qemu/include/qemu/queue.h
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   1/*      $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */
   2
   3/*
   4 * QEMU version: Copy from netbsd, removed debug code, removed some of
   5 * the implementations.  Left in singly-linked lists, lists, simple
   6 * queues, and tail queues.
   7 */
   8
   9/*
  10 * Copyright (c) 1991, 1993
  11 *      The Regents of the University of California.  All rights reserved.
  12 *
  13 * Redistribution and use in source and binary forms, with or without
  14 * modification, are permitted provided that the following conditions
  15 * are met:
  16 * 1. Redistributions of source code must retain the above copyright
  17 *    notice, this list of conditions and the following disclaimer.
  18 * 2. Redistributions in binary form must reproduce the above copyright
  19 *    notice, this list of conditions and the following disclaimer in the
  20 *    documentation and/or other materials provided with the distribution.
  21 * 3. Neither the name of the University nor the names of its contributors
  22 *    may be used to endorse or promote products derived from this software
  23 *    without specific prior written permission.
  24 *
  25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35 * SUCH DAMAGE.
  36 *
  37 *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  38 */
  39
  40#ifndef QEMU_SYS_QUEUE_H
  41#define QEMU_SYS_QUEUE_H
  42
  43/*
  44 * This file defines four types of data structures: singly-linked lists,
  45 * lists, simple queues, and tail queues.
  46 *
  47 * A singly-linked list is headed by a single forward pointer. The
  48 * elements are singly linked for minimum space and pointer manipulation
  49 * overhead at the expense of O(n) removal for arbitrary elements. New
  50 * elements can be added to the list after an existing element or at the
  51 * head of the list.  Elements being removed from the head of the list
  52 * should use the explicit macro for this purpose for optimum
  53 * efficiency. A singly-linked list may only be traversed in the forward
  54 * direction.  Singly-linked lists are ideal for applications with large
  55 * datasets and few or no removals or for implementing a LIFO queue.
  56 *
  57 * A list is headed by a single forward pointer (or an array of forward
  58 * pointers for a hash table header). The elements are doubly linked
  59 * so that an arbitrary element can be removed without a need to
  60 * traverse the list. New elements can be added to the list before
  61 * or after an existing element or at the head of the list. A list
  62 * may only be traversed in the forward direction.
  63 *
  64 * A simple queue is headed by a pair of pointers, one the head of the
  65 * list and the other to the tail of the list. The elements are singly
  66 * linked to save space, so elements can only be removed from the
  67 * head of the list. New elements can be added to the list after
  68 * an existing element, at the head of the list, or at the end of the
  69 * list. A simple queue may only be traversed in the forward direction.
  70 *
  71 * A tail queue is headed by a pair of pointers, one to the head of the
  72 * list and the other to the tail of the list. The elements are doubly
  73 * linked so that an arbitrary element can be removed without a need to
  74 * traverse the list. New elements can be added to the list before or
  75 * after an existing element, at the head of the list, or at the end of
  76 * the list. A tail queue may be traversed in either direction.
  77 *
  78 * For details on the use of these macros, see the queue(3) manual page.
  79 */
  80
  81#include "qemu/atomic.h" /* for smp_wmb() */
  82
  83/*
  84 * List definitions.
  85 */
  86#define QLIST_HEAD(name, type)                                          \
  87struct name {                                                           \
  88        struct type *lh_first;  /* first element */                     \
  89}
  90
  91#define QLIST_HEAD_INITIALIZER(head)                                    \
  92        { NULL }
  93
  94#define QLIST_ENTRY(type)                                               \
  95struct {                                                                \
  96        struct type *le_next;   /* next element */                      \
  97        struct type **le_prev;  /* address of previous next element */  \
  98}
  99
 100/*
 101 * List functions.
 102 */
 103#define QLIST_INIT(head) do {                                           \
 104        (head)->lh_first = NULL;                                        \
 105} while (/*CONSTCOND*/0)
 106
 107#define QLIST_SWAP(dstlist, srclist, field) do {                        \
 108        void *tmplist;                                                  \
 109        tmplist = (srclist)->lh_first;                                  \
 110        (srclist)->lh_first = (dstlist)->lh_first;                      \
 111        if ((srclist)->lh_first != NULL) {                              \
 112            (srclist)->lh_first->field.le_prev = &(srclist)->lh_first;  \
 113        }                                                               \
 114        (dstlist)->lh_first = tmplist;                                  \
 115        if ((dstlist)->lh_first != NULL) {                              \
 116            (dstlist)->lh_first->field.le_prev = &(dstlist)->lh_first;  \
 117        }                                                               \
 118} while (/*CONSTCOND*/0)
 119
 120#define QLIST_INSERT_AFTER(listelm, elm, field) do {                    \
 121        if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 122                (listelm)->field.le_next->field.le_prev =               \
 123                    &(elm)->field.le_next;                              \
 124        (listelm)->field.le_next = (elm);                               \
 125        (elm)->field.le_prev = &(listelm)->field.le_next;               \
 126} while (/*CONSTCOND*/0)
 127
 128#define QLIST_INSERT_BEFORE(listelm, elm, field) do {                   \
 129        (elm)->field.le_prev = (listelm)->field.le_prev;                \
 130        (elm)->field.le_next = (listelm);                               \
 131        *(listelm)->field.le_prev = (elm);                              \
 132        (listelm)->field.le_prev = &(elm)->field.le_next;               \
 133} while (/*CONSTCOND*/0)
 134
 135#define QLIST_INSERT_HEAD(head, elm, field) do {                        \
 136        if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 137                (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 138        (head)->lh_first = (elm);                                       \
 139        (elm)->field.le_prev = &(head)->lh_first;                       \
 140} while (/*CONSTCOND*/0)
 141
 142#define QLIST_REMOVE(elm, field) do {                                   \
 143        if ((elm)->field.le_next != NULL)                               \
 144                (elm)->field.le_next->field.le_prev =                   \
 145                    (elm)->field.le_prev;                               \
 146        *(elm)->field.le_prev = (elm)->field.le_next;                   \
 147} while (/*CONSTCOND*/0)
 148
 149#define QLIST_FOREACH(var, head, field)                                 \
 150        for ((var) = ((head)->lh_first);                                \
 151                (var);                                                  \
 152                (var) = ((var)->field.le_next))
 153
 154#define QLIST_FOREACH_SAFE(var, head, field, next_var)                  \
 155        for ((var) = ((head)->lh_first);                                \
 156                (var) && ((next_var) = ((var)->field.le_next), 1);      \
 157                (var) = (next_var))
 158
 159/*
 160 * List access methods.
 161 */
 162#define QLIST_EMPTY(head)                ((head)->lh_first == NULL)
 163#define QLIST_FIRST(head)                ((head)->lh_first)
 164#define QLIST_NEXT(elm, field)           ((elm)->field.le_next)
 165
 166
 167/*
 168 * Singly-linked List definitions.
 169 */
 170#define QSLIST_HEAD(name, type)                                          \
 171struct name {                                                           \
 172        struct type *slh_first; /* first element */                     \
 173}
 174
 175#define QSLIST_HEAD_INITIALIZER(head)                                    \
 176        { NULL }
 177
 178#define QSLIST_ENTRY(type)                                               \
 179struct {                                                                \
 180        struct type *sle_next;  /* next element */                      \
 181}
 182
 183/*
 184 * Singly-linked List functions.
 185 */
 186#define QSLIST_INIT(head) do {                                           \
 187        (head)->slh_first = NULL;                                       \
 188} while (/*CONSTCOND*/0)
 189
 190#define QSLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 191        (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 192        (slistelm)->field.sle_next = (elm);                             \
 193} while (/*CONSTCOND*/0)
 194
 195#define QSLIST_INSERT_HEAD(head, elm, field) do {                        \
 196        (elm)->field.sle_next = (head)->slh_first;                       \
 197        (head)->slh_first = (elm);                                       \
 198} while (/*CONSTCOND*/0)
 199
 200#define QSLIST_INSERT_HEAD_ATOMIC(head, elm, field) do {                     \
 201        typeof(elm) save_sle_next;                                           \
 202        do {                                                                 \
 203            save_sle_next = (elm)->field.sle_next = (head)->slh_first;       \
 204        } while (atomic_cmpxchg(&(head)->slh_first, save_sle_next, (elm)) != \
 205                 save_sle_next);                                             \
 206} while (/*CONSTCOND*/0)
 207
 208#define QSLIST_MOVE_ATOMIC(dest, src) do {                               \
 209        (dest)->slh_first = atomic_xchg(&(src)->slh_first, NULL);        \
 210} while (/*CONSTCOND*/0)
 211
 212#define QSLIST_REMOVE_HEAD(head, field) do {                             \
 213        (head)->slh_first = (head)->slh_first->field.sle_next;          \
 214} while (/*CONSTCOND*/0)
 215
 216#define QSLIST_REMOVE_AFTER(slistelm, field) do {                        \
 217        (slistelm)->field.sle_next =                                    \
 218            QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field);           \
 219} while (/*CONSTCOND*/0)
 220
 221#define QSLIST_FOREACH(var, head, field)                                 \
 222        for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
 223
 224#define QSLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 225        for ((var) = QSLIST_FIRST((head));                               \
 226            (var) && ((tvar) = QSLIST_NEXT((var), field), 1);            \
 227            (var) = (tvar))
 228
 229/*
 230 * Singly-linked List access methods.
 231 */
 232#define QSLIST_EMPTY(head)       ((head)->slh_first == NULL)
 233#define QSLIST_FIRST(head)       ((head)->slh_first)
 234#define QSLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 235
 236
 237/*
 238 * Simple queue definitions.
 239 */
 240#define QSIMPLEQ_HEAD(name, type)                                       \
 241struct name {                                                           \
 242    struct type *sqh_first;    /* first element */                      \
 243    struct type **sqh_last;    /* addr of last next element */          \
 244}
 245
 246#define QSIMPLEQ_HEAD_INITIALIZER(head)                                 \
 247    { NULL, &(head).sqh_first }
 248
 249#define QSIMPLEQ_ENTRY(type)                                            \
 250struct {                                                                \
 251    struct type *sqe_next;    /* next element */                        \
 252}
 253
 254/*
 255 * Simple queue functions.
 256 */
 257#define QSIMPLEQ_INIT(head) do {                                        \
 258    (head)->sqh_first = NULL;                                           \
 259    (head)->sqh_last = &(head)->sqh_first;                              \
 260} while (/*CONSTCOND*/0)
 261
 262#define QSIMPLEQ_INSERT_HEAD(head, elm, field) do {                     \
 263    if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)            \
 264        (head)->sqh_last = &(elm)->field.sqe_next;                      \
 265    (head)->sqh_first = (elm);                                          \
 266} while (/*CONSTCOND*/0)
 267
 268#define QSIMPLEQ_INSERT_TAIL(head, elm, field) do {                     \
 269    (elm)->field.sqe_next = NULL;                                       \
 270    *(head)->sqh_last = (elm);                                          \
 271    (head)->sqh_last = &(elm)->field.sqe_next;                          \
 272} while (/*CONSTCOND*/0)
 273
 274#define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
 275    if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)    \
 276        (head)->sqh_last = &(elm)->field.sqe_next;                      \
 277    (listelm)->field.sqe_next = (elm);                                  \
 278} while (/*CONSTCOND*/0)
 279
 280#define QSIMPLEQ_REMOVE_HEAD(head, field) do {                          \
 281    if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\
 282        (head)->sqh_last = &(head)->sqh_first;                          \
 283} while (/*CONSTCOND*/0)
 284
 285#define QSIMPLEQ_SPLIT_AFTER(head, elm, field, removed) do {            \
 286    QSIMPLEQ_INIT(removed);                                             \
 287    if (((removed)->sqh_first = (head)->sqh_first) != NULL) {           \
 288        if (((head)->sqh_first = (elm)->field.sqe_next) == NULL) {      \
 289            (head)->sqh_last = &(head)->sqh_first;                      \
 290        }                                                               \
 291        (removed)->sqh_last = &(elm)->field.sqe_next;                   \
 292        (elm)->field.sqe_next = NULL;                                   \
 293    }                                                                   \
 294} while (/*CONSTCOND*/0)
 295
 296#define QSIMPLEQ_REMOVE(head, elm, type, field) do {                    \
 297    if ((head)->sqh_first == (elm)) {                                   \
 298        QSIMPLEQ_REMOVE_HEAD((head), field);                            \
 299    } else {                                                            \
 300        struct type *curelm = (head)->sqh_first;                        \
 301        while (curelm->field.sqe_next != (elm))                         \
 302            curelm = curelm->field.sqe_next;                            \
 303        if ((curelm->field.sqe_next =                                   \
 304            curelm->field.sqe_next->field.sqe_next) == NULL)            \
 305                (head)->sqh_last = &(curelm)->field.sqe_next;           \
 306    }                                                                   \
 307} while (/*CONSTCOND*/0)
 308
 309#define QSIMPLEQ_FOREACH(var, head, field)                              \
 310    for ((var) = ((head)->sqh_first);                                   \
 311        (var);                                                          \
 312        (var) = ((var)->field.sqe_next))
 313
 314#define QSIMPLEQ_FOREACH_SAFE(var, head, field, next)                   \
 315    for ((var) = ((head)->sqh_first);                                   \
 316        (var) && ((next = ((var)->field.sqe_next)), 1);                 \
 317        (var) = (next))
 318
 319#define QSIMPLEQ_CONCAT(head1, head2) do {                              \
 320    if (!QSIMPLEQ_EMPTY((head2))) {                                     \
 321        *(head1)->sqh_last = (head2)->sqh_first;                        \
 322        (head1)->sqh_last = (head2)->sqh_last;                          \
 323        QSIMPLEQ_INIT((head2));                                         \
 324    }                                                                   \
 325} while (/*CONSTCOND*/0)
 326
 327#define QSIMPLEQ_LAST(head, type, field)                                \
 328    (QSIMPLEQ_EMPTY((head)) ?                                           \
 329        NULL :                                                          \
 330            ((struct type *)(void *)                                    \
 331        ((char *)((head)->sqh_last) - offsetof(struct type, field))))
 332
 333/*
 334 * Simple queue access methods.
 335 */
 336#define QSIMPLEQ_EMPTY(head)        ((head)->sqh_first == NULL)
 337#define QSIMPLEQ_FIRST(head)        ((head)->sqh_first)
 338#define QSIMPLEQ_NEXT(elm, field)   ((elm)->field.sqe_next)
 339
 340
 341/*
 342 * Tail queue definitions.
 343 */
 344#define Q_TAILQ_HEAD(name, type, qual)                                  \
 345struct name {                                                           \
 346        qual type *tqh_first;           /* first element */             \
 347        qual type *qual *tqh_last;      /* addr of last next element */ \
 348}
 349#define QTAILQ_HEAD(name, type)  Q_TAILQ_HEAD(name, struct type,)
 350
 351#define QTAILQ_HEAD_INITIALIZER(head)                                   \
 352        { NULL, &(head).tqh_first }
 353
 354#define Q_TAILQ_ENTRY(type, qual)                                       \
 355struct {                                                                \
 356        qual type *tqe_next;            /* next element */              \
 357        qual type *qual *tqe_prev;      /* address of previous next element */\
 358}
 359#define QTAILQ_ENTRY(type)       Q_TAILQ_ENTRY(struct type,)
 360
 361/*
 362 * Tail queue functions.
 363 */
 364#define QTAILQ_INIT(head) do {                                          \
 365        (head)->tqh_first = NULL;                                       \
 366        (head)->tqh_last = &(head)->tqh_first;                          \
 367} while (/*CONSTCOND*/0)
 368
 369#define QTAILQ_INSERT_HEAD(head, elm, field) do {                       \
 370        if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 371                (head)->tqh_first->field.tqe_prev =                     \
 372                    &(elm)->field.tqe_next;                             \
 373        else                                                            \
 374                (head)->tqh_last = &(elm)->field.tqe_next;              \
 375        (head)->tqh_first = (elm);                                      \
 376        (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 377} while (/*CONSTCOND*/0)
 378
 379#define QTAILQ_INSERT_TAIL(head, elm, field) do {                       \
 380        (elm)->field.tqe_next = NULL;                                   \
 381        (elm)->field.tqe_prev = (head)->tqh_last;                       \
 382        *(head)->tqh_last = (elm);                                      \
 383        (head)->tqh_last = &(elm)->field.tqe_next;                      \
 384} while (/*CONSTCOND*/0)
 385
 386#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
 387        if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 388                (elm)->field.tqe_next->field.tqe_prev =                 \
 389                    &(elm)->field.tqe_next;                             \
 390        else                                                            \
 391                (head)->tqh_last = &(elm)->field.tqe_next;              \
 392        (listelm)->field.tqe_next = (elm);                              \
 393        (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 394} while (/*CONSTCOND*/0)
 395
 396#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do {                  \
 397        (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 398        (elm)->field.tqe_next = (listelm);                              \
 399        *(listelm)->field.tqe_prev = (elm);                             \
 400        (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 401} while (/*CONSTCOND*/0)
 402
 403#define QTAILQ_REMOVE(head, elm, field) do {                            \
 404        if (((elm)->field.tqe_next) != NULL)                            \
 405                (elm)->field.tqe_next->field.tqe_prev =                 \
 406                    (elm)->field.tqe_prev;                              \
 407        else                                                            \
 408                (head)->tqh_last = (elm)->field.tqe_prev;               \
 409        *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 410        (elm)->field.tqe_prev = NULL;                                   \
 411} while (/*CONSTCOND*/0)
 412
 413#define QTAILQ_FOREACH(var, head, field)                                \
 414        for ((var) = ((head)->tqh_first);                               \
 415                (var);                                                  \
 416                (var) = ((var)->field.tqe_next))
 417
 418#define QTAILQ_FOREACH_SAFE(var, head, field, next_var)                 \
 419        for ((var) = ((head)->tqh_first);                               \
 420                (var) && ((next_var) = ((var)->field.tqe_next), 1);     \
 421                (var) = (next_var))
 422
 423#define QTAILQ_FOREACH_REVERSE(var, head, headname, field)              \
 424        for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \
 425                (var);                                                  \
 426                (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))
 427
 428/*
 429 * Tail queue access methods.
 430 */
 431#define QTAILQ_EMPTY(head)               ((head)->tqh_first == NULL)
 432#define QTAILQ_FIRST(head)               ((head)->tqh_first)
 433#define QTAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)
 434#define QTAILQ_IN_USE(elm, field)        ((elm)->field.tqe_prev != NULL)
 435
 436#define QTAILQ_LAST(head, headname) \
 437        (*(((struct headname *)((head)->tqh_last))->tqh_last))
 438#define QTAILQ_PREV(elm, headname, field) \
 439        (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 440
 441#define field_at_offset(base, offset, type)                                    \
 442        ((type) (((char *) (base)) + (offset)))
 443
 444typedef struct DUMMY_Q_ENTRY DUMMY_Q_ENTRY;
 445typedef struct DUMMY_Q DUMMY_Q;
 446
 447struct DUMMY_Q_ENTRY {
 448        QTAILQ_ENTRY(DUMMY_Q_ENTRY) next;
 449};
 450
 451struct DUMMY_Q {
 452        QTAILQ_HEAD(DUMMY_Q_HEAD, DUMMY_Q_ENTRY) head;
 453};
 454
 455#define dummy_q ((DUMMY_Q *) 0)
 456#define dummy_qe ((DUMMY_Q_ENTRY *) 0)
 457
 458/*
 459 * Offsets of layout of a tail queue head.
 460 */
 461#define QTAILQ_FIRST_OFFSET (offsetof(typeof(dummy_q->head), tqh_first))
 462#define QTAILQ_LAST_OFFSET  (offsetof(typeof(dummy_q->head), tqh_last))
 463/*
 464 * Raw access of elements of a tail queue
 465 */
 466#define QTAILQ_RAW_FIRST(head)                                                 \
 467        (*field_at_offset(head, QTAILQ_FIRST_OFFSET, void **))
 468#define QTAILQ_RAW_TQH_LAST(head)                                              \
 469        (*field_at_offset(head, QTAILQ_LAST_OFFSET, void ***))
 470
 471/*
 472 * Offsets of layout of a tail queue element.
 473 */
 474#define QTAILQ_NEXT_OFFSET (offsetof(typeof(dummy_qe->next), tqe_next))
 475#define QTAILQ_PREV_OFFSET (offsetof(typeof(dummy_qe->next), tqe_prev))
 476
 477/*
 478 * Raw access of elements of a tail entry
 479 */
 480#define QTAILQ_RAW_NEXT(elm, entry)                                            \
 481        (*field_at_offset(elm, entry + QTAILQ_NEXT_OFFSET, void **))
 482#define QTAILQ_RAW_TQE_PREV(elm, entry)                                        \
 483        (*field_at_offset(elm, entry + QTAILQ_PREV_OFFSET, void ***))
 484/*
 485 * Tail queue tranversal using pointer arithmetic.
 486 */
 487#define QTAILQ_RAW_FOREACH(elm, head, entry)                                   \
 488        for ((elm) = QTAILQ_RAW_FIRST(head);                                   \
 489             (elm);                                                            \
 490             (elm) = QTAILQ_RAW_NEXT(elm, entry))
 491/*
 492 * Tail queue insertion using pointer arithmetic.
 493 */
 494#define QTAILQ_RAW_INSERT_TAIL(head, elm, entry) do {                          \
 495        QTAILQ_RAW_NEXT(elm, entry) = NULL;                                    \
 496        QTAILQ_RAW_TQE_PREV(elm, entry) = QTAILQ_RAW_TQH_LAST(head);           \
 497        *QTAILQ_RAW_TQH_LAST(head) = (elm);                                    \
 498        QTAILQ_RAW_TQH_LAST(head) = &QTAILQ_RAW_NEXT(elm, entry);              \
 499} while (/*CONSTCOND*/0)
 500
 501#endif /* QEMU_SYS_QUEUE_H */
 502