Re: [PATCH v2] random: unify cycles_t and jiffies usage and types

[Jason A. Donenfeld]

On Fri, Feb 25, 2022 at 8:06 AM Dominik Brodowski
<linux@xxxxxxxxxxxxxxxxxxxx> wrote:
> maybe "flags, now = jiffies" is a bit more reader-friendly?

Good idea. Will do.

> >       enum { MIX_INFLIGHT = 1U << 31 };
> > +     cycles_t cycles = random_get_entropy();
> > +     unsigned long now = jiffies;
> >       struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness);
> >       struct pt_regs *regs = get_irq_regs();
> > -     unsigned long now = jiffies;
> > -     cycles_t cycles = random_get_entropy();
> >       unsigned int new_count;
> >
> >       if (cycles == 0)
>
>
> Why do you change the ordering here?

So that get_cycles() is called as closest to the actual interrupt as
possible, and so that we retain the order as elsewhere of reading
cycles before jiffies.

v+1 on its way.

Jason