Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <12d6b267-7c1b-1f2b-2ab1-8d24433f16ea@gmail.com>
Date:   Thu, 27 Jan 2022 13:53:29 +0000
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.5.0
Subject: Re: [PATCH for-next v4] cgroup/bpf: fast path skb BPF filtering
Content-Language: en-US
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Martin KaFai Lau <kafai@fb.com>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Song Liu <songliubraving@fb.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Stanislav Fomichev <sdf@google.com>
References: <94e36de3cc2b579e45f95c189a6f5378bf1480ac.1643156174.git.asml.silence@gmail.com>
 <20220126203055.3xre2m276g2q2tkx@kafai-mbp.dhcp.thefacebook.com>
 <fbc8acbe-4c12-9c68-0418-51e97457d30b@gmail.com>
 <CAADnVQ+p0B-2_b8hYHEW4UGJ7-T0RMfnZ8cZ4NgpvjMiTo6YKA@mail.gmail.com>
From:   Pavel Begunkov <asml.silence@gmail.com>
In-Reply-To: <CAADnVQ+p0B-2_b8hYHEW4UGJ7-T0RMfnZ8cZ4NgpvjMiTo6YKA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 1/27/22 05:08, Alexei Starovoitov wrote:
> On Wed, Jan 26, 2022 at 1:29 PM Pavel Begunkov <asml.silence@gmail.com> wrote:
>>
>> On 1/26/22 20:30, Martin KaFai Lau wrote:
>>> On Wed, Jan 26, 2022 at 12:22:13AM +0000, Pavel Begunkov wrote:
>>>>    #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, skb)                        \
>>>>    ({                                                                       \
>>>>       int __ret = 0;                                                        \
>>>> -    if (cgroup_bpf_enabled(CGROUP_INET_INGRESS))                  \
>>>> +    if (cgroup_bpf_enabled(CGROUP_INET_INGRESS) && sk &&                  \
>>>   From reading sk_filter_trim_cap() where this will be called, sk cannot be NULL.
>>> If yes, the new sk test is not needed.
>>
>> Well, there is no sane way to verify how it's used considering
>>
>> EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
> 
> BPF_CGROUP_RUN_PROG_INET_INGRESS() is used in one place.
> Are you folks saying that you want to remove !sk check
> from __cgroup_bpf_run_filter_skb()?
> Seems like micro optimization, but sure why not.
> 
> EXPORT_SYMBOL() is there because of "ipv6 as a module" mess.
> So it's not a concern.

Ok. I'd usually assume symbols for internal use only to be GPL.


> Pls tag the subj of the patch with [PATCH bpf-next]
> instead of "for-next".

-- 
Pavel Begunkov