diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 0ba8d69dd6c9..d5106c0f46cb 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -150,7 +150,7 @@ utf16_strnlen(efi_char16_t *s, size_t maxlength)
 	return length;
 }
 
-static unsigned long
+static inline unsigned long
 utf16_strlen(efi_char16_t *s)
 {
 	return utf16_strnlen(s, ~0UL);