core/musl/files/queue.h

   1 /*      $NetBSD: queue.h,v 1.70 2015/11/02 15:21:23 christos Exp $      */
   2
   3 /*
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  *
  31  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  32  */
  33
  34 #ifndef _SYS_QUEUE_H_
  35 #define _SYS_QUEUE_H_
  36
  37 /*
  38  * This file defines five types of data structures: singly-linked lists,
  39  * lists, simple queues, tail queues, and circular queues.
  40  *
  41  * A singly-linked list is headed by a single forward pointer. The
  42  * elements are singly linked for minimum space and pointer manipulation
  43  * overhead at the expense of O(n) removal for arbitrary elements. New
  44  * elements can be added to the list after an existing element or at the
  45  * head of the list.  Elements being removed from the head of the list
  46  * should use the explicit macro for this purpose for optimum
  47  * efficiency. A singly-linked list may only be traversed in the forward
  48  * direction.  Singly-linked lists are ideal for applications with large
  49  * datasets and few or no removals or for implementing a LIFO queue.
  50  *
  51  * A list is headed by a single forward pointer (or an array of forward
  52  * pointers for a hash table header). The elements are doubly linked
  53  * so that an arbitrary element can be removed without a need to
  54  * traverse the list. New elements can be added to the list before
  55  * or after an existing element or at the head of the list. A list
  56  * may only be traversed in the forward direction.
  57  *
  58  * A simple queue is headed by a pair of pointers, one the head of the
  59  * list and the other to the tail of the list. The elements are singly
  60  * linked to save space, so elements can only be removed from the
  61  * head of the list. New elements can be added to the list after
  62  * an existing element, at the head of the list, or at the end of the
  63  * list. A simple queue may only be traversed in the forward direction.
  64  *
  65  * A tail queue is headed by a pair of pointers, one to the head of the
  66  * list and the other to the tail of the list. The elements are doubly
  67  * linked so that an arbitrary element can be removed without a need to
  68  * traverse the list. New elements can be added to the list before or
  69  * after an existing element, at the head of the list, or at the end of
  70  * the list. A tail queue may be traversed in either direction.
  71  *
  72  * A circle queue is headed by a pair of pointers, one to the head of the
  73  * list and the other to the tail of the list. The elements are doubly
  74  * linked so that an arbitrary element can be removed without a need to
  75  * traverse the list. New elements can be added to the list before or after
  76  * an existing element, at the head of the list, or at the end of the list.
  77  * A circle queue may be traversed in either direction, but has a more
  78  * complex end of list detection.
  79  *
  80  * For details on the use of these macros, see the queue(3) manual page.
  81  */
  82
  83 /*
  84  * Include the definition of NULL only on NetBSD because sys/null.h
  85  * is not available elsewhere.  This conditional makes the header
  86  * portable and it can simply be dropped verbatim into any system.
  87  * The caveat is that on other systems some other header
  88  * must provide NULL before the macros can be used.
  89  */
  90 #ifdef __NetBSD__
  91 #include <sys/null.h>
  92 #endif
  93
  94 #if defined(QUEUEDEBUG)
  95 # if defined(_KERNEL)
  96 #  define QUEUEDEBUG_ABORT(...) panic(__VA_ARGS__)
  97 # else
  98 #  include <err.h>
  99 #  define QUEUEDEBUG_ABORT(...) err(1, __VA_ARGS__)
 100 # endif
 101 #endif
 102
 103 /*
 104  * Singly-linked List definitions.
 105  */
 106 #define SLIST_HEAD(name, type)                                          \
 107 struct name {                                                           \
 108         struct type *slh_first; /* first element */                     \
 109 }
 110
 111 #define SLIST_HEAD_INITIALIZER(head)                                    \
 112         { NULL }
 113
 114 #define SLIST_ENTRY(type)                                               \
 115 struct {                                                                \
 116         struct type *sle_next;  /* next element */                      \
 117 }
 118
 119 /*
 120  * Singly-linked List access methods.
 121  */
 122 #define SLIST_FIRST(head)       ((head)->slh_first)
 123 #define SLIST_END(head)         NULL
 124 #define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 125 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 126
 127 #define SLIST_FOREACH(var, head, field)                                 \
 128         for((var) = (head)->slh_first;                                  \
 129             (var) != SLIST_END(head);                                   \
 130             (var) = (var)->field.sle_next)
 131
 132 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 133         for ((var) = SLIST_FIRST((head));                               \
 134             (var) != SLIST_END(head) &&                                 \
 135             ((tvar) = SLIST_NEXT((var), field), 1);                     \
 136             (var) = (tvar))
 137
 138 /*
 139  * Singly-linked List functions.
 140  */
 141 #define SLIST_INIT(head) do {                                           \
 142         (head)->slh_first = SLIST_END(head);                            \
 143 } while (/*CONSTCOND*/0)
 144
 145 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 146         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 147         (slistelm)->field.sle_next = (elm);                             \
 148 } while (/*CONSTCOND*/0)
 149
 150 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 151         (elm)->field.sle_next = (head)->slh_first;                      \
 152         (head)->slh_first = (elm);                                      \
 153 } while (/*CONSTCOND*/0)
 154
 155 #define SLIST_REMOVE_AFTER(slistelm, field) do {                        \
 156         (slistelm)->field.sle_next =                                    \
 157             SLIST_NEXT(SLIST_NEXT((slistelm), field), field);           \
 158 } while (/*CONSTCOND*/0)
 159
 160 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 161         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 162 } while (/*CONSTCOND*/0)
 163
 164 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 165         if ((head)->slh_first == (elm)) {                               \
 166                 SLIST_REMOVE_HEAD((head), field);                       \
 167         }                                                               \
 168         else {                                                          \
 169                 struct type *curelm = (head)->slh_first;                \
 170                 while(curelm->field.sle_next != (elm))                  \
 171                         curelm = curelm->field.sle_next;                \
 172                 curelm->field.sle_next =                                \
 173                     curelm->field.sle_next->field.sle_next;             \
 174         }                                                               \
 175 } while (/*CONSTCOND*/0)
 176
 177
 178 /*
 179  * List definitions.
 180  */
 181 #define LIST_HEAD(name, type)                                           \
 182 struct name {                                                           \
 183         struct type *lh_first;  /* first element */                     \
 184 }
 185
 186 #define LIST_HEAD_INITIALIZER(head)                                     \
 187         { NULL }
 188
 189 #define LIST_ENTRY(type)                                                \
 190 struct {                                                                \
 191         struct type *le_next;   /* next element */                      \
 192         struct type **le_prev;  /* address of previous next element */  \
 193 }
 194
 195 /*
 196  * List access methods.
 197  */
 198 #define LIST_FIRST(head)                ((head)->lh_first)
 199 #define LIST_END(head)                  NULL
 200 #define LIST_EMPTY(head)                ((head)->lh_first == LIST_END(head))
 201 #define LIST_NEXT(elm, field)           ((elm)->field.le_next)
 202
 203 #define LIST_FOREACH(var, head, field)                                  \
 204         for ((var) = ((head)->lh_first);                                \
 205             (var) != LIST_END(head);                                    \
 206             (var) = ((var)->field.le_next))
 207
 208 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 209         for ((var) = LIST_FIRST((head));                                \
 210             (var) != LIST_END(head) &&                                  \
 211             ((tvar) = LIST_NEXT((var), field), 1);                      \
 212             (var) = (tvar))
 213
 214 #define LIST_MOVE(head1, head2) do {                                    \
 215         LIST_INIT((head2));                                             \
 216         if (!LIST_EMPTY((head1))) {                                     \
 217                 (head2)->lh_first = (head1)->lh_first;                  \
 218                 LIST_INIT((head1));                                     \
 219         }                                                               \
 220 } while (/*CONSTCOND*/0)
 221
 222 /*
 223  * List functions.
 224  */
 225 #if defined(QUEUEDEBUG)
 226 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)                   \
 227         if ((head)->lh_first &&                                         \
 228             (head)->lh_first->field.le_prev != &(head)->lh_first)       \
 229                 QUEUEDEBUG_ABORT("LIST_INSERT_HEAD %p %s:%d", (head),   \
 230                     __FILE__, __LINE__);
 231 #define QUEUEDEBUG_LIST_OP(elm, field)                                  \
 232         if ((elm)->field.le_next &&                                     \
 233             (elm)->field.le_next->field.le_prev !=                      \
 234             &(elm)->field.le_next)                                      \
 235                 QUEUEDEBUG_ABORT("LIST_* forw %p %s:%d", (elm),         \
 236                     __FILE__, __LINE__);                                \
 237         if (*(elm)->field.le_prev != (elm))                             \
 238                 QUEUEDEBUG_ABORT("LIST_* back %p %s:%d", (elm),         \
 239                     __FILE__, __LINE__);
 240 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field)                          \
 241         (elm)->field.le_next = (void *)1L;                              \
 242         (elm)->field.le_prev = (void *)1L;
 243 #else
 244 #define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)
 245 #define QUEUEDEBUG_LIST_OP(elm, field)
 246 #define QUEUEDEBUG_LIST_POSTREMOVE(elm, field)
 247 #endif
 248
 249 #define LIST_INIT(head) do {                                            \
 250         (head)->lh_first = LIST_END(head);                              \
 251 } while (/*CONSTCOND*/0)
 252
 253 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 254         QUEUEDEBUG_LIST_OP((listelm), field)                            \
 255         if (((elm)->field.le_next = (listelm)->field.le_next) !=        \
 256             LIST_END(head))                                             \
 257                 (listelm)->field.le_next->field.le_prev =               \
 258                     &(elm)->field.le_next;                              \
 259         (listelm)->field.le_next = (elm);                               \
 260         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 261 } while (/*CONSTCOND*/0)
 262
 263 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 264         QUEUEDEBUG_LIST_OP((listelm), field)                            \
 265         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 266         (elm)->field.le_next = (listelm);                               \
 267         *(listelm)->field.le_prev = (elm);                              \
 268         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 269 } while (/*CONSTCOND*/0)
 270
 271 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 272         QUEUEDEBUG_LIST_INSERT_HEAD((head), (elm), field)               \
 273         if (((elm)->field.le_next = (head)->lh_first) != LIST_END(head))\
 274                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 275         (head)->lh_first = (elm);                                       \
 276         (elm)->field.le_prev = &(head)->lh_first;                       \
 277 } while (/*CONSTCOND*/0)
 278
 279 #define LIST_REMOVE(elm, field) do {                                    \
 280         QUEUEDEBUG_LIST_OP((elm), field)                                \
 281         if ((elm)->field.le_next != NULL)                               \
 282                 (elm)->field.le_next->field.le_prev =                   \
 283                     (elm)->field.le_prev;                               \
 284         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 285         QUEUEDEBUG_LIST_POSTREMOVE((elm), field)                        \
 286 } while (/*CONSTCOND*/0)
 287
 288 #define LIST_REPLACE(elm, elm2, field) do {                             \
 289         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 290                 (elm2)->field.le_next->field.le_prev =                  \
 291                     &(elm2)->field.le_next;                             \
 292         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 293         *(elm2)->field.le_prev = (elm2);                                \
 294         QUEUEDEBUG_LIST_POSTREMOVE((elm), field)                        \
 295 } while (/*CONSTCOND*/0)
 296
 297 /*
 298  * Simple queue definitions.
 299  */
 300 #define SIMPLEQ_HEAD(name, type)                                        \
 301 struct name {                                                           \
 302         struct type *sqh_first; /* first element */                     \
 303         struct type **sqh_last; /* addr of last next element */         \
 304 }
 305
 306 #define SIMPLEQ_HEAD_INITIALIZER(head)                                  \
 307         { NULL, &(head).sqh_first }
 308
 309 #define SIMPLEQ_ENTRY(type)                                             \
 310 struct {                                                                \
 311         struct type *sqe_next;  /* next element */                      \
 312 }
 313
 314 /*
 315  * Simple queue access methods.
 316  */
 317 #define SIMPLEQ_FIRST(head)             ((head)->sqh_first)
 318 #define SIMPLEQ_END(head)               NULL
 319 #define SIMPLEQ_EMPTY(head)             ((head)->sqh_first == SIMPLEQ_END(head))
 320 #define SIMPLEQ_NEXT(elm, field)        ((elm)->field.sqe_next)
 321
 322 #define SIMPLEQ_FOREACH(var, head, field)                               \
 323         for ((var) = ((head)->sqh_first);                               \
 324             (var) != SIMPLEQ_END(head);                                 \
 325             (var) = ((var)->field.sqe_next))
 326
 327 #define SIMPLEQ_FOREACH_SAFE(var, head, field, next)                    \
 328         for ((var) = ((head)->sqh_first);                               \
 329             (var) != SIMPLEQ_END(head) &&                               \
 330             ((next = ((var)->field.sqe_next)), 1);                      \
 331             (var) = (next))
 332
 333 /*
 334  * Simple queue functions.
 335  */
 336 #define SIMPLEQ_INIT(head) do {                                         \
 337         (head)->sqh_first = NULL;                                       \
 338         (head)->sqh_last = &(head)->sqh_first;                          \
 339 } while (/*CONSTCOND*/0)
 340
 341 #define SIMPLEQ_INSERT_HEAD(head, elm, field) do {                      \
 342         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 343                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 344         (head)->sqh_first = (elm);                                      \
 345 } while (/*CONSTCOND*/0)
 346
 347 #define SIMPLEQ_INSERT_TAIL(head, elm, field) do {                      \
 348         (elm)->field.sqe_next = NULL;                                   \
 349         *(head)->sqh_last = (elm);                                      \
 350         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 351 } while (/*CONSTCOND*/0)
 352
 353 #define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 354         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 355                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 356         (listelm)->field.sqe_next = (elm);                              \
 357 } while (/*CONSTCOND*/0)
 358
 359 #define SIMPLEQ_REMOVE_HEAD(head, field) do {                           \
 360         if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
 361                 (head)->sqh_last = &(head)->sqh_first;                  \
 362 } while (/*CONSTCOND*/0)
 363
 364 #define SIMPLEQ_REMOVE_AFTER(head, elm, field) do {                     \
 365         if (((elm)->field.sqe_next = (elm)->field.sqe_next->field.sqe_next) \
 366             == NULL)                                                    \
 367                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 368 } while (/*CONSTCOND*/0)
 369
 370 #define SIMPLEQ_REMOVE(head, elm, type, field) do {                     \
 371         if ((head)->sqh_first == (elm)) {                               \
 372                 SIMPLEQ_REMOVE_HEAD((head), field);                     \
 373         } else {                                                        \
 374                 struct type *curelm = (head)->sqh_first;                \
 375                 while (curelm->field.sqe_next != (elm))                 \
 376                         curelm = curelm->field.sqe_next;                \
 377                 if ((curelm->field.sqe_next =                           \
 378                         curelm->field.sqe_next->field.sqe_next) == NULL) \
 379                             (head)->sqh_last = &(curelm)->field.sqe_next; \
 380         }                                                               \
 381 } while (/*CONSTCOND*/0)
 382
 383 #define SIMPLEQ_CONCAT(head1, head2) do {                               \
 384         if (!SIMPLEQ_EMPTY((head2))) {                                  \
 385                 *(head1)->sqh_last = (head2)->sqh_first;                \
 386                 (head1)->sqh_last = (head2)->sqh_last;          \
 387                 SIMPLEQ_INIT((head2));                                  \
 388         }                                                               \
 389 } while (/*CONSTCOND*/0)
 390
 391 #define SIMPLEQ_LAST(head, type, field)                                 \
 392         (SIMPLEQ_EMPTY((head)) ?                                                \
 393                 NULL :                                                  \
 394                 ((struct type *)(void *)                                \
 395                 ((char *)((head)->sqh_last) - offsetof(struct type, field))))
 396
 397 /*
 398  * Tail queue definitions.
 399  */
 400 #define _TAILQ_HEAD(name, type, qual)                                   \
 401 struct name {                                                           \
 402         qual type *tqh_first;           /* first element */             \
 403         qual type *qual *tqh_last;      /* addr of last next element */ \
 404 }
 405 #define TAILQ_HEAD(name, type)  _TAILQ_HEAD(name, struct type,)
 406
 407 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 408         { TAILQ_END(head), &(head).tqh_first }
 409
 410 #define _TAILQ_ENTRY(type, qual)                                        \
 411 struct {                                                                \
 412         qual type *tqe_next;            /* next element */              \
 413         qual type *qual *tqe_prev;      /* address of previous next element */\
 414 }
 415 #define TAILQ_ENTRY(type)       _TAILQ_ENTRY(struct type,)
 416
 417 /*
 418  * Tail queue access methods.
 419  */
 420 #define TAILQ_FIRST(head)               ((head)->tqh_first)
 421 #define TAILQ_END(head)                 (NULL)
 422 #define TAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 423 #define TAILQ_LAST(head, headname) \
 424         (*(((struct headname *)(void *)((head)->tqh_last))->tqh_last))
 425 #define TAILQ_PREV(elm, headname, field) \
 426         (*(((struct headname *)(void *)((elm)->field.tqe_prev))->tqh_last))
 427 #define TAILQ_EMPTY(head)               (TAILQ_FIRST(head) == TAILQ_END(head))
 428
 429
 430 #define TAILQ_FOREACH(var, head, field)                                 \
 431         for ((var) = ((head)->tqh_first);                               \
 432             (var) != TAILQ_END(head);                                   \
 433             (var) = ((var)->field.tqe_next))
 434
 435 #define TAILQ_FOREACH_SAFE(var, head, field, next)                      \
 436         for ((var) = ((head)->tqh_first);                               \
 437             (var) != TAILQ_END(head) &&                                 \
 438             ((next) = TAILQ_NEXT(var, field), 1); (var) = (next))
 439
 440 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 441         for ((var) = TAILQ_LAST((head), headname);                      \
 442             (var) != TAILQ_END(head);                                   \
 443             (var) = TAILQ_PREV((var), headname, field))
 444
 445 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, prev)    \
 446         for ((var) = TAILQ_LAST((head), headname);                      \
 447             (var) != TAILQ_END(head) &&                                 \
 448             ((prev) = TAILQ_PREV((var), headname, field), 1); (var) = (prev))
 449
 450 /*
 451  * Tail queue functions.
 452  */
 453 #if defined(QUEUEDEBUG)
 454 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)                  \
 455         if ((head)->tqh_first &&                                        \
 456             (head)->tqh_first->field.tqe_prev != &(head)->tqh_first)    \
 457                 QUEUEDEBUG_ABORT("TAILQ_INSERT_HEAD %p %s:%d", (head),  \
 458                     __FILE__, __LINE__);
 459 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)                  \
 460         if (*(head)->tqh_last != NULL)                                  \
 461                 QUEUEDEBUG_ABORT("TAILQ_INSERT_TAIL %p %s:%d", (head),  \
 462                     __FILE__, __LINE__);
 463 #define QUEUEDEBUG_TAILQ_OP(elm, field)                                 \
 464         if ((elm)->field.tqe_next &&                                    \
 465             (elm)->field.tqe_next->field.tqe_prev !=                    \
 466             &(elm)->field.tqe_next)                                     \
 467                 QUEUEDEBUG_ABORT("TAILQ_* forw %p %s:%d", (elm),        \
 468                     __FILE__, __LINE__);                                \
 469         if (*(elm)->field.tqe_prev != (elm))                            \
 470                 QUEUEDEBUG_ABORT("TAILQ_* back %p %s:%d", (elm),        \
 471                     __FILE__, __LINE__);
 472 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)                    \
 473         if ((elm)->field.tqe_next == NULL &&                            \
 474             (head)->tqh_last != &(elm)->field.tqe_next)                 \
 475                 QUEUEDEBUG_ABORT("TAILQ_PREREMOVE head %p elm %p %s:%d",\
 476                     (head), (elm), __FILE__, __LINE__);
 477 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)                         \
 478         (elm)->field.tqe_next = (void *)1L;                             \
 479         (elm)->field.tqe_prev = (void *)1L;
 480 #else
 481 #define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)
 482 #define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)
 483 #define QUEUEDEBUG_TAILQ_OP(elm, field)
 484 #define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)
 485 #define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)
 486 #endif
 487
 488 #define TAILQ_INIT(head) do {                                           \
 489         (head)->tqh_first = TAILQ_END(head);                            \
 490         (head)->tqh_last = &(head)->tqh_first;                          \
 491 } while (/*CONSTCOND*/0)
 492
 493 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 494         QUEUEDEBUG_TAILQ_INSERT_HEAD((head), (elm), field)              \
 495         if (((elm)->field.tqe_next = (head)->tqh_first) != TAILQ_END(head))\
 496                 (head)->tqh_first->field.tqe_prev =                     \
 497                     &(elm)->field.tqe_next;                             \
 498         else                                                            \
 499                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 500         (head)->tqh_first = (elm);                                      \
 501         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 502 } while (/*CONSTCOND*/0)
 503
 504 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 505         QUEUEDEBUG_TAILQ_INSERT_TAIL((head), (elm), field)              \
 506         (elm)->field.tqe_next = TAILQ_END(head);                        \
 507         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 508         *(head)->tqh_last = (elm);                                      \
 509         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 510 } while (/*CONSTCOND*/0)
 511
 512 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 513         QUEUEDEBUG_TAILQ_OP((listelm), field)                           \
 514         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) !=      \
 515             TAILQ_END(head))                                            \
 516                 (elm)->field.tqe_next->field.tqe_prev =                 \
 517                     &(elm)->field.tqe_next;                             \
 518         else                                                            \
 519                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 520         (listelm)->field.tqe_next = (elm);                              \
 521         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 522 } while (/*CONSTCOND*/0)
 523
 524 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 525         QUEUEDEBUG_TAILQ_OP((listelm), field)                           \
 526         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 527         (elm)->field.tqe_next = (listelm);                              \
 528         *(listelm)->field.tqe_prev = (elm);                             \
 529         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 530 } while (/*CONSTCOND*/0)
 531
 532 #define TAILQ_REMOVE(head, elm, field) do {                             \
 533         QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field)                \
 534         QUEUEDEBUG_TAILQ_OP((elm), field)                               \
 535         if (((elm)->field.tqe_next) != TAILQ_END(head))                 \
 536                 (elm)->field.tqe_next->field.tqe_prev =                 \
 537                     (elm)->field.tqe_prev;                              \
 538         else                                                            \
 539                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 540         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 541         QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field);                      \
 542 } while (/*CONSTCOND*/0)
 543
 544 #define TAILQ_REPLACE(head, elm, elm2, field) do {                      \
 545         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) !=         \
 546             TAILQ_END(head))                                            \
 547                 (elm2)->field.tqe_next->field.tqe_prev =                \
 548                     &(elm2)->field.tqe_next;                            \
 549         else                                                            \
 550                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 551         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 552         *(elm2)->field.tqe_prev = (elm2);                               \
 553         QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field);                      \
 554 } while (/*CONSTCOND*/0)
 555
 556 #define TAILQ_CONCAT(head1, head2, field) do {                          \
 557         if (!TAILQ_EMPTY(head2)) {                                      \
 558                 *(head1)->tqh_last = (head2)->tqh_first;                \
 559                 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
 560                 (head1)->tqh_last = (head2)->tqh_last;                  \
 561                 TAILQ_INIT((head2));                                    \
 562         }                                                               \
 563 } while (/*CONSTCOND*/0)
 564
 565 /*
 566  * Singly-linked Tail queue declarations.
 567  */
 568 #define STAILQ_HEAD(name, type)                                         \
 569 struct name {                                                           \
 570         struct type *stqh_first;        /* first element */             \
 571         struct type **stqh_last;        /* addr of last next element */ \
 572 }
 573
 574 #define STAILQ_HEAD_INITIALIZER(head)                                   \
 575         { NULL, &(head).stqh_first }
 576
 577 #define STAILQ_ENTRY(type)                                              \
 578 struct {                                                                \
 579         struct type *stqe_next; /* next element */                      \
 580 }
 581
 582 /*
 583  * Singly-linked Tail queue access methods.
 584  */
 585 #define STAILQ_FIRST(head)      ((head)->stqh_first)
 586 #define STAILQ_END(head)        NULL
 587 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 588 #define STAILQ_EMPTY(head)      (STAILQ_FIRST(head) == STAILQ_END(head))
 589
 590 /*
 591  * Singly-linked Tail queue functions.
 592  */
 593 #define STAILQ_INIT(head) do {                                          \
 594         (head)->stqh_first = NULL;                                      \
 595         (head)->stqh_last = &(head)->stqh_first;                                \
 596 } while (/*CONSTCOND*/0)
 597
 598 #define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 599         if (((elm)->field.stqe_next = (head)->stqh_first) == NULL)      \
 600                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 601         (head)->stqh_first = (elm);                                     \
 602 } while (/*CONSTCOND*/0)
 603
 604 #define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 605         (elm)->field.stqe_next = NULL;                                  \
 606         *(head)->stqh_last = (elm);                                     \
 607         (head)->stqh_last = &(elm)->field.stqe_next;                    \
 608 } while (/*CONSTCOND*/0)
 609
 610 #define STAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
 611         if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
 612                 (head)->stqh_last = &(elm)->field.stqe_next;            \
 613         (listelm)->field.stqe_next = (elm);                             \
 614 } while (/*CONSTCOND*/0)
 615
 616 #define STAILQ_REMOVE_HEAD(head, field) do {                            \
 617         if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
 618                 (head)->stqh_last = &(head)->stqh_first;                        \
 619 } while (/*CONSTCOND*/0)
 620
 621 #define STAILQ_REMOVE(head, elm, type, field) do {                      \
 622         if ((head)->stqh_first == (elm)) {                              \
 623                 STAILQ_REMOVE_HEAD((head), field);                      \
 624         } else {                                                        \
 625                 struct type *curelm = (head)->stqh_first;               \
 626                 while (curelm->field.stqe_next != (elm))                        \
 627                         curelm = curelm->field.stqe_next;               \
 628                 if ((curelm->field.stqe_next =                          \
 629                         curelm->field.stqe_next->field.stqe_next) == NULL) \
 630                             (head)->stqh_last = &(curelm)->field.stqe_next; \
 631         }                                                               \
 632 } while (/*CONSTCOND*/0)
 633
 634 #define STAILQ_FOREACH(var, head, field)                                \
 635         for ((var) = ((head)->stqh_first);                              \
 636                 (var);                                                  \
 637                 (var) = ((var)->field.stqe_next))
 638
 639 #define STAILQ_FOREACH_SAFE(var, head, field, tvar)                     \
 640         for ((var) = STAILQ_FIRST((head));                              \
 641             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 642             (var) = (tvar))
 643
 644 #define STAILQ_CONCAT(head1, head2) do {                                \
 645         if (!STAILQ_EMPTY((head2))) {                                   \
 646                 *(head1)->stqh_last = (head2)->stqh_first;              \
 647                 (head1)->stqh_last = (head2)->stqh_last;                \
 648                 STAILQ_INIT((head2));                                   \
 649         }                                                               \
 650 } while (/*CONSTCOND*/0)
 651
 652 #define STAILQ_LAST(head, type, field)                                  \
 653         (STAILQ_EMPTY((head)) ?                                         \
 654                 NULL :                                                  \
 655                 ((struct type *)(void *)                                \
 656                 ((char *)((head)->stqh_last) - offsetof(struct type, field))))
 657
 658
 659 #ifndef _KERNEL
 660 /*
 661  * Circular queue definitions. Do not use. We still keep the macros
 662  * for compatibility but because of pointer aliasing issues their use
 663  * is discouraged!
 664  */
 665
 666 /*
 667  * __launder_type():  We use this ugly hack to work around the the compiler
 668  * noticing that two types may not alias each other and elide tests in code.
 669  * We hit this in the CIRCLEQ macros when comparing 'struct name *' and
 670  * 'struct type *' (see CIRCLEQ_HEAD()).  Modern compilers (such as GCC
 671  * 4.8) declare these comparisons as always false, causing the code to
 672  * not run as designed.
 673  *
 674  * This hack is only to be used for comparisons and thus can be fully const.
 675  * Do not use for assignment.
 676  *
 677  * If we ever choose to change the ABI of the CIRCLEQ macros, we could fix
 678  * this by changing the head/tail sentinal values, but see the note above
 679  * this one.
 680  */
 681 static __inline const void * __launder_type(const void *);
 682 static __inline const void *
 683 __launder_type(const void *__x)
 684 {
 685         __asm __volatile("" : "+r" (__x));
 686         return __x;
 687 }
 688
 689 #if defined(QUEUEDEBUG)
 690 #define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)                            \
 691         if ((head)->cqh_first != CIRCLEQ_ENDC(head) &&                  \
 692             (head)->cqh_first->field.cqe_prev != CIRCLEQ_ENDC(head))    \
 693                 QUEUEDEBUG_ABORT("CIRCLEQ head forw %p %s:%d", (head),  \
 694                       __FILE__, __LINE__);                              \
 695         if ((head)->cqh_last != CIRCLEQ_ENDC(head) &&                   \
 696             (head)->cqh_last->field.cqe_next != CIRCLEQ_ENDC(head))     \
 697                 QUEUEDEBUG_ABORT("CIRCLEQ head back %p %s:%d", (head),  \
 698                       __FILE__, __LINE__);
 699 #define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)                        \
 700         if ((elm)->field.cqe_next == CIRCLEQ_ENDC(head)) {              \
 701                 if ((head)->cqh_last != (elm))                          \
 702                         QUEUEDEBUG_ABORT("CIRCLEQ elm last %p %s:%d",   \
 703                             (elm), __FILE__, __LINE__);                 \
 704         } else {                                                        \
 705                 if ((elm)->field.cqe_next->field.cqe_prev != (elm))     \
 706                         QUEUEDEBUG_ABORT("CIRCLEQ elm forw %p %s:%d",   \
 707                             (elm), __FILE__, __LINE__);                 \
 708         }                                                               \
 709         if ((elm)->field.cqe_prev == CIRCLEQ_ENDC(head)) {              \
 710                 if ((head)->cqh_first != (elm))                         \
 711                         QUEUEDEBUG_ABORT("CIRCLEQ elm first %p %s:%d",  \
 712                             (elm), __FILE__, __LINE__);                 \
 713         } else {                                                        \
 714                 if ((elm)->field.cqe_prev->field.cqe_next != (elm))     \
 715                         QUEUEDEBUG_ABORT("CIRCLEQ elm prev %p %s:%d",   \
 716                             (elm), __FILE__, __LINE__);                 \
 717         }
 718 #define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)                       \
 719         (elm)->field.cqe_next = (void *)1L;                             \
 720         (elm)->field.cqe_prev = (void *)1L;
 721 #else
 722 #define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)
 723 #define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)
 724 #define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)
 725 #endif
 726
 727 #define CIRCLEQ_HEAD(name, type)                                        \
 728 struct name {                                                           \
 729         struct type *cqh_first;         /* first element */             \
 730         struct type *cqh_last;          /* last element */              \
 731 }
 732
 733 #define CIRCLEQ_HEAD_INITIALIZER(head)                                  \
 734         { CIRCLEQ_END(&head), CIRCLEQ_END(&head) }
 735
 736 #define CIRCLEQ_ENTRY(type)                                             \
 737 struct {                                                                \
 738         struct type *cqe_next;          /* next element */              \
 739         struct type *cqe_prev;          /* previous element */          \
 740 }
 741
 742 /*
 743  * Circular queue functions.
 744  */
 745 #define CIRCLEQ_INIT(head) do {                                         \
 746         (head)->cqh_first = CIRCLEQ_END(head);                          \
 747         (head)->cqh_last = CIRCLEQ_END(head);                           \
 748 } while (/*CONSTCOND*/0)
 749
 750 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {            \
 751         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 752         QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)                \
 753         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 754         (elm)->field.cqe_prev = (listelm);                              \
 755         if ((listelm)->field.cqe_next == CIRCLEQ_ENDC(head))            \
 756                 (head)->cqh_last = (elm);                               \
 757         else                                                            \
 758                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 759         (listelm)->field.cqe_next = (elm);                              \
 760 } while (/*CONSTCOND*/0)
 761
 762 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {           \
 763         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 764         QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), field)                \
 765         (elm)->field.cqe_next = (listelm);                              \
 766         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 767         if ((listelm)->field.cqe_prev == CIRCLEQ_ENDC(head))            \
 768                 (head)->cqh_first = (elm);                              \
 769         else                                                            \
 770                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 771         (listelm)->field.cqe_prev = (elm);                              \
 772 } while (/*CONSTCOND*/0)
 773
 774 #define CIRCLEQ_INSERT_HEAD(head, elm, field) do {                      \
 775         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 776         (elm)->field.cqe_next = (head)->cqh_first;                      \
 777         (elm)->field.cqe_prev = CIRCLEQ_END(head);                      \
 778         if ((head)->cqh_last == CIRCLEQ_ENDC(head))                     \
 779                 (head)->cqh_last = (elm);                               \
 780         else                                                            \
 781                 (head)->cqh_first->field.cqe_prev = (elm);              \
 782         (head)->cqh_first = (elm);                                      \
 783 } while (/*CONSTCOND*/0)
 784
 785 #define CIRCLEQ_INSERT_TAIL(head, elm, field) do {                      \
 786         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 787         (elm)->field.cqe_next = CIRCLEQ_END(head);                      \
 788         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 789         if ((head)->cqh_first == CIRCLEQ_ENDC(head))                    \
 790                 (head)->cqh_first = (elm);                              \
 791         else                                                            \
 792                 (head)->cqh_last->field.cqe_next = (elm);               \
 793         (head)->cqh_last = (elm);                                       \
 794 } while (/*CONSTCOND*/0)
 795
 796 #define CIRCLEQ_REMOVE(head, elm, field) do {                           \
 797         QUEUEDEBUG_CIRCLEQ_HEAD((head), field)                          \
 798         QUEUEDEBUG_CIRCLEQ_ELM((head), (elm), field)                    \
 799         if ((elm)->field.cqe_next == CIRCLEQ_ENDC(head))                \
 800                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 801         else                                                            \
 802                 (elm)->field.cqe_next->field.cqe_prev =                 \
 803                     (elm)->field.cqe_prev;                              \
 804         if ((elm)->field.cqe_prev == CIRCLEQ_ENDC(head))                \
 805                 (head)->cqh_first = (elm)->field.cqe_next;              \
 806         else                                                            \
 807                 (elm)->field.cqe_prev->field.cqe_next =                 \
 808                     (elm)->field.cqe_next;                              \
 809         QUEUEDEBUG_CIRCLEQ_POSTREMOVE((elm), field)                     \
 810 } while (/*CONSTCOND*/0)
 811
 812 #define CIRCLEQ_FOREACH(var, head, field)                               \
 813         for ((var) = ((head)->cqh_first);                               \
 814                 (var) != CIRCLEQ_ENDC(head);                            \
 815                 (var) = ((var)->field.cqe_next))
 816
 817 #define CIRCLEQ_FOREACH_REVERSE(var, head, field)                       \
 818         for ((var) = ((head)->cqh_last);                                \
 819                 (var) != CIRCLEQ_ENDC(head);                            \
 820                 (var) = ((var)->field.cqe_prev))
 821
 822 /*
 823  * Circular queue access methods.
 824  */
 825 #define CIRCLEQ_FIRST(head)             ((head)->cqh_first)
 826 #define CIRCLEQ_LAST(head)              ((head)->cqh_last)
 827 /* For comparisons */
 828 #define CIRCLEQ_ENDC(head)              (__launder_type(head))
 829 /* For assignments */
 830 #define CIRCLEQ_END(head)               ((void *)(head))
 831 #define CIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
 832 #define CIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)
 833 #define CIRCLEQ_EMPTY(head)                                             \
 834     (CIRCLEQ_FIRST(head) == CIRCLEQ_ENDC(head))
 835
 836 #define CIRCLEQ_LOOP_NEXT(head, elm, field)                             \
 837         (((elm)->field.cqe_next == CIRCLEQ_ENDC(head))                  \
 838             ? ((head)->cqh_first)                                       \
 839             : (elm->field.cqe_next))
 840 #define CIRCLEQ_LOOP_PREV(head, elm, field)                             \
 841         (((elm)->field.cqe_prev == CIRCLEQ_ENDC(head))                  \
 842             ? ((head)->cqh_last)                                        \
 843             : (elm->field.cqe_prev))
 844 #endif /* !_KERNEL */
 845
 846 #endif  /* !_SYS_QUEUE_H_ */