diff --git a/tools/testing/nvdimm/test/iomap.c b/tools/testing/nvdimm/test/iomap.c
index c62d372d426fb3f58f049d9ff94684790107570c..ed563bdd88f39a1f9d6b5bfc6aadf4d6f50788d1 100644
--- a/tools/testing/nvdimm/test/iomap.c
+++ b/tools/testing/nvdimm/test/iomap.c
@@ -62,7 +62,7 @@ struct nfit_test_resource *get_nfit_res(resource_size_t resource)
 }
 EXPORT_SYMBOL(get_nfit_res);
 
-void __iomem *__nfit_test_ioremap(resource_size_t offset, unsigned long size,
+static void __iomem *__nfit_test_ioremap(resource_size_t offset, unsigned long size,
 		void __iomem *(*fallback_fn)(resource_size_t, unsigned long))
 {
 	struct nfit_test_resource *nfit_res = get_nfit_res(offset);