From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Date: Thu, 31 Aug 2017 14:06:53 +0000 Subject: Re: [PATCH 04/12] x86: make dma_cache_sync a no-op Message-Id: List-Id: References: <20170827161032.22772-1-hch@lst.de> <20170827161032.22772-5-hch@lst.de> In-Reply-To: <20170827161032.22772-5-hch-jcswGhMUV9g@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig Cc: Chris Zankel , Michal Simek , linux-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org, linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-xtensa-PjhNF2WwrV/0Sa2dR60CXw@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Howells , Max Filippov , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Guan Xuetao On Sun, 27 Aug 2017, Christoph Hellwig wrote: > x86 does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't > make any sense to do any work in dma_cache_sync given that it must be a > no-op when dma_alloc_attrs returns coherent memory. > > Signed-off-by: Christoph Hellwig > --- > arch/x86/include/asm/dma-mapping.h | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h > index 398c79889f5c..04877267ad18 100644 > --- a/arch/x86/include/asm/dma-mapping.h > +++ b/arch/x86/include/asm/dma-mapping.h > @@ -70,7 +70,6 @@ static inline void > dma_cache_sync(struct device *dev, void *vaddr, size_t size, > enum dma_data_direction dir) > { > - flush_write_buffers(); > } > > static inline unsigned long dma_alloc_coherent_mask(struct device *dev, > -- > 2.11.0 > > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751512AbdHaOHS (ORCPT ); Thu, 31 Aug 2017 10:07:18 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:33279 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323AbdHaOHQ (ORCPT ); Thu, 31 Aug 2017 10:07:16 -0400 Date: Thu, 31 Aug 2017 16:06:53 +0200 (CEST) From: Thomas Gleixner To: Christoph Hellwig cc: iommu@lists.linux-foundation.org, Marek Szyprowski , Robin Murphy , Michal Simek , David Howells , Guan Xuetao , Chris Zankel , Max Filippov , x86@kernel.org, linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-xtensa@linux-xtensa.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/12] x86: make dma_cache_sync a no-op In-Reply-To: <20170827161032.22772-5-hch@lst.de> Message-ID: References: <20170827161032.22772-1-hch@lst.de> <20170827161032.22772-5-hch@lst.de> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 27 Aug 2017, Christoph Hellwig wrote: > x86 does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't > make any sense to do any work in dma_cache_sync given that it must be a > no-op when dma_alloc_attrs returns coherent memory. > > Signed-off-by: Christoph Hellwig > --- > arch/x86/include/asm/dma-mapping.h | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h > index 398c79889f5c..04877267ad18 100644 > --- a/arch/x86/include/asm/dma-mapping.h > +++ b/arch/x86/include/asm/dma-mapping.h > @@ -70,7 +70,6 @@ static inline void > dma_cache_sync(struct device *dev, void *vaddr, size_t size, > enum dma_data_direction dir) > { > - flush_write_buffers(); > } > > static inline unsigned long dma_alloc_coherent_mask(struct device *dev, > -- > 2.11.0 > > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [PATCH 04/12] x86: make dma_cache_sync a no-op Date: Thu, 31 Aug 2017 16:06:53 +0200 (CEST) Message-ID: References: <20170827161032.22772-1-hch@lst.de> <20170827161032.22772-5-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170827161032.22772-5-hch-jcswGhMUV9g@public.gmane.org> 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: Chris Zankel , Michal Simek , linux-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org, linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-xtensa-PjhNF2WwrV/0Sa2dR60CXw@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Howells , Max Filippov , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Guan Xuetao List-Id: iommu@lists.linux-foundation.org On Sun, 27 Aug 2017, Christoph Hellwig wrote: > x86 does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't > make any sense to do any work in dma_cache_sync given that it must be a > no-op when dma_alloc_attrs returns coherent memory. > > Signed-off-by: Christoph Hellwig > --- > arch/x86/include/asm/dma-mapping.h | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h > index 398c79889f5c..04877267ad18 100644 > --- a/arch/x86/include/asm/dma-mapping.h > +++ b/arch/x86/include/asm/dma-mapping.h > @@ -70,7 +70,6 @@ static inline void > dma_cache_sync(struct device *dev, void *vaddr, size_t size, > enum dma_data_direction dir) > { > - flush_write_buffers(); > } > > static inline unsigned long dma_alloc_coherent_mask(struct device *dev, > -- > 2.11.0 > >