Just as a sidenote: >From [PATCH v2] kbuild: enable unused-function warnings for W= build with Clang: "Per the documentation [1], -Wno-unused-function will also disable -Wunneeded-internal-declaration, which can help find bugs like commit 8289c4b6f2e5 ("platform/x86: mlx-platform: Properly use mlxplat_mlxcpld_msn201x_items"). (pointed out by Nathan Chancellor) I added -Wunneeded-internal-declaration to address it. If you contribute to code clean-up, please run "make CC=clang W=1" and check -Wunused-function warnings. You will find lots of unused functions." Isn't that missing in your double? - Sedat - [1] https://lkml.org/lkml/2019/8/27/729