Re: [PATCH bpf-next v4 05/10] bpf: Add reference tracking support to kfunc

[Kumar Kartikeya Dwivedi <memxor@gmail.com>]

On Sun, Dec 19, 2021 at 07:52:48AM IST, Alexei Starovoitov wrote:
> On Fri, Dec 17, 2021 at 07:20:26AM +0530, Kumar Kartikeya Dwivedi wrote:
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 965fffaf0308..015cb633838b 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -521,6 +521,9 @@ struct bpf_verifier_ops {
> >  				 enum bpf_access_type atype,
> >  				 u32 *next_btf_id);
> >  	bool (*check_kfunc_call)(u32 kfunc_btf_id, struct module *owner);
> > +	bool (*is_acquire_kfunc)(u32 kfunc_btf_id, struct module *owner);
> > +	bool (*is_release_kfunc)(u32 kfunc_btf_id, struct module *owner);
> > +	bool (*is_kfunc_ret_type_null)(u32 kfunc_btf_id, struct module *owner);
>
> Same feedback as before...
>
> Those callbacks are not necessary.
> The existing check_kfunc_call() is just as inconvenient.
> When module's BTF comes in could you add it to mod's info instead of
> introducing callbacks for every kind of data the module has.
> Those callbacks don't server any purpose other than passing the particular
> data set back. The verifier side should access those data sets directly.

Ok, interesting idea. So these then go into the ".modinfo" section? I think then
we can also drop the check_kfunc_call callback?

--
Kartikeya