cond.c

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/* -*- C -*- */
/*
 * Copyright (c) 2011-2020 Seagate Technology LLC and/or its Affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For any questions about this software or licensing,
 * please email opensource@seagate.com or cortx-questions@seagate.com.
 *
 */


#include "lib/cond.h"
#include "lib/mutex.h"
#include "lib/assert.h"

M0_INTERNAL void m0_cond_init(struct m0_cond *cond, struct m0_mutex *mutex)
{
        m0_chan_init(&cond->c_chan, mutex);
}
M0_EXPORTED(m0_cond_init);

M0_INTERNAL void m0_cond_fini(struct m0_cond *cond)
{
        m0_chan_fini_lock(&cond->c_chan);
}
M0_EXPORTED(m0_cond_fini);

M0_INTERNAL void m0_cond_wait(struct m0_cond *cond)
{
        struct m0_clink clink;

        /*
         * First, register the clink with the channel, *then* unlock the
         * mutex. This guarantees that signals to the condition variable are not
         * missed, because they are done under the mutex.
         */

        M0_PRE(m0_chan_is_locked(&cond->c_chan));

        m0_clink_init(&clink, NULL);
        m0_clink_add(&cond->c_chan, &clink);
        m0_chan_unlock(&cond->c_chan);
        m0_chan_wait(&clink);
        m0_chan_lock(&cond->c_chan);
        m0_clink_del(&clink);
        m0_clink_fini(&clink);
}
M0_EXPORTED(m0_cond_wait);

M0_INTERNAL bool m0_cond_timedwait(struct m0_cond *cond,
                                   const m0_time_t abs_timeout)
{
        struct m0_clink clink;
        bool            retval;

        M0_PRE(m0_chan_is_locked(&cond->c_chan));

        m0_clink_init(&clink, NULL);
        m0_clink_add(&cond->c_chan, &clink);
        m0_chan_unlock(&cond->c_chan);
        retval = m0_chan_timedwait(&clink, abs_timeout);
        m0_chan_lock(&cond->c_chan);
        m0_clink_del(&clink);
        m0_clink_fini(&clink);

        return retval;
}
M0_EXPORTED(m0_cond_timedwait);

M0_INTERNAL void m0_cond_signal(struct m0_cond *cond)
{
        m0_chan_signal(&cond->c_chan);
}
M0_EXPORTED(m0_cond_signal);

M0_INTERNAL void m0_cond_broadcast(struct m0_cond *cond)
{
        m0_chan_broadcast(&cond->c_chan);
}

/*
 *  Local variables:
 *  c-indentation-style: "K&R"
 *  c-basic-offset: 8
 *  tab-width: 8
 *  fill-column: 80
 *  scroll-step: 1
 *  End:
 */