diff --git a/sys/compat/linuxkpi/common/include/linux/mm.h b/sys/compat/linuxkpi/common/include/linux/mm.h
--- a/sys/compat/linuxkpi/common/include/linux/mm.h
+++ b/sys/compat/linuxkpi/common/include/linux/mm.h
@@ -317,4 +317,6 @@
 
 void vma_set_file(struct vm_area_struct *vma, struct linux_file *file);
 
+#define	is_cow_mapping(flags)	(false)
+
 #endif					/* _LINUXKPI_LINUX_MM_H_ */