Re: [PATCH] x86/syscalls: Mark expected switch fall-throughs

From: Thomas Gleixner
Date: Tue Nov 28 2017 - 16:26:05 EST


On Tue, 28 Nov 2017, Gustavo A. R. Silva wrote:
> The thing about taking 'any comment' as valid is false if you add the
> following to your Makefile:
>
> KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough)
>
> This option takes the following comments as valid:
>
> /* fall through */
> /* Fall through */
> /* fall through - ... */
> /* Fall through - ... */
>
> Comments as fallthru, fallthrough, FALLTHRU are invalid.
>
> And of course if you intentionally change the option to:
>
> KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough=1)
>
> it means that you obviously want to ignore any warning.

So I have to ask WHY this information was not in the changelog of the patch
in question:

1) How it works

2) Why comments have been chosen over macros

> In preparation to enabling -Wimplicit-fallthrough, mark switch cases
> where we are expecting to fall through.

It's not a reviewers job to chase that information down.

While I can understand that the comments are intentional due to existing
tools, I still prefer the macro/annotation. But I'm not religious about it
when there is common consensus. :)

Thanks,

tglx