blk_execute_rq — insert a request into queue for execution
int blk_execute_rq
(struct request_queue * q, struct gendisk * bd_disk, struct request * rq, int at_head);
queue to insert the request in
matching gendisk
request to insert
insert request at head or tail of queue
Insert a fully prepared request at the back of the io scheduler queue for execution and wait for completion.