On Thu, Mar 03, 2022 at 01:17:05PM +0000, Shameerali Kolothum Thodi wrote: > > Tthere is a scenario that transfers only QM_MATCH_SIZE in stop_copy? > > This doesn't seem like a good idea, I think you should transfer a > > positive indication 'this device is not ready' instead of truncating > > the stream. A truncated stream should not be a valid stream. > > > > ie always transfer the whole struct. > > We could add a 'qm_state' and return the whole struct. But the rest > of the struct is basically invalid if qm_state = QM_NOT_REDAY. This seems like the right thing to do to me > > > Looks like setting the total_length = 0 in STOP_COPY is a better > > > solution(If there are no other issues with that) as it will avoid > > > grabbing the state_mutex as you mentioned above. > > > > That seems really weird, I wouldn't recommend doing that.. > > Does that mean we don't support a zero data transfer in STOP_COPY? total_length should not go backwards > The concern is if we always transfer the whole struct, we end up reading > and writing the whole thing even if most of the data is invalid. Well, you can't know if the device is not ready or not until the reaching STOP_COPY, so you have to transfer something to avoid truncating the data stream. The state here is tiny, is the extra transfer a real worry? Jason
