On Thu, Mar 23, 2017 at 10:55:22AM -0400, Mike Snitzer wrote: > See commit 70d6c400a ("dm kcopyd: add WRITE SAME support to dm_kcopyd_zero") > drivers/md/dm-io.c:do_region() adjusts the WRITE SAME payload to be a > single page. > > So you'd want to tweak dm-io.c accordingly for WRITE ZEROES (presummably > no payload?) Yeah, I'll look into it. Any good test case for verifying this code while I've got your attention?