm)->field.tqe_circ.tql_prev->tql_next = (elm); \ 410 (listelm)->field.tqe_circ.tql_prev = &(elm)->field.tqe_circ; \ 411 } while (/*CONSTCOND*/0) 412 413 #define QTAILQ_REMOVE(head, elm, field) do { \ 414 if (((elm)->field.tqe_next) != NULL) \ 415 (elm)->field.tqe_next->field.tqe_circ.tql_prev = \ 416 (elm)->field.tqe_circ.tql_prev; \ 417 else \ 418 (head)->tqh_circ.tql_prev = (elm)->field.tqe_circ.tql_prev; \ 419 (elm)->field.tqe_circ.tql_prev->tql_next = (elm)->field.tqe_next; \ 420 (elm)->field.tqe_circ.tql_prev = NULL; \ 421 } while (/*CONSTCOND*/0) 422 423 /* remove @left, @right and all elements in between from @head */ 424 #define QTAILQ_REMOVE_SEVERAL(head, left, right, field) do { \ 425 if (((right)->field.tqe_next) != NULL) \ 426 (right)->field.tqe_next->field.tqe_circ.tql_prev = \ 427 (left)->field.tqe_circ.tql_prev; \ 428 else \ 429 (head)->tqh_circ.tql_prev = (left)->field.tqe_circ.tql_prev; \ 430 (left)->field.tqe_circ.tql_prev->tql_next = (right)->field.tqe_next; \ 431 } while (/*CONSTCOND*/0) 432 433 #define QTAILQ_FOREACH(var, head, field) \ 434 for ((var) = ((head)->tqh_first); \ 435 (var); \ 436 (var) = ((var)->field.tqe_next)) 437 438 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \ 439 for ((var) = ((head)->tqh_first); \ 440 (var) && ((next_var) = ((var)->field.tqe_next), 1); \ 441 (var) = (next_var)) 442 443 #define QTAILQ_FOREACH_REVERSE(var, head, field) \ 444 for ((var) = QTAILQ_LAST(head); \ 445 (var); \ 446 (var) = QTAILQ_PREV(var, field)) 447 448 #define QTAILQ_FOREACH_REVERSE_SAFE(var, head, field, prev_var) \ 449 for ((var) = QTAILQ_LAST(head); \ 450 (var) && ((prev_var) = QTAILQ_PREV(var, field), 1); \ 451 (var) = (prev_var)) 452 453 /* 454 * Tail queue access methods. 455 */ 456 #define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL) 457 #define QTAILQ_FIRST(head) ((head)->tqh_first) 458 #define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 459 #define QTAILQ_IN_USE(elm, field) ((elm)->field.tqe_circ.tql_prev != NULL) 460 461 #define QTAILQ_LINK_PREV(link) \ 462 ((link).tql_prev->tql_prev->tql_next) 463 #define QTAILQ_LAST(head) \ 464 ((typeof((head)->tqh_first)) QTAILQ_LINK_PREV((head)->tqh_circ)) 465 #define QTAILQ_PREV(elm, field) \ 466 ((typeof((elm)->field.tqe_next)) QTAILQ_LINK_PREV((elm)->field.tqe_circ)) 467 468 #define field_at_offset(base, offset, type) \ 469 ((type *) (((char *) (base)) + (offset))) 470 471 /* 472 * Raw access of elements of a tail queue head. Offsets are all zero 473 * because it's a union. 474 */ 475 #define QTAILQ_RAW_FIRST(head) \ 476 field_at_offset(head, 0, void *) 477 #define QTAILQ_RAW_TQH_CIRC(head) \ 478 field_at_offset(head, 0, QTailQLink) 479 480 /* 481 * Raw access of elements of a tail entry 482 */ 483 #define QTAILQ_RAW_NEXT(elm, entry) \ 484 field_at_offset(elm, entry, void *) 485 #define QTAILQ_RAW_TQE_CIRC(elm, entry) \ 486 field_at_offset(elm, entry, QTailQLink) 487 /* 488 * Tail queue traversal using pointer arithmetic. 489 */ 490 #define QTAILQ_RAW_FOREACH(elm, head, entry) \ 491 for ((elm) = *QTAILQ_RAW_FIRST(head); \ 492 (elm); \ 493 (elm) = *QTAILQ_RAW_NEXT(elm, entry)) 494 /* 495 * Tail queue insertion using pointer arithmetic. 496 */ 497 #define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do { \ 498 *QTAILQ_RAW_NEXT(elm, entry) = NULL; \ 499 QTAILQ_RAW_TQE_CIRC(elm, entry)->tql_prev = QTAILQ_RAW_TQH_CIRC(head)->tql_prev; \ 500 QTAILQ_RAW_TQH_CIRC(head)->tql_prev->tql_next = (elm); \ 501 QTAILQ_RAW_TQH_CIRC(head)->tql_prev = QTAILQ_RAW_TQE_CIRC(elm, entry); \ 502 } while (/*CONSTCOND*/0) 503 504 #endif /* QEMU_SYS_QUEUE_H */ 505