From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754246AbbJ0W6L (ORCPT ); Tue, 27 Oct 2015 18:58:11 -0400 Received: from mail-io0-f170.google.com ([209.85.223.170]:33482 "EHLO mail-io0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752475AbbJ0W6J (ORCPT ); Tue, 27 Oct 2015 18:58:09 -0400 MIME-Version: 1.0 In-Reply-To: <20151027222010.GD7716@linux.vnet.ibm.com> References: <20151023205420.GA10197@linux.vnet.ibm.com> <20151026.182746.1323901353520152838.davem@davemloft.net> <20151027222010.GD7716@linux.vnet.ibm.com> From: Julian Calaby Date: Wed, 28 Oct 2015 09:57:48 +1100 Message-ID: Subject: Re: [PATCH 0/5 v3] Fix NVMe driver support on Power with 32-bit DMA To: Nishanth Aravamudan Cc: David Miller , willy@linux.intel.com, keith.busch@intel.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, aik@ozlabs.ru, david@gibson.dropbear.id.au, Christoph Hellwig , linux-nvme@lists.infradead.org, "linux-kernel@vger.kernel.org" , linuxppc-dev@lists.ozlabs.org, sparclinux Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Nishanth, On Wed, Oct 28, 2015 at 9:20 AM, Nishanth Aravamudan wrote: > On 26.10.2015 [18:27:46 -0700], David Miller wrote: >> From: Nishanth Aravamudan >> Date: Fri, 23 Oct 2015 13:54:20 -0700 >> >> > 1) add a generic dma_get_page_shift implementation that just returns >> > PAGE_SHIFT >> >> I won't object to this patch series, but if I had implemented this I >> would have required the architectures to implement this explicitly, >> one-by-one. I think it is less error prone and more likely to end >> up with all the architectures setting this correctly. > > Well, looks like I should spin up a v4 anyways for the powerpc changes. > So, to make sure I understand your point, should I make the generic > dma_get_page_shift a compile-error kind of thing? It will only fail on > architectures that actually build the NVME driver (as the only caller). > But I'm not sure how exactly to achieve that, if you could give a bit > more detail I'd appreciate it! He's suggesting that you _don't_ put a generic implementation in /include/linux/dma-mapping.h and instead add it to _every_ architecture. Thanks, -- Julian Calaby Email: julian.calaby@gmail.com Profile: http://www.google.com/profiles/julian.calaby/