Commit 76418421 authored by Alexander Duyck's avatar Alexander Duyck Committed by Konrad Rzeszutek Wilk
Browse files

swiotlb-xen: Enforce return of DMA_ERROR_CODE in mapping function 



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@oracle.com>
Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad@kernel.org>
parent ebcf6f97

arch/arm/xen/mm.c

+0 −1
Original line number Diff line number Diff line
@@ -186,7 +186,6 @@ struct dma_map_ops *xen_dma_ops; 
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,

arch/x86/xen/pci-swiotlb-xen.c

+0 −1
Original line number Diff line number Diff line
@@ -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,

drivers/xen/swiotlb-xen.c

+6 −12
Original line number Diff line number Diff line
@@ -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;

	}

	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 @@ xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, 
}

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

include/xen/swiotlb-xen.h

+0 −3
Original line number Diff line number Diff line
@@ -50,9 +50,6 @@ extern void 
xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,

			       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);

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