From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to rdma_rw_ctx_[init|destroy]() Date: Mon, 8 Jan 2018 11:29:45 -0700 Message-ID: <20180108182945.GG11348@ziepe.ca> References: <20180104190137.7654-1-logang@deltatee.com> <20180104190137.7654-7-logang@deltatee.com> <20180104192225.GS11348@ziepe.ca> <1f8fb3fb-e3dc-94d3-e837-0cd942cf5b87@deltatee.com> <20180104221337.GV11348@ziepe.ca> <3e8391a9-8924-be6d-8c43-162a360d75b6@deltatee.com> <20180105045031.GX11348@ziepe.ca> <20180108145901.GA10743@lst.de> <20180108180917.GF11348@ziepe.ca> <3daea7fe-f64a-36a9-ca80-0cb4d9acf171@deltatee.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3daea7fe-f64a-36a9-ca80-0cb4d9acf171-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Logan Gunthorpe Cc: Christoph Hellwig , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Stephen Bates , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Max Gurtovoy , Dan Williams , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Benjamin Herrenschmidt List-Id: linux-rdma@vger.kernel.org On Mon, Jan 08, 2018 at 11:17:38AM -0700, Logan Gunthorpe wrote: > >>If at all it should be in the dma_map* wrappers, but for that we'd need > >>a good identifier. And it still would not solve the whole fake dma > >>ops issue. > > > >Very long term the IOMMUs under the ops will need to care about this, > >so the wrapper is not an optimal place to put it - but I wouldn't > >object if it gets it out of RDMA :) > > Well, creating the extra op doesn't really change anything to the RDMA patch > in this series. Not fundamentally, but it lets us solve the bugs the patch introduces with hfi/etc > The point is, for the time being, we need to track whether we are > doing a P2P or normal mapping using a side channel as we don't have > a good way of tracking it in the SGL at this time. Well, that is disappointing for now, but I'm OK with the flag in the RW interface - as long as we all sort of agree it is not desirable and the SG should self-identify in an ideal someday future world.. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html