diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index ded13a6afa66..0c0acf6fda87 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2560,7 +2560,7 @@ out_unmap:
 			bus_addr  = address + s->dma_address + (j << PAGE_SHIFT);
 			iommu_unmap_page(domain, bus_addr, PAGE_SIZE);
 
-			if (--mapped_pages)
+			if (--mapped_pages == 0)
 				goto out_free_iova;
 		}
 	}