From mboxrd@z Thu Jan 1 00:00:00 1970 From: Haggai Eran Subject: Re: [PATCH v1 1/5] IB/uverbs: ex_query_device: answer must not depend on request's comp_mask Date: Sun, 1 Feb 2015 13:25:15 +0200 Message-ID: <54CE0D1B.400@mellanox.com> References: <24ceb1fc5b2b6563532e5776b1b2320b1ae37543.1422553023.git.ydroneaud@opteya.com> <20150129182800.GH11842@obsidianresearch.com> <1422568741.3133.247.camel@opteya.com> <1422638760.3133.260.camel@opteya.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1422638760.3133.260.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Yann Droneaud , Roland Dreier Cc: Jason Gunthorpe , Sagi Grimberg , Shachar Raindel , Eli Cohen , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On 30/01/2015 19:26, Yann Droneaud wrote: > Hi, >=20 > Le jeudi 29 janvier 2015 =C3=A0 15:17 -0800, Roland Dreier a =C3=A9cr= it : >> On Thu, Jan 29, 2015 at 1:59 PM, Yann Droneaud wrote: >>>> Roland: I agree with Yann, these patches need to go in, or the ODP >>>> patches reverted. >> >>> Reverting all On Demand Paging patches seems overkill: >>> if something as to be reverted it should be commit 5a77abf9a97a >>> ("IB/core: Add support for extended query device caps") and the par= t of >>> commit 860f10a799c8 ("IB/core: Add flags for on demand paging suppo= rt") >>> which modify ib_uverbs_ex_query_device(). >> >> Thank you and Jason for taking on this interface. >> >> At this point I feel like I do about the IPoIB changes -- we should >> revert the broken stuff and get it right for 3.20. >> >> If we revert the two things you describe above, is everything else O= K >> to leave in 3.19 with respect to ABI? >> >=20 > I've tried to review every changes since v3.18 on drivers/infiniband > include/rdma and include/uapi/rdma with respect to ABI issues. >=20 > I've noticed no other issue, but I have to admit I've not well review= ed > the drivers (hw/) internal changes. >=20 > If the IB_USER_VERBS_EX_CMD_QUERY_DEVICE and ib_uverbs_ex_query_devic= e > changes are going to be reverted for v3.19, the on-demand-paging > feature will be available (IB_DEVICE_ON_DEMAND_PAGING will be set=20 > device_cap_flags in response to non extended QUERY_DEVICE for mlx5 HC= A > and IB_ACCESS_ON_DEMAND access flag will be effective for REG_MR=20 > uverbs), but its parameters won't be.=20 =46or user-space to make use of on demand paging, it should verify the specific transport and operation is supported. If they don't, they will encounter errors when a page fault occurs. > I don't know if it's a no-go for=20 > the usage of on-demand paging by userspace: I have not the chance > of owning HCA with the support for this feature, nor the patches > libibverbs / libmlx5 ... (anyway I would not have the time to test). > I've hoped people from Mellanox would have commented on the revert=20 > option too. I would prefer it if Yann's patches are accepted. I understand it is very late, but they are quite short, and I think they provide the right semantic for this new verb. As a second option, in case you prefer to revert the extended query device patch, I will send a patch shortly to do that. Regards, Haggai