From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH 08/22] swiotlb: wire up ->dma_supported in swiotlb_dma_ops Date: Wed, 10 Jan 2018 17:23:08 +0000 Message-ID: <5b14af5b-e6e9-17c5-d433-f50ccb466f90@arm.com> References: <20180110080932.14157-1-hch@lst.de> <20180110080932.14157-9-hch@lst.de> <7a058876-08fc-7323-7cb3-fe85116e2ea8@arm.com> <20180110153517.GF17790@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180110153517.GF17790-jcswGhMUV9g@public.gmane.org> Content-Language: en-GB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Christoph Hellwig Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org, Michal Simek , linux-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, =?UTF-8?Q?Christian_K=c3=b6nig?= , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Konrad Rzeszutek Wilk , Guan Xuetao , linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-arch.vger.kernel.org On 10/01/18 15:35, Christoph Hellwig wrote: > On Wed, Jan 10, 2018 at 12:16:15PM +0000, Robin Murphy wrote: >> On 10/01/18 08:09, Christoph Hellwig wrote: >>> To properly reject too small DMA masks based on the addressability of the >>> bounce buffer. >> >> I reckon this is self-evident enough that it should simply be squashed into >> the previous patch. > > x86 didn't wire it up before, so I want a clear blaimpoint for this > change instead of mixing it up. That almost makes sense, if x86 were using this generic swiotlb_dma_ops already. AFAICS it's only ia64, unicore and tile who end up using it, and they all had swiotlb_dma_supported hooked up to begin with. Am I missing something? If regressions are going to happen, they'll surely point at whichever commit pulls the ops into the relevant arch code - there doesn't seem to be a great deal of value in having a piecemeal history of said ops *before* that point. Robin. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:46344 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751829AbeAJRXM (ORCPT ); Wed, 10 Jan 2018 12:23:12 -0500 Subject: Re: [PATCH 08/22] swiotlb: wire up ->dma_supported in swiotlb_dma_ops References: <20180110080932.14157-1-hch@lst.de> <20180110080932.14157-9-hch@lst.de> <7a058876-08fc-7323-7cb3-fe85116e2ea8@arm.com> <20180110153517.GF17790@lst.de> From: Robin Murphy Message-ID: <5b14af5b-e6e9-17c5-d433-f50ccb466f90@arm.com> Date: Wed, 10 Jan 2018 17:23:08 +0000 MIME-Version: 1.0 In-Reply-To: <20180110153517.GF17790@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Christoph Hellwig Cc: iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-mips@linux-mips.org, Michal Simek , linux-ia64@vger.kernel.org, =?UTF-8?Q?Christian_K=c3=b6nig?= , x86@kernel.org, linux-kernel@vger.kernel.org, Konrad Rzeszutek Wilk , Guan Xuetao , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Message-ID: <20180110172308.73fiFHM7i1-CZIMwSxJyBff_MlZDybQpmPlOTWc-Z44@z> On 10/01/18 15:35, Christoph Hellwig wrote: > On Wed, Jan 10, 2018 at 12:16:15PM +0000, Robin Murphy wrote: >> On 10/01/18 08:09, Christoph Hellwig wrote: >>> To properly reject too small DMA masks based on the addressability of the >>> bounce buffer. >> >> I reckon this is self-evident enough that it should simply be squashed into >> the previous patch. > > x86 didn't wire it up before, so I want a clear blaimpoint for this > change instead of mixing it up. That almost makes sense, if x86 were using this generic swiotlb_dma_ops already. AFAICS it's only ia64, unicore and tile who end up using it, and they all had swiotlb_dma_supported hooked up to begin with. Am I missing something? If regressions are going to happen, they'll surely point at whichever commit pulls the ops into the relevant arch code - there doesn't seem to be a great deal of value in having a piecemeal history of said ops *before* that point. Robin.