/*
* Attempt to lock for write access, don't wait
*/
int devlock::writetrylock()
{
devlock *rwl = this;
int status, status2;
if (rwl->valid != DEVLOCK_VALID) {
return EINVAL;
}
if ((status = pthread_mutex_lock(&rwl->mutex)) != 0) {
return status;
}
if (rwl->w_active && pthread_equal(rwl->writer_id, pthread_self())) {
rwl->w_active++;
pthread_mutex_unlock(&rwl->mutex);
return 0;
}
if (rwl->w_active || rwl->r_active > 0) {
status = EBUSY;
} else {
rwl->w_active = 1; /* we are running */
rwl->writer_id = pthread_self(); /* save writer thread's id */
lmgr_do_lock(rwl, rwl->priority, __FILE__, __LINE__);
}
status2 = pthread_mutex_unlock(&rwl->mutex);
return (status == 0 ? status2 : status);
}
/*
* Attempt to lock for write access, don't wait
*/
int rwl_writetrylock(brwlock_t *rwl)
{
int stat, stat2;
if (rwl->valid != RWLOCK_VALID) {
return EINVAL;
}
if ((stat = pthread_mutex_lock(&rwl->mutex)) != 0) {
return stat;
}
if (rwl->w_active && pthread_equal(rwl->writer_id, pthread_self())) {
rwl->w_active++;
pthread_mutex_unlock(&rwl->mutex);
return 0;
}
if (rwl->w_active || rwl->r_active > 0) {
stat = EBUSY;
} else {
rwl->w_active = 1; /* we are running */
rwl->writer_id = pthread_self(); /* save writer thread's id */
lmgr_do_lock(rwl, rwl->priority, __FILE__, __LINE__);
}
stat2 = pthread_mutex_unlock(&rwl->mutex);
return (stat == 0 ? stat2 : stat);
}
