Re: [PATCH 19/33] dma-mapping: warn when there is no coherent_dma_mask

[Konrad Rzeszutek Wilk]

On Wed, Jan 10, 2018 at 09:00:13AM +0100, Christoph Hellwig wrote:
> These days all devices should have a DMA coherent mask, and most dma_ops
> implementations rely on that fact.  But just to be sure add an assert to
> ring the warning bell if that is not the case.
> 
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
>  include/linux/dma-mapping.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index d84951865be7..9f28b2fa329e 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -513,6 +513,7 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size,
>  	void *cpu_addr;
>  
>  	BUG_ON(!ops);
> +	WARN_ON_ONCE(!dev->coherent_dma_mask);
>  
>  	if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
>  		return cpu_addr;
> -- 
> 2.14.2
>