[dm-devel] RFC: remove REQ_OP_WRITE_SAME

[Mike Christie]

On 04/10/2017 11:07 AM, Christoph Hellwig wrote:
> Now that we are using REQ_OP_WRITE_ZEROES for all zeroing needs in the
> kernel there is very little use left for REQ_OP_WRITE_SAME.  We only
> have two callers left, and both just export optional protocol features
> to remote systems: DRBD and the target code.
> 
> Do we have any major users of those?  If not removing it will clean up
> a few warts in the block layer.

I added the iblock write same support because for RBD/ceph we were going
to pass it from rbd down to the OSD. We are using tcmu right now, so we
no longer need iblock support.