rwlock.c

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/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 * See COPYRIGHT in top-level directory.
 */
 
#include "abti.h"
 
int ABT_rwlock_create(ABT_rwlock *newrwlock)
{
    ABTI_UB_ASSERT(ABTI_initialized());
    ABTI_UB_ASSERT(newrwlock);
 
#ifndef ABT_CONFIG_ENABLE_VER_20_API
    /* Argobots 1.x sets newrwlock to NULL on error. */
    *newrwlock = ABT_RWLOCK_NULL;
#endif
    ABTI_rwlock *p_newrwlock;
 
    int abt_errno = ABTU_malloc(sizeof(ABTI_rwlock), (void **)&p_newrwlock);
    ABTI_CHECK_ERROR(abt_errno);
 
    ABTI_mutex_init(&p_newrwlock->mutex);
    ABTI_cond_init(&p_newrwlock->cond);
    p_newrwlock->reader_count = 0;
    p_newrwlock->write_flag = 0;
 
    /* Return value */
    *newrwlock = ABTI_rwlock_get_handle(p_newrwlock);
    return ABT_SUCCESS;
}
 
int ABT_rwlock_free(ABT_rwlock *rwlock)
{
    ABTI_UB_ASSERT(ABTI_initialized());
    ABTI_UB_ASSERT(rwlock);
 
    ABT_rwlock h_rwlock = *rwlock;
    ABTI_rwlock *p_rwlock = ABTI_rwlock_get_ptr(h_rwlock);
    ABTI_CHECK_NULL_RWLOCK_PTR(p_rwlock);
 
    ABTI_cond_fini(&p_rwlock->cond);
    ABTU_free(p_rwlock);
 
    /* Return value */
    *rwlock = ABT_RWLOCK_NULL;
    return ABT_SUCCESS;
}
 
int ABT_rwlock_rdlock(ABT_rwlock rwlock)
{
    ABTI_UB_ASSERT(ABTI_initialized());
 
    ABTI_local *p_local = ABTI_local_get_local();
    ABTI_rwlock *p_rwlock = ABTI_rwlock_get_ptr(rwlock);
    ABTI_CHECK_NULL_RWLOCK_PTR(p_rwlock);
 
#ifndef ABT_CONFIG_ENABLE_VER_20_API
    /* Calling this routine on a tasklet is not allowed. */
    if (ABTI_IS_ERROR_CHECK_ENABLED && p_local) {
        ABTI_xstream *p_local_xstream = ABTI_local_get_xstream(p_local);
        ABTI_CHECK_TRUE(p_local_xstream->p_thread->type &
                            ABTI_THREAD_TYPE_YIELDABLE,
                        ABT_ERR_RWLOCK);
    }
#endif
 
    ABTI_mutex_lock(&p_local, &p_rwlock->mutex);
    int abt_errno = ABT_SUCCESS;
    while (p_rwlock->write_flag && abt_errno == ABT_SUCCESS) {
        abt_errno = ABTI_cond_wait(&p_local, &p_rwlock->cond, &p_rwlock->mutex);
    }
    if (abt_errno == ABT_SUCCESS) {
        p_rwlock->reader_count++;
    }
    ABTI_mutex_unlock(p_local, &p_rwlock->mutex);
    ABTI_CHECK_ERROR(abt_errno);
    return ABT_SUCCESS;
}
 
int ABT_rwlock_wrlock(ABT_rwlock rwlock)
{
    ABTI_UB_ASSERT(ABTI_initialized());
 
    ABTI_local *p_local = ABTI_local_get_local();
    ABTI_rwlock *p_rwlock = ABTI_rwlock_get_ptr(rwlock);
    ABTI_CHECK_NULL_RWLOCK_PTR(p_rwlock);
 
#ifndef ABT_CONFIG_ENABLE_VER_20_API
    /* Calling this routine on a tasklet is not allowed. */
    if (ABTI_IS_ERROR_CHECK_ENABLED && p_local) {
        ABTI_xstream *p_local_xstream = ABTI_local_get_xstream(p_local);
        ABTI_CHECK_TRUE(p_local_xstream->p_thread->type &
                            ABTI_THREAD_TYPE_YIELDABLE,
                        ABT_ERR_RWLOCK);
    }
#endif
 
    ABTI_mutex_lock(&p_local, &p_rwlock->mutex);
    int abt_errno = ABT_SUCCESS;
    while ((p_rwlock->write_flag || p_rwlock->reader_count) &&
           abt_errno == ABT_SUCCESS) {
        abt_errno = ABTI_cond_wait(&p_local, &p_rwlock->cond, &p_rwlock->mutex);
    }
    if (abt_errno == ABT_SUCCESS) {
        p_rwlock->write_flag = 1;
    }
    ABTI_mutex_unlock(p_local, &p_rwlock->mutex);
    ABTI_CHECK_ERROR(abt_errno);
    return ABT_SUCCESS;
}
 
int ABT_rwlock_unlock(ABT_rwlock rwlock)
{
    ABTI_UB_ASSERT(ABTI_initialized());
 
    ABTI_local *p_local = ABTI_local_get_local();
    ABTI_rwlock *p_rwlock = ABTI_rwlock_get_ptr(rwlock);
    ABTI_CHECK_NULL_RWLOCK_PTR(p_rwlock);
 
    ABTI_mutex_lock(&p_local, &p_rwlock->mutex);
    if (p_rwlock->write_flag) {
        p_rwlock->write_flag = 0;
    } else {
        ABTI_UB_ASSERT(p_rwlock->reader_count > 0);
        p_rwlock->reader_count--;
    }
    ABTI_cond_broadcast(p_local, &p_rwlock->cond);
    ABTI_mutex_unlock(p_local, &p_rwlock->mutex);
    return ABT_SUCCESS;
}