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 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-barrier.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_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)                                          \
 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_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)                                       \
 227 struct 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)                                            \
 236 struct {                                                                \
 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)                                  \
 320 struct 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)                                       \
 330 struct {                                                                \
 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_ */