set a prepare_request function for queue
void blk_queue_prep_rq (
|struct request_queue * q, |
| ||prep_rq_fn * pfn|
It's possible for a queue to register a prepare_request callback which
is invoked before the request is handed to the request_fn. The goal of
the function is to prepare a request for I/O, it can be used to build a
cdb from the request data for instance.