Re: [PATCH 1/2] efi: payload: iomem: add commented out #define DEBUG 1

[Sascha Hauer <sha@pengutronix.de>]

On Tue, May 23, 2023 at 11:40:34AM +0200, Ahmad Fatoum wrote:
> The code uses __is_defined, which only works for undefined macros and
> defined ones with a value. This is different than the debugging prints
> that accept empty defined DEBUG, so add a commented out #define DEBUG 1
> to alert those seeking to debug the code.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  common/efi/payload/iomem.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/common/efi/payload/iomem.c b/common/efi/payload/iomem.c
> index 6b92ca993aa7..550d832668ed 100644
> --- a/common/efi/payload/iomem.c
> +++ b/common/efi/payload/iomem.c
> @@ -3,6 +3,7 @@
>  
>  #define pr_fmt(fmt) "efi-iomem: " fmt
>  
> +// #define DEBUG 1

I don't like this very much.

Generally being able to do this is really appealing:

	if (__is_defined(DEBUG))
		...

Indeed this is so appealing that others may copy this. Having to
remember then that there's a subtle difference between __is_defined() and
#ifdef is not so nice though.

We could add

#define __ARG_PLACEHOLDER_ 0,

to include/linux/kconfig.h. With this __is_defined() and #ifdef should
do the same thing. It would even better to add this to the Linux
upstream version of this file. I am not sure though if that has any
unwanted side effects. Masahiro, do you have an opinion about this?

Another option would be to add this somewhere:

#ifdef DEBUG
#undef DEBUG
#define DEBUG 1
#endif

Sascha

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