Re: [RFC PATCH 5/6] implement per-cpu&per-domain state machinecall_srcu()

[Peter Zijlstra]

On Tue, 2012-03-06 at 17:57 +0800, Lai Jiangshan wrote:
>  /*
> + * 'return left < right;' but handle the overflow issues.
> + * The same as 'return (long)(right - left) > 0;' but it cares more.

About what? And why? We do the (long)(a - b) thing all over the kernel,
why would you care more?

> + */
> +static inline
> +bool safe_less_than(unsigned long left, unsigned long right, unsigned long max)
> +{
> +       unsigned long a = right - left;
> +       unsigned long b = max - left;
> +
> +       return !!a && (a <= b);
> +} 
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