From: Suzuki K. Poulose <suzuki.poulose@arm.com>
Date: Thu, 19 Mar 2015 18:17:09 +0000 (+0000)
Subject: arm64: Honor __GFP_ZERO in dma allocations
X-Git-Tag: v3.16.35~2412
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0dc78f85211105a1bdde5dac45e83dd373b5a50b;p=thirdparty%2Fkernel%2Fstable.git

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 4164c5ace9f8f..de3abbe6c59f9 100644
--- 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);
 	}