diff --git a/include/linux/pci.h b/include/linux/pci.h
index f26fda7..b6cb5f6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1212,6 +1212,9 @@ static inline struct pci_dev *pci_get_bus_and_slot(unsigned int bus,
 						unsigned int devfn)
 { return NULL; }
 
+static inline int pci_domain_nr(struct pci_bus *bus)
+{ return 0; }
+
 #define dev_is_pci(d) (false)
 #define dev_is_pf(d) (false)
 #define dev_num_vf(d) (0)