[$] Merging copy offload

Kernel support for copy offload is a feature that has been floating aroundin limbo for a decade or more at this point; it has been implemented along the way, but never merged. The idea is that the hostsystem can simply ask a block storage device to copy some data within the deviceand it will do so without further involving the host; instead of reading data intothe host so that it can be written back out again, the device circumventsthat process. At the2023 Linux Storage, Filesystem,Memory-Management and BPF Summit, Nitesh Shetty led a storage andfilesystem session to discuss the current status of a patch set that he andothers have been working on, with aneye toward getting something merged fairly soon.