thread.c

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/* -*- C -*- */
/*
 * Copyright (c) 2012-2020 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.
 *
 */


#ifndef __KERNEL__
#  include <stdarg.h>
#  include <stdio.h>          /* vsnprintf */
#endif

#include "lib/thread.h"
#include "lib/misc.h"         /* M0_SET0 */
#include "module/instance.h"  /* m0_get */
#include "addb2/global.h"

int m0_thread_init(struct m0_thread *q, int (*init)(void *),
                   void (*func)(void *), void *arg, const char *namefmt, ...)
{
        int     result;
        va_list varargs;

        M0_PRE(M0_IS0(q));
        M0_PRE(q->t_func == NULL);
        M0_PRE(q->t_state == TS_PARKED);

        va_start(varargs, namefmt);
        result = vsnprintf(q->t_namebuf, sizeof q->t_namebuf, namefmt, varargs);
        va_end(varargs);
        M0_ASSERT_INFO(result < sizeof q->t_namebuf,
                       "namebuf truncated to \"%s\"", q->t_namebuf);

        q->t_state = TS_RUNNING;
        q->t_init  = init;
        q->t_func  = func;
        q->t_arg   = arg;

        result = m0_semaphore_init(&q->t_wait, 0);
        if (result != 0)
                return result;

        /* Let `q' inherit the pointer from current thread's TLS.
         * m0_set() is of no use here, since it has no impact on the TLS
         * of `q'. */
        q->t_tls.tls_m0_instance = m0_get();
        q->t_tls.tls_self = q;

        result = m0_thread_init_impl(q, q->t_namebuf);
        if (result != 0)
                goto err;

        if (q->t_init != NULL) {
                m0_semaphore_down(&q->t_wait);
                result = q->t_initrc;
                if (result != 0)
                        m0_thread_join(q);
        }

        if (result == 0)
                return 0;
err:
        m0_semaphore_fini(&q->t_wait);
        q->t_state = TS_PARKED;
        return result;
}
M0_EXPORTED(m0_thread_init);

void m0_thread_fini(struct m0_thread *q)
{
        M0_PRE(q->t_state == TS_PARKED);

        m0_semaphore_fini(&q->t_wait);
        M0_SET0(q);
}
M0_EXPORTED(m0_thread_fini);

M0_INTERNAL void *m0_thread_trampoline(void *arg)
{
        struct m0_thread *t = arg;

        M0_PRE(t->t_state == TS_RUNNING);
        M0_PRE(t->t_initrc == 0);
        M0_PRE(t->t_tls.tls_m0_instance != NULL);
        M0_PRE(t->t_tls.tls_self == t);

        m0_set(t->t_tls.tls_m0_instance);
        m0_addb2_global_thread_enter();
        if (t->t_init != NULL) {
                t->t_initrc = t->t_init(t->t_arg);
                m0_semaphore_up(&t->t_wait);
        }
        if (t->t_initrc == 0)
                t->t_func(t->t_arg);
        m0_addb2_global_thread_leave();
        return NULL;
}

M0_INTERNAL struct m0_thread *m0_thread_self(void)
{
        return m0_thread_tls()->tls_self;
}

M0_INTERNAL int m0_thread_adopt(struct m0_thread *thread, struct m0 *instance)
{
        M0_PRE(M0_IS0(thread));

        return m0_thread_arch_adopt(thread, instance, true);
}

M0_INTERNAL void m0_thread_shun(void)
{
        m0_thread_arch_shun();
}

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