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Commit 5b91a98c authored by Richard Zhao's avatar Richard Zhao Committed by Marek Szyprowski
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ARM: dma: Drop __GFP_COMP for iommu dma memory allocations 



__iommu_alloc_buffer wants to split pages after allocation in order to
reduce the memory footprint. This does not work well with __GFP_COMP
pages, so drop this flag before allocation

One failure example is snd_malloc_dev_pages call dma_alloc_coherent with
__GFP_COMP.

Signed-off-by: default avatarRichard Zhao <rizhao@nvidia.com>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
parent 63c18192

arch/arm/mm/dma-mapping.c

+9 −0
Original line number Original line Diff line number Diff line
@@ -1328,6 +1328,15 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size, 
	if (gfp & GFP_ATOMIC)

	if (gfp & GFP_ATOMIC)

		return __iommu_alloc_atomic(dev, size, handle);

		return __iommu_alloc_atomic(dev, size, handle);





	/*

	 * Following is a work-around (a.k.a. hack) to prevent pages

	 * with __GFP_COMP being passed to split_page() which cannot

	 * handle them.  The real problem is that this flag probably

	 * should be 0 on ARM as it is not supported on this

	 * platform; see CONFIG_HUGETLBFS.

	 */

	gfp &= ~(__GFP_COMP);



	pages = __iommu_alloc_buffer(dev, size, gfp, attrs);

	pages = __iommu_alloc_buffer(dev, size, gfp, attrs);

	if (!pages)

	if (!pages)

		return NULL;

		return NULL;