/*      $OpenBSD: eventvar.h,v 1.17 2022/07/09 12:48:21 visa Exp $      */

/*-
 * Copyright (c) 1999,2000 Jonathan Lemon <jlemon@FreeBSD.org>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 *      $FreeBSD: src/sys/sys/eventvar.h,v 1.3 2000/05/26 02:06:54 jake Exp $
 */

#ifndef _SYS_EVENTVAR_H_
#define _SYS_EVENTVAR_H_

#include <sys/mutex.h>
#include <sys/refcnt.h>
#include <sys/task.h>

#define KQ_NEVENTS      8               /* minimize copy{in,out} calls */
#define KQEXTENT        256             /* linear growth by this amount */

/*
 * Locking:
 *      I       immutable after creation
 *      L       kqueue_klist_lock
 *      a       atomic operations
 *      q       kq_lock
 */
struct kqueue {
        struct          mutex kq_lock;          /* lock for queue access */
        TAILQ_HEAD(, knote) kq_head;            /* [q] list of pending event */
        int             kq_count;               /* [q] # of pending events */
        struct          refcnt kq_refcnt;       /* [a] # of references */
        struct          klist kq_klist;         /* [L] knotes of other kqs */
        struct          filedesc *kq_fdp;       /* [I] fd table of this kq */

        LIST_ENTRY(kqueue) kq_next;

        u_int           kq_nknotes;             /* [q] # of registered knotes */

        int             kq_knlistsize;          /* [q] size of kq_knlist */
        struct          knlist *kq_knlist;      /* [q] list of
                                                 *     attached knotes */
        u_long          kq_knhashmask;          /* [q] size of kq_knhash */
        struct          knlist *kq_knhash;      /* [q] hash table for
                                                 *     attached knotes */
        struct          task kq_task;           /* deferring of activation */

        int             kq_state;               /* [q] */
#define KQ_SLEEP        0x02
#define KQ_DYING        0x04
#define KQ_TASK         0x08
};

#endif /* !_SYS_EVENTVAR_H_ */