[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 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 four types of data structures:
 * lists, simple queues, tail queues, and circular queues.
 *
 * 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)


/*
 * 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
c616bbe1 PR	5	* the implementations. Left in lists, simple queues, tail queues and
c616bbe1 PR	6	* 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	/*
c616bbe1 PR	44	* This file defines four types of data structures:
c616bbe1 PR	45	* lists, simple queues, tail queues, and circular queues.
fc56ef08 BS	46	*
	47	* A list is headed by a single forward pointer (or an array of forward
	48	* pointers for a hash table header). The elements are doubly linked
	49	* so that an arbitrary element can be removed without a need to
	50	* traverse the list. New elements can be added to the list before
	51	* or after an existing element or at the head of the list. A list
	52	* may only be traversed in the forward direction.
	53	*
c616bbe1 PR	54	* A simple queue is headed by a pair of pointers, one the head of the
	55	* list and the other to the tail of the list. The elements are singly
	56	* linked to save space, so elements can only be removed from the
	57	* head of the list. New elements can be added to the list after
	58	* an existing element, at the head of the list, or at the end of the
	59	* list. A simple queue may only be traversed in the forward direction.
	60	*
fc56ef08 BS	61	* A tail queue is headed by a pair of pointers, one to the head of the
	62	* list and the other to the tail of the list. The elements are doubly
	63	* linked 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 or
	65	* after an existing element, at the head of the list, or at the end of
	66	* the list. A tail queue may be traversed in either direction.
	67	*
	68	* A circle 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 after
	72	* an existing element, at the head of the list, or at the end of the list.
	73	* A circle queue may be traversed in either direction, but has a more
	74	* complex end of list detection.
	75	*
	76	* For details on the use of these macros, see the queue(3) manual page.
	77	*/
	78
5f7d05ec HPB	79	#include "qemu-barrier.h" /* for smp_wmb() */
5f7d05ec HPB	80
fc56ef08 BS	81	/*
	82	* List definitions.
	83	*/
72cf2d4f	84	#define QLIST_HEAD(name, type) \
fc56ef08 BS	85	struct name { \
	86	struct type lh_first; / first element */ \
	87	}
	88
72cf2d4f	89	#define QLIST_HEAD_INITIALIZER(head) \
fc56ef08 BS	90	{ NULL }
fc56ef08 BS	91
72cf2d4f	92	#define QLIST_ENTRY(type) \
fc56ef08 BS	93	struct { \
	94	struct type le_next; / next element */ \
	95	struct type *le_prev; / address of previous next element */ \
	96	}
	97
	98	/*
	99	* List functions.
	100	*/
72cf2d4f	101	#define QLIST_INIT(head) do { \
fc56ef08 BS	102	(head)->lh_first = NULL; \
	103	} while (/CONSTCOND/0)
	104
72cf2d4f	105	#define QLIST_INSERT_AFTER(listelm, elm, field) do { \
fc56ef08 BS	106	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
	107	(listelm)->field.le_next->field.le_prev = \
	108	&(elm)->field.le_next; \
	109	(listelm)->field.le_next = (elm); \
	110	(elm)->field.le_prev = &(listelm)->field.le_next; \
	111	} while (/CONSTCOND/0)
	112
72cf2d4f	113	#define QLIST_INSERT_BEFORE(listelm, elm, field) do { \
fc56ef08 BS	114	(elm)->field.le_prev = (listelm)->field.le_prev; \
	115	(elm)->field.le_next = (listelm); \
	116	*(listelm)->field.le_prev = (elm); \
	117	(listelm)->field.le_prev = &(elm)->field.le_next; \
	118	} while (/CONSTCOND/0)
	119
72cf2d4f	120	#define QLIST_INSERT_HEAD(head, elm, field) do { \
fc56ef08 BS	121	if (((elm)->field.le_next = (head)->lh_first) != NULL) \
	122	(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
	123	(head)->lh_first = (elm); \
	124	(elm)->field.le_prev = &(head)->lh_first; \
	125	} while (/CONSTCOND/0)
	126
5f7d05ec HPB	127	#define QLIST_INSERT_HEAD_RCU(head, elm, field) do { \
	128	(elm)->field.le_prev = &(head)->lh_first; \
	129	(elm)->field.le_next = (head)->lh_first; \
	130	smp_wmb(); /* fill elm before linking it */ \
	131	if ((head)->lh_first != NULL) { \
	132	(head)->lh_first->field.le_prev = &(elm)->field.le_next; \
	133	} \
	134	(head)->lh_first = (elm); \
	135	smp_wmb(); \
	136	} while (/* CONSTCOND*/0)
	137
72cf2d4f	138	#define QLIST_REMOVE(elm, field) do { \
fc56ef08 BS	139	if ((elm)->field.le_next != NULL) \
	140	(elm)->field.le_next->field.le_prev = \
	141	(elm)->field.le_prev; \
	142	*(elm)->field.le_prev = (elm)->field.le_next; \
	143	} while (/CONSTCOND/0)
	144
72cf2d4f	145	#define QLIST_FOREACH(var, head, field) \
fc56ef08 BS	146	for ((var) = ((head)->lh_first); \
	147	(var); \
	148	(var) = ((var)->field.le_next))
	149
72cf2d4f	150	#define QLIST_FOREACH_SAFE(var, head, field, next_var) \
bb150dc8 JQ	151	for ((var) = ((head)->lh_first); \
	152	(var) && ((next_var) = ((var)->field.le_next), 1); \
	153	(var) = (next_var))
	154
fc56ef08 BS	155	/*
	156	* List access methods.
	157	*/
72cf2d4f BS	158	#define QLIST_EMPTY(head) ((head)->lh_first == NULL)
	159	#define QLIST_FIRST(head) ((head)->lh_first)
	160	#define QLIST_NEXT(elm, field) ((elm)->field.le_next)
fc56ef08 BS	161
fc56ef08 BS	162
c616bbe1 PR	163	/*
	164	* Simple queue definitions.
	165	*/
	166	#define QSIMPLEQ_HEAD(name, type) \
	167	struct name { \
	168	struct type sqh_first; / first element */ \
	169	struct type *sqh_last; / addr of last next element */ \
	170	}
	171
	172	#define QSIMPLEQ_HEAD_INITIALIZER(head) \
	173	{ NULL, &(head).sqh_first }
	174
	175	#define QSIMPLEQ_ENTRY(type) \
	176	struct { \
	177	struct type sqe_next; / next element */ \
	178	}
	179
	180	/*
	181	* Simple queue functions.
	182	*/
	183	#define QSIMPLEQ_INIT(head) do { \
	184	(head)->sqh_first = NULL; \
	185	(head)->sqh_last = &(head)->sqh_first; \
	186	} while (/CONSTCOND/0)
	187
	188	#define QSIMPLEQ_INSERT_HEAD(head, elm, field) do { \
	189	if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
	190	(head)->sqh_last = &(elm)->field.sqe_next; \
	191	(head)->sqh_first = (elm); \
	192	} while (/CONSTCOND/0)
	193
	194	#define QSIMPLEQ_INSERT_TAIL(head, elm, field) do { \
	195	(elm)->field.sqe_next = NULL; \
	196	*(head)->sqh_last = (elm); \
	197	(head)->sqh_last = &(elm)->field.sqe_next; \
	198	} while (/CONSTCOND/0)
	199
	200	#define QSIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
	201	if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL) \
	202	(head)->sqh_last = &(elm)->field.sqe_next; \
	203	(listelm)->field.sqe_next = (elm); \
	204	} while (/CONSTCOND/0)
	205
	206	#define QSIMPLEQ_REMOVE_HEAD(head, field) do { \
	207	if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL)\
	208	(head)->sqh_last = &(head)->sqh_first; \
	209	} while (/CONSTCOND/0)
	210
	211	#define QSIMPLEQ_REMOVE(head, elm, type, field) do { \
	212	if ((head)->sqh_first == (elm)) { \
	213	QSIMPLEQ_REMOVE_HEAD((head), field); \
	214	} else { \
	215	struct type *curelm = (head)->sqh_first; \
	216	while (curelm->field.sqe_next != (elm)) \
	217	curelm = curelm->field.sqe_next; \
	218	if ((curelm->field.sqe_next = \
	219	curelm->field.sqe_next->field.sqe_next) == NULL) \
	220	(head)->sqh_last = &(curelm)->field.sqe_next; \
	221	} \
	222	} while (/CONSTCOND/0)
	223
	224	#define QSIMPLEQ_FOREACH(var, head, field) \
	225	for ((var) = ((head)->sqh_first); \
	226	(var); \
227	(var) = ((var)->field.sqe_next))
228
229	#define QSIMPLEQ_FOREACH_SAFE(var, head, field, next) \
230	for ((var) = ((head)->sqh_first); \
231	(var) && ((next = ((var)->field.sqe_next)), 1); \
232	(var) = (next))
233
234	#define QSIMPLEQ_CONCAT(head1, head2) do { \
235	if (!QSIMPLEQ_EMPTY((head2))) { \
236	*(head1)->sqh_last = (head2)->sqh_first; \
237	(head1)->sqh_last = (head2)->sqh_last; \
238	QSIMPLEQ_INIT((head2)); \
239	} \
240	} while (/CONSTCOND/0)
241
242	#define QSIMPLEQ_LAST(head, type, field) \
243	(QSIMPLEQ_EMPTY((head)) ? \
244	NULL : \
245	((struct type )(void ) \
246	((char *)((head)->sqh_last) - offsetof(struct type, field))))
247
248	/*
249	* Simple queue access methods.
250	*/
251	#define QSIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL)
252	#define QSIMPLEQ_FIRST(head) ((head)->sqh_first)
253	#define QSIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)
254
255
fc56ef08 BS	256	/*
	257	* Tail queue definitions.
	258	*/
72cf2d4f	259	#define Q_TAILQ_HEAD(name, type, qual) \
fc56ef08 BS	260	struct name { \
	261	qual type tqh_first; / first element */ \
	262	qual type qual tqh_last; /* addr of last next element */ \
	263	}
72cf2d4f	264	#define QTAILQ_HEAD(name, type) Q_TAILQ_HEAD(name, struct type,)
fc56ef08	265
72cf2d4f	266	#define QTAILQ_HEAD_INITIALIZER(head) \
fc56ef08 BS	267	{ NULL, &(head).tqh_first }
fc56ef08 BS	268
72cf2d4f	269	#define Q_TAILQ_ENTRY(type, qual) \
fc56ef08 BS	270	struct { \
	271	qual type tqe_next; / next element */ \
	272	qual type qual tqe_prev; /* address of previous next element */\
	273	}
72cf2d4f	274	#define QTAILQ_ENTRY(type) Q_TAILQ_ENTRY(struct type,)
fc56ef08 BS	275
	276	/*
	277	* Tail queue functions.
	278	*/
72cf2d4f	279	#define QTAILQ_INIT(head) do { \
fc56ef08 BS	280	(head)->tqh_first = NULL; \
	281	(head)->tqh_last = &(head)->tqh_first; \
	282	} while (/CONSTCOND/0)
	283
72cf2d4f	284	#define QTAILQ_INSERT_HEAD(head, elm, field) do { \
fc56ef08 BS	285	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
	286	(head)->tqh_first->field.tqe_prev = \
	287	&(elm)->field.tqe_next; \
	288	else \
	289	(head)->tqh_last = &(elm)->field.tqe_next; \
	290	(head)->tqh_first = (elm); \
	291	(elm)->field.tqe_prev = &(head)->tqh_first; \
	292	} while (/CONSTCOND/0)
	293
72cf2d4f	294	#define QTAILQ_INSERT_TAIL(head, elm, field) do { \
fc56ef08 BS	295	(elm)->field.tqe_next = NULL; \
	296	(elm)->field.tqe_prev = (head)->tqh_last; \
	297	*(head)->tqh_last = (elm); \
	298	(head)->tqh_last = &(elm)->field.tqe_next; \
	299	} while (/CONSTCOND/0)
	300
72cf2d4f	301	#define QTAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
fc56ef08 BS	302	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
	303	(elm)->field.tqe_next->field.tqe_prev = \
	304	&(elm)->field.tqe_next; \
	305	else \
	306	(head)->tqh_last = &(elm)->field.tqe_next; \
	307	(listelm)->field.tqe_next = (elm); \
	308	(elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
	309	} while (/CONSTCOND/0)
	310
72cf2d4f	311	#define QTAILQ_INSERT_BEFORE(listelm, elm, field) do { \
fc56ef08 BS	312	(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
	313	(elm)->field.tqe_next = (listelm); \
	314	*(listelm)->field.tqe_prev = (elm); \
	315	(listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
	316	} while (/CONSTCOND/0)
	317
72cf2d4f	318	#define QTAILQ_REMOVE(head, elm, field) do { \
fc56ef08 BS	319	if (((elm)->field.tqe_next) != NULL) \
	320	(elm)->field.tqe_next->field.tqe_prev = \
	321	(elm)->field.tqe_prev; \
	322	else \
	323	(head)->tqh_last = (elm)->field.tqe_prev; \
	324	*(elm)->field.tqe_prev = (elm)->field.tqe_next; \
	325	} while (/CONSTCOND/0)
	326
72cf2d4f	327	#define QTAILQ_FOREACH(var, head, field) \
fc56ef08 BS	328	for ((var) = ((head)->tqh_first); \
	329	(var); \
	330	(var) = ((var)->field.tqe_next))
	331
72cf2d4f	332	#define QTAILQ_FOREACH_SAFE(var, head, field, next_var) \
fc56ef08 BS	333	for ((var) = ((head)->tqh_first); \
	334	(var) && ((next_var) = ((var)->field.tqe_next), 1); \
	335	(var) = (next_var))
	336
72cf2d4f	337	#define QTAILQ_FOREACH_REVERSE(var, head, headname, field) \
fc56ef08 BS	338	for ((var) = ((((struct headname )((head)->tqh_last))->tqh_last)); \
	339	(var); \
	340	(var) = ((((struct headname )((var)->field.tqe_prev))->tqh_last)))
	341
	342	/*
	343	* Tail queue access methods.
	344	*/
72cf2d4f BS	345	#define QTAILQ_EMPTY(head) ((head)->tqh_first == NULL)
	346	#define QTAILQ_FIRST(head) ((head)->tqh_first)
	347	#define QTAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
fc56ef08	348
72cf2d4f	349	#define QTAILQ_LAST(head, headname) \
fc56ef08	350	((((struct headname )((head)->tqh_last))->tqh_last))
72cf2d4f	351	#define QTAILQ_PREV(elm, headname, field) \
fc56ef08 BS	352	((((struct headname )((elm)->field.tqe_prev))->tqh_last))
	353
	354
	355	/*
	356	* Circular queue definitions.
	357	*/
72cf2d4f	358	#define QCIRCLEQ_HEAD(name, type) \
fc56ef08 BS	359	struct name { \
	360	struct type cqh_first; / first element */ \
	361	struct type cqh_last; / last element */ \
	362	}
	363
72cf2d4f	364	#define QCIRCLEQ_HEAD_INITIALIZER(head) \
fc56ef08 BS	365	{ (void )&head, (void )&head }
fc56ef08 BS	366
72cf2d4f	367	#define QCIRCLEQ_ENTRY(type) \
fc56ef08 BS	368	struct { \
	369	struct type cqe_next; / next element */ \
	370	struct type cqe_prev; / previous element */ \
	371	}
	372
	373	/*
	374	* Circular queue functions.
	375	*/
72cf2d4f	376	#define QCIRCLEQ_INIT(head) do { \
fc56ef08 BS	377	(head)->cqh_first = (void *)(head); \
	378	(head)->cqh_last = (void *)(head); \
	379	} while (/CONSTCOND/0)
	380
72cf2d4f	381	#define QCIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
fc56ef08 BS	382	(elm)->field.cqe_next = (listelm)->field.cqe_next; \
	383	(elm)->field.cqe_prev = (listelm); \
	384	if ((listelm)->field.cqe_next == (void *)(head)) \
	385	(head)->cqh_last = (elm); \
	386	else \
	387	(listelm)->field.cqe_next->field.cqe_prev = (elm); \
	388	(listelm)->field.cqe_next = (elm); \
	389	} while (/CONSTCOND/0)
	390
72cf2d4f	391	#define QCIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
fc56ef08 BS	392	(elm)->field.cqe_next = (listelm); \
	393	(elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
	394	if ((listelm)->field.cqe_prev == (void *)(head)) \
	395	(head)->cqh_first = (elm); \
	396	else \
	397	(listelm)->field.cqe_prev->field.cqe_next = (elm); \
	398	(listelm)->field.cqe_prev = (elm); \
	399	} while (/CONSTCOND/0)
	400
72cf2d4f	401	#define QCIRCLEQ_INSERT_HEAD(head, elm, field) do { \
fc56ef08 BS	402	(elm)->field.cqe_next = (head)->cqh_first; \
	403	(elm)->field.cqe_prev = (void *)(head); \
	404	if ((head)->cqh_last == (void *)(head)) \
	405	(head)->cqh_last = (elm); \
	406	else \
	407	(head)->cqh_first->field.cqe_prev = (elm); \
	408	(head)->cqh_first = (elm); \
	409	} while (/CONSTCOND/0)
	410
72cf2d4f	411	#define QCIRCLEQ_INSERT_TAIL(head, elm, field) do { \
fc56ef08 BS	412	(elm)->field.cqe_next = (void *)(head); \
	413	(elm)->field.cqe_prev = (head)->cqh_last; \
	414	if ((head)->cqh_first == (void *)(head)) \
	415	(head)->cqh_first = (elm); \
	416	else \
	417	(head)->cqh_last->field.cqe_next = (elm); \
	418	(head)->cqh_last = (elm); \
	419	} while (/CONSTCOND/0)
	420
72cf2d4f	421	#define QCIRCLEQ_REMOVE(head, elm, field) do { \
fc56ef08 BS	422	if ((elm)->field.cqe_next == (void *)(head)) \
	423	(head)->cqh_last = (elm)->field.cqe_prev; \
	424	else \
	425	(elm)->field.cqe_next->field.cqe_prev = \
	426	(elm)->field.cqe_prev; \
	427	if ((elm)->field.cqe_prev == (void *)(head)) \
	428	(head)->cqh_first = (elm)->field.cqe_next; \
	429	else \
	430	(elm)->field.cqe_prev->field.cqe_next = \
	431	(elm)->field.cqe_next; \
	432	} while (/CONSTCOND/0)
	433
72cf2d4f	434	#define QCIRCLEQ_FOREACH(var, head, field) \
fc56ef08 BS	435	for ((var) = ((head)->cqh_first); \
	436	(var) != (const void *)(head); \
	437	(var) = ((var)->field.cqe_next))
	438
72cf2d4f	439	#define QCIRCLEQ_FOREACH_REVERSE(var, head, field) \
fc56ef08 BS	440	for ((var) = ((head)->cqh_last); \
	441	(var) != (const void *)(head); \
	442	(var) = ((var)->field.cqe_prev))
	443
	444	/*
	445	* Circular queue access methods.
	446	*/
72cf2d4f BS	447	#define QCIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
	448	#define QCIRCLEQ_FIRST(head) ((head)->cqh_first)
	449	#define QCIRCLEQ_LAST(head) ((head)->cqh_last)
	450	#define QCIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
	451	#define QCIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
fc56ef08	452
72cf2d4f	453	#define QCIRCLEQ_LOOP_NEXT(head, elm, field) \
fc56ef08 BS	454	(((elm)->field.cqe_next == (void *)(head)) \
	455	? ((head)->cqh_first) \
	456	: (elm->field.cqe_next))
72cf2d4f	457	#define QCIRCLEQ_LOOP_PREV(head, elm, field) \
fc56ef08 BS	458	(((elm)->field.cqe_prev == (void *)(head)) \
	459	? ((head)->cqh_last) \
	460	: (elm->field.cqe_prev))
	461
72cf2d4f	462	#endif /* !QEMU_SYS_QUEUE_H_ */