IA64: fix VT-d dma_mapping_error

dma_mapping_error is used to see if dma_map_single and dma_map_page
succeed. IA64 VT-d dma_mapping_error always says that dma_map_single
is successful even though it could fail. Note that X86 VT-d works
properly in this regard.

This patch fixes IA64 VT-d dma_mapping_error by adding VT-d's own
dma_mapping_error() that works for both X86_64 and IA64. VT-d uses
zero as an error dma address so VT-d's dma_mapping_error returns 1 if
a passed dma address is zero (as x86's VT-d dma_mapping_error does
now).
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/ia64/kernel/pci-dma.c

@@ -99,11 +99,6 @@ int iommu_dma_supported(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(iommu_dma_supported);
 
-static int vtd_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
-{
-	return 0;
-}
-
 void __init pci_iommu_alloc(void)
 {
 	dma_ops = &intel_dma_ops;
@@ -113,7 +108,6 @@ void __init pci_iommu_alloc(void)
 	dma_ops->sync_single_for_device = machvec_dma_sync_single;
 	dma_ops->sync_sg_for_device = machvec_dma_sync_sg;
 	dma_ops->dma_supported = iommu_dma_supported;
-	dma_ops->mapping_error = vtd_dma_mapping_error;
 
 	/*
 	 * The order of these functions is important for

drivers/pci/intel-iommu.c

@@ -2581,6 +2581,11 @@ int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int nelems,
 	return nelems;
 }
 
+static int intel_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	return !dma_addr;
+}
+
 struct dma_map_ops intel_dma_ops = {
 	.alloc_coherent = intel_alloc_coherent,
 	.free_coherent = intel_free_coherent,
@@ -2588,6 +2593,7 @@ struct dma_map_ops intel_dma_ops = {
 	.unmap_sg = intel_unmap_sg,
 	.map_page = intel_map_page,
 	.unmap_page = intel_unmap_page,
+	.mapping_error = intel_mapping_error,
 };
 
 static inline int iommu_domain_cache_init(void)