qemu-queue.h

   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 lists, simple queues, tail queues and
   6  * circular 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:
  45  * lists, simple queues, tail queues, and circular queues.
  46  *
  47  * A list is headed by a single forward pointer (or an array of forward
  48  * pointers for a hash table header). The elements are doubly linked
  49  * so that an arbitrary element can be removed without a need to
  50  * traverse the list. New elements can be added to the list before
  51  * or after an existing element or at the head of the list. A list
  52  * may only be traversed in the forward direction.
  53  *
  54  * A simple queue is headed by a pair of pointers, one the head of the
  55  * list and the other to the tail of the list. The elements are singly
  56  * linked to save space, so elements can only be removed from the
  57  * head of the list. New elements can be added to the list after
  58  * an existing element, at the head of the list, or at the end of the
  59  * list. A simple queue may only be traversed in the forward direction.
  60  *
  61  * A tail queue is headed by a pair of pointers, one to the head of the
  62  * list and the other to the tail of the list. The elements are doubly
  63  * linked so that an arbitrary element can be removed without a need to
  64  * traverse the list. New elements can be added to the list before or
  65  * after an existing element, at the head of the list, or at the end of
  66  * the list. A tail queue may be traversed in either direction.
  67  *
  68  * A circle queue is headed by a pair of pointers, one to the head of the
  69  * list and the other to the tail of the list. The elements are doubly
  70  * linked so that an arbitrary element can be removed without a need to
  71  * traverse the list. New elements can be added to the list before or after
  72  * an existing element, at the head of the list, or at the end of the list.
  73  * A circle queue may be traversed in either direction, but has a more
  74  * complex end of list detection.
  75  *
  76  * For details on the use of these macros, see the queue(3) manual page.
  77  */
  78
  79 #include "qemu-barrier.h" /* for smp_wmb() */
  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_INSERT_AFTER(listelm, elm, field) do {                    \
 106         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 107                 (listelm)->field.le_next->field.le_prev =               \
 108                     &(elm)->field.le_next;                              \
 109         (listelm)->field.le_next = (elm);                               \
 110         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 111 } while (/*CONSTCOND*/0)
 112
 113 #define QLIST_INSERT_BEFORE(listelm, elm, field) do {                   \
 114         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 115         (elm)->field.le_next = (listelm);                               \
 116         *(listelm)->field.le_prev = (elm);                              \
 117         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 118 } while (/*CONSTCOND*/0)
 119
 120 #define QLIST_INSERT_HEAD(head, elm, field) do {                        \
 121         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 122                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 123         (head)->lh_first = (elm);                                       \
 124         (elm)->field.le_prev = &(head)->lh_first;                       \
 125 } while (/*CONSTCOND*/0)
 126
 127 #define QLIST_INSERT_HEAD_RCU(head, elm, field) do {                    \
 128         (elm)->field.le_prev = &(head)->lh_first;                       \
 129         (elm)->field.le_next = (head)->lh_first;                        \
 130         smp_wmb(); /* fill elm before linking it */                     \
 131         if ((head)->lh_first != NULL)  {                                \
 132             (head)->lh_first->field.le_prev = &(elm)->field.le_next;    \
 133         }                                                               \
 134         (head)->lh_first = (elm);                                       \
 135         smp_wmb();                                                      \
 136 } while (/* CONSTCOND*/0)
 137
 138 #define QLIST_REMOVE(elm, field) do {                                   \
 139         if ((elm)->field.le_next != NULL)                               \
 140                 (elm)->field.le_next->field.le_prev =                   \
 141                     (elm)->field.le_prev;                               \
 142         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 143 } while (/*CONSTCOND*/0)
 144
 145 #define QLIST_FOREACH(var, head, field)                                 \
 146         for ((var) = ((head)->lh_first);                                \
 147                 (var);                                                  \
 148                 (var) = ((var)->field.le_next))
 149
 150 #define QLIST_FOREACH_SAFE(var, head, field, next_var)                  \
 151         for ((var) = ((head)->lh_first);                                \
 152                 (var) && ((next_var) = ((var)->field.le_next), 1);      \
 153                 (var) = (next_var))
 154
 155 /*
 156  * List access methods.
 157  */
 158 #define QLIST_EMPTY(head)                ((head)->lh_first == NULL)
 159 #define QLIST_FIRST(head)                ((head)->lh_first)
 160 #define QLIST_NEXT(elm, field)           ((elm)->field.le_next)
 161
 162
 163 /*
 164  * Simple queue definitions.
 165  */
 166 #define QSIMPLEQ_HEAD(name, type)                                       \
 167 struct name {                                                           \
 168     struct type *sqh_first;    /* first element */                      \
 169     struct type **sqh_last;    /* addr of last next element */          \
 170 }
 171
 172 #define QSIMPLEQ_HEAD_INITIALIZER(head)                                 \
 173     { NULL, &(head).sqh_first }
 174
 175 #define QSIMPLEQ_ENTRY(type)                                            \
 176 struct {                                                                \
 177     struct type *sqe_next;    /* next element */                        \
 178 }
 179
 180 /*
 181  * Simple queue functions.
 182  */
 183 #define QSIMPLEQ_INIT(head) do {                                        \
 184     (head)->sqh_first = NULL;                                           \
 185     (head)->sqh_last = &(head)->sqh_first;                              \
 186 } while (/*CONSTCOND*/0)
 187
 188 #define QSIMPLEQ_INSERT_HEAD(head, elm, field) do {                     \
 189     if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)            \
 190         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 191     (head)->sqh_first = (elm);                                          \
 192 } while (/*CONSTCOND*/0)
 193
 194 #define QSIMPLEQ_INSERT_TAIL(head, elm, field) do {                     \
 195     (elm)->field.sqe_next = NULL;                                       \
 196     *(head)->sqh_last = (elm);                                          \
 197     (head)->sqh_last = &(elm)->field.sqe_next;                          \
 198 } while (/*CONSTCOND*/0)
 199
 200 #define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
 201     if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)    \
 202         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 203     (listelm)->field.sqe_next = (elm);                                  \
 204 } while (/*CONSTCOND*/0)
 205
 206 #define QSIMPLEQ_REMOVE_HEAD(head, field) do {                          \
 207     if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\
 208         (head)->sqh_last = &(head)->sqh_first;                          \
 209 } while (/*CONSTCOND*/0)
 210
 211 #define QSIMPLEQ_REMOVE(head, elm, type, field) do {                    \
 212     if ((head)->sqh_first == (elm)) {                                   \
 213         QSIMPLEQ_REMOVE_HEAD((head), field);                            \
 214     } else {                                                            \
 215         struct type *curelm = (head)->sqh_first;                        \
 216         while (curelm->field.sqe_next != (elm))                         \
 217             curelm = curelm->field.sqe_next;                            \
 218         if ((curelm->field.sqe_next =                                   \
 219             curelm->field.sqe_next->field.sqe_next) == NULL)            \
 220                 (head)->sqh_last = &(curelm)->field.sqe_next;           \
 221     }                                                                   \
 222 } while (/*CONSTCOND*/0)
 223
 224 #define QSIMPLEQ_FOREACH(var, head, field)                              \
 225     for ((var) = ((head)->sqh_first);                                   \
 226         (var);                                                          \
 227         (var) = ((var)->field.sqe_next))
 228
 229 #define QSIMPLEQ_FOREACH_SAFE(var, head, field, next)                   \
 230     for ((var) = ((head)->sqh_first);                                   \
 231         (var) && ((next = ((var)->field.sqe_next)), 1);                 \
 232         (var) = (next))
 233
 234 #define QSIMPLEQ_CONCAT(head1, head2) do {                              \
 235     if (!QSIMPLEQ_EMPTY((head2))) {                                     \
 236         *(head1)->sqh_last = (head2)->sqh_first;                        \
 237         (head1)->sqh_last = (head2)->sqh_last;                          \
 238         QSIMPLEQ_INIT((head2));                                         \
 239     }                                                                   \
 240 } while (/*CONSTCOND*/0)
 241
 242 #define QSIMPLEQ_LAST(head, type, field)                                \
 243     (QSIMPLEQ_EMPTY((head)) ?                                           \
 244         NULL :                                                          \
 245             ((struct type *)(void *)                                    \
 246         ((char *)((head)->sqh_last) - offsetof(struct type, field))))
 247
 248 /*
 249  * Simple queue access methods.
 250  */
 251 #define QSIMPLEQ_EMPTY(head)        ((head)->sqh_first == NULL)
 252 #define QSIMPLEQ_FIRST(head)        ((head)->sqh_first)
 253 #define QSIMPLEQ_NEXT(elm, field)   ((elm)->field.sqe_next)
 254
 255
 256 /*
 257  * Tail queue definitions.
 258  */
 259 #define Q_TAILQ_HEAD(name, type, qual)                                  \
 260 struct name {                                                           \
 261         qual type *tqh_first;           /* first element */             \
 262         qual type *qual *tqh_last;      /* addr of last next element */ \
 263 }
 264 #define QTAILQ_HEAD(name, type)  Q_TAILQ_HEAD(name, struct type,)
 265
 266 #define QTAILQ_HEAD_INITIALIZER(head)                                   \
 267         { NULL, &(head).tqh_first }
 268
 269 #define Q_TAILQ_ENTRY(type, qual)                                       \
 270 struct {                                                                \
 271         qual type *tqe_next;            /* next element */              \
 272         qual type *qual *tqe_prev;      /* address of previous next element */\
 273 }
 274 #define QTAILQ_ENTRY(type)       Q_TAILQ_ENTRY(struct type,)
 275
 276 /*
 277  * Tail queue functions.
 278  */
 279 #define QTAILQ_INIT(head) do {                                          \
 280         (head)->tqh_first = NULL;                                       \
 281         (head)->tqh_last = &(head)->tqh_first;                          \
 282 } while (/*CONSTCOND*/0)
 283
 284 #define QTAILQ_INSERT_HEAD(head, elm, field) do {                       \
 285         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 286                 (head)->tqh_first->field.tqe_prev =                     \
 287                     &(elm)->field.tqe_next;                             \
 288         else                                                            \
 289                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 290         (head)->tqh_first = (elm);                                      \
 291         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 292 } while (/*CONSTCOND*/0)
 293
 294 #define QTAILQ_INSERT_TAIL(head, elm, field) do {                       \
 295         (elm)->field.tqe_next = NULL;                                   \
 296         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 297         *(head)->tqh_last = (elm);                                      \
 298         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 299 } while (/*CONSTCOND*/0)
 300
 301 #define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
 302         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 303                 (elm)->field.tqe_next->field.tqe_prev =                 \
 304                     &(elm)->field.tqe_next;                             \
 305         else                                                            \
 306                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 307         (listelm)->field.tqe_next = (elm);                              \
 308         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 309 } while (/*CONSTCOND*/0)
 310
 311 #define QTAILQ_INSERT_BEFORE(listelm, elm, field) do {                  \
 312         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 313         (elm)->field.tqe_next = (listelm);                              \
 314         *(listelm)->field.tqe_prev = (elm);                             \
 315         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 316 } while (/*CONSTCOND*/0)
 317
 318 #define QTAILQ_REMOVE(head, elm, field) do {                            \
 319         if (((elm)->field.tqe_next) != NULL)                            \
 320                 (elm)->field.tqe_next->field.tqe_prev =                 \
 321                     (elm)->field.tqe_prev;                              \
 322         else                                                            \
 323                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 324         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 325 } while (/*CONSTCOND*/0)
 326
 327 #define QTAILQ_FOREACH(var, head, field)                                \
 328         for ((var) = ((head)->tqh_first);                               \
 329                 (var);                                                  \
 330                 (var) = ((var)->field.tqe_next))
 331
 332 #define QTAILQ_FOREACH_SAFE(var, head, field, next_var)                 \
 333         for ((var) = ((head)->tqh_first);                               \
 334                 (var) && ((next_var) = ((var)->field.tqe_next), 1);     \
 335                 (var) = (next_var))
 336
 337 #define QTAILQ_FOREACH_REVERSE(var, head, headname, field)              \
 338         for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \
 339                 (var);                                                  \
 340                 (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
 341
 342 /*
 343  * Tail queue access methods.
 344  */
 345 #define QTAILQ_EMPTY(head)               ((head)->tqh_first == NULL)
 346 #define QTAILQ_FIRST(head)               ((head)->tqh_first)
 347 #define QTAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 348
 349 #define QTAILQ_LAST(head, headname) \
 350         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 351 #define QTAILQ_PREV(elm, headname, field) \
 352         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 353
 354
 355 /*
 356  * Circular queue definitions.
 357  */
 358 #define QCIRCLEQ_HEAD(name, type)                                       \
 359 struct name {                                                           \
 360         struct type *cqh_first;         /* first element */             \
 361         struct type *cqh_last;          /* last element */              \
 362 }
 363
 364 #define QCIRCLEQ_HEAD_INITIALIZER(head)                                 \
 365         { (void *)&head, (void *)&head }
 366
 367 #define QCIRCLEQ_ENTRY(type)                                            \
 368 struct {                                                                \
 369         struct type *cqe_next;          /* next element */              \
 370         struct type *cqe_prev;          /* previous element */          \
 371 }
 372
 373 /*
 374  * Circular queue functions.
 375  */
 376 #define QCIRCLEQ_INIT(head) do {                                        \
 377         (head)->cqh_first = (void *)(head);                             \
 378         (head)->cqh_last = (void *)(head);                              \
 379 } while (/*CONSTCOND*/0)
 380
 381 #define QCIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
 382         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 383         (elm)->field.cqe_prev = (listelm);                              \
 384         if ((listelm)->field.cqe_next == (void *)(head))                \
 385                 (head)->cqh_last = (elm);                               \
 386         else                                                            \
 387                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 388         (listelm)->field.cqe_next = (elm);                              \
 389 } while (/*CONSTCOND*/0)
 390
 391 #define QCIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {          \
 392         (elm)->field.cqe_next = (listelm);                              \
 393         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 394         if ((listelm)->field.cqe_prev == (void *)(head))                \
 395                 (head)->cqh_first = (elm);                              \
 396         else                                                            \
 397                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 398         (listelm)->field.cqe_prev = (elm);                              \
 399 } while (/*CONSTCOND*/0)
 400
 401 #define QCIRCLEQ_INSERT_HEAD(head, elm, field) do {                     \
 402         (elm)->field.cqe_next = (head)->cqh_first;                      \
 403         (elm)->field.cqe_prev = (void *)(head);                         \
 404         if ((head)->cqh_last == (void *)(head))                         \
 405                 (head)->cqh_last = (elm);                               \
 406         else                                                            \
 407                 (head)->cqh_first->field.cqe_prev = (elm);              \
 408         (head)->cqh_first = (elm);                                      \
 409 } while (/*CONSTCOND*/0)
 410
 411 #define QCIRCLEQ_INSERT_TAIL(head, elm, field) do {                     \
 412         (elm)->field.cqe_next = (void *)(head);                         \
 413         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 414         if ((head)->cqh_first == (void *)(head))                        \
 415                 (head)->cqh_first = (elm);                              \
 416         else                                                            \
 417                 (head)->cqh_last->field.cqe_next = (elm);               \
 418         (head)->cqh_last = (elm);                                       \
 419 } while (/*CONSTCOND*/0)
 420
 421 #define QCIRCLEQ_REMOVE(head, elm, field) do {                          \
 422         if ((elm)->field.cqe_next == (void *)(head))                    \
 423                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 424         else                                                            \
 425                 (elm)->field.cqe_next->field.cqe_prev =                 \
 426                     (elm)->field.cqe_prev;                              \
 427         if ((elm)->field.cqe_prev == (void *)(head))                    \
 428                 (head)->cqh_first = (elm)->field.cqe_next;              \
 429         else                                                            \
 430                 (elm)->field.cqe_prev->field.cqe_next =                 \
 431                     (elm)->field.cqe_next;                              \
 432 } while (/*CONSTCOND*/0)
 433
 434 #define QCIRCLEQ_FOREACH(var, head, field)                              \
 435         for ((var) = ((head)->cqh_first);                               \
 436                 (var) != (const void *)(head);                          \
 437                 (var) = ((var)->field.cqe_next))
 438
 439 #define QCIRCLEQ_FOREACH_REVERSE(var, head, field)                      \
 440         for ((var) = ((head)->cqh_last);                                \
 441                 (var) != (const void *)(head);                          \
 442                 (var) = ((var)->field.cqe_prev))
 443
 444 /*
 445  * Circular queue access methods.
 446  */
 447 #define QCIRCLEQ_EMPTY(head)             ((head)->cqh_first == (void *)(head))
 448 #define QCIRCLEQ_FIRST(head)             ((head)->cqh_first)
 449 #define QCIRCLEQ_LAST(head)              ((head)->cqh_last)
 450 #define QCIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 451 #define QCIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 452
 453 #define QCIRCLEQ_LOOP_NEXT(head, elm, field)                            \
 454         (((elm)->field.cqe_next == (void *)(head))                      \
 455             ? ((head)->cqh_first)                                       \
 456             : (elm->field.cqe_next))
 457 #define QCIRCLEQ_LOOP_PREV(head, elm, field)                            \
 458         (((elm)->field.cqe_prev == (void *)(head))                      \
 459             ? ((head)->cqh_last)                                        \
 460             : (elm->field.cqe_prev))
 461
 462 #endif  /* !QEMU_SYS_QUEUE_H_ */