Return-Path: Received: from mail-wi0-f179.google.com ([209.85.212.179]:38807 "EHLO mail-wi0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752004AbbGNIGZ (ORCPT ); Tue, 14 Jul 2015 04:06:25 -0400 Received: by wicmv11 with SMTP id mv11so7278155wic.1 for ; Tue, 14 Jul 2015 01:06:24 -0700 (PDT) Subject: Re: [PATCH V3 1/5] RDMA/core: Transport-independent access flags To: Jason Gunthorpe References: <559CD174.4040901@dev.mellanox.co.il> <20150708081320.GB24203@infradead.org> <559CF5E8.6080000@dev.mellanox.co.il> <20150708102035.GA28421@infradead.org> <559D0498.9050809@dev.mellanox.co.il> <1828884A29C6694DAF28B7E6B8A82373A8FFD4C0@ORSMSX109.amr.corp.intel.com> <559E34F8.4080507@dev.mellanox.co.il> <2189DB0A-DD00-4818-AC17-020FCE42D39B@oracle.com> <20150710193409.GA9815@infradead.org> <55A21BF4.7090601@dev.mellanox.co.il> <20150713165007.GD23832@obsidianresearch.com> Cc: Christoph Hellwig , Chuck Lever , "Hefty, Sean" , Steve Wise , "dledford@redhat.com" , "sagig@mellanox.com" , "ogerlitz@mellanox.com" , "roid@mellanox.com" , "linux-rdma@vger.kernel.org" , "eli@mellanox.com" , "target-devel@vger.kernel.org" , Linux NFS Mailing List , Trond Myklebust , "J. Bruce Fields" , Oren Duer From: Sagi Grimberg Message-ID: <55A4C2FA.9060707@dev.mellanox.co.il> Date: Tue, 14 Jul 2015 11:06:18 +0300 MIME-Version: 1.0 In-Reply-To: <20150713165007.GD23832@obsidianresearch.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 7/13/2015 7:50 PM, Jason Gunthorpe wrote: > On Sun, Jul 12, 2015 at 10:49:08AM +0300, Sagi Grimberg wrote: >> On 7/10/2015 10:34 PM, Christoph Hellwig wrote: >>> On Thu, Jul 09, 2015 at 09:52:59AM -0400, Chuck Lever wrote: >>>> There is one remaining kernel user of ib_reg_phys_mr() in 4.2: Lustre. >>> >>> It's in the staging tree, which proper in-tree code doesn't have to >>> cater for. So as soon as sunrpc is done using the interface we can and >>> should kill it off. >>> >> >> I think we should probably ask the Lustre folks if they have a real use >> case for it before we remove it completely. > > I had an interesting conversation with some Lustre devs where they > were very concerned that FMR was going to be removed and they didn't really > seem to even know that FRMR existed. > > I'm sure their PHYS_MR usage is crufty old code to support old > adaptors. > > And again, here is a great example of how the API is not helping the > ULPs do what they want to do. Lustre doesn't care one bit about this > stuff, they just want to send messages.. All protocols cares about transferring data and sending messages, so it's not a good enough reason for a poor registration method choice. This just emphasizes why we need to converge to a single method. Sagi.