Re: [PATCH] blkcg: add sanity check for blkcg policy operations

[weiping zhang <zwp10758@gmail.com>]

On Wed, Oct 11, 2017 at 09:58:33AM +0200, Johannes Thumshirn wrote:
> On Wed, Oct 11, 2017 at 12:00:55AM +0800, weiping zhang wrote:
> > + * blkcg_policy_check_ops - check policy's operations
> > + * @pol: blkcg policy to check
> > + *
> > + * Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs.
> > + * Return true on success and false on failure.
> > + */
> > +static bool blkcg_policy_check_ops(struct blkcg_policy *pol)
> > +{
> > +	if ((pol->cpd_alloc_fn && !pol->cpd_free_fn) ||
> > +		(!pol->cpd_alloc_fn && pol->cpd_free_fn))
> > +		return false;
> > +
> > +	if ((pol->pd_alloc_fn && !pol->pd_free_fn) ||
> > +		(!pol->pd_alloc_fn && pol->pd_free_fn))
> > +		return false;
> > +
> > +	return true;
> > +}
> > +
> > +/**
> >   * blkcg_policy_register - register a blkcg policy
> >   * @pol: blkcg policy to register
> >   *
> > @@ -1419,6 +1439,9 @@ int blkcg_policy_register(struct blkcg_policy *pol)
> >  	if (i >= BLKCG_MAX_POLS)
> >  		goto err_unlock;
> >  
> > +	if (!blkcg_policy_check_ops(pol))
> > +		goto err_unlock;
> > +
> 
> Can you merge it into the caller?
> 
> +	if ((pol->cpd_alloc_fn && !pol->cpd_free_fn) ||
> +		(!pol->cpd_alloc_fn && pol->cpd_free_fn))
> +		goto err_unlock;
> +
> +	if ((pol->pd_alloc_fn && !pol->pd_free_fn) ||
> +		(!pol->pd_alloc_fn && pol->pd_free_fn))
> +		goto err_unlock;
> 
> 
It's ok for me, I send V2 later.

Thanks
Weiping