sig_mutex_trylock
extern int sig_mutex_trylock(mutex_t *);
extern int sig_mutex_trylock(mutex_t *);
if (sig_mutex_trylock(&aiowp->work_qlock1) == 0) {
if (sig_mutex_trylock(&aiowp->work_qlock1) == 0) {
while (sig_mutex_trylock(&aiowp->work_qlock1) != 0) {