arm_iommu_alloc_attrs 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.
ref: ea2e7057c0234cfb8b09467d8f137760d371fc72:
ARM: 7172/1: dma: Drop GFP_COMP for DMA memory allocations
dma_alloc_coherent 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.
Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx>
---
arch/arm/mm/dma-mapping.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f5e1a84..955dd3e 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1321,6 +1321,13 @@ static void *arm_iommu_alloc_attrs(struct device *dev, size_t size,
struct page **pages;
void *addr = NULL;
+ /* 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_HUGETLB_PAGE. */
+ gfp &= ~(__GFP_COMP);
+
*handle = DMA_ERROR_CODE;
size = PAGE_ALIGN(size);
--
1.8.1.5
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