Re: [KJ] [Patch 8/9] BUG_ON() Conversion in md/raid6main.c

[Eric Sesterhenn / snakebyte <snakebyte@gmx.de>]

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hi,

> >  this changes if() BUG(); constructs to BUG_ON() which is
> >  cleaner and can better optimized away
> > 
> gcc optimizes them away if BUG() is not defined, so this is not a true
> statement.

if BUG() is defined to nothing it still leaves the if, which must be optimized
away by the compiler, not by the preprocessor


> > -		if (!list_empty(&sh->lru))
> > -			BUG();
> > -		if (atomic_read(&conf->active_stripes)==0)
> > -			BUG();
> > +		BUG_ON(!list_empty(&sh->lru));
> > +		BUG_ON(atomic_read(&conf->active_stripes)==0);
> 
> Also, no, do not do this!
> If BUG_ON() is turned off, then the logic changes here.

list_empty() just returns wheter the list is empty or not, so there is no logic
change. and atomic_read() as far as i can see just reads the
conf->active_stripes->counter value, so there is nothing changed somewhere
and the logic still stays the same. Or did i miss something here?

Thanks, Eric Sesterhenn


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