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Message-ID: <82c74693-db42-2491-868e-b6cb1cead4ec@linux.alibaba.com>
Date: Mon, 18 Dec 2023 11:06:56 +0800
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Subject: Re: [RFC nf-next v1 1/2] netfilter: bpf: support prog update
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To: Florian Westphal <fw@strlen.de>
Cc: pablo@netfilter.org, kadlec@netfilter.org, bpf@vger.kernel.org,
 linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
 coreteam@netfilter.org, netfilter-devel@vger.kernel.org,
 davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
 pabeni@redhat.com, ast@kernel.org
References: <1702609653-45835-1-git-send-email-alibuda@linux.alibaba.com>
 <1702609653-45835-2-git-send-email-alibuda@linux.alibaba.com>
 <20231215141712.GA17065@breakpoint.cc>
From: "D. Wythe" <alibuda@linux.alibaba.com>
In-Reply-To: <20231215141712.GA17065@breakpoint.cc>
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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.