x86: move dma_unmap_single to common header

i386 base does not need it, so it gets an empty function.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/pci-base_32.c

@@ -14,6 +14,7 @@ static dma_addr_t pci32_map_single(struct device *dev, void *ptr,
 
 static const struct dma_mapping_ops pci32_dma_ops = {
 	.map_single = pci32_map_single,
+	.unmap_single = NULL,
 };
 
 const struct dma_mapping_ops *dma_ops = &pci32_dma_ops;

include/asm-x86/dma-mapping.h

@@ -66,4 +66,14 @@ dma_map_single(struct device *hwdev, void *ptr, size_t size,
 	return dma_ops->map_single(hwdev, ptr, size, direction);
 }
 
+static inline void
+dma_unmap_single(struct device *dev, dma_addr_t addr, size_t size,
+		 int direction)
+{
+	BUG_ON(!valid_dma_direction(direction));
+	if (dma_ops->unmap_single)
+		dma_ops->unmap_single(dev, addr, size, direction);
+}
+
+
 #endif

include/asm-x86/dma-mapping_32.h

@@ -17,13 +17,6 @@ void *dma_alloc_coherent(struct device *dev, size_t size,
 void dma_free_coherent(struct device *dev, size_t size,
 			 void *vaddr, dma_addr_t dma_handle);
 
-static inline void
-dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
-		 enum dma_data_direction direction)
-{
-	BUG_ON(!valid_dma_direction(direction));
-}
-
 static inline int
 dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
 	   enum dma_data_direction direction)

include/asm-x86/dma-mapping_64.h

@@ -23,14 +23,6 @@ extern void *dma_alloc_coherent(struct device *dev, size_t size,
 extern void dma_free_coherent(struct device *dev, size_t size, void *vaddr,
 			      dma_addr_t dma_handle);
 
-static inline void
-dma_unmap_single(struct device *dev, dma_addr_t addr,size_t size,
-		 int direction)
-{
-	BUG_ON(!valid_dma_direction(direction));
-	dma_ops->unmap_single(dev, addr, size, direction);
-}
-
 #define dma_map_page(dev,page,offset,size,dir) \
 	dma_map_single((dev), page_address(page)+(offset), (size), (dir))