Re: [ [git pull] headers_check fixes]

From: H. Peter Anvin
Date: Tue Jan 27 2009 - 18:23:17 EST

Linus Torvalds wrote:

So I think it makes our headers worse. Code like

> +#ifdef __KERNEL__
> +# ifdef CONFIG_X86_BSWAP
> +# define __X86_BSWAP > +# endif /* CONFIG_X86_BSWAP */
> +#endif /* __KERNEL__ */

just doesn't make sense. It doesn't make sense _inside_ the kernel, and it doesn't make sense _outside_ it either.

As far as I can tell, the header install script could literally just do something like run 'sed' over the headers as it installs them, and do something like

sed 's/\<CONFIG_[A-Z0-9_]*\>/__kernel_only__/g'

which I realize is not really the complete/correct solution (ie you could write a nicer thing that does a better job), but my point here is that rather than have scripts that _whine_ about these kinds of trivial things and cause people to write less readable header files, we should just make sure that if we can recognize them so easily, we can just fix them instead.

We already run the headers through unifdef, so this should be trivial to add.

The intent of headers_check is to try to catch people who put things that depend on CONFIG_* stuff in exported headers (which, as we have seen, have been too sadly common.) If we declare that the export process will treat all CONFIG_* as undefined, we do lose some coverage but potentially end up with cleaner code. Not sure which is worse...

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