[qemu.git] / qemu-queue.h

/*      $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */

/*
 * Qemu version: Copy from netbsd, removed debug code, removed some of
 * the implementations.  Left in singly-linked lists, lists, simple
 * queues, tail queues and circular queues.
 */

/*
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)queue.h     8.5 (Berkeley) 8/20/94
 */

#ifndef QEMU_SYS_QUEUE_H_
#define QEMU_SYS_QUEUE_H_

/*
 * This file defines five types of data structures: singly-linked lists,
 * lists, simple queues, tail queues, and circular queues.
 *
 * A singly-linked list is headed by a single forward pointer. The
 * elements are singly linked for minimum space and pointer manipulation
 * overhead at the expense of O(n) removal for arbitrary elements. New
 * elements can be added to the list after an existing element or at the
 * head of the list.  Elements being removed from the head of the list
 * should use the explicit macro for this purpose for optimum
 * efficiency. A singly-linked list may only be traversed in the forward
 * direction.  Singly-linked lists are ideal for applications with large
 * datasets and few or no removals or for implementing a LIFO queue.
 *
 * A list is headed by a single forward pointer (or an array of forward
 * pointers for a hash table header). The elements are doubly linked
 * so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before
 * or after an existing element or at the head of the list. A list
 * may only be traversed in the forward direction.
 *
 * A simple queue is headed by a pair of pointers, one the head of the
 * list and the other to the tail of the list. The elements are singly
 * linked to save space, so elements can only be removed from the
 * head of the list. New elements can be added to the list after
 * an existing element, at the head of the list, or at the end of the
 * list. A simple queue may only be traversed in the forward direction.
 *
 * A tail queue is headed by a pair of pointers, one to the head of the
 * list and the other to the tail of the list. The elements are doubly
 * linked so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before or
 * after an existing element, at the head of the list, or at the end of
 * the list. A tail queue may be traversed in either direction.
 *
 * A circle queue is headed by a pair of pointers, one to the head of the
 * list and the other to the tail of the list. The elements are doubly
 * linked so that an arbitrary element can be removed without a need to
 * traverse the list. New elements can be added to the list before or after
 * an existing element, at the head of the list, or at the end of the list.
 * A circle queue may be traversed in either direction, but has a more
 * complex end of list detection.
 *
 * For details on the use of these macros, see the queue(3) manual page.
 */

#include "qemu-barrier.h" /* for smp_wmb() */

/*
 * List definitions.
 */
#define QLIST_HEAD(name, type)                                          \
struct name {                                                           \
        struct type *lh_first;  /* first element */                     \
}

#define QLIST_HEAD_INITIALIZER(head)                                    \
        { NULL }

#define QLIST_ENTRY(type)                                               \
struct {                                                                \
        struct type *le_next;   /* next element */                      \
        struct type **le_prev;  /* address of previous next element */  \
}

/*
 * List functions.
 */
#define QLIST_INIT(head) do {                                           \
        (head)->lh_first = NULL;                                        \
} while (/*CONSTCOND*/0)

#define QLIST_INSERT_AFTER(listelm, elm, field) do {                    \
        if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
                (listelm)->field.le_next->field.le_prev =               \
                    &(elm)->field.le_next;                              \
        (listelm)->field.le_next = (elm);                               \
        (elm)->field.le_prev = &(listelm)->field.le_next;               \
} while (/*CONSTCOND*/0)

#define QLIST_INSERT_BEFORE(listelm, elm, field) do {                   \
        (elm)->field.le_prev = (listelm)->field.le_prev;                \
        (elm)->field.le_next = (listelm);                               \
        *(listelm)->field.le_prev = (elm);                              \
        (listelm)->field.le_prev = &(elm)->field.le_next;               \
} while (/*CONSTCOND*/0)

#define QLIST_INSERT_HEAD(head, elm, field) do {                        \
        if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
                (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
        (head)->lh_first = (elm);                                       \
        (elm)->field.le_prev = &(head)->lh_first;                       \
} while (/*CONSTCOND*/0)

#define QLIST_INSERT_HEAD_RCU(head, elm, field) do {                    \
        (elm)->field.le_prev = &(head)->lh_first;                       \
        (elm)->field.le_next = (head)->lh_first;                        \
        smp_wmb(); /* fill elm before linking it */                     \
        if ((head)->lh_first != NULL)  {                                \
            (head)->lh_first->field.le_prev = &(elm)->field.le_next;    \
        }                                                               \
        (head)->lh_first = (elm);                                       \
        smp_wmb();                                                      \
} while (/* CONSTCOND*/0)

#define QLIST_REMOVE(elm, field) do {                                   \
        if ((elm)->field.le_next != NULL)                               \
                (elm)->field.le_next->field.le_prev =                   \
                    (elm)->field.le_prev;                               \
        *(elm)->field.le_prev = (elm)->field.le_next;                   \
} while (/*CONSTCOND*/0)

#define QLIST_FOREACH(var, head, field)                                 \
        for ((var) = ((head)->lh_first);                                \
                (var);                                                  \
                (var) = ((var)->field.le_next))

#define QLIST_FOREACH_SAFE(var, head, field, next_var)                  \
        for ((var) = ((head)->lh_first);                                \
                (var) && ((next_var) = ((var)->field.le_next), 1);      \
                (var) = (next_var))

/*
 * List access methods.
 */
#define QLIST_EMPTY(head)                ((head)->lh_first == NULL)
#define QLIST_FIRST(head)                ((head)->lh_first)
#define QLIST_NEXT(elm, field)           ((elm)->field.le_next)


/*
 * Singly-linked List definitions.
 */
#define QSLIST_HEAD(name, type)                                          \
struct name {                                                           \
        struct type *slh_first; /* first element */                     \
}

#define QSLIST_HEAD_INITIALIZER(head)                                    \
        { NULL }

#define QSLIST_ENTRY(type)                                               \
struct {                                                                \
        struct type *sle_next;  /* next element */                      \
}

/*
 * Singly-linked List functions.
 */
#define QSLIST_INIT(head) do {                                           \
        (head)->slh_first = NULL;                                       \
} while (/*CONSTCOND*/0)

#define QSLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
        (elm)->field.sle_next = (slistelm)->field.sle_next;             \
        (slistelm)->field.sle_next = (elm);                             \
} while (/*CONSTCOND*/0)

#define QSLIST_INSERT_HEAD(head, elm, field) do {                        \
        (elm)->field.sle_next = (head)->slh_first;                      \
        (head)->slh_first = (elm);                                      \
} while (/*CONSTCOND*/0)

#define QSLIST_REMOVE_HEAD(head, field) do {                             \
        (head)->slh_first = (head)->slh_first->field.sle_next;          \
} while (/*CONSTCOND*/0)

#define QSLIST_REMOVE_AFTER(slistelm, field) do {                        \
        (slistelm)->field.sle_next =                                    \
            QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field);           \
} while (/*CONSTCOND*/0)

#define QSLIST_FOREACH(var, head, field)                                 \
        for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)

#define QSLIST_FOREACH_SAFE(var, head, field, tvar)                      \
        for ((var) = QSLIST_FIRST((head));                               \
            (var) && ((tvar) = QSLIST_NEXT((var), field), 1);            \
            (var) = (tvar))

/*
 * Singly-linked List access methods.
 */
#define QSLIST_EMPTY(head)       ((head)->slh_first == NULL)
#define QSLIST_FIRST(head)       ((head)->slh_first)
#define QSLIST_NEXT(elm, field)  ((elm)->field.sle_next)


/*
 * Simple queue definitions.
 */
#define QSIMPLEQ_HEAD(name, type)                                       \
struct name {                                                           \
    struct type *sqh_first;    /* first element */                      \
    struct type **sqh_last;    /* addr of last next element */          \
}

#define QSIMPLEQ_HEAD_INITIALIZER(head)                                 \
    { NULL, &(head).sqh_first }

#define QSIMPLEQ_ENTRY(type)                                            \
struct {                                                                \
    struct type *sqe_next;    /* next element */                        \
}

/*
 * Simple queue functions.
 */
#define QSIMPLEQ_INIT(head) do {                                        \
    (head)->sqh_first = NULL;                                           \
    (head)->sqh_last = &(head)->sqh_first;                              \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_INSERT_HEAD(head, elm, field) do {                     \
    if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)            \
        (head)->sqh_last = &(elm)->field.sqe_next;                      \
    (head)->sqh_first = (elm);                                          \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_INSERT_TAIL(head, elm, field) do {                     \
    (elm)->field.sqe_next = NULL;                                       \
    *(head)->sqh_last = (elm);                                          \
    (head)->sqh_last = &(elm)->field.sqe_next;                          \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
    if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)    \
        (head)->sqh_last = &(elm)->field.sqe_next;                      \
    (listelm)->field.sqe_next = (elm);                                  \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_REMOVE_HEAD(head, field) do {                          \
    if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\
        (head)->sqh_last = &(head)->sqh_first;                          \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_REMOVE(head, elm, type, field) do {                    \
    if ((head)->sqh_first == (elm)) {                                   \
        QSIMPLEQ_REMOVE_HEAD((head), field);                            \
    } else {                                                            \
        struct type *curelm = (head)->sqh_first;                        \
        while (curelm->field.sqe_next != (elm))                         \
            curelm = curelm->field.sqe_next;                            \
        if ((curelm->field.sqe_next =                                   \
            curelm->field.sqe_next->field.sqe_next) == NULL)            \
                (head)->sqh_last = &(curelm)->field.sqe_next;           \
    }                                                                   \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_FOREACH(var, head, field)                              \
    for ((var) = ((head)->sqh_first);                                   \
        (var);                                                          \
        (var) = ((var)->field.sqe_next))

#define QSIMPLEQ_FOREACH_SAFE(var, head, field, next)                   \
    for ((var) = ((head)->sqh_first);                                   \
        (var) && ((next = ((var)->field.sqe_next)), 1);                 \
        (var) = (next))

#define QSIMPLEQ_CONCAT(head1, head2) do {                              \
    if (!QSIMPLEQ_EMPTY((head2))) {                                     \
        *(head1)->sqh_last = (head2)->sqh_first;                        \
        (head1)->sqh_last = (head2)->sqh_last;                          \
        QSIMPLEQ_INIT((head2));                                         \
    }                                                                   \
} while (/*CONSTCOND*/0)

#define QSIMPLEQ_LAST(head, type, field)                                \
    (QSIMPLEQ_EMPTY((head)) ?                                           \
        NULL :                                                          \
            ((struct type *)(void *)                                    \
        ((char *)((head)->sqh_last) - offsetof(struct type, field))))

/*
 * Simple queue access methods.
 */
#define QSIMPLEQ_EMPTY(head)        ((head)->sqh_first == NULL)
#define QSIMPLEQ_FIRST(head)        ((head)->sqh_first)
#define QSIMPLEQ_NEXT(elm, field)   ((elm)->field.sqe_next)


/*
 * Tail queue definitions.
 */
#define Q_TAILQ_HEAD(name, type, qual)                                  \
struct name {                                                           \
        qual type *tqh_first;           /* first element */             \
        qual type *qual *tqh_last;      /* addr of last next element */ \
}
#define QTAILQ_HEAD(name, type)  Q_TAILQ_HEAD(name, struct type,)

#define QTAILQ_HEAD_INITIALIZER(head)                                   \
        { NULL, &(head).tqh_first }

#define Q_TAILQ_ENTRY(type, qual)                                       \
struct {                                                                \
        qual type *tqe_next;            /* next element */              \
        qual type *qual *tqe_prev;      /* address of previous next element */\
}
#define QTAILQ_ENTRY(type)       Q_TAILQ_ENTRY(struct type,)

/*
 * Tail queue functions.
 */
#define QTAILQ_INIT(head) do {                                          \
        (head)->tqh_first = NULL;                                       \
        (head)->tqh_last = &(head)->tqh_first;                          \
} while (/*CONSTCOND*/0)

#define QTAILQ_INSERT_HEAD(head, elm, field) do {                       \
        if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
                (head)->tqh_first->field.tqe_prev =                     \
                    &(elm)->field.tqe_next;                             \
        else                                                            \
                (head)->tqh_last = &(elm)->field.tqe_next;              \
        (head)->tqh_first = (elm);                                      \
        (elm)->field.tqe_prev = &(head)->tqh_first;                     \
} while (/*CONSTCOND*/0)

#define QTAILQ_INSERT_TAIL(head, elm, field) do {                       \
        (elm)->field.tqe_next = NULL;                                   \
        (elm)->field.tqe_prev = (head)->tqh_last;                       \
        *(head)->tqh_last = (elm);                                      \
        (head)->tqh_last = &(elm)->field.tqe_next;                      \
} while (/*CONSTCOND*/0)

#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do {             \
        if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
                (elm)->field.tqe_next->field.tqe_prev =                 \
                    &(elm)->field.tqe_next;                             \
        else                                                            \
                (head)->tqh_last = &(elm)->field.tqe_next;              \
        (listelm)->field.tqe_next = (elm);                              \
        (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
} while (/*CONSTCOND*/0)

#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do {                  \
        (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
        (elm)->field.tqe_next = (listelm);                              \
        *(listelm)->field.tqe_prev = (elm);                             \
        (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
} while (/*CONSTCOND*/0)

#define QTAILQ_REMOVE(head, elm, field) do {                            \
        if (((elm)->field.tqe_next) != NULL)                            \
                (elm)->field.tqe_next->field.tqe_prev =                 \
                    (elm)->field.tqe_prev;                              \
        else                                                            \
                (head)->tqh_last = (elm)->field.tqe_prev;               \
        *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
} while (/*CONSTCOND*/0)

#define QTAILQ_FOREACH(var, head, field)                                \
        for ((var) = ((head)->tqh_first);                               \
                (var);                                                  \
                (var) = ((var)->field.tqe_next))

#define QTAILQ_FOREACH_SAFE(var, head, field, next_var)                 \
        for ((var) = ((head)->tqh_first);                               \
                (var) && ((next_var) = ((var)->field.tqe_next), 1);     \
                (var) = (next_var))

#define QTAILQ_FOREACH_REVERSE(var, head, headname, field)              \
        for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \
                (var);                                                  \
                (var) = (*(((struct headname *)((var)->field.tqe_prev))->tqh_last)))

/*
 * Tail queue access methods.
 */
#define QTAILQ_EMPTY(head)               ((head)->tqh_first == NULL)
#define QTAILQ_FIRST(head)               ((head)->tqh_first)
#define QTAILQ_NEXT(elm, field)          ((elm)->field.tqe_next)

#define QTAILQ_LAST(head, headname) \
        (*(((struct headname *)((head)->tqh_last))->tqh_last))
#define QTAILQ_PREV(elm, headname, field) \
        (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))


/*
 * Circular queue definitions.
 */
#define QCIRCLEQ_HEAD(name, type)                                       \
struct name {                                                           \
        struct type *cqh_first;         /* first element */             \
        struct type *cqh_last;          /* last element */              \
}

#define QCIRCLEQ_HEAD_INITIALIZER(head)                                 \
        { (void *)&head, (void *)&head }

#define QCIRCLEQ_ENTRY(type)                                            \
struct {                                                                \
        struct type *cqe_next;          /* next element */              \
        struct type *cqe_prev;          /* previous element */          \
}

/*
 * Circular queue functions.
 */
#define QCIRCLEQ_INIT(head) do {                                        \
        (head)->cqh_first = (void *)(head);                             \
        (head)->cqh_last = (void *)(head);                              \
} while (/*CONSTCOND*/0)

#define QCIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {           \
        (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
        (elm)->field.cqe_prev = (listelm);                              \
        if ((listelm)->field.cqe_next == (void *)(head))                \
                (head)->cqh_last = (elm);                               \
        else                                                            \
                (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
        (listelm)->field.cqe_next = (elm);                              \
} while (/*CONSTCOND*/0)

#define QCIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {          \
        (elm)->field.cqe_next = (listelm);                              \
        (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
        if ((listelm)->field.cqe_prev == (void *)(head))                \
                (head)->cqh_first = (elm);                              \
        else                                                            \
                (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
        (listelm)->field.cqe_prev = (elm);                              \
} while (/*CONSTCOND*/0)

#define QCIRCLEQ_INSERT_HEAD(head, elm, field) do {                     \
        (elm)->field.cqe_next = (head)->cqh_first;                      \
        (elm)->field.cqe_prev = (void *)(head);                         \
        if ((head)->cqh_last == (void *)(head))                         \
                (head)->cqh_last = (elm);                               \
        else                                                            \
                (head)->cqh_first->field.cqe_prev = (elm);              \
        (head)->cqh_first = (elm);                                      \
} while (/*CONSTCOND*/0)

#define QCIRCLEQ_INSERT_TAIL(head, elm, field) do {                     \
        (elm)->field.cqe_next = (void *)(head);                         \
        (elm)->field.cqe_prev = (head)->cqh_last;                       \
        if ((head)->cqh_first == (void *)(head))                        \
                (head)->cqh_first = (elm);                              \
        else                                                            \
                (head)->cqh_last->field.cqe_next = (elm);               \
        (head)->cqh_last = (elm);                                       \
} while (/*CONSTCOND*/0)

#define QCIRCLEQ_REMOVE(head, elm, field) do {                          \
        if ((elm)->field.cqe_next == (void *)(head))                    \
                (head)->cqh_last = (elm)->field.cqe_prev;               \
        else                                                            \
                (elm)->field.cqe_next->field.cqe_prev =                 \
                    (elm)->field.cqe_prev;                              \
        if ((elm)->field.cqe_prev == (void *)(head))                    \
                (head)->cqh_first = (elm)->field.cqe_next;              \
        else                                                            \
                (elm)->field.cqe_prev->field.cqe_next =                 \
                    (elm)->field.cqe_next;                              \
} while (/*CONSTCOND*/0)

#define QCIRCLEQ_FOREACH(var, head, field)                              \
        for ((var) = ((head)->cqh_first);                               \
                (var) != (const void *)(head);                          \
                (var) = ((var)->field.cqe_next))

#define QCIRCLEQ_FOREACH_REVERSE(var, head, field)                      \
        for ((var) = ((head)->cqh_last);                                \
                (var) != (const void *)(head);                          \
                (var) = ((var)->field.cqe_prev))

/*
 * Circular queue access methods.
 */
#define QCIRCLEQ_EMPTY(head)             ((head)->cqh_first == (void *)(head))
#define QCIRCLEQ_FIRST(head)             ((head)->cqh_first)
#define QCIRCLEQ_LAST(head)              ((head)->cqh_last)
#define QCIRCLEQ_NEXT(elm, field)        ((elm)->field.cqe_next)
#define QCIRCLEQ_PREV(elm, field)        ((elm)->field.cqe_prev)

#define QCIRCLEQ_LOOP_NEXT(head, elm, field)                            \
        (((elm)->field.cqe_next == (void *)(head))                      \
            ? ((head)->cqh_first)                                       \
            : (elm->field.cqe_next))
#define QCIRCLEQ_LOOP_PREV(head, elm, field)                            \
        (((elm)->field.cqe_prev == (void *)(head))                      \
            ? ((head)->cqh_last)                                        \
            : (elm->field.cqe_prev))

#endif  /* !QEMU_SYS_QUEUE_H_ */
Commit	Line	Data
c616bbe1	1	/* $NetBSD: queue.h,v 1.52 2009/04/20 09:56:08 mschuett Exp $ */
fc56ef08 BS	2
	3	/*
	4	* Qemu version: Copy from netbsd, removed debug code, removed some of
6095aa88 PB	5	* the implementations. Left in singly-linked lists, lists, simple
6095aa88 PB	6	* queues, tail queues and circular queues.
fc56ef08 BS	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
72cf2d4f BS	40	#ifndef QEMU_SYS_QUEUE_H_
72cf2d4f BS	41	#define QEMU_SYS_QUEUE_H_
fc56ef08 BS	42
fc56ef08 BS	43	/*
6095aa88	44	* This file defines five types of data structures: singly-linked lists,
c616bbe1	45	* lists, simple queues, tail queues, and circular queues.
fc56ef08	46	*
6095aa88 PB	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	*
fc56ef08 BS	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	*
c616bbe1 PR	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	*
fc56ef08 BS	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	* A circle queue is headed by a pair of pointers, one to the head of the
	79	* list and the other to the tail of the list. The elements are doubly
	80	* linked so that an arbitrary element can be removed without a need to
	81	* traverse the list. New elements can be added to the list before or after
	82	* an existing element, at the head of the list, or at the end of the list.
	83	* A circle queue may be traversed in either direction, but has a more
	84	* complex end of list detection.
	85	*
	86	* For details on the use of these macros, see the queue(3) manual page.
	87	*/
	88
5f7d05ec HPB	89	#include "qemu-barrier.h" /* for smp_wmb() */
5f7d05ec HPB	90
fc56ef08 BS	91	/*
	92	* List definitions.
	93	*/
72cf2d4f	94	#define QLIST_HEAD(name, type) \
fc56ef08 BS	95	struct name { \
	96	struct type lh_first; / first element */ \
	97	}
	98
72cf2d4f	99	#define QLIST_HEAD_INITIALIZER(head) \
fc56ef08 BS	100	{ NULL }
fc56ef08 BS	101
72cf2d4f	102	#define QLIST_ENTRY(type) \
fc56ef08 BS	103	struct { \
	104	struct type le_next; / next element */ \
	105	struct type *le_prev; / address of previous next element */ \
	106	}
	107
	108	/*
	109	* List functions.
	110	*/
72cf2d4f	111	#define QLIST_INIT(head) do { \
fc56ef08 BS	112	(head)->lh_first = NULL; \
	113	} while (/CONSTCOND/0)
	114
72cf2d4f	115	#define QLIST_INSERT_AFTER(listelm, elm, field) do { \
fc56ef08 BS	116	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
	117	(listelm)->field.le_next->field.le_prev = \
	118	&(elm)->field.le_next; \
	119	(listelm)->field.le_next = (elm); \
	120	(elm)->field.le_prev = &(listelm)->field.le_next; \
	121	} while (/CONSTCOND/0)
	122
72cf2d4f	123	#define QLIST_INSERT_BEFORE(listelm, elm, field) do { \
fc56ef08 BS	124	(elm)->field.le_prev = (listelm)->field.le_prev; \
	125	(elm)->field.le_next = (listelm); \
	126	*(listelm)->field.le_prev = (elm); \
	127	(listelm)->field.le_prev = &(elm)->field.le_next; \
	128	} while (/CONSTCOND/0)
	129
72cf2d4f	130	#define QLIST_INSERT_HEAD(head, elm, field) do { \
fc56ef08 BS	131	if (((elm)->field.le_next = (head)->lh_first) != NULL) \
	132	(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
	133	(head)->lh_first = (elm); \
	134	(elm)->field.le_prev = &(head)->lh_first; \
	135	} while (/CONSTCOND/0)
	136
5f7d05ec HPB	137	#define QLIST_INSERT_HEAD_RCU(head, elm, field) do { \
	138	(elm)->field.le_prev = &(head)->lh_first; \
	139	(elm)->field.le_next = (head)->lh_first; \
	140	smp_wmb(); /* fill elm before linking it */ \
	141	if ((head)->lh_first != NULL) { \
	142	(head)->lh_first->field.le_prev = &(elm)->field.le_next; \
	143	} \
	144	(head)->lh_first = (elm); \
	145	smp_wmb(); \
	146	} while (/* CONSTCOND*/0)
	147
72cf2d4f	148	#define QLIST_REMOVE(elm, field) do { \
fc56ef08 BS	149	if ((elm)->field.le_next != NULL) \
	150	(elm)->field.le_next->field.le_prev = \
	151	(elm)->field.le_prev; \
	152	*(elm)->field.le_prev = (elm)->field.le_next; \
	153	} while (/CONSTCOND/0)
	154
72cf2d4f	155	#define QLIST_FOREACH(var, head, field) \
fc56ef08 BS	156	for ((var) = ((head)->lh_first); \
	157	(var); \
	158	(var) = ((var)->field.le_next))
	159
72cf2d4f	160	#define QLIST_FOREACH_SAFE(var, head, field, next_var) \
bb150dc8 JQ	161	for ((var) = ((head)->lh_first); \
	162	(var) && ((next_var) = ((var)->field.le_next), 1); \
	163	(var) = (next_var))
	164
fc56ef08 BS	165	/*
	166	* List access methods.
	167	*/
72cf2d4f BS	168	#define QLIST_EMPTY(head) ((head)->lh_first == NULL)
	169	#define QLIST_FIRST(head) ((head)->lh_first)
	170	#define QLIST_NEXT(elm, field) ((elm)->field.le_next)
fc56ef08 BS	171
fc56ef08 BS	172
6095aa88 PB	173	/*
	174	* Singly-linked List definitions.
	175	*/
	176	#define QSLIST_HEAD(name, type) \
	177	struct name { \
	178	struct type slh_first; / first element */ \
	179	}
	180
	181	#define QSLIST_HEAD_INITIALIZER(head) \
	182	{ NULL }
	183
	184	#define QSLIST_ENTRY(type) \
	185	struct { \
	186	struct type sle_next; / next element */ \
	187	}
	188
	189	/*
	190	* Singly-linked List functions.
	191	*/
	192	#define QSLIST_INIT(head) do { \
	193	(head)->slh_first = NULL; \
	194	} while (/CONSTCOND/0)
	195
	196	#define QSLIST_INSERT_AFTER(slistelm, elm, field) do { \
	197	(elm)->field.sle_next = (slistelm)->field.sle_next; \
	198	(slistelm)->field.sle_next = (elm); \
	199	} while (/CONSTCOND/0)
	200
	201	#define QSLIST_INSERT_HEAD(head, elm, field) do { \
	202	(elm)->field.sle_next = (head)->slh_first; \
	203	(head)->slh_first = (elm); \
	204	} while (/CONSTCOND/0)
	205
	206	#define QSLIST_REMOVE_HEAD(head, field) do { \
	207	(head)->slh_first = (head)->slh_first->field.sle_next; \
	208	} while (/CONSTCOND/0)
	209
	210	#define QSLIST_REMOVE_AFTER(slistelm, field) do { \
	211	(slistelm)->field.sle_next = \
	212	QSLIST_NEXT(QSLIST_NEXT((slistelm), field), field); \
	213	} while (/CONSTCOND/0)
	214
	215	#define QSLIST_FOREACH(var, head, field) \
	216	for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)
	217
	218	#define QSLIST_FOREACH_SAFE(var, head, field, tvar) \
	219	for ((var) = QSLIST_FIRST((head)); \
	220	(var) && ((tvar) = QSLIST_NEXT((var), field), 1); \
	221	(var) = (tvar))
	222
	223	/*
	224	* Singly-linked List access methods.
	225	*/
	226	#define QSLIST_EMPTY(head) ((head)->slh_first == NULL)
	227	#define QSLIST_FIRST(head) ((head)->slh_first)
	228	#define QSLIST_NEXT(elm, field) ((elm)->field.sle_next)
	229
	230
c616bbe1 PR	231	/*
	232	* Simple queue definitions.
	233	*/
	234	#define QSIMPLEQ_HEAD(name, type) \
	235	struct name { \
	236	struct type sqh_first; / first element */ \
	237	struct type *sqh_last; / addr of last next element */ \
	238	}
	239
	240	#define QSIMPLEQ_HEAD_INITIALIZER(head) \
	241	{ NULL, &(head).sqh_first }
	242
	243	#define QSIMPLEQ_ENTRY(type) \
	244	struct { \
	245	struct type sqe_next; / next element */ \
	246	}
	247
	248	/*
	249	* Simple queue functions.
	250	*/
	251	#define QSIMPLEQ_INIT(head) do { \
	252	(head)->sqh_first = NULL; \
	253	(head)->sqh_last = &(head)->sqh_first; \
	254	} while (/CONSTCOND/0)
	255
	256	#define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \
	257	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
	258	(head)->sqh_last = &(elm)->field.sqe_next; \
	259	(head)->sqh_first = (elm); \
	260	} while (/CONSTCOND/0)
	261
	262	#define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \
	263	(elm)->field.sqe_next = NULL; \
	264	*(head)->sqh_last = (elm); \
	265	(head)->sqh_last = &(elm)->field.sqe_next; \
	266	} while (/CONSTCOND/0)
	267
	268	#define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
	269	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \
	270	(head)->sqh_last = &(elm)->field.sqe_next; \
	271	(listelm)->field.sqe_next = (elm); \
	272	} while (/CONSTCOND/0)
	273
	274	#define QSIMPLEQ_REMOVE_HEAD(head, field) do { \
	275	if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\
	276	(head)->sqh_last = &(head)->sqh_first; \
	277	} while (/CONSTCOND/0)
	278
	279	#define QSIMPLEQ_REMOVE(head, elm, type, field) do { \
	280	if ((head)->sqh_first == (elm)) { \
	281	QSIMPLEQ_REMOVE_HEAD((head), field); \
	282	} else { \
	283	struct type *curelm = (head)->sqh_first; \
	284	while (curelm->field.sqe_next != (elm)) \
	285	curelm = curelm->field.sqe_next; \
	286	if ((curelm->field.sqe_next = \
	287	curelm->field.sqe_next->field.sqe_next) == NULL) \
	288	(head)->sqh_last = &(curelm)->field.sqe_next; \
	289	} \
	290	} while (/CONSTCOND/0)
	291
	292	#define QSIMPLEQ_FOREACH(var, head, field) \
	293	for ((var) = ((head)->sqh_first); \
	294	(var); \
295	(var) = ((var)->field.sqe_next))
296
297	#define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \
298	for ((var) = ((head)->sqh_first); \
299	(var) && ((next = ((var)->field.sqe_next)), 1); \
300	(var) = (next))
301
302	#define QSIMPLEQ_CONCAT(head1, head2) do { \
303	if (!QSIMPLEQ_EMPTY((head2))) { \
304	*(head1)->sqh_last = (head2)->sqh_first; \
305	(head1)->sqh_last = (head2)->sqh_last; \
306	QSIMPLEQ_INIT((head2)); \
307	} \
308	} while (/CONSTCOND/0)
309
310	#define QSIMPLEQ_LAST(head, type, field) \
311	(QSIMPLEQ_EMPTY((head)) ? \
312	NULL : \
313	((struct type )(void ) \
314	((char *)((head)->sqh_last) - offsetof(struct type, field))))
315
316	/*
317	* Simple queue access methods.
318	*/
319	#define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL)
320	#define QSIMPLEQ_FIRST(head) ((head)->sqh_first)
321	#define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
322
323
fc56ef08 BS	324	/*
	325	* Tail queue definitions.
	326	*/
72cf2d4f	327	#define Q_TAILQ_HEAD(name, type, qual) \
fc56ef08 BS	328	struct name { \
	329	qual type tqh_first; / first element */ \
	330	qual type qual tqh_last; /* addr of last next element */ \
	331	}
72cf2d4f	332	#define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,)
fc56ef08	333
72cf2d4f	334	#define QTAILQ_HEAD_INITIALIZER(head) \
fc56ef08 BS	335	{ NULL, &(head).tqh_first }
fc56ef08 BS	336
72cf2d4f	337	#define Q_TAILQ_ENTRY(type, qual) \
fc56ef08 BS	338	struct { \
	339	qual type tqe_next; / next element */ \
	340	qual type qual tqe_prev; /* address of previous next element */\
	341	}
72cf2d4f	342	#define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,)
fc56ef08 BS	343
	344	/*
	345	* Tail queue functions.
	346	*/
72cf2d4f	347	#define QTAILQ_INIT(head) do { \
fc56ef08 BS	348	(head)->tqh_first = NULL; \
	349	(head)->tqh_last = &(head)->tqh_first; \
	350	} while (/CONSTCOND/0)
	351
72cf2d4f	352	#define QTAILQ_INSERT_HEAD(head, elm, field) do { \
fc56ef08 BS	353	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
	354	(head)->tqh_first->field.tqe_prev = \
	355	&(elm)->field.tqe_next; \
	356	else \
	357	(head)->tqh_last = &(elm)->field.tqe_next; \
	358	(head)->tqh_first = (elm); \
	359	(elm)->field.tqe_prev = &(head)->tqh_first; \
	360	} while (/CONSTCOND/0)
	361
72cf2d4f	362	#define QTAILQ_INSERT_TAIL(head, elm, field) do { \
fc56ef08 BS	363	(elm)->field.tqe_next = NULL; \
	364	(elm)->field.tqe_prev = (head)->tqh_last; \
	365	*(head)->tqh_last = (elm); \
	366	(head)->tqh_last = &(elm)->field.tqe_next; \
	367	} while (/CONSTCOND/0)
	368
72cf2d4f	369	#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
fc56ef08 BS	370	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
	371	(elm)->field.tqe_next->field.tqe_prev = \
	372	&(elm)->field.tqe_next; \
	373	else \
	374	(head)->tqh_last = &(elm)->field.tqe_next; \
	375	(listelm)->field.tqe_next = (elm); \
	376	(elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
	377	} while (/CONSTCOND/0)
	378
72cf2d4f	379	#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \
fc56ef08 BS	380	(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
	381	(elm)->field.tqe_next = (listelm); \
	382	*(listelm)->field.tqe_prev = (elm); \
	383	(listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
	384	} while (/CONSTCOND/0)
	385
72cf2d4f	386	#define QTAILQ_REMOVE(head, elm, field) do { \
fc56ef08 BS	387	if (((elm)->field.tqe_next) != NULL) \
	388	(elm)->field.tqe_next->field.tqe_prev = \
	389	(elm)->field.tqe_prev; \
	390	else \
	391	(head)->tqh_last = (elm)->field.tqe_prev; \
	392	*(elm)->field.tqe_prev = (elm)->field.tqe_next; \
	393	} while (/CONSTCOND/0)
	394
72cf2d4f	395	#define QTAILQ_FOREACH(var, head, field) \
fc56ef08 BS	396	for ((var) = ((head)->tqh_first); \
	397	(var); \
	398	(var) = ((var)->field.tqe_next))
	399
72cf2d4f	400	#define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \
fc56ef08 BS	401	for ((var) = ((head)->tqh_first); \
	402	(var) && ((next_var) = ((var)->field.tqe_next), 1); \
	403	(var) = (next_var))
	404
72cf2d4f	405	#define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \
fc56ef08 BS	406	for ((var) = ((((struct headname )((head)->tqh_last))->tqh_last)); \
	407	(var); \
	408	(var) = ((((struct headname )((var)->field.tqe_prev))->tqh_last)))
	409
	410	/*
	411	* Tail queue access methods.
	412	*/
72cf2d4f BS	413	#define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL)
	414	#define QTAILQ_FIRST(head) ((head)->tqh_first)
	415	#define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
fc56ef08	416
72cf2d4f	417	#define QTAILQ_LAST(head, headname) \
fc56ef08	418	((((struct headname )((head)->tqh_last))->tqh_last))
72cf2d4f	419	#define QTAILQ_PREV(elm, headname, field) \
fc56ef08 BS	420	((((struct headname )((elm)->field.tqe_prev))->tqh_last))
	421
	422
	423	/*
	424	* Circular queue definitions.
	425	*/
72cf2d4f	426	#define QCIRCLEQ_HEAD(name, type) \
fc56ef08 BS	427	struct name { \
	428	struct type cqh_first; / first element */ \
	429	struct type cqh_last; / last element */ \
	430	}
	431
72cf2d4f	432	#define QCIRCLEQ_HEAD_INITIALIZER(head) \
fc56ef08 BS	433	{ (void )&head, (void )&head }
fc56ef08 BS	434
72cf2d4f	435	#define QCIRCLEQ_ENTRY(type) \
fc56ef08 BS	436	struct { \
	437	struct type cqe_next; / next element */ \
	438	struct type cqe_prev; / previous element */ \
	439	}
	440
	441	/*
	442	* Circular queue functions.
	443	*/
72cf2d4f	444	#define QCIRCLEQ_INIT(head) do { \
fc56ef08 BS	445	(head)->cqh_first = (void *)(head); \
	446	(head)->cqh_last = (void *)(head); \
	447	} while (/CONSTCOND/0)
	448
72cf2d4f	449	#define QCIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
fc56ef08 BS	450	(elm)->field.cqe_next = (listelm)->field.cqe_next; \
	451	(elm)->field.cqe_prev = (listelm); \
	452	if ((listelm)->field.cqe_next == (void *)(head)) \
	453	(head)->cqh_last = (elm); \
	454	else \
	455	(listelm)->field.cqe_next->field.cqe_prev = (elm); \
	456	(listelm)->field.cqe_next = (elm); \
	457	} while (/CONSTCOND/0)
	458
72cf2d4f	459	#define QCIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
fc56ef08 BS	460	(elm)->field.cqe_next = (listelm); \
	461	(elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
	462	if ((listelm)->field.cqe_prev == (void *)(head)) \
	463	(head)->cqh_first = (elm); \
	464	else \
	465	(listelm)->field.cqe_prev->field.cqe_next = (elm); \
	466	(listelm)->field.cqe_prev = (elm); \
	467	} while (/CONSTCOND/0)
	468
72cf2d4f	469	#define QCIRCLEQ_INSERT_HEAD(head, elm, field) do { \
fc56ef08 BS	470	(elm)->field.cqe_next = (head)->cqh_first; \
	471	(elm)->field.cqe_prev = (void *)(head); \
	472	if ((head)->cqh_last == (void *)(head)) \
	473	(head)->cqh_last = (elm); \
	474	else \
	475	(head)->cqh_first->field.cqe_prev = (elm); \
	476	(head)->cqh_first = (elm); \
	477	} while (/CONSTCOND/0)
	478
72cf2d4f	479	#define QCIRCLEQ_INSERT_TAIL(head, elm, field) do { \
fc56ef08 BS	480	(elm)->field.cqe_next = (void *)(head); \
	481	(elm)->field.cqe_prev = (head)->cqh_last; \
	482	if ((head)->cqh_first == (void *)(head)) \
	483	(head)->cqh_first = (elm); \
	484	else \
	485	(head)->cqh_last->field.cqe_next = (elm); \
	486	(head)->cqh_last = (elm); \
	487	} while (/CONSTCOND/0)
	488
72cf2d4f	489	#define QCIRCLEQ_REMOVE(head, elm, field) do { \
fc56ef08 BS	490	if ((elm)->field.cqe_next == (void *)(head)) \
	491	(head)->cqh_last = (elm)->field.cqe_prev; \
	492	else \
	493	(elm)->field.cqe_next->field.cqe_prev = \
	494	(elm)->field.cqe_prev; \
	495	if ((elm)->field.cqe_prev == (void *)(head)) \
	496	(head)->cqh_first = (elm)->field.cqe_next; \
	497	else \
	498	(elm)->field.cqe_prev->field.cqe_next = \
	499	(elm)->field.cqe_next; \
	500	} while (/CONSTCOND/0)
	501
72cf2d4f	502	#define QCIRCLEQ_FOREACH(var, head, field) \
fc56ef08 BS	503	for ((var) = ((head)->cqh_first); \
	504	(var) != (const void *)(head); \
	505	(var) = ((var)->field.cqe_next))
	506
72cf2d4f	507	#define QCIRCLEQ_FOREACH_REVERSE(var, head, field) \
fc56ef08 BS	508	for ((var) = ((head)->cqh_last); \
	509	(var) != (const void *)(head); \
	510	(var) = ((var)->field.cqe_prev))
	511
	512	/*
	513	* Circular queue access methods.
	514	*/
72cf2d4f BS	515	#define QCIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
	516	#define QCIRCLEQ_FIRST(head) ((head)->cqh_first)
	517	#define QCIRCLEQ_LAST(head) ((head)->cqh_last)
	518	#define QCIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
	519	#define QCIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
fc56ef08	520
72cf2d4f	521	#define QCIRCLEQ_LOOP_NEXT(head, elm, field) \
fc56ef08 BS	522	(((elm)->field.cqe_next == (void *)(head)) \
	523	? ((head)->cqh_first) \
	524	: (elm->field.cqe_next))
72cf2d4f	525	#define QCIRCLEQ_LOOP_PREV(head, elm, field) \
fc56ef08 BS	526	(((elm)->field.cqe_prev == (void *)(head)) \
	527	? ((head)->cqh_last) \
	528	: (elm->field.cqe_prev))
	529
72cf2d4f	530	#endif /* !QEMU_SYS_QUEUE_H_ */