int ide_do_drive_cmd (ide_drive_t * drive, struct request * rq, ide_action_t action);
This function issues a special IDE device request onto the request queue.
If action is ide_wait, then the rq is queued at the end of the request queue, and the function sleeps until it has been processed. This is for use when invoked from an ioctl handler.
If action is ide_preempt, then the rq is queued at the head of the request queue, displacing the currently-being-processed request and this function returns immediately without waiting for the new rq to be completed. This is VERY DANGEROUS, and is intended for careful use by the ATAPI tape/cdrom driver code.
If action is ide_next, then the rq is queued immediately after the currently-being-processed-request (if any), and the function returns without waiting for the new rq to be completed. As above, This is VERY DANGEROUS, and is intended for careful use by the ATAPI tape/cdrom driver code.
If action is ide_end, then the rq is queued at the end of the request queue, and the function returns immediately without waiting for the new rq to be completed. This is again intended for careful use by the ATAPI tape/cdrom driver code.