Re: [RFC] Splitting kernel headers and deprecating __KERNEL__

[hpa@zytor.com (H. Peter Anvin)]

Followup to:  <Pine.LNX.4.58.0411301243000.22796@ppc970.osdl.org>
By author:    Linus Torvalds <torvalds@osdl.org>
In newsgroup: linux.dev.kernel
> 
> But claiming that __KERNEL__ doesn't work is clearly a bunch of crapola. 
> As is the notion that you can somehow do it all. We do it in small pieces.
> 

IMNSHO, based on my experience with klibc, the problem is not #ifdef
__KERNEL__, the *specific* problems are:

- The kernel exporting libc4/5 internals, which are neither what the
  kernel nor any kind of modern userspace wants.  This should be
  possible to get rid of easily enough.

- The kernel exporting things into the userspace namespace.  The
  kernel's definition of "struct stat" isn't usable -- the one that is
  useful is called "struct stat64" on most, but not all,
  architectures, but because it's a structure tag it can't be pulled
  from the exported kernel ABI in such a way that what userspace calls
  "struct stat" is what the kernel currently calls "struct stat64" if
  that exists.

  This one is a bit uglier, since it probably needs something like:

  #ifdef __KERNEL__
  #define __kabi_stat64 stat64
  #endif

  struct __kabi_stat64 { ... };

	-hpa