arm64: Honor __GFP_ZERO in dma allocations

commit 7132813c384515c9dede1ae20e56f3895feb7f1e upstream.

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

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
[ luis: backported to 3.16: based on Suzuki's 3.14 backport ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 4164c5ace9f8f515c6e9ea16402b1cc18e16a432..de3abbe6c59f98e0e0229981bbf464872f2c9b0d 100644 (file)
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -55,6 +55,7 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
                flags |= GFP_DMA;
        if (IS_ENABLED(CONFIG_DMA_CMA)) {
                struct page *page;
+               void *addr;
 
                size = PAGE_ALIGN(size);
                page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
@@ -63,7 +64,10 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
                        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);
        }