Subject: [PATCH v6 15/19] swiotlb-xen: call dma_capable only if dev->dma_mask is allocated

From: [email-masked] (Konrad Rzeszutek Wilk)
Date: Mon, 30 Sep 2013 12:02:23 -0400

On Fri, Sep 27, 2013 at 05:10:03PM +0100, Stefano Stabellini wrote:

Why? I am looking at X86 and IA64 and I see:

 79         if (!dev->dma_mask)                                                     
 80                 return 0;           

Why not port dma_capable over to ARM?

> Signed-off-by: Stefano Stabellini <[email-masked]>
> ---
>  drivers/xen/swiotlb-xen.c |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 790c2eb..3011736 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -512,7 +512,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
>  	 * buffering it.
>  	 */
>  	if (!xen_feature(XENFEAT_auto_translated_physmap) &&
> -	    dma_capable(dev, dev_addr, size) &&
> +	    dev->dma_mask && dma_capable(dev, dev_addr, size) &&
>  	    !range_straddles_page_boundary(phys, size) && !swiotlb_force)
>  		return dev_addr;
>  
> @@ -532,7 +532,7 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
>  	/*
>  	 * Ensure that the address returned is DMA'ble
>  	 */
> -	if (!dma_capable(dev, dev_addr, size)) {
> +	if (dev->dma_mask && !dma_capable(dev, dev_addr, size)) {
>  		swiotlb_tbl_unmap_single(dev, map, size, dir);
>  		dev_addr = 0;
>  	}
> @@ -660,7 +660,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
>  
>  		if (swiotlb_force ||
>  		    xen_feature(XENFEAT_auto_translated_physmap) ||
> -		    !dma_capable(hwdev, dev_addr, sg->length) ||
> +		    (hwdev->dma_mask && !dma_capable(hwdev, dev_addr, sg->length)) ||
>  		    range_straddles_page_boundary(paddr, sg->length)) {
>  			/*
>  			 * Pass the dma_addr of the first slab in the iotlb buffer as
> -- 
> 1.7.2.5
>