Re: [net-next PATCH 04/27] arch/arc: Add option to skip sync on DMA mapping

[Vineet Gupta]

On 10/25/2016 02:38 PM, Alexander Duyck wrote:
> This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
> avoid invoking cache line invalidation if the driver will just handle it
> later via a sync_for_cpu or sync_for_device call.
>
> Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
> Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
> Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> ---
>  arch/arc/mm/dma.c |    5 ++++-

Acked-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>

>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
> index 20afc65..6303c34 100644
> --- a/arch/arc/mm/dma.c
> +++ b/arch/arc/mm/dma.c
> @@ -133,7 +133,10 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
>  		unsigned long attrs)
>  {
>  	phys_addr_t paddr = page_to_phys(page) + offset;
> -	_dma_cache_sync(paddr, size, dir);
> +
> +	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
> +		_dma_cache_sync(paddr, size, dir);
> +
>  	return plat_phys_to_dma(dev, paddr);
>  }
>  
>
>