From mboxrd@z Thu Jan 1 00:00:00 1970 From: hch@lst.de (Christoph Hellwig) Date: Thu, 21 Feb 2019 14:37:00 +0100 Subject: Regression: NVMe: kernel BUG at lib/sg_pool.c:103! In-Reply-To: <722BE5B7-B32B-4B2F-9AC2-E6F5AB5E12D4@wdc.com> References: <20190220031122.GA17298@ming.t460p> <20190220141701.GA26537@lst.de> <722BE5B7-B32B-4B2F-9AC2-E6F5AB5E12D4@wdc.com> Message-ID: <20190221133700.GA20189@lst.de> On Thu, Feb 21, 2019@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.