Re: [PATCH v2 07/10] avr32: use for_each_sg()

[Hans-Christian Egtvedt <egtvedt@samfundet.no>]

Around Fri 01 May 2015 22:56:40 +0900 or thereabout, Akinobu Mita wrote:
> This replaces the plain loop over the sglist array with for_each_sg()
> macro which consists of sg_next() function calls.  Since avr32 doesn't
> select ARCH_HAS_SG_CHAIN, it is not necessary to use for_each_sg() in
> order to loop over each sg element.  But this can help find problems
> with drivers that do not properly initialize their sg tables when
> CONFIG_DEBUG_SG is enabled.

Nice

> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
> Cc: linux-arch@vger.kernel.org

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>

> ---
> * New patch from v2
> 
>  arch/avr32/include/asm/dma-mapping.h | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/avr32/include/asm/dma-mapping.h b/arch/avr32/include/asm/dma-mapping.h
> index b3d18f9..ae7ac92 100644
> --- a/arch/avr32/include/asm/dma-mapping.h
> +++ b/arch/avr32/include/asm/dma-mapping.h
> @@ -209,17 +209,18 @@ dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size,
>   * the same here.
>   */
>  static inline int
> -dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
> +dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
>  	   enum dma_data_direction direction)
>  {
>  	int i;
> +	struct scatterlist *sg;
>  
> -	for (i = 0; i < nents; i++) {
> +	for_each_sg(sglist, sg, nents, i) {
>  		char *virt;
>  
> -		sg[i].dma_address = page_to_bus(sg_page(&sg[i])) + sg[i].offset;
> -		virt = sg_virt(&sg[i]);
> -		dma_cache_sync(dev, virt, sg[i].length, direction);
> +		sg->dma_address = page_to_bus(sg_page(sg)) + sg->offset;
> +		virt = sg_virt(sg);
> +		dma_cache_sync(dev, virt, sg->length, direction);
>  	}
>  
>  	return nents;
> @@ -321,14 +322,14 @@ dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
>  }
>  
>  static inline void
> -dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
> +dma_sync_sg_for_device(struct device *dev, struct scatterlist *sglist,
>  		       int nents, enum dma_data_direction direction)
>  {
>  	int i;
> +	struct scatterlist *sg;
>  
> -	for (i = 0; i < nents; i++) {
> -		dma_cache_sync(dev, sg_virt(&sg[i]), sg[i].length, direction);
> -	}
> +	for_each_sg(sglist, sg, nents, i)
> +		dma_cache_sync(dev, sg_virt(sg), sg->length, direction);
>  }
>  
>  /* Now for the API extensions over the pci_ one */
-- 
mvh
Hans-Christian Egtvedt