Functions are declared 'extern' implicitly by the compiler. There's no reason to prepend every prototype with it. Remove the 'extern' keyword from all function declarations in linux/device.h. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Link: https://lore.kernel.org/r/20200629065008.27620-4-brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>