Re: [PATCH v2] drm/i915: Explicitly cast divisor and use div_u64()

From: Andi Shyti
Date: Wed Aug 07 2024 - 10:59:11 EST


Hi Thorsten,

> > /* This check is primarily to ensure that oa_period <=
> > - * UINT32_MAX (before passing to do_div which only
> > + * UINT32_MAX (before passing it to div_u64 which only
> > * accepts a u32 denominator), but we can also skip
> > * checking anything < 1Hz which implicitly can't be
> > * limited via an integer oa_max_sample_rate.
> > */
> > if (oa_period <= NSEC_PER_SEC) {
> > - u64 tmp = NSEC_PER_SEC;
> > - do_div(tmp, oa_period);
> > - oa_freq_hz = tmp;
> > + oa_freq_hz = div_u64(NSEC_PER_SEC, (u32)oa_period);
> > } else
> > oa_freq_hz = 0;
>
> Non-blocking suggestion: this looks like it can be inlined. And if the
> inline route is taken, it might be best to invert the conditional check
> like such:
>
> oa_freq_hz = oa_period > NSEC_PER_SEC ? 0 :
> div_u64(NSEC_PER_SEC, (u32)oa_period);
>
> I think this is just a matter of preference, though. The explicit if-else
> block is definitely clearer.

It's also stylistically wrong given that now the if/else don't
need the brackets anymore, triggering a checkpatch error.

Thorsten do you mind resending it either following Jonathan's
suggestion (my favourite, as well) or fix the bracket issue
following the kernel style.

Andi