arm64: add missing PAGE_ALIGN() to __dma_free()

__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.

Cc: stable@vger.kernel.org
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NDean Nelson <dnelson@redhat.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/mm/dma-mapping.c

@@ -104,7 +104,6 @@ static void *__dma_alloc_coherent(struct device *dev, size_t size,
 		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 *dev, size_t size,
 {
 	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;