On Tue, Oct 25, 2016 at 11:36:58AM -0400, Alexander Duyck wrote:
> The mapping function should always return DMA_ERROR_CODE when a mapping has
> failed as this is what the DMA API expects when a DMA error has occurred.
> The current function for mapping a page in Xen was returning either
> DMA_ERROR_CODE or 0 depending on where it failed.
>
> On x86 DMA_ERROR_CODE is 0, but on other architectures such as ARM it is
> ~0. We need to make sure we return the same error value if either the
> mapping failed or the device is not capable of accessing the mapping.
>
> If we are returning DMA_ERROR_CODE as our error value we can drop the
> function for checking the error code as the default is to compare the
> return value against DMA_ERROR_CODE if no function is defined.
>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
I am pretty sure I gave an Ack. Any particular reason from dropping it
(if so, please add a comment under the --- of the reason).
Thanks.
> Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
> ---
> arch/arm/xen/mm.c | 1 -
> arch/x86/xen/pci-swiotlb-xen.c | 1 -
> drivers/xen/swiotlb-xen.c | 18 ++++++------------
> include/xen/swiotlb-xen.h | 3 ---
> 4 files changed, 6 insertions(+), 17 deletions(-)
>
> diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
> index d062f08..bd62d94 100644
> --- a/arch/arm/xen/mm.c
> +++ b/arch/arm/xen/mm.c
> @@ -186,7 +186,6 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
> EXPORT_SYMBOL(xen_dma_ops);
>
> static struct dma_map_ops xen_swiotlb_dma_ops = {
> - .mapping_error = xen_swiotlb_dma_mapping_error,
> .alloc = xen_swiotlb_alloc_coherent,
> .free = xen_swiotlb_free_coherent,
> .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
> index 0e98e5d..a9fafb5 100644
> --- a/arch/x86/xen/pci-swiotlb-xen.c
> +++ b/arch/x86/xen/pci-swiotlb-xen.c
> @@ -19,7 +19,6 @@
> int xen_swiotlb __read_mostly;
>
> static struct dma_map_ops xen_swiotlb_dma_ops = {
> - .mapping_error = xen_swiotlb_dma_mapping_error,
> .alloc = xen_swiotlb_alloc_coherent,
> .free = xen_swiotlb_free_coherent,
> .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 87e6035..b8014bf 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -416,11 +416,12 @@ 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)) {
> - swiotlb_tbl_unmap_single(dev, map, size, dir);
> - dev_addr = 0;
> - }
> - return dev_addr;
> + if (dma_capable(dev, dev_addr, size))
> + return dev_addr;
> +
> + swiotlb_tbl_unmap_single(dev, map, size, dir);
> +
> + return DMA_ERROR_CODE;
> }
> EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
>
> @@ -648,13 +649,6 @@ void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
> }
> EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
>
> -int
> -xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
> -{
> - return !dma_addr;
> -}
> -EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
> -
> /*
> * Return whether the given device DMA address mask can be supported
> * properly. For example, if your device can only drive the low 24-bits
> diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
> index 7c35e27..a0083be 100644
> --- a/include/xen/swiotlb-xen.h
> +++ b/include/xen/swiotlb-xen.h
> @@ -51,9 +51,6 @@ extern void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
> int nelems, enum dma_data_direction dir);
>
> extern int
> -xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr);
> -
> -extern int
> xen_swiotlb_dma_supported(struct device *hwdev, u64 mask);
>
> extern int
>
--
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