Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751896AbaAOUN0 (ORCPT ); Wed, 15 Jan 2014 15:13:26 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:40513 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973AbaAOUNX (ORCPT ); Wed, 15 Jan 2014 15:13:23 -0500 Date: Wed, 15 Jan 2014 15:12:24 -0500 From: Konrad Rzeszutek Wilk To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Marek Szyprowski , David Woodhouse , Don Dutile , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andi Kleen , x86@kernel.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH v2 2/5] x86: enable DMA CMA with swiotlb Message-ID: <20140115201224.GD5201@phenom.dumpdata.com> References: <1389708830-5841-1-git-send-email-akinobu.mita@gmail.com> <1389708830-5841-3-git-send-email-akinobu.mita@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389708830-5841-3-git-send-email-akinobu.mita@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 14, 2014 at 11:13:47PM +0900, Akinobu Mita wrote: > The DMA Contiguous Memory Allocator support on x86 is disabled when > swiotlb config option is enabled. So DMA CMA is always disabled on > x86_64 because swiotlb is always enabled. This attempts to support > for DMA CMA with enabling swiotlb config option. > > The contiguous memory allocator on x86 is integrated in the function > dma_generic_alloc_coherent() which is .alloc callback in nommu_dma_ops > for dma_alloc_coherent(). > > x86_swiotlb_alloc_coherent() which is .alloc callback in swiotlb_dma_ops > tries to allocate with dma_generic_alloc_coherent() firstly and then > swiotlb_alloc_coherent() is called as a fallback. > > The main part of supporting DMA CMA with swiotlb is that changing > x86_swiotlb_free_coherent() which is .free callback in swiotlb_dma_ops > for dma_free_coherent() so that it can distinguish memory allocated by > dma_generic_alloc_coherent() from one allocated by swiotlb_alloc_coherent() > and release it with dma_generic_free_coherent() which can handle contiguous > memory. This change requires making is_swiotlb_buffer() global function. > > This also needs to change .free callback in the dma_map_ops for amd_gart > and sta2x11, because these dma_ops are also using > dma_generic_alloc_coherent(). > > Cc: Marek Szyprowski > Cc: Konrad Rzeszutek Wilk > Cc: David Woodhouse > Cc: Don Dutile > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: "H. Peter Anvin" > Cc: Andi Kleen > Cc: x86@kernel.org > Cc: iommu@lists.linux-foundation.org > Signed-off-by: Akinobu Mita > Acked-by: Marek Szyprowski > --- > No change from the previous version > > arch/x86/Kconfig | 2 +- > arch/x86/include/asm/swiotlb.h | 7 +++++++ > arch/x86/kernel/amd_gart_64.c | 2 +- > arch/x86/kernel/pci-swiotlb.c | 9 ++++++--- > arch/x86/pci/sta2x11-fixup.c | 6 ++---- > include/linux/swiotlb.h | 2 ++ > lib/swiotlb.c | 2 +- It looks reasonable from my perspective (as swiotlb maintainer). Not too thrilled about the 'is_swiotlb_buffer' but that code is quite small so it should be fast enough. > 7 files changed, 20 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 0952ecd..1b6275d 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -40,7 +40,7 @@ config X86 > select ARCH_WANT_OPTIONAL_GPIOLIB > select ARCH_WANT_FRAME_POINTERS > select HAVE_DMA_ATTRS > - select HAVE_DMA_CONTIGUOUS if !SWIOTLB > + select HAVE_DMA_CONTIGUOUS > select HAVE_KRETPROBES > select HAVE_OPTPROBES > select HAVE_KPROBES_ON_FTRACE > diff --git a/arch/x86/include/asm/swiotlb.h b/arch/x86/include/asm/swiotlb.h > index 977f176..ab05d73 100644 > --- a/arch/x86/include/asm/swiotlb.h > +++ b/arch/x86/include/asm/swiotlb.h > @@ -29,4 +29,11 @@ static inline void pci_swiotlb_late_init(void) > > static inline void dma_mark_clean(void *addr, size_t size) {} > > +extern void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, > + dma_addr_t *dma_handle, gfp_t flags, > + struct dma_attrs *attrs); > +extern void x86_swiotlb_free_coherent(struct device *dev, size_t size, > + void *vaddr, dma_addr_t dma_addr, > + struct dma_attrs *attrs); > + > #endif /* _ASM_X86_SWIOTLB_H */ > diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c > index b574b29..8e3842f 100644 > --- a/arch/x86/kernel/amd_gart_64.c > +++ b/arch/x86/kernel/amd_gart_64.c > @@ -512,7 +512,7 @@ gart_free_coherent(struct device *dev, size_t size, void *vaddr, > dma_addr_t dma_addr, struct dma_attrs *attrs) > { > gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, NULL); > - free_pages((unsigned long)vaddr, get_order(size)); > + dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs); > } > > static int gart_mapping_error(struct device *dev, dma_addr_t dma_addr) > diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c > index 6c483ba..77dd0ad 100644 > --- a/arch/x86/kernel/pci-swiotlb.c > +++ b/arch/x86/kernel/pci-swiotlb.c > @@ -14,7 +14,7 @@ > #include > int swiotlb __read_mostly; > > -static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, > +void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, > dma_addr_t *dma_handle, gfp_t flags, > struct dma_attrs *attrs) > { > @@ -28,11 +28,14 @@ static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, > return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags); > } > > -static void x86_swiotlb_free_coherent(struct device *dev, size_t size, > +void x86_swiotlb_free_coherent(struct device *dev, size_t size, > void *vaddr, dma_addr_t dma_addr, > struct dma_attrs *attrs) > { > - swiotlb_free_coherent(dev, size, vaddr, dma_addr); > + if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr))) > + swiotlb_free_coherent(dev, size, vaddr, dma_addr); > + else > + dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs); > } > > static struct dma_map_ops swiotlb_dma_ops = { > diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c > index 9d8a509..5ceda85 100644 > --- a/arch/x86/pci/sta2x11-fixup.c > +++ b/arch/x86/pci/sta2x11-fixup.c > @@ -173,9 +173,7 @@ static void *sta2x11_swiotlb_alloc_coherent(struct device *dev, > { > void *vaddr; > > - vaddr = dma_generic_alloc_coherent(dev, size, dma_handle, flags, attrs); > - if (!vaddr) > - vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, flags); > + vaddr = x86_swiotlb_alloc_coherent(dev, size, dma_handle, flags, attrs); > *dma_handle = p2a(*dma_handle, to_pci_dev(dev)); > return vaddr; > } > @@ -183,7 +181,7 @@ static void *sta2x11_swiotlb_alloc_coherent(struct device *dev, > /* We have our own dma_ops: the same as swiotlb but from alloc (above) */ > static struct dma_map_ops sta2x11_dma_ops = { > .alloc = sta2x11_swiotlb_alloc_coherent, > - .free = swiotlb_free_coherent, > + .free = x86_swiotlb_free_coherent, > .map_page = swiotlb_map_page, > .unmap_page = swiotlb_unmap_page, > .map_sg = swiotlb_map_sg_attrs, > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index a5ffd32..e7a018e 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -116,4 +116,6 @@ static inline void swiotlb_free(void) { } > #endif > > extern void swiotlb_print_info(void); > +extern int is_swiotlb_buffer(phys_addr_t paddr); > + > #endif /* __LINUX_SWIOTLB_H */ > diff --git a/lib/swiotlb.c b/lib/swiotlb.c > index fe978e0..6e4a798 100644 > --- a/lib/swiotlb.c > +++ b/lib/swiotlb.c > @@ -369,7 +369,7 @@ void __init swiotlb_free(void) > io_tlb_nslabs = 0; > } > > -static int is_swiotlb_buffer(phys_addr_t paddr) > +int is_swiotlb_buffer(phys_addr_t paddr) > { > return paddr >= io_tlb_start && paddr < io_tlb_end; > } > -- > 1.8.3.2 > -- 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/