From: Tom Tucker Subject: Re: [PATCH 10/10] svcrdma: Documentation update for the FastReg memory model Date: Mon, 29 Sep 2008 22:07:25 -0500 Message-ID: <48E197ED.6080409@opengridcomputing.com> References: <1221564879-85046-4-git-send-email-tom@opengridcomputing.com> <1221564879-85046-5-git-send-email-tom@opengridcomputing.com> <1221564879-85046-6-git-send-email-tom@opengridcomputing.com> <1221564879-85046-7-git-send-email-tom@opengridcomputing.com> <1221564879-85046-8-git-send-email-tom@opengridcomputing.com> <1221564879-85046-9-git-send-email-tom@opengridcomputing.com> <1221564879-85046-10-git-send-email-tom@opengridcomputing.com> <1221564879-85046-11-git-send-email-tom@opengridcomputing.com> <20080924212102.GD10841@fieldses.org> <48DB939E.4090503@opengridcomputing.com> <20080926234006.GA9889@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linux-nfs@vger.kernel.org, Tom Talpey To: "J. Bruce Fields" Return-path: Received: from smtp.opengridcomputing.com ([209.198.142.2]:55020 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753473AbYI3DHZ (ORCPT ); Mon, 29 Sep 2008 23:07:25 -0400 In-Reply-To: <20080926234006.GA9889@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: J. Bruce Fields wrote: > On Thu, Sep 25, 2008 at 08:35:26AM -0500, Tom Tucker wrote: >> J. Bruce Fields wrote: >>> This explanation is helpful, thanks. It would also be helpful if we >>> could boil down the advice to just a sentence or two for the busy admin. >>> Something like: unless you have card XYZ and kernel 2.6.y, do *not* use >>> rdma on a network where you cannot trust every machine.... >> >> Would it be better to say, "Do not use RDMA on a network where your >> policy requires a security model stronger than tcp/auth_unix." > > I'm not worried about the case where the security provided is roughly > equivalent to that provided by tcp/auth_unix. > > I'm worried about the non-"Fast Reg" case where I thought you were > saying that the network could access memory other than that meant to > hold rpc data. > Ok, so maybe we could state the security exposure of ALLPHYSICAL instead of dwelling on the relative differences between the similar exposures of tcp/auth_unix vs. fastreg? I'd also like to get to fastreg as a default at some point. Tom: What's your perspective on the lifetime of bounce buffers, memory windows, and the other strategies in client? Tom > --b.