Re: [dpdk-stable] [EXT] Re: [PATCH] eal: fix macros to align value

[Harman Kalra <hkalra@marvell.com>]

On Wed, Jun 24, 2020 at 10:13:18AM +0200, Thomas Monjalon wrote:
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> ----------------------------------------------------------------------
> 09/06/2020 21:17, Harman Kalra:
> > Found an issue while using RTE_ALIGN_MUL_NEAR with an
> > expression, like as passed in estimate_tsc_freq().
> > RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
> > above function as division has more precedence over
> > substraction.
> 
> The only change I see is adding parenthesis around v.
> Am I right?

Yes, parathesis are required if an expression is passed.

> 
> >  #define RTE_ALIGN_MUL_CEIL(v, mul) \
> > -	(((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > +	((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> [...]
> >  #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> > -	((v / ((typeof(v))(mul))) * (typeof(v))(mul))
> > +	(((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
> [...]
> >  	({							\
> >  		typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul);	\
> >  		typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul);	\
> > -		(ceil - v) > (v - floor) ? floor : ceil;	\
> > +		(ceil - (v)) > ((v) - floor) ? floor : ceil;	\
> >  	})
> 
> 
> 
>