[3.16.y-ckt stable] Patch "arm64: Honor __GFP_ZERO in dma allocations" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    arm64: Honor __GFP_ZERO in dma allocations

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 0dc78f85211105a1bdde5dac45e83dd373b5a50b Mon Sep 17 00:00:00 2001
From: "Suzuki K. Poulose" <suzuki.poulose at arm.com>
Date: Thu, 19 Mar 2015 18:17:09 +0000
Subject: 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 at arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose at arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
[ luis: backported to 3.16: based on Suzuki's 3.14 backport ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm64/mm/dma-mapping.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 4164c5ace9f8..de3abbe6c59f 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);
 	}