Return-Path: Received: from quartz.orcorp.ca ([184.70.90.242]:51988 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753249AbbGTWlf (ORCPT ); Mon, 20 Jul 2015 18:41:35 -0400 Date: Mon, 20 Jul 2015 16:41:34 -0600 From: Jason Gunthorpe To: Chuck Lever Cc: linux-rdma , Linux NFS Mailing List Subject: Re: [PATCH v3 05/15] xprtrdma: Remove last ib_reg_phys_mr() call site Message-ID: <20150720224134.GA12278@obsidianresearch.com> References: <20150720185624.10997.51574.stgit@manet.1015granger.net> <20150720190311.10997.12636.stgit@manet.1015granger.net> <20150720222608.GA12005@obsidianresearch.com> <73A27338-7EFC-4F54-A15E-09B9D5145242@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <73A27338-7EFC-4F54-A15E-09B9D5145242@oracle.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Jul 20, 2015 at 06:31:11PM -0400, Chuck Lever wrote: > > On Jul 20, 2015, at 6:26 PM, Jason Gunthorpe wrote: > > > On Mon, Jul 20, 2015 at 03:03:11PM -0400, Chuck Lever wrote: > >> + iov->length = size; > >> + iov->lkey = ia->ri_have_dma_lkey ? > >> + ia->ri_dma_lkey : ia->ri_bind_mem->lkey; > >> + rb->rg_size = size; > >> + rb->rg_owner = NULL; > >> return rb; > > > > There is something odd looking about this.. > > > > ri_bind_mem is only setup in the RPCRDMA_ALLPHYSICAL and > > RPCRDMA_MTHCAFMR cases. > > > > RPCRDMA_FRMR doesn't set it up. > > > > So this code in rpcrdma_alloc_regbuf is never called for the FRMR > > case? > > > > If yes, then, how is FRMR working? There is absolutely no reason to > > use FRMR to register local send buffers, just use the global all > > memory lkey... > > > > If no, then that is an oops? > > I’ve tested this code, no oops. > > FRWR always uses the DMA lkey. xprtrdma does not use FRWR if > IB_DEVICE_LOCAL_DMA_LKEY is not asserted. Ah, I see. Ok. Is there a reason to link FRWR and LOCAL_DMA_LKEY together? Just use the code you have for fmr with frwr to get the lkey, probably move it to rpcrdma_ia_open .. Physical MR should create a 2nd MR dedicated for rkey use. That will work really well with the series I'm working on: https://github.com/jgunthorpe/linux/tree/remove-ib_get_dma_mr To just drop ib_get_dma_mr entirely. Jason