Re: [PATCH 2/3] dma: Introduce dma_max_mapping_size()

[Christoph Hellwig]

> +size_t dma_direct_max_mapping_size(struct device *dev)
> +{
> +	/*
> +	 * Return the minimum of the direct DMA limit and the SWIOTLB limit.
> +	 * Since direct DMA has no limit, it is fine to just return the SWIOTLB
> +	 * limit.
> +	 */
> +	return swiotlb_max_mapping_size(dev);

Well, if we don't actually use the swiotlb buffers despite it being
compiled in or even allocated we don't need the limit.