Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758373AbYJWChQ (ORCPT ); Wed, 22 Oct 2008 22:37:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758085AbYJWCgq (ORCPT ); Wed, 22 Oct 2008 22:36:46 -0400 Received: from sh.osrg.net ([192.16.179.4]:33167 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758030AbYJWCgp (ORCPT ); Wed, 22 Oct 2008 22:36:45 -0400 Date: Thu, 23 Oct 2008 11:36:20 +0900 To: tiwai@suse.de Cc: fujita.tomonori@lab.ntt.co.jp, svens@stackframe.org, joerg.roedel@amd.com, mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: swiotlb_alloc_coherent: allocated memory is out of range for device From: FUJITA Tomonori In-Reply-To: References: <20081022221321J.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20081023113618T.fujita.tomonori@lab.ntt.co.jp> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1984 Lines: 47 On Wed, 22 Oct 2008 15:32:52 +0200 Takashi Iwai wrote: > > About the bug that you hit, I suspect that dma_map_coherent() in > > asm-x86/dma-mapping.h doesn't set gfp flags correctly. > > > > dma_map_coherent() calls swiotlb_alloc_coherent with the flags GFP_DMA > > set? parport driver set dev->coherent_dma_mask properly? > > The parport driver itself passes always GFP_KERNEL. So I added > GFP_DMA in my initial patch as a workaround. Hmm, have you actually tried your patch? dma_alloc_coherent clears the gfp zone flags that the callers pass. So even if a driver passes GFP_DMA, swiotlb_alloc_coherent doesn't get GFP_DMA. So I'm not sure how your patch fixes the parport problem. The current dma_alloc_coherent (asm-x86/dma-mapping.h) handles the gfp flags in the exact same way as the old dma_alloc_coherent (pci-dma.c). Neither sets GFP_DMA even if coherent_dma_mask is 24bits. The old code is fine because of the GFP_DMA retry mechanism. But if coherent_dma_mask is 24bits, there is no point to go into the GFP_DMA retry mechanism. We should use GFP_DMA in the first place. How about the following patch? diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h index 219c33d..05fcec5 100644 --- a/include/asm-x86/dma-mapping.h +++ b/include/asm-x86/dma-mapping.h @@ -255,9 +255,11 @@ static inline unsigned long dma_alloc_coherent_mask(struct device *dev, static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp) { -#ifdef CONFIG_X86_64 unsigned long dma_mask = dma_alloc_coherent_mask(dev, gfp); + if (dma_mask <= DMA_24BIT_MASK) + gfp |= GFP_DMA; +#ifdef CONFIG_X86_64 if (dma_mask <= DMA_32BIT_MASK && !(gfp & GFP_DMA)) gfp |= GFP_DMA32; #endif -- 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/