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Commit 1a9777a8 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: reject too small dma masks 



Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
parent 19dca8c0

include/linux/dma-direct.h

+1 −0
Original line number Diff line number Diff line
@@ -42,5 +42,6 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, 
		gfp_t gfp, unsigned long attrs);

void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,

		dma_addr_t dma_addr, unsigned long attrs);

int dma_direct_supported(struct device *dev, u64 mask);



#endif /* _LINUX_DMA_DIRECT_H */

lib/dma-direct.c

+19 −0
Original line number Diff line number Diff line
@@ -122,6 +122,24 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, 
	return nents;

}



int dma_direct_supported(struct device *dev, u64 mask)

{

#ifdef CONFIG_ZONE_DMA

	if (mask < DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))

		return 0;

#else

	/*

	 * Because 32-bit DMA masks are so common we expect every architecture

	 * to be able to satisfy them - either by not supporting more physical

	 * memory, or by providing a ZONE_DMA32.  If neither is the case, the

	 * architecture needs to use an IOMMU instead of the direct mapping.

	 */

	if (mask < DMA_BIT_MASK(32))

		return 0;

#endif

	return 1;

}



static int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr)

{

	return dma_addr == DIRECT_MAPPING_ERROR;
@@ -132,6 +150,7 @@ const struct dma_map_ops dma_direct_ops = { 
	.free			= dma_direct_free,

	.map_page		= dma_direct_map_page,

	.map_sg			= dma_direct_map_sg,

	.dma_supported		= dma_direct_supported,

	.mapping_error		= dma_direct_mapping_error,

};

EXPORT_SYMBOL(dma_direct_ops);