Re: [PATCH 1/2] percpu_ref: percpu_ref_tryget_live() version holding RCU

[Pavel Begunkov]

On 10/20/21 21:10, Tejun Heo wrote:
> On Wed, Oct 20, 2021 at 09:03:18PM +0100, Pavel Begunkov wrote:
> > +/**
> > + * percpu_ref_tryget_live_rcu - same as percpu_ref_tryget_live() but the
> > + * caller is responsible for taking RCU.
> > + *
> > + * This function is safe to call as long as @ref is between init and exit.
> > + */
> > +static inline bool percpu_ref_tryget_live_rcu(struct percpu_ref *ref)
> > +{
> > +	unsigned long __percpu *percpu_count;
> > +	bool ret = false;
> > +
> > +	if (likely(__ref_is_percpu(ref, &percpu_count))) {
> > +		this_cpu_inc(*percpu_count);
> > +		ret = true;
> > +	} else if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD)) {
> > +		ret = atomic_long_inc_not_zero(&ref->data->count);
> > +	}
> > +	return ret;
> > +}
>
> Can we please add rcu_read_lock_held() assertion? Other than that, looks
> fine to me.

Will add, thanks

--
Pavel Begunkov