Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-we0-f178.google.com ([74.125.82.178]:41243 "EHLO mail-we0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751358AbbAMKHM (ORCPT ); Tue, 13 Jan 2015 05:07:12 -0500 Received: by mail-we0-f178.google.com with SMTP id p10so1887137wes.9 for ; Tue, 13 Jan 2015 02:07:10 -0800 (PST) Message-ID: <54B4EE4B.9050500@dev.mellanox.co.il> Date: Tue, 13 Jan 2015 12:07:07 +0200 From: Sagi Grimberg MIME-Version: 1.0 To: Chuck Lever CC: linux-rdma , Linux NFS Mailing List Subject: Re: [PATCH v1 05/10] svcrdma: Find rmsgp more reliably References: <20150109191910.4901.29548.stgit@klimt.1015granger.net> <20150109192237.4901.92644.stgit@klimt.1015granger.net> <54B2B4E0.5060901@dev.mellanox.co.il> <3C09A798-2BA9-46A1-AA60-122C2274974C@oracle.com> In-Reply-To: <3C09A798-2BA9-46A1-AA60-122C2274974C@oracle.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 1/12/2015 2:30 AM, Chuck Lever wrote: > Hi Sagi- > > Thanks for the review. > > On Jan 11, 2015, at 12:37 PM, Sagi Grimberg wrote: > >> On 1/9/2015 9:22 PM, Chuck Lever wrote: >>> xdr_start() can return the wrong rmsgp address if an assumption >>> about how the xdr_buf was constructed changes. When it gets it >>> wrong, the client receives a reply that has gibberish in the >>> RPC/RDMA header, preventing it from matching a waiting RPC request. >>> >>> Instead, make (and document) just one assumption: that the RDMA >>> header for the client's RPC call is at the start of the first page >>> in rq_pages. >> >> Would it make more sense to add another pointer assigned at req >> initialization (maybe in the RDMA request context) instead of hard >> coding this assumption? I may be completely wrong here though... > > I considered this. I couldn?t find an appropriate place to add > such a pointer. > > I think that?s why xdr_start() was there in the first place: there > is no convenient place to save a pointer to the request?s RDMA > header. > > Bruce might have other thoughts about this. Yep, I didn't find any nice place to put that also, thought you might have an idea... Sagi.