rem: if (m->sem < 0) return m->sem;
add: if (m->sem >= B_OK) {  return B_OK; }
context: mutex_init(mutex *m, const char *in_name){	const char *name;	if (m == NULL)		return EINVAL;	if (in_name == NULL)		name = "mutex_sem";	else		name = in_name;	m->holder = -1;	m->sem = create_sem(1, name);	if (m->sem < 0)		return m->sem;	return 0;}