On Fri, Sep 08, 2023 at 08:13:37AM +0200, Hannes Reinecke wrote: > On 9/6/23 18:38, Nitesh Shetty wrote: > > Before enabling copy for dm target, check if underlying devices and > > dm target support copy. Avoid split happening inside dm target. > > Fail early if the request needs split, currently splitting copy > > request is not supported. > > > And here is where I would have expected the emulation to take place; > didn't you have it in one of the earlier iterations? No, but it was the other way round. In dm-kcopyd we used device offload, if that was possible, before using default dm-mapper copy. It was dropped in the current series, to streamline the patches and make the series easier to review. > After all, device-mapper already has the infrastructure for copying > data between devices, so adding a copy-offload emulation for device-mapper > should be trivial. I did not understand this, can you please elaborate ? Thank you, Nitesh Shetty
