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

Thomas Monjalon thomas at monjalon.net
Wed Jun 24 10:13:18 CEST 2020


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?

>  #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;	\
>  	})






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