Re: [PATCH] iommu/amd: Propagate IOVA allocation failure

[Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>]

On Fri, May 26, 2017 at 07:31:26PM +0100, Robin Murphy wrote:
> Unlike the old allocator, alloc_iova_fast() will return 0 if it failed
> to allocate a PFN. Since the callers of dma_ops_alloc_iova() would end
> up treating that as a valid address, translate it to the DMA_ERROR_CODE
> that they would expect.
> 
> Fixes: 256e4621c21a ("iommu/amd: Make use of the generic IOVA allocator")
> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> ---
> 
> Just something I spotted whilst comparing dma_map_page() callchains...
> 
>  drivers/iommu/amd_iommu.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 63cacf5d6cf2..489dc302899e 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -1555,6 +1555,9 @@ static unsigned long dma_ops_alloc_iova(struct device *dev,
>  	if (!pfn)
>  		pfn = alloc_iova_fast(&dma_dom->iovad, pages, IOVA_PFN(dma_mask));
>  
> +	if (!pfn)
> +		return DMA_ERROR_CODE;
> +

That shouldn't make a difference on x86 because the DMA_ERROR_CODE is 0
as well.


	Joerg