Subject: Re: why so many unexported headers checking __KERNEL__?
From: David Woodhouse <dwmw2@infradead.org>
To: "Robert P. J. Day" <rpjday@crashcourse.ca>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Date: Wed, 26 Mar 2008 12:08:44 +0000
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On Sun, 2008-03-23 at 02:31 -0400, Robert P. J. Day wrote:
> 
>   as an unintended side effect of checking for proper exporting to
> user space and unifdef'ing, i noticed that there are literally
> hundreds of kernel header files that check the value of __KERNEL__ in
> some way, but are never exported to user space.  what's the point of
> that?  thanks.

There's no point -- we just haven't got round to removing it yet. 

We should probably make headers_check or some other automated check
catch these two cases:

If a header is exported by header-y or not exported at all, it shouldn't
contain any #ifdef __KERNEL__.

And if it's exported and doesn't contain any #ifdef __KERNEL__, it
should be header-y not unifdef-y (and that's the case we should be
moving towards, by cleaning up headers to have separate files for the
user-visible parts).

-- 
dwmw2

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