[3.16.y-ckt stable] Patch "arm64: add missing PAGE_ALIGN() to __dma_free()" 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: add missing PAGE_ALIGN() to __dma_free()

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/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt13.

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 0df938e72051812f16e0f8aa421568317c379e98 Mon Sep 17 00:00:00 2001
From: Dean Nelson <dnelson at redhat.com>
Date: Wed, 29 Apr 2015 16:09:18 +0100
Subject: arm64: add missing PAGE_ALIGN() to __dma_free()

commit 2cff98b99c469880ce830cbcde015b53b67e0a7b upstream.

__dma_alloc() does a PAGE_ALIGN() on the passed in size argument before
doing anything else. __dma_free() does not. And because it doesn't, it is
possible to leak memory should size not be an integer multiple of PAGE_SIZE.

The solution is to add a PAGE_ALIGN() to __dma_free() like is done in
__dma_alloc().

Additionally, this patch removes a redundant PAGE_ALIGN() from
__dma_alloc_coherent(), since __dma_alloc_coherent() can only be called
from __dma_alloc(), which already does a PAGE_ALIGN() before the call.

Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Signed-off-by: Dean Nelson <dnelson at redhat.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
[ luis: backported to 3.16: based on Dean's 3.19 backport ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/arm64/mm/dma-mapping.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 893802645efe..0ada77e5d9e7 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -86,7 +86,7 @@ static void __dma_free_coherent(struct device *dev, size_t size,

 		dma_release_from_contiguous(dev,
 					phys_to_page(paddr),
-					size >> PAGE_SHIFT);
+					PAGE_ALIGN(size) >> PAGE_SHIFT);
 	} else {
 		swiotlb_free_coherent(dev, size, vaddr, dma_handle);
 	}
@@ -138,6 +138,8 @@ static void __dma_free_noncoherent(struct device *dev, size_t size,
 {
 	void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));

+	size = PAGE_ALIGN(size);
+
 	vunmap(vaddr);
 	__dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
 }