intel-iommu: fix return value of iommu_unmap() API

iommu_unmap() API expects IOMMU drivers to return the actual page order
of the address being unmapped.  Previous code was just returning page
order passed in from the caller.  This patch fixes this problem.
Signed-off-by: Allen Kay <allen.m.kay@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/iommu/intel-iommu.c

@@ -819,13 +819,14 @@ static struct dma_pte *dma_pfn_level_pte(struct dmar_domain *domain,
 }
 
 /* clear last level pte, a tlb flush should be followed */
-static void dma_pte_clear_range(struct dmar_domain *domain,
+static int dma_pte_clear_range(struct dmar_domain *domain,
 				unsigned long start_pfn,
 				unsigned long last_pfn)
 {
 	int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
 	unsigned int large_page = 1;
 	struct dma_pte *first_pte, *pte;
+	int order;
 
 	BUG_ON(addr_width < BITS_PER_LONG && start_pfn >> addr_width);
 	BUG_ON(addr_width < BITS_PER_LONG && last_pfn >> addr_width);
@@ -849,6 +850,9 @@ static void dma_pte_clear_range(struct dmar_domain *domain,
 				   (void *)pte - (void *)first_pte);
 
 	} while (start_pfn && start_pfn <= last_pfn);
+
+	order = (large_page - 1) * 9;
+	return order;
 }
 
 /* free page table pages. last level pte should already be cleared */
@@ -3869,14 +3873,15 @@ static int intel_iommu_unmap(struct iommu_domain *domain,
 {
 	struct dmar_domain *dmar_domain = domain->priv;
 	size_t size = PAGE_SIZE << gfp_order;
+	int order;
 
-	dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
+	order = dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
 			    (iova + size - 1) >> VTD_PAGE_SHIFT);
 
 	if (dmar_domain->max_addr == iova + size)
 		dmar_domain->max_addr = iova;
 
-	return gfp_order;
+	return order;
 }
 
 static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,