Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754076AbZA3LYb (ORCPT ); Fri, 30 Jan 2009 06:24:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752364AbZA3LYV (ORCPT ); Fri, 30 Jan 2009 06:24:21 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:48819 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752215AbZA3LYU (ORCPT ); Fri, 30 Jan 2009 06:24:20 -0500 Date: Fri, 30 Jan 2009 20:24:13 +0900 From: Yasunori Goto To: FUJITA Tomonori Subject: Re: [PATCH -tip 1/3] IA64: fix swiotlb alloc_coherent for non DMA_64BIT_MASK devices Cc: mingo@elte.hu, tony.luck@intel.com, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org In-Reply-To: <20090130083654U.fujita.tomonori@lab.ntt.co.jp> References: <20090130073511.F48F.E1E9C6FF@jp.fujitsu.com> <20090130083654U.fujita.tomonori@lab.ntt.co.jp> X-Mailer-Plugin: BkASPil for Becky!2 Ver.2.068 Message-Id: <20090130184210.4A8E.E1E9C6FF@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.45 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4561 Lines: 120 > On Fri, 30 Jan 2009 07:54:07 +0900 > Yasunori Goto wrote: > > > > On Thu, 29 Jan 2009 20:41:07 +0900 > > > Yasunori Goto wrote: > > > > > > > > Before the dma ops unification, IA64 always uses GFP_DMA for > > > > > dma_alloc_coherent like: > > > > > > > > > > #define dma_alloc_coherent(dev, size, handle, gfp) \ > > > > > platform_dma_alloc_coherent(dev, size, handle, (gfp) | GFP_DMA) > > > > > > > > > > This GFP_DMA enforcement doesn't make sense for IOMMUs since they can > > > > > do address translation to give addresses that devices can access > > > > > to. The IOMMU drivers ignore the zone flag. However, this is still > > > > > necessary for swiotlb since it can't do address translation. > > > > > > > > > > We don't always need to use GFP_DMA for swiotlb. We need GFP_DMA for > > > > > devices incapable of 64bit DMA. > > > > > > > > > > This patch is sorta updated version of: > > > > > > > > > > http://marc.info/?l=linux-kernel&m=122638215612705&w=2 > > > > > > > > > > Signed-off-by: FUJITA Tomonori > > > > > Cc: Yasunori Goto > > > > > --- > > > > > arch/ia64/kernel/pci-swiotlb.c | 10 +++++++++- > > > > > 1 files changed, 9 insertions(+), 1 deletions(-) > > > > > > > > > > diff --git a/arch/ia64/kernel/pci-swiotlb.c b/arch/ia64/kernel/pci-swiotlb.c > > > > > index 717ad4f..573f02c 100644 > > > > > --- a/arch/ia64/kernel/pci-swiotlb.c > > > > > +++ b/arch/ia64/kernel/pci-swiotlb.c > > > > > @@ -13,8 +13,16 @@ > > > > > int swiotlb __read_mostly; > > > > > EXPORT_SYMBOL(swiotlb); > > > > > > > > > > +static void *ia64_swiotlb_alloc_coherent(struct device *dev, size_t size, > > > > > + dma_addr_t *dma_handle, gfp_t gfp) > > > > > +{ > > > > > + if (dev->coherent_dma_mask != DMA_64BIT_MASK) > > > > > + gfp |= GFP_DMA; > > > > > + return swiotlb_alloc_coherent(dev, size, dma_handle, gfp); > > > > > +} > > > > > + > > > > > struct dma_map_ops swiotlb_dma_ops = { > > > > > - .alloc_coherent = swiotlb_alloc_coherent, > > > > > + .alloc_coherent = ia64_swiotlb_alloc_coherent, > > > > > .free_coherent = swiotlb_free_coherent, > > > > > .map_page = swiotlb_map_page, > > > > > .unmap_page = swiotlb_unmap_page, > > > > > -- > > > > > 1.6.0.6 > > > > > > > > > > > > Though I may be misunderstanding something, this initialization seems to be > > > > called only when CONFIG_IA64_DIG_VTD is on. > > > > > > Hmm, what's 'this initialization'? > > > > > > This patch always sets swiotlb_dma_ops.alloc_coherent to > > > ia64_swiotlb_alloc_coherent. > > > > I tested your patch, but, ia64_swiotlb_alloc_coherent() was not called with > > CONFIG_GENERIC. > > You use the generic kernel on a DIG box, right? If so, yeah, there is > something wrong. > > > > swiotlb_dma_ops is set by pci_swiotlb_init(). > > However, it seems to be not called when CONFIG_IA64_DIG/Generic configuration. > > You are talking about setting dma_ops to swiotlb_dma_ops? > > I think that swiotlb_dma_init() also sets dma_ops to swiotlb_dma_ops. Certainly. I overlooked the 7th patch of your unifying dma_ops patch set. ia64_swiotlb_alloc_coherent was called when I tested again. I'm sorry. However, GFP_DMA is still always on in ia64_swiotlb_alloc_coherent() regardless of the value of dev->coherent_dma_mask. After following patch applied, GFP_DMA is set correctly by your patch. Am I still overlooking other your patch? Bye. --- arch/ia64/include/asm/dma-mapping.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: dma_fix_test/arch/ia64/include/asm/dma-mapping.h =================================================================== --- dma_fix_test.orig/arch/ia64/include/asm/dma-mapping.h 2009-01-30 19:36:33.000000000 +0900 +++ dma_fix_test/arch/ia64/include/asm/dma-mapping.h 2009-01-30 20:20:06.000000000 +0900 @@ -71,7 +71,7 @@ static inline void *dma_alloc_coherent(s dma_addr_t *daddr, gfp_t gfp) { struct dma_mapping_ops *ops = platform_dma_get_ops(dev); - return ops->alloc_coherent(dev, size, daddr, gfp | GFP_DMA); + return ops->alloc_coherent(dev, size, daddr, gfp); } static inline void dma_free_coherent(struct device *dev, size_t size, -- Yasunori Goto -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/