Re: [Xen-devel] [PATCH] x86: fix cache flushing condition in map_pages_to_xen()

[Keir Fraser <keir.xen@xxxxxxxxx>]

On 18/07/2013 06:49, "Jan Beulich" <jbeulich@xxxxxxxx> wrote:

>>> Ugly. I actually picked the same name intentionally.
>> 
>> I'm not too strongly opinionated on this one, but it did make me look twice.
>> I think it would be cleaner something like:
>> #define flush_flags(oldf) ({ unsigned int f_ = 0; ...; _f; })
>> ...
>> flush_flags |= flush_flags(...);
>> The 'name collision' I'm fine with, whereas going directly at a caller's
>> variable within a macro is rather grubby behaviour. ;)
> 
> But that would still leave the macro access "flags" directly.

Hmmm true. Don't really want to expand the verbiage at each macro call site
any further, so I guess your existing approach is also my preferred one.

> And while I 
> realize
> that this is (slightly) odd behavior for a macro, that's precisely the reason
> why
> I #undef it right after the function. Perhaps this could be made even more
> clear
> by moving #define and #undef inside the function...

Yes, that might be slightly preferable.

 -- Keir



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