The system is fully preemptible when this function is called. The kernel does no processing, but it passes all parameters directly to the function supplied by you. （当这个函数被调用的时候系统完全可能被抢占，内核没有处理，直接传递参数到你提供的函数。这个我觉得说的很别扭，估计是直接传递参数到OEMIoControl ）-The sys