On Tue, Jun 06, 2023 at 05:05:35PM +0530, Nitesh Shetty wrote: > Downside will be duplicating checks which are present for read, write in > block layer, device-mapper and zoned devices. > But we can do this, shouldn't be an issue. Yes. Please never overload operations, this is just causing problems everywhere, and that why I split the operations from the flag a few years ago. > The idea behind subsys is to prevent copy across different subsystem. > For example, copy across nvme subsystem and the scsi subsystem. [1] > At present, we don't support inter-namespace(copy across NVMe namespace), > but after community feedback for previous series we left scope for it. Never leave scope for something that isn't actually added. That just creates a giant maintainance nightmare. Cross-device copies are giant nightmare in general, and in the case of NVMe completely unusable as currently done in the working group. Messing up something that is entirely reasonable (local copy) for something like that is a sure way to never get this series in.