Re: [tip:x86/asm] x86, 64-bit: ifdef out struct thread_struct::ip

[Ingo Molnar]

* Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:

> On Mon, May 11, 2009 at 8:03 PM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> > On Mon, May 11, 2009 at 03:09:40PM +0000, tip-bot for Alexey Dobriyan wrote:
> >> +#ifdef CONFIG_X86_32
> >>       unsigned long           ip;
> >> +#endif
> >>  #ifdef CONFIG_X86_64
> >>       unsigned long           fs;
> >>  #endif
> >
> > What happened to the good old concept of #if #else #endif?
> 
> #else suggests alternative which is not the case.
> ->ip and ->fs can be in different parts of thread_struct.

Yes, it's cleaner to have them separate. #if / #else / #endif would 
be shorter by one line, and it would be thicker by a big confusion 
factor: "why is fs the alternative on 64-bit of 32-bit's ip??"

They could also move apart later on, if structure packing 
constraints call for it.

	Ingo
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