[PATCH] arm64: Use and error-check DMA_ERROR_CODE

[Sean Paul]

This patch replaces the static assignment of ~0 to dma_handle with
DMA_ERROR_CODE to be consistent with other platforms.

In addition to that, it also adds a check for DMA_ERROR_CODE before
calling __dma_free_coherent with an invalid dma_handle.

Signed-off-by: Sean Paul <seanpaul at chromium.org>
---
 arch/arm64/mm/dma-mapping.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 4164c5a..69fd2c4 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -125,7 +125,7 @@ static void *__dma_alloc_noncoherent(struct device *dev, size_t size,
 no_map:
 	__dma_free_coherent(dev, size, ptr, *dma_handle, attrs);
 no_mem:
-	*dma_handle = ~0;
+	*dma_handle = DMA_ERROR_CODE;
 	return NULL;
 }
 
@@ -136,7 +136,9 @@ static void __dma_free_noncoherent(struct device *dev, size_t size,
 	void *swiotlb_addr = phys_to_virt(dma_to_phys(dev, dma_handle));
 
 	vunmap(vaddr);
-	__dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
+
+	if (dma_handle != DMA_ERROR_CODE)
+		__dma_free_coherent(dev, size, swiotlb_addr, dma_handle, attrs);
 }
 
 static dma_addr_t __swiotlb_map_page(struct device *dev, struct page *page,
-- 
2.1.1