[PATCH 3.14 68/79] arm64: Honor __GFP_ZERO in dma allocations

[Greg Kroah-Hartman]

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Suzuki K. Poulose" <suzuki.poulose@xxxxxxx>

commit 7132813c384515c9dede1ae20e56f3895feb7f1e upstream.

Current implementation doesn't zero out the pages allocated.
Honor the __GFP_ZERO flag and zero out if set.

Cc: <stable@xxxxxxxxxxxxxxx> # v3.14+
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/arm64/mm/dma-mapping.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -44,6 +44,7 @@ static void *arm64_swiotlb_alloc_coheren
 		flags |= GFP_DMA32;
 	if (IS_ENABLED(CONFIG_DMA_CMA)) {
 		struct page *page;
+		void *addr;
 
 		size = PAGE_ALIGN(size);
 		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
@@ -52,7 +53,10 @@ static void *arm64_swiotlb_alloc_coheren
 			return NULL;
 
 		*dma_handle = phys_to_dma(dev, page_to_phys(page));
-		return page_address(page);
+		addr = page_address(page);
+		if (flags & __GFP_ZERO)
+			memset(addr, 0, size);
+		return addr;
 	} else {
 		return swiotlb_alloc_coherent(dev, size, dma_handle, flags);
 	}


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