Re: [PATCH v4 04/22] kthread: Add create_kthread_worker*()

[Petr Mladek]

On Mon 2016-01-25 13:53:39, Tejun Heo wrote:
> On Mon, Jan 25, 2016 at 04:44:53PM +0100, Petr Mladek wrote:
> > +struct kthread_worker *
> > +create_kthread_worker_on_cpu(int cpu, const char namefmt[])
> > +{
> > +	if (cpu < 0 || cpu > num_possible_cpus())
> > +		return ERR_PTR(-EINVAL);
> 
> Comparing cpu ID to num_possible_cpus() doesn't make any sense.  It
> should either be testing against cpu_possible_mask or testing against
> nr_cpu_ids.  Does this test need to be in this function at all?

I wanted to be sure. The cpu number is later passed to
cpu_to_node(cpu) in kthread_create_on_cpu().

I am going to replace this with a check against nr_cpu_ids in
kthread_create_on_cpu() which makes more sense.

I might be too paranoid. But this is slow path. People
do mistakes...

Thanks,
Petr