linux-kernel - Re: [PATCH 1/8] remove flush_write_buffers() in dma-mapping-common.h

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Message-Id: <20090805104735P.fujita.tomonori@lab.ntt.co.jp>
Date:	Wed, 5 Aug 2009 10:48:14 +0900
From:	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
To:	mingo@...e.hu
Cc:	davem@...emloft.net, sparclinux@...r.kernel.org,
	linux-kernel@...r.kernel.org, reif@...thlink.net, x86@...nel.org,
	tony.luck@...el.com, akpm@...ux-foundation.org, arnd@...db.de
Subject: Re: [PATCH 1/8] remove flush_write_buffers() in
 dma-mapping-common.h

On Mon, 13 Jul 2009 15:25:53 +0900
FUJITA Tomonori <fujita.tomonori@....ntt.co.jp> wrote:

> From: Arnd Bergmann <arnd@...db.de>
> 
> This moves flush_write_buffers() in asm-generic/dma-mapping-common.h to
> arch/x86/kernel/pci-nommu.c.
> 
> The purpose of this patch is that, we can avoid defining NULL
> flush_write_buffers() on IA64 and SPARC.
> 
> dma-mapping-common.h is used by X86 and IA64 (and SPARC soon) but only
> X86 with CONFIG_X86_OOSTORE or CONFIG_X86_PPRO_FENCE actually uses
> flush_write_buffers(). CONFIG_X86_OOSTORE or CONFIG_X86_PPRO_FENCE is
> usable with only kernel/pci-nommu.c (that is, not usable with other
> X86 IOMMU implementations such as SWIOTLB, VT-d, etc) so we can safely
> move flush_write_buffers() in asm-generic/dma-mapping-common.h to
> arch/x86/kernel/pci-nommu.c.
> 
> The further discussion is:
> 
> http://lkml.org/lkml/2009/6/28/104
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> Acked-by: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>

Ping?

> ---
>  arch/x86/kernel/pci-nommu.c              |   27 ++++++++++++++++++++++-----
>  include/asm-generic/dma-mapping-common.h |    6 ------
>  2 files changed, 22 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
> index 71d412a..f7eb967 100644
> --- a/arch/x86/kernel/pci-nommu.c
> +++ b/arch/x86/kernel/pci-nommu.c
> @@ -79,12 +79,29 @@ static void nommu_free_coherent(struct device *dev, size_t size, void *vaddr,
>  	free_pages((unsigned long)vaddr, get_order(size));
>  }
>  
> +static void nommu_sync_single_for_device(struct device *dev,
> +			dma_addr_t addr, size_t size,
> +			enum dma_data_direction dir)
> +{
> +	flush_write_buffers();
> +}
> +
> +
> +static void nommu_sync_sg_for_device(struct device *dev,
> +			struct scatterlist *sg, int nelems,
> +			enum dma_data_direction dir)
> +{
> +	flush_write_buffers();
> +}
> +
>  struct dma_map_ops nommu_dma_ops = {
> -	.alloc_coherent	= dma_generic_alloc_coherent,
> -	.free_coherent	= nommu_free_coherent,
> -	.map_sg		= nommu_map_sg,
> -	.map_page	= nommu_map_page,
> -	.is_phys	= 1,
> +	.alloc_coherent		= dma_generic_alloc_coherent,
> +	.free_coherent		= nommu_free_coherent,
> +	.map_sg			= nommu_map_sg,
> +	.map_page		= nommu_map_page,
> +	.sync_single_for_device = nommu_sync_single_for_device,
> +	.sync_sg_for_device	= nommu_sync_sg_for_device,
> +	.is_phys		= 1,
>  };
>  
>  void __init no_iommu_init(void)
> diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h
> index 5406a60..e694263 100644
> --- a/include/asm-generic/dma-mapping-common.h
> +++ b/include/asm-generic/dma-mapping-common.h
> @@ -103,7 +103,6 @@ static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
>  	if (ops->sync_single_for_cpu)
>  		ops->sync_single_for_cpu(dev, addr, size, dir);
>  	debug_dma_sync_single_for_cpu(dev, addr, size, dir);
> -	flush_write_buffers();
>  }
>  
>  static inline void dma_sync_single_for_device(struct device *dev,
> @@ -116,7 +115,6 @@ static inline void dma_sync_single_for_device(struct device *dev,
>  	if (ops->sync_single_for_device)
>  		ops->sync_single_for_device(dev, addr, size, dir);
>  	debug_dma_sync_single_for_device(dev, addr, size, dir);
> -	flush_write_buffers();
>  }
>  
>  static inline void dma_sync_single_range_for_cpu(struct device *dev,
> @@ -132,7 +130,6 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev,
>  		ops->sync_single_range_for_cpu(dev, addr, offset, size, dir);
>  		debug_dma_sync_single_range_for_cpu(dev, addr, offset, size, dir);
>  
> -		flush_write_buffers();
>  	} else
>  		dma_sync_single_for_cpu(dev, addr, size, dir);
>  }
> @@ -150,7 +147,6 @@ static inline void dma_sync_single_range_for_device(struct device *dev,
>  		ops->sync_single_range_for_device(dev, addr, offset, size, dir);
>  		debug_dma_sync_single_range_for_device(dev, addr, offset, size, dir);
>  
> -		flush_write_buffers();
>  	} else
>  		dma_sync_single_for_device(dev, addr, size, dir);
>  }
> @@ -165,7 +161,6 @@ dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
>  	if (ops->sync_sg_for_cpu)
>  		ops->sync_sg_for_cpu(dev, sg, nelems, dir);
>  	debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
> -	flush_write_buffers();
>  }
>  
>  static inline void
> @@ -179,7 +174,6 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
>  		ops->sync_sg_for_device(dev, sg, nelems, dir);
>  	debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
>  
> -	flush_write_buffers();
>  }
>  
>  #define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, NULL)
> -- 
> 1.6.0.6
> 
> --
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