fmd/common/fmd_eventq.c

	fmd_eventq.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <fmd_alloc.h>
#include <fmd_eventq.h>
#include <fmd_module.h>

fmd_eventq_t *
fmd_eventq_create(fmd_module_t *mp, uint_t limit)
{
    fmd_eventq_t *eq = fmd_zalloc(sizeof (fmd_eventq_t), FMD_SLEEP);

    (void) pthread_mutex_init(&eq->eq_lock, NULL);
    (void) pthread_cond_init(&eq->eq_cv, NULL);

    eq->eq_mod = mp;
    eq->eq_limit = limit;

    return (eq);
}

void
fmd_eventq_destroy(fmd_eventq_t *eq)
{
    fmd_eventqelem_t *eqe;

    while ((eqe = fmd_list_next(&eq->eq_list)) != NULL) {
        fmd_list_delete(&eq->eq_list, eqe);
        fmd_event_rele(eqe->eqe_event);
        fmd_free(eqe, sizeof (fmd_eventqelem_t));
    }

    fmd_free(eq, sizeof (fmd_eventq_t));
}

static void
fmd_eventq_drop(fmd_eventq_t *eq, fmd_eventqelem_t *eqe)
{
    (void) pthread_mutex_lock(&eq->eq_mod->mod_stats_lock);
    eq->eq_mod->mod_stats->ms_dropped.fmds_value.ui64++;
    (void) pthread_mutex_unlock(&eq->eq_mod->mod_stats_lock);

    fmd_event_rele(eqe->eqe_event);
    fmd_free(eqe, sizeof (fmd_eventqelem_t));
}

void
fmd_eventq_insert_at_head(fmd_eventq_t *eq, fmd_event_t *ep)
{
    fmd_eventqelem_t *eqe = fmd_alloc(sizeof (fmd_eventqelem_t), FMD_SLEEP);
    uint_t evt = ((fmd_event_impl_t *)ep)->ev_type;
    int ok;

    fmd_event_hold(ep);
    eqe->eqe_event = ep;

    (void) pthread_mutex_lock(&eq->eq_lock);

    if ((ok = eq->eq_size < eq->eq_limit || evt != FMD_EVT_PROTOCOL) != 0) {
        if (evt != FMD_EVT_CTL)
            fmd_modstat_eventq_dispatch(eq->eq_mod);

        fmd_list_prepend(&eq->eq_list, eqe);
        eq->eq_size++;
    }

    (void) pthread_mutex_unlock(&eq->eq_lock);
    (void) pthread_cond_broadcast(&eq->eq_cv);

    if (!ok)
        fmd_eventq_drop(eq, eqe);
}

void
fmd_eventq_insert_at_time(fmd_eventq_t *eq, fmd_event_t *ep)
{
    fmd_eventqelem_t *eqe = fmd_alloc(sizeof (fmd_eventqelem_t), FMD_SLEEP);
    uint_t evt = ((fmd_event_impl_t *)ep)->ev_type;
    hrtime_t hrt = fmd_event_hrtime(ep);

    fmd_eventqelem_t *oqe;
    int ok;

    fmd_event_hold(ep);
    eqe->eqe_event = ep;

    (void) pthread_mutex_lock(&eq->eq_lock);

    /*
     * fmd makes no guarantees that events will be delivered in time order
     * because its transport can make no such guarantees.  Instead we make
     * a looser guarantee that an enqueued event will be dequeued before
     * any newer *pending* events according to event time.  This permits us
     * to state, for example, that a timer expiry event will be delivered
     * prior to any enqueued event whose time is after the timer expired.
     * We use a simple insertion sort for this task, as queue lengths are
     * typically short and events do *tend* to be received chronologically.
     */
    for (oqe = fmd_list_prev(&eq->eq_list); oqe; oqe = fmd_list_prev(oqe)) {
        if (hrt >= fmd_event_hrtime(oqe->eqe_event))
            break; /* 'ep' is newer than the event in 'oqe' */
    }

    if ((ok = eq->eq_size < eq->eq_limit || evt != FMD_EVT_PROTOCOL) != 0) {
        if (evt != FMD_EVT_CTL)
            fmd_modstat_eventq_dispatch(eq->eq_mod);

        fmd_list_insert_after(&eq->eq_list, oqe, eqe);
        eq->eq_size++;
    }

    (void) pthread_mutex_unlock(&eq->eq_lock);
    (void) pthread_cond_broadcast(&eq->eq_cv);

    if (!ok)
        fmd_eventq_drop(eq, eqe);
}

fmd_event_t *
fmd_eventq_delete(fmd_eventq_t *eq)
{
    fmd_eventqelem_t *eqe;
    fmd_event_t *ep;

    (void) pthread_mutex_lock(&eq->eq_lock);

    while (eq->eq_size == 0 && eq->eq_abort == 0)
        (void) pthread_cond_wait(&eq->eq_cv, &eq->eq_lock);

    if (eq->eq_abort) {
        (void) pthread_mutex_unlock(&eq->eq_lock);
        return (NULL);
    }

    eqe = fmd_list_next(&eq->eq_list);
    fmd_list_delete(&eq->eq_list, eqe);
    eq->eq_size--;

    (void) pthread_mutex_unlock(&eq->eq_lock);

    ep = eqe->eqe_event;
    fmd_free(eqe, sizeof (fmd_eventqelem_t));

    return (ep);
}

void
fmd_eventq_cancel(fmd_eventq_t *eq, uint_t type, void *data)
{
    fmd_eventqelem_t *eqe, *nqe;

    (void) pthread_mutex_lock(&eq->eq_lock);

    for (eqe = fmd_list_next(&eq->eq_list); eqe != NULL; eqe = nqe) {
        nqe = fmd_list_next(eqe);

        if (fmd_event_match(eqe->eqe_event, type, data)) {
            fmd_list_delete(&eq->eq_list, eqe);
            eq->eq_size--;
            fmd_event_rele(eqe->eqe_event);
            fmd_free(eqe, sizeof (fmd_eventqelem_t));
        }
    }

    (void) pthread_mutex_unlock(&eq->eq_lock);
}

void
fmd_eventq_abort(fmd_eventq_t *eq)
{
    fmd_eventqelem_t *eqe;

    (void) pthread_mutex_lock(&eq->eq_lock);

    while ((eqe = fmd_list_next(&eq->eq_list)) != NULL) {
        fmd_list_delete(&eq->eq_list, eqe);
        fmd_event_rele(eqe->eqe_event);
        fmd_free(eqe, sizeof (fmd_eventqelem_t));
    }

    eq->eq_abort++; /* signal fmd_eventq_delete() to abort */

    (void) pthread_mutex_unlock(&eq->eq_lock);
    (void) pthread_cond_broadcast(&eq->eq_cv);
}