akaros/tools/compilers/gcc-glibc/glibc-2.19-akaros/sysdeps/akaros/sys/queue.h
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   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 * 4. 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 * $FreeBSD$
  31 */
  32
  33#ifndef _SYS_QUEUE_H
  34#define _SYS_QUEUE_H
  35
  36/*
  37 * This file defines four types of data structures: singly-linked lists,
  38 * singly-linked tail queues, lists and tail queues.
  39 *
  40 * A singly-linked list is headed by a single forward pointer. The elements
  41 * are singly linked for minimum space and pointer manipulation overhead at
  42 * the expense of O(n) removal for arbitrary elements. New elements can be
  43 * added to the list after an existing element or at the head of the list.
  44 * Elements being removed from the head of the list should use the explicit
  45 * macro for this purpose for optimum efficiency. A singly-linked list may
  46 * only be traversed in the forward direction.  Singly-linked lists are ideal
  47 * for applications with large datasets and few or no removals or for
  48 * implementing a LIFO queue.
  49 *
  50 * A singly-linked tail queue is headed by a pair of pointers, one to the
  51 * head of the list and the other to the tail of the list. The elements are
  52 * singly linked for minimum space and pointer manipulation overhead at the
  53 * expense of O(n) removal for arbitrary elements. New elements can be added
  54 * to the list after an existing element, at the head of the list, or at the
  55 * end of the list. Elements being removed from the head of the tail queue
  56 * should use the explicit macro for this purpose for optimum efficiency.
  57 * A singly-linked tail queue may only be traversed in the forward direction.
  58 * Singly-linked tail queues are ideal for applications with large datasets
  59 * and few or no removals or for implementing a FIFO queue.
  60 *
  61 * A list is headed by a single forward pointer (or an array of forward
  62 * pointers for a hash table header). The elements are doubly linked
  63 * so that an arbitrary element can be removed without a need to
  64 * traverse the list. New elements can be added to the list before
  65 * or after an existing element or at the head of the list. A list
  66 * may only be traversed in the forward direction.
  67 *
  68 * A tail queue is headed by a pair of pointers, one to the head of the
  69 * list and the other to the tail of the list. The elements are doubly
  70 * linked so that an arbitrary element can be removed without a need to
  71 * traverse the list. New elements can be added to the list before or
  72 * after an existing element, at the head of the list, or at the end of
  73 * the list. A tail queue may be traversed in either direction.
  74 *
  75 * For details on the use of these macros, see the queue(3) manual page.
  76 *
  77 *
  78 *                              SLIST   LIST    STAILQ  TAILQ
  79 * _HEAD                        +       +       +       +
  80 * _HEAD_INITIALIZER            +       +       +       +
  81 * _ENTRY                       +       +       +       +
  82 * _INIT                        +       +       +       +
  83 * _EMPTY                       +       +       +       +
  84 * _FIRST                       +       +       +       +
  85 * _NEXT                        +       +       +       +
  86 * _PREV                        -       -       -       +
  87 * _LAST                        -       -       +       +
  88 * _FOREACH                     +       +       +       +
  89 * _FOREACH_SAFE                +       +       +       +
  90 * _FOREACH_REVERSE             -       -       -       +
  91 * _FOREACH_REVERSE_SAFE        -       -       -       +
  92 * _INSERT_HEAD                 +       +       +       +
  93 * _INSERT_BEFORE               -       +       -       +
  94 * _INSERT_AFTER                +       +       +       +
  95 * _INSERT_TAIL                 -       -       +       +
  96 * _CONCAT                      -       -       +       +
  97 * _REMOVE_AFTER                +       -       +       -
  98 * _REMOVE_HEAD                 +       -       +       -
  99 * _REMOVE                      +       +       +       +
 100 *
 101 */
 102#ifdef QUEUE_MACRO_DEBUG
 103/* Store the last 2 places the queue element or head was altered */
 104struct qm_trace {
 105        char * lastfile;
 106        int lastline;
 107        char * prevfile;
 108        int prevline;
 109};
 110
 111#define TRACEBUF        struct qm_trace trace;
 112#define TRASHIT(x)      do {(x) = (void *)-1;} while (0)
 113#define QMD_SAVELINK(name, link)        void **name = (void *)&(link)
 114
 115#define QMD_TRACE_HEAD(head) do {                                       \
 116        (head)->trace.prevline = (head)->trace.lastline;                \
 117        (head)->trace.prevfile = (head)->trace.lastfile;                \
 118        (head)->trace.lastline = __LINE__;                              \
 119        (head)->trace.lastfile = __FILE__;                              \
 120} while (0)
 121
 122#define QMD_TRACE_ELEM(elem) do {                                       \
 123        (elem)->trace.prevline = (elem)->trace.lastline;                \
 124        (elem)->trace.prevfile = (elem)->trace.lastfile;                \
 125        (elem)->trace.lastline = __LINE__;                              \
 126        (elem)->trace.lastfile = __FILE__;                              \
 127} while (0)
 128
 129#else
 130#define QMD_TRACE_ELEM(elem)
 131#define QMD_TRACE_HEAD(head)
 132#define QMD_SAVELINK(name, link)
 133#define TRACEBUF
 134#define TRASHIT(x)
 135#endif  /* QUEUE_MACRO_DEBUG */
 136
 137/*
 138 * Singly-linked List declarations.
 139 */
 140#define SLIST_HEAD(name, type)                                          \
 141struct name {                                                           \
 142        struct type *slh_first; /* first element */                     \
 143}
 144
 145#define SLIST_HEAD_INITIALIZER(head)                                    \
 146        { NULL }
 147
 148#define SLIST_ENTRY(type)                                               \
 149struct {                                                                \
 150        struct type *sle_next;  /* next element */                      \
 151}
 152
 153/*
 154 * Singly-linked List functions.
 155 */
 156#define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 157
 158#define SLIST_FIRST(head)       ((head)->slh_first)
 159
 160#define SLIST_FOREACH(var, head, field)                                 \
 161        for ((var) = SLIST_FIRST((head));                               \
 162            (var);                                                      \
 163            (var) = SLIST_NEXT((var), field))
 164
 165#define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 166        for ((var) = SLIST_FIRST((head));                               \
 167            (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
 168            (var) = (tvar))
 169
 170#define SLIST_FOREACH_PREVPTR(var, varp, head, field)                   \
 171        for ((varp) = &SLIST_FIRST((head));                             \
 172            ((var) = *(varp)) != NULL;                                  \
 173            (varp) = &SLIST_NEXT((var), field))
 174
 175#define SLIST_INIT(head) do {                                           \
 176        SLIST_FIRST((head)) = NULL;                                     \
 177} while (0)
 178
 179#define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 180        SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);       \
 181        SLIST_NEXT((slistelm), field) = (elm);                          \
 182} while (0)
 183
 184#define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 185        SLIST_NEXT((elm), field) = SLIST_FIRST((head));                 \
 186        SLIST_FIRST((head)) = (elm);                                    \
 187} while (0)
 188
 189#define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 190
 191#define SLIST_REMOVE(head, elm, type, field) do {                       \
 192        QMD_SAVELINK(oldnext, (elm)->field.sle_next);                   \
 193        if (SLIST_FIRST((head)) == (elm)) {                             \
 194                SLIST_REMOVE_HEAD((head), field);                       \
 195        }                                                               \
 196        else {                                                          \
 197                struct type *curelm = SLIST_FIRST((head));              \
 198                while (SLIST_NEXT(curelm, field) != (elm))              \
 199                        curelm = SLIST_NEXT(curelm, field);             \
 200                SLIST_REMOVE_AFTER(curelm, field);                      \
 201        }                                                               \
 202        TRASHIT(*oldnext);                                              \
 203} while (0)
 204
 205#define SLIST_REMOVE_AFTER(elm, field) do {                             \
 206        SLIST_NEXT(elm, field) =                                        \
 207            SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
 208} while (0)
 209
 210#define SLIST_REMOVE_HEAD(head, field) do {                             \
 211        SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
 212} while (0)
 213
 214/*
 215 * Singly-linked Tail queue declarations.
 216 */
 217#define STAILQ_HEAD(name, type)                                         \
 218struct name {                                                           \
 219        struct type *stqh_first;/* first element */                     \
 220        struct type **stqh_last;/* addr of last next element */         \
 221}
 222
 223#define STAILQ_HEAD_INITIALIZER(head)                                   \
 224        { NULL, &(head).stqh_first }
 225
 226#define STAILQ_ENTRY(type)                                              \
 227struct {                                                                \
 228        struct type *stqe_next; /* next element */                      \
 229}
 230
 231/*
 232 * Singly-linked Tail queue functions.
 233 */
 234#define STAILQ_CONCAT(head1, head2) do {                                \
 235        if (!STAILQ_EMPTY((head2))) {                                   \
 236                *(head1)->stqh_last = (head2)->stqh_first;              \
 237                (head1)->stqh_last = (head2)->stqh_last;                \
 238                STAILQ_INIT((head2));                                   \
 239        }                                                               \
 240} while (0)
 241
 242#define STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
 243
 244#define STAILQ_FIRST(head)      ((head)->stqh_first)
 245
 246#define STAILQ_FOREACH(var, head, field)                                \
 247        for((var) = STAILQ_FIRST((head));                               \
 248           (var);                                                       \
 249           (var) = STAILQ_NEXT((var), field))
 250
 251
 252#define STAILQ_FOREACH_SAFE(var, head, field, tvar)                     \
 253        for ((var) = STAILQ_FIRST((head));                              \
 254            (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 255            (var) = (tvar))
 256
 257#define STAILQ_INIT(head) do {                                          \
 258        STAILQ_FIRST((head)) = NULL;                                    \
 259        (head)->stqh_last = &STAILQ_FIRST((head));                      \
 260} while (0)
 261
 262#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {               \
 263        if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
 264                (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 265        STAILQ_NEXT((tqelm), field) = (elm);                            \
 266} while (0)
 267
 268#define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 269        if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
 270                (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 271        STAILQ_FIRST((head)) = (elm);                                   \
 272} while (0)
 273
 274#define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 275        STAILQ_NEXT((elm), field) = NULL;                               \
 276        *(head)->stqh_last = (elm);                                     \
 277        (head)->stqh_last = &STAILQ_NEXT((elm), field);                 \
 278} while (0)
 279
 280#define STAILQ_LAST(head, type, field)                                  \
 281        (STAILQ_EMPTY((head)) ?                                         \
 282                NULL :                                                  \
 283                ((struct type *)(void *)                                \
 284                ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
 285
 286#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 287
 288#define STAILQ_REMOVE(head, elm, type, field) do {                      \
 289        QMD_SAVELINK(oldnext, (elm)->field.stqe_next);                  \
 290        if (STAILQ_FIRST((head)) == (elm)) {                            \
 291                STAILQ_REMOVE_HEAD((head), field);                      \
 292        }                                                               \
 293        else {                                                          \
 294                struct type *curelm = STAILQ_FIRST((head));             \
 295                while (STAILQ_NEXT(curelm, field) != (elm))             \
 296                        curelm = STAILQ_NEXT(curelm, field);            \
 297                STAILQ_REMOVE_AFTER(head, curelm, field);               \
 298        }                                                               \
 299        TRASHIT(*oldnext);                                              \
 300} while (0)
 301
 302#define STAILQ_REMOVE_HEAD(head, field) do {                            \
 303        if ((STAILQ_FIRST((head)) =                                     \
 304             STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)         \
 305                (head)->stqh_last = &STAILQ_FIRST((head));              \
 306} while (0)
 307
 308#define STAILQ_REMOVE_AFTER(head, elm, field) do {                      \
 309        if ((STAILQ_NEXT(elm, field) =                                  \
 310             STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)      \
 311                (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 312} while (0)
 313
 314#define STAILQ_SWAP(head1, head2, type) do {                            \
 315        struct type *swap_first = STAILQ_FIRST(head1);                  \
 316        struct type **swap_last = (head1)->stqh_last;                   \
 317        STAILQ_FIRST(head1) = STAILQ_FIRST(head2);                      \
 318        (head1)->stqh_last = (head2)->stqh_last;                        \
 319        STAILQ_FIRST(head2) = swap_first;                               \
 320        (head2)->stqh_last = swap_last;                                 \
 321        if (STAILQ_EMPTY(head1))                                        \
 322                (head1)->stqh_last = &STAILQ_FIRST(head1);              \
 323        if (STAILQ_EMPTY(head2))                                        \
 324                (head2)->stqh_last = &STAILQ_FIRST(head2);              \
 325} while (0)
 326
 327
 328/*
 329 * List declarations.
 330 */
 331#define LIST_HEAD(name, type)                                           \
 332struct name {                                                           \
 333        struct type *lh_first;  /* first element */                     \
 334}
 335
 336#define LIST_HEAD_INITIALIZER(head)                                     \
 337        { NULL }
 338
 339#define LIST_ENTRY(type)                                                \
 340struct {                                                                \
 341        struct type *le_next;   /* next element */                      \
 342        struct type **le_prev;  /* address of previous next element */  \
 343}
 344
 345/*
 346 * List functions.
 347 */
 348
 349#if (defined(_KERNEL) && defined(INVARIANTS))
 350#define QMD_LIST_CHECK_HEAD(head, field) do {                           \
 351        if (LIST_FIRST((head)) != NULL &&                               \
 352            LIST_FIRST((head))->field.le_prev !=                        \
 353             &LIST_FIRST((head)))                                       \
 354                panic("Bad list head %p first->prev != head", (head));  \
 355} while (0)
 356
 357#define QMD_LIST_CHECK_NEXT(elm, field) do {                            \
 358        if (LIST_NEXT((elm), field) != NULL &&                          \
 359            LIST_NEXT((elm), field)->field.le_prev !=                   \
 360             &((elm)->field.le_next))                                   \
 361                panic("Bad link elm %p next->prev != elm", (elm));      \
 362} while (0)
 363
 364#define QMD_LIST_CHECK_PREV(elm, field) do {                            \
 365        if (*(elm)->field.le_prev != (elm))                             \
 366                panic("Bad link elm %p prev->next != elm", (elm));      \
 367} while (0)
 368#else
 369#define QMD_LIST_CHECK_HEAD(head, field)
 370#define QMD_LIST_CHECK_NEXT(elm, field)
 371#define QMD_LIST_CHECK_PREV(elm, field)
 372#endif /* (_KERNEL && INVARIANTS) */
 373
 374#define LIST_EMPTY(head)        ((head)->lh_first == NULL)
 375
 376#define LIST_FIRST(head)        ((head)->lh_first)
 377
 378#define LIST_FOREACH(var, head, field)                                  \
 379        for ((var) = LIST_FIRST((head));                                \
 380            (var);                                                      \
 381            (var) = LIST_NEXT((var), field))
 382
 383#define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 384        for ((var) = LIST_FIRST((head));                                \
 385            (var) && ((tvar) = LIST_NEXT((var), field), 1);             \
 386            (var) = (tvar))
 387
 388#define LIST_INIT(head) do {                                            \
 389        LIST_FIRST((head)) = NULL;                                      \
 390} while (0)
 391
 392#define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 393        QMD_LIST_CHECK_NEXT(listelm, field);                            \
 394        if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
 395                LIST_NEXT((listelm), field)->field.le_prev =            \
 396                    &LIST_NEXT((elm), field);                           \
 397        LIST_NEXT((listelm), field) = (elm);                            \
 398        (elm)->field.le_prev = &LIST_NEXT((listelm), field);            \
 399} while (0)
 400
 401#define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 402        QMD_LIST_CHECK_PREV(listelm, field);                            \
 403        (elm)->field.le_prev = (listelm)->field.le_prev;                \
 404        LIST_NEXT((elm), field) = (listelm);                            \
 405        *(listelm)->field.le_prev = (elm);                              \
 406        (listelm)->field.le_prev = &LIST_NEXT((elm), field);            \
 407} while (0)
 408
 409#define LIST_INSERT_HEAD(head, elm, field) do {                         \
 410        QMD_LIST_CHECK_HEAD((head), field);                             \
 411        if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)     \
 412                LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
 413        LIST_FIRST((head)) = (elm);                                     \
 414        (elm)->field.le_prev = &LIST_FIRST((head));                     \
 415} while (0)
 416
 417#define LIST_NEXT(elm, field)   ((elm)->field.le_next)
 418
 419#define LIST_REMOVE(elm, field) do {                                    \
 420        QMD_SAVELINK(oldnext, (elm)->field.le_next);                    \
 421        QMD_SAVELINK(oldprev, (elm)->field.le_prev);                    \
 422        QMD_LIST_CHECK_NEXT(elm, field);                                \
 423        QMD_LIST_CHECK_PREV(elm, field);                                \
 424        if (LIST_NEXT((elm), field) != NULL)                            \
 425                LIST_NEXT((elm), field)->field.le_prev =                \
 426                    (elm)->field.le_prev;                               \
 427        *(elm)->field.le_prev = LIST_NEXT((elm), field);                \
 428        TRASHIT(*oldnext);                                              \
 429        TRASHIT(*oldprev);                                              \
 430} while (0)
 431
 432#define LIST_SWAP(head1, head2, type, field) do {                       \
 433        struct type *swap_tmp = LIST_FIRST((head1));                    \
 434        LIST_FIRST((head1)) = LIST_FIRST((head2));                      \
 435        LIST_FIRST((head2)) = swap_tmp;                                 \
 436        if ((swap_tmp = LIST_FIRST((head1))) != NULL)                   \
 437                swap_tmp->field.le_prev = &LIST_FIRST((head1));         \
 438        if ((swap_tmp = LIST_FIRST((head2))) != NULL)                   \
 439                swap_tmp->field.le_prev = &LIST_FIRST((head2));         \
 440} while (0)
 441
 442/*
 443 * Tail queue declarations.
 444 */
 445#define TAILQ_HEAD(name, type)                                          \
 446struct name {                                                           \
 447        struct type *tqh_first; /* first element */                     \
 448        struct type **tqh_last; /* addr of last next element */         \
 449        TRACEBUF                                                        \
 450}
 451
 452#define TAILQ_HEAD_INITIALIZER(head)                                    \
 453        { NULL, &(head).tqh_first }
 454
 455#define TAILQ_ENTRY(type)                                               \
 456struct {                                                                \
 457        struct type *tqe_next;  /* next element */                      \
 458        struct type **tqe_prev; /* address of previous next element */  \
 459        TRACEBUF                                                        \
 460}
 461
 462/*
 463 * Tail queue functions.
 464 */
 465#if (defined(_KERNEL) && defined(INVARIANTS))
 466#define QMD_TAILQ_CHECK_HEAD(head, field) do {                          \
 467        if (!TAILQ_EMPTY(head) &&                                       \
 468            TAILQ_FIRST((head))->field.tqe_prev !=                      \
 469             &TAILQ_FIRST((head)))                                      \
 470                panic("Bad tailq head %p first->prev != head", (head)); \
 471} while (0)
 472
 473#define QMD_TAILQ_CHECK_TAIL(head, field) do {                          \
 474        if (*(head)->tqh_last != NULL)                                  \
 475                panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head));  \
 476} while (0)
 477
 478#define QMD_TAILQ_CHECK_NEXT(elm, field) do {                           \
 479        if (TAILQ_NEXT((elm), field) != NULL &&                         \
 480            TAILQ_NEXT((elm), field)->field.tqe_prev !=                 \
 481             &((elm)->field.tqe_next))                                  \
 482                panic("Bad link elm %p next->prev != elm", (elm));      \
 483} while (0)
 484
 485#define QMD_TAILQ_CHECK_PREV(elm, field) do {                           \
 486        if (*(elm)->field.tqe_prev != (elm))                            \
 487                panic("Bad link elm %p prev->next != elm", (elm));      \
 488} while (0)
 489#else
 490#define QMD_TAILQ_CHECK_HEAD(head, field)
 491#define QMD_TAILQ_CHECK_TAIL(head, headname)
 492#define QMD_TAILQ_CHECK_NEXT(elm, field)
 493#define QMD_TAILQ_CHECK_PREV(elm, field)
 494#endif /* (_KERNEL && INVARIANTS) */
 495
 496#define TAILQ_CONCAT(head1, head2, field) do {                          \
 497        if (!TAILQ_EMPTY(head2)) {                                      \
 498                *(head1)->tqh_last = (head2)->tqh_first;                \
 499                (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
 500                (head1)->tqh_last = (head2)->tqh_last;                  \
 501                TAILQ_INIT((head2));                                    \
 502                QMD_TRACE_HEAD(head1);                                  \
 503                QMD_TRACE_HEAD(head2);                                  \
 504        }                                                               \
 505} while (0)
 506
 507#define TAILQ_EMPTY(head)       ((head)->tqh_first == NULL)
 508
 509#define TAILQ_FIRST(head)       ((head)->tqh_first)
 510
 511#define TAILQ_FOREACH(var, head, field)                                 \
 512        for ((var) = TAILQ_FIRST((head));                               \
 513            (var);                                                      \
 514            (var) = TAILQ_NEXT((var), field))
 515
 516#define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 517        for ((var) = TAILQ_FIRST((head));                               \
 518            (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
 519            (var) = (tvar))
 520
 521#define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 522        for ((var) = TAILQ_LAST((head), headname);                      \
 523            (var);                                                      \
 524            (var) = TAILQ_PREV((var), headname, field))
 525
 526#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 527        for ((var) = TAILQ_LAST((head), headname);                      \
 528            (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
 529            (var) = (tvar))
 530
 531#define TAILQ_INIT(head) do {                                           \
 532        TAILQ_FIRST((head)) = NULL;                                     \
 533        (head)->tqh_last = &TAILQ_FIRST((head));                        \
 534        QMD_TRACE_HEAD(head);                                           \
 535} while (0)
 536
 537#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 538        QMD_TAILQ_CHECK_NEXT(listelm, field);                           \
 539        if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
 540                TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 541                    &TAILQ_NEXT((elm), field);                          \
 542        else {                                                          \
 543                (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 544                QMD_TRACE_HEAD(head);                                   \
 545        }                                                               \
 546        TAILQ_NEXT((listelm), field) = (elm);                           \
 547        (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);          \
 548        QMD_TRACE_ELEM(&(elm)->field);                                  \
 549        QMD_TRACE_ELEM(&listelm->field);                                \
 550} while (0)
 551
 552#define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 553        QMD_TAILQ_CHECK_PREV(listelm, field);                           \
 554        (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 555        TAILQ_NEXT((elm), field) = (listelm);                           \
 556        *(listelm)->field.tqe_prev = (elm);                             \
 557        (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);          \
 558        QMD_TRACE_ELEM(&(elm)->field);                                  \
 559        QMD_TRACE_ELEM(&listelm->field);                                \
 560} while (0)
 561
 562#define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 563        QMD_TAILQ_CHECK_HEAD(head, field);                              \
 564        if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)   \
 565                TAILQ_FIRST((head))->field.tqe_prev =                   \
 566                    &TAILQ_NEXT((elm), field);                          \
 567        else                                                            \
 568                (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 569        TAILQ_FIRST((head)) = (elm);                                    \
 570        (elm)->field.tqe_prev = &TAILQ_FIRST((head));                   \
 571        QMD_TRACE_HEAD(head);                                           \
 572        QMD_TRACE_ELEM(&(elm)->field);                                  \
 573} while (0)
 574
 575#define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 576        QMD_TAILQ_CHECK_TAIL(head, field);                              \
 577        TAILQ_NEXT((elm), field) = NULL;                                \
 578        (elm)->field.tqe_prev = (head)->tqh_last;                       \
 579        *(head)->tqh_last = (elm);                                      \
 580        (head)->tqh_last = &TAILQ_NEXT((elm), field);                   \
 581        QMD_TRACE_HEAD(head);                                           \
 582        QMD_TRACE_ELEM(&(elm)->field);                                  \
 583} while (0)
 584
 585#define TAILQ_LAST(head, headname)                                      \
 586        (*(((struct headname *)((head)->tqh_last))->tqh_last))
 587
 588#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 589
 590#define TAILQ_PREV(elm, headname, field)                                \
 591        (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 592
 593#define TAILQ_REMOVE(head, elm, field) do {                             \
 594        QMD_SAVELINK(oldnext, (elm)->field.tqe_next);                   \
 595        QMD_SAVELINK(oldprev, (elm)->field.tqe_prev);                   \
 596        QMD_TAILQ_CHECK_NEXT(elm, field);                               \
 597        QMD_TAILQ_CHECK_PREV(elm, field);                               \
 598        if ((TAILQ_NEXT((elm), field)) != NULL)                         \
 599                TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 600                    (elm)->field.tqe_prev;                              \
 601        else {                                                          \
 602                (head)->tqh_last = (elm)->field.tqe_prev;               \
 603                QMD_TRACE_HEAD(head);                                   \
 604        }                                                               \
 605        *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);              \
 606        TRASHIT(*oldnext);                                              \
 607        TRASHIT(*oldprev);                                              \
 608        QMD_TRACE_ELEM(&(elm)->field);                                  \
 609} while (0)
 610
 611#define TAILQ_SWAP(head1, head2, type, field) do {                      \
 612        struct type *swap_first = (head1)->tqh_first;                   \
 613        struct type **swap_last = (head1)->tqh_last;                    \
 614        (head1)->tqh_first = (head2)->tqh_first;                        \
 615        (head1)->tqh_last = (head2)->tqh_last;                          \
 616        (head2)->tqh_first = swap_first;                                \
 617        (head2)->tqh_last = swap_last;                                  \
 618        if ((swap_first = (head1)->tqh_first) != NULL)                  \
 619                swap_first->field.tqe_prev = &(head1)->tqh_first;       \
 620        else                                                            \
 621                (head1)->tqh_last = &(head1)->tqh_first;                \
 622        if ((swap_first = (head2)->tqh_first) != NULL)                  \
 623                swap_first->field.tqe_prev = &(head2)->tqh_first;       \
 624        else                                                            \
 625                (head2)->tqh_last = &(head2)->tqh_first;                \
 626} while (0)
 627
 628#endif /* _SYS_QUEUE_H */
 629