On Sat, May 16, 2020 at 08:44:45PM +0800, Coly Li wrote: > Yes you are right, just like REQ_OP_DISCARD which does not transfer any > data but changes the data on device. If the request changes the stored > data, it does transfer data. REQ_OP_DISCARD is a special case, because most implementation end up transferring data, it just gets attached in the low-level driver.
