On Sat, Feb 20, 2021 at 06:01:56PM +0000, David Laight wrote:

From: SelvaKumar S

quoted

Sent: 19 February 2021 12:45

This patchset tries to add support for TP4065a ("Simple Copy Command"),
v2020.05.04 ("Ratified")

The Specification can be found in following link.
https://nvmexpress.org/wp-content/uploads/NVM-Express-1.4-Ratified-TPs-1.zip

Simple copy command is a copy offloading operation and is  used to copy
multiple contiguous ranges (source_ranges) of LBA's to a single destination
LBA within the device reducing traffic between host and device.

Sounds to me like the real reason is that the copy just ends up changing
some indirect block pointers rather than having to actually copy the data.

I guess an implementation could do that, but I think that's missing the
point of the command. The intention is to copy the data to a new
location on the media for host managed garbage collection.