diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 9a7ffd13c7f07d037814b3eb7f1bba75a13641f2..accf58388bdb4892369f0bac43f928667e937035 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -806,7 +806,7 @@ int __init dmar_dev_scope_init(void)
 	return dmar_dev_scope_status;
 }
 
-void dmar_register_bus_notifier(void)
+void __init dmar_register_bus_notifier(void)
 {
 	bus_register_notifier(&pci_bus_type, &dmar_pci_bus_nb);
 }