Re: [PATCH] ARM: supplementing IO accessors with 64 bit capability

[Russell King - ARM Linux]

On Wed, Oct 22, 2014 at 06:22:09PM +0200, Mathieu Poirier wrote:
> I had this conversation with a colleague who reviewed the work.  If
> the architecture is < 5 the __raw_ versions aren't included and the
> compiler won't complain until someone tries to use the macros.  We
> achieve the same result - the macros aren't accessible when the
> architecture doesn't support it - while saving an #if condition in the
> file.
> 
> I'm not strongly opinionated on this - I can enclose the macros in an
> #if statement.

What you're missing is that some driver may test for their presence by
doing:

#ifndef readq_relaxed
... do something else

which would now break as a detection method, as the macro is always
defined no matter whether it's present or not.

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