[PATCH 04/12] x86: make dma_cache_sync a no-op

[Thomas Gleixner]

On Sun, 27 Aug 2017, Christoph Hellwig wrote:

> x86 does not implement DMA_ATTR_NON_CONSISTENT allocations, so it doesn't
> make any sense to do any work in dma_cache_sync given that it must be a
> no-op when dma_alloc_attrs returns coherent memory.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de

Reviewed-by: Thomas Gleixner <tglx at linutronix.de>

> ---
>  arch/x86/include/asm/dma-mapping.h | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
> index 398c79889f5c..04877267ad18 100644
> --- a/arch/x86/include/asm/dma-mapping.h
> +++ b/arch/x86/include/asm/dma-mapping.h
> @@ -70,7 +70,6 @@ static inline void
>  dma_cache_sync(struct device *dev, void *vaddr, size_t size,
>  	enum dma_data_direction dir)
>  {
> -	flush_write_buffers();
>  }
>  
>  static inline unsigned long dma_alloc_coherent_mask(struct device *dev,
> -- 
> 2.11.0
> 
>