arch/avr/include/sys/queue.h

   1 /*
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  30  */
  31
  32 #ifndef _SYS_QUEUE_H_
  33 #define _SYS_QUEUE_H_
  34
  35 /*
  36  * This file defines five types of data structures: singly-linked lists,
  37  * lists, simple queues, tail queues, and circular queues.
  38  *
  39  * A singly-linked list is headed by a single forward pointer. The
  40  * elements are singly linked for minimum space and pointer manipulation
  41  * overhead at the expense of O(n) removal for arbitrary elements. New
  42  * elements can be added to the list after an existing element or at the
  43  * head of the list.  Elements being removed from the head of the list
  44  * should use the explicit macro for this purpose for optimum
  45  * efficiency. A singly-linked list may only be traversed in the forward
  46  * direction.  Singly-linked lists are ideal for applications with large
  47  * datasets and few or no removals or for implementing a LIFO queue.
  48  *
  49  * A list is headed by a single forward pointer (or an array of forward
  50  * pointers for a hash table header). The elements are doubly linked
  51  * so that an arbitrary element can be removed without a need to
  52  * traverse the list. New elements can be added to the list before
  53  * or after an existing element or at the head of the list. A list
  54  * may only be traversed in the forward direction.
  55  *
  56  * A simple queue is headed by a pair of pointers, one the head of the
  57  * list and the other to the tail of the list. The elements are singly
  58  * linked to save space, so elements can only be removed from the
  59  * head of the list. New elements can be added to the list after
  60  * an existing element, at the head of the list, or at the end of the
  61  * list. A simple queue may only be traversed in the forward direction.
  62  *
  63  * A tail queue is headed by a pair of pointers, one to the head of the
  64  * list and the other to the tail of the list. The elements are doubly
  65  * linked so that an arbitrary element can be removed without a need to
  66  * traverse the list. New elements can be added to the list before or
  67  * after an existing element, at the head of the list, or at the end of
  68  * the list. A tail queue may be traversed in either direction.
  69  *
  70  * A circle queue is headed by a pair of pointers, one to the head of the
  71  * list and the other to the tail of the list. The elements are doubly
  72  * linked so that an arbitrary element can be removed without a need to
  73  * traverse the list. New elements can be added to the list before or after
  74  * an existing element, at the head of the list, or at the end of the list.
  75  * A circle queue may be traversed in either direction, but has a more
  76  * complex end of list detection.
  77  *
  78  * For details on the use of these macros, see the queue(3) manual page.
  79  */
  80
  81 /*
  82  * Include the definition of NULL only on NetBSD because sys/null.h
  83  * is not available elsewhere.  This conditional makes the header
  84  * portable and it can simply be dropped verbatim into any system.
  85  * The caveat is that on other systems some other header
  86  * must provide NULL before the macros can be used.
  87  */
  88 #ifdef __NetBSD__
  89 #include <sys/null.h>
  90 #endif
  91
  92 #if defined(QUEUEDEBUG)
  93 # if defined(_KERNEL)
  94 #  define QUEUEDEBUG_ABORT(...) panic(__VA_ARGS__)
  95 # else
  96 #  include <err.h>
  97 #  define QUEUEDEBUG_ABORT(...) err(1, __VA_ARGS__)
  98 # endif
  99 #endif
 100
 101 /*
 102  * Singly-linked List definitions.
 103  */
 104 #define SLIST_HEAD(name, type)                                          \
 105 struct name {                                                           \
 106         struct type *slh_first; /* first element */                     \
 107 }
 108
 109 #define SLIST_HEAD_INITIALIZER(head)                                    \
 110         { NULL }
 111
 112 #define SLIST_ENTRY(type)                                               \
 113 struct {                                                                \
 114         struct type *sle_next;  /* next element */                      \
 115 }
 116
 117 /*
 118  * Singly-linked List access methods.
 119  */
 120 #define SLIST_FIRST(head)       ((head)->slh_first)
 121 #define SLIST_END(head)         NULL
 122 #define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 123 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 124
 125 #define SLIST_FOREACH(var, head, field)                                 \
 126         for((var) = (head)->slh_first;                                  \
 127             (var) != SLIST_END(head);                                   \
 128             (var) = (var)->field.sle_next)
 129
 130 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 131         for ((var) = SLIST_FIRST((head));                               \
 132             (var) != SLIST_END(head) &&                                 \
 133             ((tvar) = SLIST_NEXT((var), field), 1);                     \
 134             (var) = (tvar))
 135
 136 /*
 137  * Singly-linked List functions.
 138  */
 139 #define SLIST_INIT(head) do {                                           \
 140         (head)->slh_first = SLIST_END(head);                            \
 141 } while (/*CONSTCOND*/0)
 142
 143 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 144         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 145         (slistelm)->field.sle_next = (elm);                             \
 146 } while (/*CONSTCOND*/0)
 147
 148 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 149         (elm)->field.sle_next = (head)->slh_first;                      \
 150         (head)->slh_first = (elm);                                      \
 151 } while (/*CONSTCOND*/0)
 152
 153 #define SLIST_REMOVE_AFTER(slistelm, field) do {                        \
 154         (slistelm)->field.sle_next =                                    \
 155             SLIST_NEXT(SLIST_NEXT((slistelm), field), field);           \
 156 } while (/*CONSTCOND*/0)
 157
 158 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 159         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 160 } while (/*CONSTCOND*/0)
 161
 162 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 163         if ((head)->slh_first == (elm)) {                               \
 164                 SLIST_REMOVE_HEAD((head), field);                       \
 165         }                                                               \
 166         else {                                                          \
 167                 struct type *curelm = (head)->slh_first;                \
 168                 while(curelm->field.sle_next != (elm))                  \
 169                         curelm = curelm->field.sle_next;                \
 170                 curelm->field.sle_next =                                \
 171                     curelm->field.sle_next->field.sle_next;             \
 172         }                                                               \
 173 } while (/*CONSTCOND*/0)
 174
 175
 176 /*
 177  * List definitions.
 178  */
 179 #define LIST_HEAD(name, type)                                           \
 180 struct name {                                                           \
 181         struct type *lh_first;  /* first element */                     \
 182 }
 183
 184 #define LIST_HEAD_INITIALIZER(head)                                     \
 185         { NULL }
 186
 187 #define LIST_ENTRY(type)                                                \
 188 struct {                                                                \
 189         struct type *le_next;   /* next element */                      \
 190         struct type **le_prev;  /* address of previous next element */  \
 191 }
 192
 193 /*
 194  * List access methods.
 195  */
 196 #define LIST_FIRST(head)                ((head)->lh_first)
 197 #define LIST_END(head)                  NULL
 198 #define LIST_EMPTY(head)                ((head)->lh_first == LIST_END(head))
 199 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 200
 201 #define LIST_FOREACH(var, head, field)                                  \
 202         for ((var) = ((head)->lh_first);                                \
 203             (var) != LIST_END(head);                                    \
 204             (var) = ((var)->field.le_next))
 205
 206 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 207         for ((var) = LIST_FIRST((head));                                \
 208             (var) != LIST_END(head) &&                                  \
 209             ((tvar) = LIST_NEXT((var), field), 1);                      \
 210             (var) = (tvar))
 211
 212 #define LIST_MOVE(head1, head2) do {                                    \
 213         LIST_INIT((head2));                                             \
 214         if (!LIST_EMPTY((head1))) {                                     \
 215                 (head2)->lh_first = (head1)->lh_first;                  \
 216                 LIST_INIT((head1));                                     \
 217         }                                                               \
 218 } while (/*CONSTCOND*/0)
 219
 220 /*
 221  * List functions.
 222  */
 223 #if defined(QUEUEDEBUG)
 224 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)                   \
 225         if ((head)->lh_first &&                                         \
 226             (head)->lh_first->field.le_prev != &(head)->lh_first)       \
 227                 QUEUEDEBUG_ABORT("LIST_INSERT_HEAD %p %s:%d", (head),   \
 228                     __FILE__, __LINE__);
 229 #define QUEUEDEBUG_LIST_OP(elm, field)                                  \
 230         if ((elm)->field.le_next &&                                     \
 231             (elm)->field.le_next->field.le_prev !=                      \
 232             &(elm)->field.le_next)                                      \
 233                 QUEUEDEBUG_ABORT("LIST_* forw %p %s:%d", (elm),         \
 234                     __FILE__, __LINE__);                                \
 235         if (*(elm)->field.le_prev != (elm))                             \
 236                 QUEUEDEBUG_ABORT("LIST_* back %p %s:%d", (elm),         \
 237                     __FILE__, __LINE__);
 238 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field)                          \
 239         (elm)->field.le_next = (void *)1L;                              \
 240         (elm)->field.le_prev = (void *)1L;
 241 #else
 242 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)
 243 #define QUEUEDEBUG_LIST_OP(elm, field)
 244 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field)
 245 #endif
 246
 247 #define LIST_INIT(head) do {                                            \
 248         (head)->lh_first = LIST_END(head);                              \
 249 } while (/*CONSTCOND*/0)
 250
 251 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 252         QUEUEDEBUG_LIST_OP((listelm), field)                            \
 253         if (((elm)->field.le_next = (listelm)->field.le_next) !=        \
 254             LIST_END(head))                                             \
 255                 (listelm)->field.le_next->field.le_prev =               \
 256                     &(elm)->field.le_next;                              \
 257         (listelm)->field.le_next = (elm);                               \
 258         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 259 } while (/*CONSTCOND*/0)
 260
 261 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 262         QUEUEDEBUG_LIST_OP((listelm), field)                            \
 263         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 264         (elm)->field.le_next = (listelm);                               \
 265         *(listelm)->field.le_prev = (elm);                              \
 266         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 267 } while (/*CONSTCOND*/0)
 268
 269 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 270         QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field)               \
 271         if (((elm)->field.le_next = (head)->lh_first) != LIST_END(head))\
 272                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 273         (head)->lh_first = (elm);                                       \
 274         (elm)->field.le_prev = &(head)->lh_first;                       \
 275 } while (/*CONSTCOND*/0)
 276
 277 #define LIST_REMOVE(elm, field) do {                                    \
 278         QUEUEDEBUG_LIST_OP((elm), field)                                \
 279         if ((elm)->field.le_next != NULL)                               \
 280                 (elm)->field.le_next->field.le_prev =                   \
 281                     (elm)->field.le_prev;                               \
 282         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 283         QUEUEDEBUG_LIST_POSTREMOVE((elm), field)                        \
 284 } while (/*CONSTCOND*/0)
 285
 286 #define LIST_REPLACE(elm, elm2, field) do {                             \
 287         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 288                 (elm2)->field.le_next->field.le_prev =                  \
 289                     &(elm2)->field.le_next;                             \
 290         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 291         *(elm2)->field.le_prev = (elm2);                                \
 292         QUEUEDEBUG_LIST_POSTREMOVE((elm), field)                        \
 293 } while (/*CONSTCOND*/0)
 294
 295 /*
 296  * Simple queue definitions.
 297  */
 298 #define SIMPLEQ_HEAD(name, type)                                        \
 299 struct name {                                                           \
 300         struct type *sqh_first; /* first element */                     \
 301         struct type **sqh_last; /* addr of last next element */         \
 302 }
 303
 304 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 305         { NULL, &(head).sqh_first }
 306
 307 #define SIMPLEQ_ENTRY(type)                                             \
 308 struct {                                                                \
 309         struct type *sqe_next;  /* next element */                      \
 310 }
 311
 312 /*
 313  * Simple queue access methods.
 314  */
 315 #define SIMPLEQ_FIRST(head)             ((head)->sqh_first)
 316 #define SIMPLEQ_END(head)               NULL
 317 #define SIMPLEQ_EMPTY(head)             ((head)->sqh_first == SIMPLEQ_END(head))
 318 #define SIMPLEQ_NEXT(elm, field)        ((elm)->field.sqe_next)
 319
 320 #define SIMPLEQ_FOREACH(var, head, field)                               \
 321         for ((var) = ((head)->sqh_first);                               \
 322             (var) != SIMPLEQ_END(head);                                 \
 323             (var) = ((var)->field.sqe_next))
 324
 325 #define SIMPLEQ_FOREACH_SAFE(var, head, field, next)                    \
 326         for ((var) = ((head)->sqh_first);                               \
 327             (var) != SIMPLEQ_END(head) &&                               \
 328             ((next = ((var)->field.sqe_next)), 1);                      \
 329             (var) = (next))
 330
 331 /*
 332  * Simple queue functions.
 333  */
 334 #define SIMPLEQ_INIT(head) do {                                         \
 335         (head)->sqh_first = NULL;                                       \
 336         (head)->sqh_last = &(head)->sqh_first;                          \
 337 } while (/*CONSTCOND*/0)
 338
 339 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 340         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 341                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 342         (head)->sqh_first = (elm);                                      \
 343 } while (/*CONSTCOND*/0)
 344
 345 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 346         (elm)->field.sqe_next = NULL;                                   \
 347         *(head)->sqh_last = (elm);                                      \
 348         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 349 } while (/*CONSTCOND*/0)
 350
 351 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 352         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 353                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 354         (listelm)->field.sqe_next = (elm);                              \
 355 } while (/*CONSTCOND*/0)
 356
 357 #define SIMPLEQ_REMOVE_HEAD(head, field) do {                           \
 358         if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
 359                 (head)->sqh_last = &(head)->sqh_first;                  \
 360 } while (/*CONSTCOND*/0)
 361
 362 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) do {                     \
 363         if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
 364             == NULL)                                                    \
 365                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 366 } while (/*CONSTCOND*/0)
 367
 368 #define SIMPLEQ_REMOVE(head, elm, type, field) do {                     \
 369         if ((head)->sqh_first == (elm)) {                               \
 370                 SIMPLEQ_REMOVE_HEAD((head), field);                     \
 371         } else {                                                        \
 372                 struct type *curelm = (head)->sqh_first;                \
 373                 while (curelm->field.sqe_next != (elm))                 \
 374                         curelm = curelm->field.sqe_next;                \
 375                 if ((curelm->field.sqe_next =                           \
 376                         curelm->field.sqe_next->field.sqe_next) == NULL) \
 377                             (head)->sqh_last = &(curelm)->field.sqe_next; \
 378         }                                                               \
 379 } while (/*CONSTCOND*/0)
 380
 381 #define SIMPLEQ_CONCAT(head1, head2) do {                               \
 382         if (!SIMPLEQ_EMPTY((head2))) {                                  \
 383                 *(head1)->sqh_last = (head2)->sqh_first;                \
 384                 (head1)->sqh_last = (head2)->sqh_last;          \
 385                 SIMPLEQ_INIT((head2));                                  \
 386         }                                                               \
 387 } while (/*CONSTCOND*/0)
 388
 389 #define SIMPLEQ_LAST(head, type, field)                                 \
 390         (SIMPLEQ_EMPTY((head)) ?                                                \
 391                 NULL :                                                  \
 392                 ((struct type *)(void *)                                \
 393                 ((char *)((head)->sqh_last) - offsetof(struct type, field))))
 394
 395 /*
 396  * Tail queue definitions.
 397  */
 398 #define _TAILQ_HEAD(name, type, qual)                                   \
 399 struct name {                                                           \
 400         qual type *tqh_first;           /* first element */             \
 401         qual type *qual *tqh_last;      /* addr of last next element */ \
 402 }
 403 #define TAILQ_HEAD(name, type)  _TAILQ_HEAD(name, struct type,)
 404
 405 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 406         { TAILQ_END(head), &(head).tqh_first }
 407
 408 #define _TAILQ_ENTRY(type, qual)                                        \
 409 struct {                                                                \
 410         qual type *tqe_next;            /* next element */              \
 411         qual type *qual *tqe_prev;      /* address of previous next element */\
 412 }
 413 #define TAILQ_ENTRY(type)       _TAILQ_ENTRY(struct type,)
 414
 415 /*
 416  * Tail queue access methods.
 417  */
 418 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 419 #define TAILQ_END(head)                 (NULL)
 420 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 421 #define TAILQ_LAST(head, headname) \
 422         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 423 #define TAILQ_PREV(elm, headname, field) \
 424         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 425 #define TAILQ_EMPTY(head)               (TAILQ_FIRST(head) == TAILQ_END(head))
 426
 427
 428 #define TAILQ_FOREACH(var, head, field)                                 \
 429         for ((var) = ((head)->tqh_first);                               \
 430             (var) != TAILQ_END(head);                                   \
 431             (var) = ((var)->field.tqe_next))
 432
 433 #define TAILQ_FOREACH_SAFE(var, head, field, next)                      \
 434         for ((var) = ((head)->tqh_first);                               \
 435             (var) != TAILQ_END(head) &&                                 \
 436             ((next) = TAILQ_NEXT(var, field), 1); (var) = (next))
 437
 438 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 439         for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));\
 440             (var) != TAILQ_END(head);                                   \
 441             (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
 442
 443 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, prev)    \
 444         for ((var) = TAILQ_LAST((head), headname);                      \
 445             (var) != TAILQ_END(head) &&                                 \
 446             ((prev) = TAILQ_PREV((var), headname, field), 1); (var) = (prev))
 447
 448 /*
 449  * Tail queue functions.
 450  */
 451 #if defined(QUEUEDEBUG)
 452 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)                  \
 453         if ((head)->tqh_first &&                                        \
 454             (head)->tqh_first->field.tqe_prev != &(head)->tqh_first)    \
 455                 QUEUEDEBUG_ABORT("TAILQ_INSERT_HEAD %p %s:%d", (head),  \
 456                     __FILE__, __LINE__);
 457 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)                  \
 458         if (*(head)->tqh_last != NULL)                                  \
 459                 QUEUEDEBUG_ABORT("TAILQ_INSERT_TAIL %p %s:%d", (head),  \
 460                     __FILE__, __LINE__);
 461 #define QUEUEDEBUG_TAILQ_OP(elm, field)                                 \
 462         if ((elm)->field.tqe_next &&                                    \
 463             (elm)->field.tqe_next->field.tqe_prev !=                    \
 464             &(elm)->field.tqe_next)                                     \
 465                 QUEUEDEBUG_ABORT("TAILQ_* forw %p %s:%d", (elm),        \
 466                     __FILE__, __LINE__);                                \
 467         if (*(elm)->field.tqe_prev != (elm))                            \
 468                 QUEUEDEBUG_ABORT("TAILQ_* back %p %s:%d", (elm),        \
 469                     __FILE__, __LINE__);
 470 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)                    \
 471         if ((elm)->field.tqe_next == NULL &&                            \
 472             (head)->tqh_last != &(elm)->field.tqe_next)                 \
 473                 QUEUEDEBUG_ABORT("TAILQ_PREREMOVE head %p elm %p %s:%d",\
 474                     (head), (elm), __FILE__, __LINE__);
 475 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)                         \
 476         (elm)->field.tqe_next = (void *)1L;                             \
 477         (elm)->field.tqe_prev = (void *)1L;
 478 #else
 479 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)
 480 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)
 481 #define QUEUEDEBUG_TAILQ_OP(elm, field)
 482 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)
 483 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)
 484 #endif
 485
 486 #define TAILQ_INIT(head) do {                                           \
 487         (head)->tqh_first = TAILQ_END(head);                            \
 488         (head)->tqh_last = &(head)->tqh_first;                          \
 489 } while (/*CONSTCOND*/0)
 490
 491 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 492         QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field)              \
 493         if (((elm)->field.tqe_next = (head)->tqh_first) != TAILQ_END(head))\
 494                 (head)->tqh_first->field.tqe_prev =                     \
 495                     &(elm)->field.tqe_next;                             \
 496         else                                                            \
 497                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 498         (head)->tqh_first = (elm);                                      \
 499         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 500 } while (/*CONSTCOND*/0)
 501
 502 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 503         QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field)              \
 504         (elm)->field.tqe_next = TAILQ_END(head);                        \
 505         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 506         *(head)->tqh_last = (elm);                                      \
 507         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 508 } while (/*CONSTCOND*/0)
 509
 510 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 511         QUEUEDEBUG_TAILQ_OP((listelm), field)                           \
 512         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) !=      \
 513             TAILQ_END(head))                                            \
 514                 (elm)->field.tqe_next->field.tqe_prev =                 \
 515                     &(elm)->field.tqe_next;                             \
 516         else                                                            \
 517                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 518         (listelm)->field.tqe_next = (elm);                              \
 519         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 520 } while (/*CONSTCOND*/0)
 521
 522 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 523         QUEUEDEBUG_TAILQ_OP((listelm), field)                           \
 524         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 525         (elm)->field.tqe_next = (listelm);                              \
 526         *(listelm)->field.tqe_prev = (elm);                             \
 527         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 528 } while (/*CONSTCOND*/0)
 529
 530 #define TAILQ_REMOVE(head, elm, field) do {                             \
 531         QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field)                \
 532         QUEUEDEBUG_TAILQ_OP((elm), field)                               \
 533         if (((elm)->field.tqe_next) != TAILQ_END(head))                 \
 534                 (elm)->field.tqe_next->field.tqe_prev =                 \
 535                     (elm)->field.tqe_prev;                              \
 536         else                                                            \
 537                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 538         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 539         QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field);                      \
 540 } while (/*CONSTCOND*/0)
 541
 542 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 543         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) !=         \
 544             TAILQ_END(head))                                            \
 545                 (elm2)->field.tqe_next->field.tqe_prev =                \
 546                     &(elm2)->field.tqe_next;                            \
 547         else                                                            \
 548                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 549         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 550         *(elm2)->field.tqe_prev = (elm2);                               \
 551         QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field);                      \
 552 } while (/*CONSTCOND*/0)
 553
 554 #define TAILQ_CONCAT(head1, head2, field) do {                          \
 555         if (!TAILQ_EMPTY(head2)) {                                      \
 556                 *(head1)->tqh_last = (head2)->tqh_first;                \
 557                 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
 558                 (head1)->tqh_last = (head2)->tqh_last;                  \
 559                 TAILQ_INIT((head2));                                    \
 560         }                                                               \
 561 } while (/*CONSTCOND*/0)
 562
 563 /*
 564  * Singly-linked Tail queue declarations.
 565  */
 566 #define STAILQ_HEAD(name, type)                                         \
 567 struct name {                                                           \
 568         struct type *stqh_first;        /* first element */             \
 569         struct type **stqh_last;        /* addr of last next element */ \
 570 }
 571
 572 #define STAILQ_HEAD_INITIALIZER(head)                                   \
 573         { NULL, &(head).stqh_first }
 574
 575 #define STAILQ_ENTRY(type)                                              \
 576 struct {                                                                \
 577         struct type *stqe_next; /* next element */                      \
 578 }
 579
 580 /*
 581  * Singly-linked Tail queue access methods.
 582  */
 583 #define STAILQ_FIRST(head)      ((head)->stqh_first)
 584 #define STAILQ_END(head)        NULL
 585 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 586 #define STAILQ_EMPTY(head)      (STAILQ_FIRST(head) == STAILQ_END(head))
 587
 588 /*
 589  * Singly-linked Tail queue functions.
 590  */
 591 #define STAILQ_INIT(head) do {                                          \
 592         (head)->stqh_first = NULL;                                      \
 593         (head)->stqh_last = &(head)->stqh_first;                                \
 594 } while (/*CONSTCOND*/0)
 595
 596 #define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 597         if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
 598                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 599         (head)->stqh_first = (elm);                                     \
 600 } while (/*CONSTCOND*/0)
 601
 602 #define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 603         (elm)->field.stqe_next = NULL;                                  \
 604         *(head)->stqh_last = (elm);                                     \
 605         (head)->stqh_last = &(elm)->field.stqe_next;                    \
 606 } while (/*CONSTCOND*/0)
 607
 608 #define STAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
 609         if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
 610                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 611         (listelm)->field.stqe_next = (elm);                             \
 612 } while (/*CONSTCOND*/0)
 613
 614 #define STAILQ_REMOVE_HEAD(head, field) do {                            \
 615         if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
 616                 (head)->stqh_last = &(head)->stqh_first;                        \
 617 } while (/*CONSTCOND*/0)
 618
 619 #define STAILQ_REMOVE(head, elm, type, field) do {                      \
 620         if ((head)->stqh_first == (elm)) {                              \
 621                 STAILQ_REMOVE_HEAD((head), field);                      \
 622         } else {                                                        \
 623                 struct type *curelm = (head)->stqh_first;               \
 624                 while (curelm->field.stqe_next != (elm))                        \
 625                         curelm = curelm->field.stqe_next;               \
 626                 if ((curelm->field.stqe_next =                          \
 627                         curelm->field.stqe_next->field.stqe_next) == NULL) \
 628                             (head)->stqh_last = &(curelm)->field.stqe_next; \
 629         }                                                               \
 630 } while (/*CONSTCOND*/0)
 631
 632 #define STAILQ_FOREACH(var, head, field)                                \
 633         for ((var) = ((head)->stqh_first);                              \
 634                 (var);                                                  \
 635                 (var) = ((var)->field.stqe_next))
 636
 637 #define STAILQ_FOREACH_SAFE(var, head, field, tvar)                     \
 638         for ((var) = STAILQ_FIRST((head));                              \
 639             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 640             (var) = (tvar))
 641
 642 #define STAILQ_CONCAT(head1, head2) do {                                \
 643         if (!STAILQ_EMPTY((head2))) {                                   \
 644                 *(head1)->stqh_last = (head2)->stqh_first;              \
 645                 (head1)->stqh_last = (head2)->stqh_last;                \
 646                 STAILQ_INIT((head2));                                   \
 647         }                                                               \
 648 } while (/*CONSTCOND*/0)
 649
 650 #define STAILQ_LAST(head, type, field)                                  \
 651         (STAILQ_EMPTY((head)) ?                                         \
 652                 NULL :                                                  \
 653                 ((struct type *)(void *)                                \
 654                 ((char *)((head)->stqh_last) - offsetof(struct type, field))))
 655
 656
 657 #ifndef _KERNEL
 658 /*
 659  * Circular queue definitions. Do not use. We still keep the macros
 660  * for compatibility but because of pointer aliasing issues their use
 661  * is discouraged!
 662  */
 663
 664 /*
 665  * __launder_type():  We use this ugly hack to work around the the compiler
 666  * noticing that two types may not alias each other and elide tests in code.
 667  * We hit this in the CIRCLEQ macros when comparing 'struct name *' and
 668  * 'struct type *' (see CIRCLEQ_HEAD()).  Modern compilers (such as GCC
 669  * 4.8) declare these comparisons as always false, causing the code to
 670  * not run as designed.
 671  *
 672  * This hack is only to be used for comparisons and thus can be fully const.
 673  * Do not use for assignment.
 674  *
 675  * If we ever choose to change the ABI of the CIRCLEQ macros, we could fix
 676  * this by changing the head/tail sentinal values, but see the note above
 677  * this one.
 678  */
 679 static __inline const void * __launder_type(const void *);
 680 static __inline const void *
 681 __launder_type(const void *__x)
 682 {
 683         __asm __volatile("" : "+r" (__x));
 684         return __x;
 685 }
 686
 687 #if defined(QUEUEDEBUG)
 688 #define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)                            \
 689         if ((head)->cqh_first != CIRCLEQ_ENDC(head) &&                  \
 690             (head)->cqh_first->field.cqe_prev != CIRCLEQ_ENDC(head))    \
 691                 QUEUEDEBUG_ABORT("CIRCLEQ head forw %p %s:%d", (head),  \
 692                       __FILE__, __LINE__);                              \
 693         if ((head)->cqh_last != CIRCLEQ_ENDC(head) &&                   \
 694             (head)->cqh_last->field.cqe_next != CIRCLEQ_ENDC(head))     \
 695                 QUEUEDEBUG_ABORT("CIRCLEQ head back %p %s:%d", (head),  \
 696                       __FILE__, __LINE__);
 697 #define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)                        \
 698         if ((elm)->field.cqe_next == CIRCLEQ_ENDC(head)) {              \
 699                 if ((head)->cqh_last != (elm))                          \
 700                         QUEUEDEBUG_ABORT("CIRCLEQ elm last %p %s:%d",   \
 701                             (elm), __FILE__, __LINE__);                 \
 702         } else {                                                        \
 703                 if ((elm)->field.cqe_next->field.cqe_prev != (elm))     \
 704                         QUEUEDEBUG_ABORT("CIRCLEQ elm forw %p %s:%d",   \
 705                             (elm), __FILE__, __LINE__);                 \
 706         }                                                               \
 707         if ((elm)->field.cqe_prev == CIRCLEQ_ENDC(head)) {              \
 708                 if ((head)->cqh_first != (elm))                         \
 709                         QUEUEDEBUG_ABORT("CIRCLEQ elm first %p %s:%d",  \
 710                             (elm), __FILE__, __LINE__);                 \
 711         } else {                                                        \
 712                 if ((elm)->field.cqe_prev->field.cqe_next != (elm))     \
 713                         QUEUEDEBUG_ABORT("CIRCLEQ elm prev %p %s:%d",   \
 714                             (elm), __FILE__, __LINE__);                 \
 715         }
 716 #define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)                       \
 717         (elm)->field.cqe_next = (void *)1L;                             \
 718         (elm)->field.cqe_prev = (void *)1L;
 719 #else
 720 #define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)
 721 #define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)
 722 #define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)
 723 #endif
 724
 725 #define CIRCLEQ_HEAD(name, type)                                        \
 726 struct name {                                                           \
 727         struct type *cqh_first;         /* first element */             \
 728         struct type *cqh_last;          /* last element */              \
 729 }
 730
 731 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 732         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 733
 734 #define CIRCLEQ_ENTRY(type)                                             \
 735 struct {                                                                \
 736         struct type *cqe_next;          /* next element */              \
 737         struct type *cqe_prev;          /* previous element */          \
 738 }
 739
 740 /*
 741  * Circular queue functions.
 742  */
 743 #define CIRCLEQ_INIT(head) do {                                         \
 744         (head)->cqh_first = CIRCLEQ_END(head);                          \
 745         (head)->cqh_last = CIRCLEQ_END(head);                           \
 746 } while (/*CONSTCOND*/0)
 747
 748 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 749         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 750         QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)                \
 751         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 752         (elm)->field.cqe_prev = (listelm);                              \
 753         if ((listelm)->field.cqe_next == CIRCLEQ_ENDC(head))            \
 754                 (head)->cqh_last = (elm);                               \
 755         else                                                            \
 756                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 757         (listelm)->field.cqe_next = (elm);                              \
 758 } while (/*CONSTCOND*/0)
 759
 760 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 761         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 762         QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)                \
 763         (elm)->field.cqe_next = (listelm);                              \
 764         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 765         if ((listelm)->field.cqe_prev == CIRCLEQ_ENDC(head))            \
 766                 (head)->cqh_first = (elm);                              \
 767         else                                                            \
 768                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 769         (listelm)->field.cqe_prev = (elm);                              \
 770 } while (/*CONSTCOND*/0)
 771
 772 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 773         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 774         (elm)->field.cqe_next = (head)->cqh_first;                      \
 775         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 776         if ((head)->cqh_last == CIRCLEQ_ENDC(head))                     \
 777                 (head)->cqh_last = (elm);                               \
 778         else                                                            \
 779                 (head)->cqh_first->field.cqe_prev = (elm);              \
 780         (head)->cqh_first = (elm);                                      \
 781 } while (/*CONSTCOND*/0)
 782
 783 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 784         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 785         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 786         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 787         if ((head)->cqh_first == CIRCLEQ_ENDC(head))                    \
 788                 (head)->cqh_first = (elm);                              \
 789         else                                                            \
 790                 (head)->cqh_last->field.cqe_next = (elm);               \
 791         (head)->cqh_last = (elm);                                       \
 792 } while (/*CONSTCOND*/0)
 793
 794 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 795         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 796         QUEUEDEBUG_CIRCLEQ_ELM((head), (elm), field)                    \
 797         if ((elm)->field.cqe_next == CIRCLEQ_ENDC(head))                \
 798                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 799         else                                                            \
 800                 (elm)->field.cqe_next->field.cqe_prev =                 \
 801                     (elm)->field.cqe_prev;                              \
 802         if ((elm)->field.cqe_prev == CIRCLEQ_ENDC(head))                \
 803                 (head)->cqh_first = (elm)->field.cqe_next;              \
 804         else                                                            \
 805                 (elm)->field.cqe_prev->field.cqe_next =                 \
 806                     (elm)->field.cqe_next;                              \
 807         QUEUEDEBUG_CIRCLEQ_POSTREMOVE((elm), field)                     \
 808 } while (/*CONSTCOND*/0)
 809
 810 #define CIRCLEQ_FOREACH(var, head, field)                               \
 811         for ((var) = ((head)->cqh_first);                               \
 812                 (var) != CIRCLEQ_ENDC(head);                            \
 813                 (var) = ((var)->field.cqe_next))
 814
 815 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 816         for ((var) = ((head)->cqh_last);                                \
 817                 (var) != CIRCLEQ_ENDC(head);                            \
 818                 (var) = ((var)->field.cqe_prev))
 819
 820 /*
 821  * Circular queue access methods.
 822  */
 823 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 824 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 825 /* For comparisons */
 826 #define CIRCLEQ_ENDC(head)              (__launder_type(head))
 827 /* For assignments */
 828 #define CIRCLEQ_END(head)               ((void *)(head))
 829 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 830 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 831 #define CIRCLEQ_EMPTY(head)                                             \
 832     (CIRCLEQ_FIRST(head) == CIRCLEQ_ENDC(head))
 833
 834 #define CIRCLEQ_LOOP_NEXT(head, elm, field)                             \
 835         (((elm)->field.cqe_next == CIRCLEQ_ENDC(head))                  \
 836             ? ((head)->cqh_first)                                       \
 837             : (elm->field.cqe_next))
 838 #define CIRCLEQ_LOOP_PREV(head, elm, field)                             \
 839         (((elm)->field.cqe_prev == CIRCLEQ_ENDC(head))                  \
 840             ? ((head)->cqh_last)                                        \
 841             : (elm->field.cqe_prev))
 842 #endif /* !_KERNEL */
 843
 844 #endif  /* !_SYS_QUEUE_H_ */