Re: Fix sparse warning

[Ingo Molnar <mingo@elte.hu>]

* "L. Alberto Giménez" <agimenez@sysvalve.homelinux.net> wrote:

> >  - All such variables need proper locking, as they can be re-entered 
> >    from multiple CPUs (while local stack variables cannot and generally 
> >    dont need such locking). Moving them to file scope makes sure it's 
> >    all visible and makes sure proper locking is done.
> 
> The same thing about visibility applies as above. Moreover, I can't 
> see any explicit lock inside the main.c file. [...]

It's implicit - all bootup execution is serialized.

So it's double important to make any global state clearly visible - 
should any of this be pushed to async bootup init functions (which would 
require the addition of a lock).

> > All in one, there's a constant trend away from statics at function 
> > scope. It can be done correctly but is subtly fragile for the above 
> > reasons.
> 
> Indeed it may be fragile. And I'm sure that you've faced tons of bugs 
> because of declaring static variables in funcion scope and not having 
> it in mind when using those variables. I'm just a newbie and I have 
> not faced serious challenges about kernel development, but I think 
> that those "sanity" things should be fixed (I'm kind of standards 
> taliban :) ), but I need your expertise to know *how* to fix it, from 
> the point of view of semantics and not just syntax.

I think it's subtly wrong if you try to 'fix a warning', as the subject 
line already says it.

Warnings are not something that should be 'fixed' - they are just a sign 
of some sort of trouble:

 1- bug/limitation in the tool (Sparse)
 2- uncleanliness in the source code
 3- bug in the source code

here it seems to be case #1, as file scope statics are perfectly fine, 
even if used by a single function.

	Ingo
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