On Thu, Feb 21, 2019 at 01:29:57AM +0000, Chaitanya Kulkarni wrote: > Hi Martin, > > I don't mind going though that route, here are some points about > benefits of not using REQ_SPECIAL_PAYLOAD for write-zeroes :- > > 1. We are using RQF_SPECIAL_PAYLOAD for only discard commands and not for > write-zeroes because it does not have any payload. Using this in the > code will > trigger more code changes to handle in the completion path.
Yes. And that is the big difference to SCSI where REQ_OP_WRITE_ZEROES turns into a WRITE SAME command that has a payload. So for SCSI RQF_SPECIAL_PAYLOAD for REQ_OP_WRITE_ZEROES makes a lot of sense, for NVMe it does not.
