[PATCH 4.0 40/72] arm64: add missing PAGE_ALIGN() to __dma_free()

Greg Kroah-Hartman
2015-05-11T18:57:07Z

From: Dean Nelson <dnelson@redhat.com>

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@arm.com>
Signed-off-by: Dean Nelson <dnelson@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm64/mm/dma-mapping.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -104,7 +104,6 @@ static void *__dma_alloc_coherent(struct
struct page *page;
void *addr;

- size = PAGE_ALIGN(size);
page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
get_order(size));
if (!page)
@@ -193,6 +192,8 @@ static void __dma_free(struct device *de
{
void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));

+ size = PAGE_ALIGN(size);
+
if (!is_device_dma_coherent(dev)) {
if (__free_from_pool(vaddr, size))
return;