Re: [PATCH] staging: rtl8723bs: Mark ACPI table declaration as used

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Sep 26, 2018 at 04:20:55PM -0700, Nathan Chancellor wrote:
> Clang emits the following warning:
> 
> drivers/staging/rtl8723bs/os_dep/sdio_intf.c:25:36: warning: variable
> 'acpi_ids' is not needed and will not be emitted
> [-Wunneeded-internal-declaration]
> static const struct acpi_device_id acpi_ids[] = {
>                                    ^
> 1 warning generated.
> 
> Mark acpi_ids with the attribute __used, which makes it clear to Clang
> that we don't want this warning while not inhibiting Clang's dead code
> elimination from removing the unreferenced internal symbol when moving
> the data to the globally available symbol with MODULE_DEVICE_TABLE.
> 
> $ nm -S drivers/staging/rtl8723bs/os_dep/sdio_intf.o | grep acpi
> 0000000000000000 0000000000000040 R __mod_acpi__acpi_ids_device_table
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/169
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  drivers/staging/rtl8723bs/os_dep/sdio_intf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> index 6d02904de63f..7c03b69b8ed3 100644
> --- a/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> +++ b/drivers/staging/rtl8723bs/os_dep/sdio_intf.c
> @@ -22,7 +22,7 @@ static const struct sdio_device_id sdio_ids[] =
>  	{ SDIO_DEVICE(0x024c, 0xb723), },
>  	{ /* end: all zeroes */				},
>  };
> -static const struct acpi_device_id acpi_ids[] = {
> +static const struct acpi_device_id acpi_ids[] __used = {

Can't we put __used somewhere in the MODULE_DEVICE_TABLE() macro so we
don't have to go adding it to all individual entries?

thanks,

greg k-h