Re: [RFC nf-next v1 1/2] netfilter: bpf: support prog update

["D. Wythe" <alibuda@linux.alibaba.com>]

On 12/15/23 10:17 PM, Florian Westphal wrote:
> D. Wythe <alibuda@linux.alibaba.com> wrote:
>>   	const struct nf_defrag_hook *defrag_hook;
>> +	const struct bpf_prog __rcu *nf_prog;
> Hmm, why do we need this pointer?
> Can't you just re-use bpf_nf_link->link.prog?
Accessing nf_link->link.prog directly is a bit strange because it is not 
marked as __rcu, which will generate a compilation warning,
thus we need to perform a type conversion.

But I do not intend to insist on it. I will remove it in the next version.

Best wishes,
D. Wythe
>
>> +	rcu_assign_pointer(nf_link->nf_prog, new_prog);
>> +	old_prog = xchg(&link->prog, new_prog);
> This looks redundant, I think you can remove the nf_prog
> pointer again.
>
> Rest LGTM.