System Trap - Wait on an io_done_queue kernel object.
kern_return_t io_done_queue_wait (mach_port_t queue, io_done_result_t *result);
The io_done_queue_wait interface is called to obtain the results of a previously requested asynchronous I/O operation. For each io_done_queue_wait invocation, the status of one I/O request is returned. If there are no pending I/O completions, io_done_queue_wait blocks in the kernel on the address of the completion queue. The mKernel, from interrupt context, enqueues (in FIFO order) completions (struct io_done_result's) on the completion queue and posts a wakeup on the queue for each I/O completion. Completion processing previously done by the mKernel io_done thread is now done by the task thread when it awakens.
Functions: io_done_queue_create, io_done_queue_wait, device_read_async, device_read_async_inband, device_read_overwrite_async, device_write_async, device_write_async_inband.