Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932240AbbD1BZL (ORCPT ); Mon, 27 Apr 2015 21:25:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44516 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751840AbbD1BZI (ORCPT ); Mon, 27 Apr 2015 21:25:08 -0400 Message-ID: <1430184275.44548.44.camel@redhat.com> Subject: Re: [PATCH v6 01/26] IB/Verbs: Implement new callback query_transport() From: Doug Ledford To: Tom Talpey Cc: "ira.weiny" , Michael Wang , Liran Liss , Roland Dreier , Sean Hefty , Hal Rosenstock , "linux-rdma@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Steve Wise , Jason Gunthorpe , Tom Tucker , Hoang-Nam Nguyen , "raisch@de.ibm.com" , Mike Marciniszyn , Eli Cohen , Faisal Latif , Jack Morgenstein , Or Gerlitz , Haggai Eran Date: Mon, 27 Apr 2015 21:24:35 -0400 In-Reply-To: <553EDA01.9040708@talpey.com> References: <1429878230-11749-1-git-send-email-yun.wang@profitbricks.com> <1429878230-11749-2-git-send-email-yun.wang@profitbricks.com> <553DE799.5050608@profitbricks.com> <20150427215229.GD5347@phlsvsds.ph.intel.com> <553ED159.2090006@talpey.com> <1430181360.44548.35.camel@redhat.com> <553EDA01.9040708@talpey.com> Organization: Red Hat, Inc. Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-c1m5++FsxOiZrTmJr0Gk" Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4936 Lines: 125 --=-c1m5++FsxOiZrTmJr0Gk Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2015-04-27 at 17:53 -0700, Tom Talpey wrote: > On 4/27/2015 5:36 PM, Doug Ledford wrote: > > On Mon, 2015-04-27 at 17:16 -0700, Tom Talpey wrote: > >> On 4/27/2015 2:52 PM, ira.weiny wrote: > >>> On Mon, Apr 27, 2015 at 09:39:05AM +0200, Michael Wang wrote: > >>>> On 04/24/2015 05:12 PM, Liran Liss wrote: > >>>>> [snip] > >>>> > >>>> Like: > >>>> > >>>> enum rdma_protocol { > >>>> RDMA_PROTOCOL_IB, > >>>> RDMA_PROTOCOL_IBOE, > >>>> RDMA_PROTOCOL_IWARP, > >>>> RDMA_PROTOCOL_USNIC_UDP > >>>> }; > >>>> > >>>> So we could use query_protocol() to ask device provide the protocol > >>>> type, and there will be no mixing with the legacy transport type > >>>> anymore :-) > >>> > >>> I'm ok with that. I like introducing a unique namespace which is cle= arly > >>> different from the previous "transport" one. > >> > >> I agree the word "transport" takes things into the weeds. > >> > >> But on the topic of naming protocols, I've been wondering, is there > >> some reason that "IBOE" is being used instead of "RoCE"? > > > > Because back in the day, when RoCE was accepted into the kernel, I'm > > pretty sure it was prior to the IBTA's final stamp of approval and > > before the name was set on RoCE, so IBoE was chosen upstream as the mor= e > > "correct" name because it properly denoted what it was deemed to truly > > be: IB Verbs over Ethernet. >=20 > Well history is all well and good, but it seems weird to not use the > current, standard name in new code. It confuses me, anyway, because > it seems like IBOE could easily mean something else. Having some of it refer to things as IBOE and some as ROCE would be similarly confusing, and switching existing IBOE usage to ROCE would cause pain to people with out of tree drivers (Lustre is the main one I know of). There's not a good answer here. There's only less sucky ones. > >> Also wondering, why add "UDP" to USNIC, is there a different USNIC? > > > > Yes, there are two transports, one a distinct ethertype and one that > > encapsulates USNIC in UDP. >=20 > But this new enum isn't about transport, it's about protocol. So is > there one USNIC protocol, with a raw layering and a separate one with > UDP? Or is it one USNIC protocol with two different framings? Seems > there should be at least the USNIC protocol, without the _UDP > decoration, and I don't see it in the enum. Keep in mind that this enum was Liran's response to Michael's original patch. In the enum in Michael's patch, there was both USNIC and USNIC_UDP. > > > >> Naming multiple layers together seems confusing and maybe in the end > >> will create more code to deal with the differences. For example, what > >> token will RoCEv2 take? RoCE_UDP, RoCE_v2 or ... ? > > > > Uncertain as of now. >=20 > Ok, but it's imminent, right? What's the preference/guidance? There is a patchset from Devesh Sharma at Emulex. It added the RoCEv2 capability. As I recall, it used a new flag added to the existing port capabilities bitmask and notably did not modify either the node type or link layer that are currently used to differentiate between the different protocols. That's from memory though, so I could be mistaken. But that patchset was not written with this patchset in mind, and merging the two may well change that. In any case, there is a proposed spec to follow, so for now that's the preference/guidance (unless this rework means that we need to depart from the spec on internals for implementation reasons). --=20 Doug Ledford GPG KeyID: 0E572FDD --=-c1m5++FsxOiZrTmJr0Gk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAABCAAGBQJVPuFTAAoJELgmozMOVy/d8GIP/ixqTvhn4RFBGDlyukSvOaz8 vSUv6IkQllnHo+gtRxlg8wgixpB/xiSq3FORyPI6jldA86d1bGNGB6jOGTgGqfRv deTN7NNcXAu42XOS3dLIjuz3lGG8l0QwBrvS4fH2PCD48Ht0sj6ilK9vSyO34oq7 ugp5m70gUAsZmfNV6RvXH7DmcRIULOTVmXCcD2lWR62XuAsAcCaFThB568NXNDrq oLlMfYXpfmy92Uqsd8G2d/kmqZKK6I2Hjf7s5esQHNUeF9hy3kJc8GfeG3YEQSxT u5n7KyVtjO2g7eK9K1HMdpL3jqdYl6Ey7PbY5kpaGWAyhkDpXOTU4gbHRERbBBBn SnYMpnEw1SsLooI5nnZEgTL8HuOjI85zvAvDY/dVwTy/UGeELH7vxmWjct8Zpc6Q 0vsfI6ZiaG46D0t3JnmTnX6KMYLnHEieAuLOI1ftNxRrXq96Ejfj3W68SOSl6xJS f4ltZLak4n0D8sEmbN54bcRJO1noO9rXjCHIealYdKGrHDFVFjiGtizHcCQCsGjH Y9oObW8FMkIFFV0ze1LY0fIfkIKWXg5Eer+M61cO8NaIT62l7/DglAn6MNioFUXv MLd5gtKTXTCVP95B9t+8KUkuUVsOkdfEfbmy+bNWxXW/CqbM0wl7iS1BX1od2AEE 5uTQEBRnrjmyYYV9r6qj =iAVA -----END PGP SIGNATURE----- --=-c1m5++FsxOiZrTmJr0Gk-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/