Re: [announce] new tree: "fix all build warnings, on all configs"

["Jörn Engel" <joern@logfs.org>]

On Wed, 22 October 2008 11:47:59 +0200, Ingo Molnar wrote:
> * Jörn Engel <joern@logfs.org> wrote:
> > On Mon, 20 October 2008 21:21:10 +0200, Ingo Molnar wrote:
> > >  
> > >  /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
> > >  #define fops_get(fops) \
> > > -	(((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
> > > +	(((fops != NULL) && try_module_get((fops)->owner) ? (fops) : NULL))
> > >  #define fops_put(fops) \
> > > -	do { if (fops) module_put((fops)->owner); } while(0)
> > > +	do { if (fops != NULL) module_put((fops)->owner); } while(0)
> > 
> > This, I would argue, makes the code worse.
> 
> In this specific case the issue is that the 'fops' parameter can 
> occasionally be a constant pointer (turning the test into always-true) 
> so the compiler is at least minimally correct at asking the "are you 
> sure you want this" question - which we answer in the affirmative via 
> the explicit NULL check. But these are really nuances.

#define fops_put(fops) do {			\
	if (fops != NULL)			\
		module_put((fops)->owner);	\
} while 0

If the code was written like this, I wouldn't mind your patch at all.
But in the one-liner form, the ' != NULL' makes the difference between
fluent reading and having to actively sort out which piece belongs
where.

And I bet that if it hadn't been a macro but an inline function, you
and checkpatch would have complained about the formatting long ago. ;)

Jörn

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