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From: Jakub Sitnicki <jakub@cloudflare.com>
To: Ferenc Fejes <fejes@inf.elte.hu>, Liu Jian <liujian56@huawei.com>
Cc: john.fastabend@gmail.com, ast@kernel.org, daniel@iogearbox.net,
	andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
	yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com,
	haoluo@google.com, jolsa@kernel.org, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	dsahern@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v2 1/7] bpf, sockmap: add BPF_F_PERMANENTLY flag for skmsg redirect
Date: Sun, 20 Aug 2023 20:19:49 +0200	[thread overview]
Message-ID: <87zg2l5zaa.fsf@cloudflare.com> (raw)
In-Reply-To: <c1ba1a3235464b8306a22c050225332fa3929a10.camel@inf.elte.hu>

On Thu, Aug 17, 2023 at 02:05 PM +02, Ferenc Fejes wrote:
> Hi Liu!
>
> On Fri, 2023-08-11 at 17:32 +0800, Liu Jian wrote:
>> If the sockmap msg redirection function is used only to forward
>> packets
>> and no other operation, the execution result of the
>> BPF_SK_MSG_VERDICT
>> program is the same each time. In this case, the BPF program only
>> needs to
>> be run once. Add BPF_F_PERMANENTLY flag to bpf_msg_redirect_map() and
>> bpf_msg_redirect_hash() to implement this ability.
>
> Did you considered other names for this flag e.g. BPF_F_SPLICED or
> BPF_F_PIPED?

Ferenc,

A reference to splice/pipe syscall certainly paints a picture.

But I'm not sure if it makes it more intutive or more confusing in the
context of bpf_{msg,sk}_redirect_{hash,map}. Consider:

  bpf_msg_redirect_map(..., BPF_F_SPLICE)

vs

  bpf_msg_redirect_map(..., BPF_F_PERMANENTLY)


Liu,

No need to go for the adverb form ("PERMANENTLY"). An adjective
("PERMANENT") will as expressive here. So BPF_F_PERMANENT is what I'm
suggesting.

Also, I'm thinking maybe it's time for a dedicated prefix to avoid name
clashes, like BPF_F_ADJ_ROOM_*.

BPF_F_INGRESS, which is also accepted by other helpers. But that won't
be the case with the new flag. BPF_F_SK_REDIR_*? That would make it
BPF_F_SK_REDIR_PERMANENT.

Alternatively, BPF_F_SK_REDIR_FIXED comes to mind. Naming is hard.

[...]

  parent reply	other threads:[~2023-08-20 18:47 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-11  9:32 [PATCH bpf-next v2 0/7] add BPF_F_PERMANENTLY flag for sockmap skmsg redirect Liu Jian
2023-08-11  9:32 ` [PATCH bpf-next v2 1/7] bpf, sockmap: add BPF_F_PERMANENTLY flag for " Liu Jian
2023-08-17  6:13   ` John Fastabend
2023-08-19  9:25     ` liujian (CE)
2023-08-20 18:03     ` Jakub Sitnicki
2023-08-17 12:05   ` Ferenc Fejes
2023-08-19  9:32     ` liujian (CE)
2023-08-20 18:19     ` Jakub Sitnicki [this message]
2023-08-21  7:40   ` Jakub Sitnicki
2023-08-11  9:32 ` [PATCH bpf-next v2 2/7] selftests/bpf: Add txmsg ingress permanently test for sockmap Liu Jian
2023-08-11  9:32 ` [PATCH bpf-next v2 3/7] selftests/bpf: Add txmsg redir " Liu Jian
2023-08-11  9:32 ` [PATCH bpf-next v2 4/7] selftests/bpf: add skmsg verdict tests Liu Jian
2023-08-11  9:32 ` [PATCH bpf-next v2 5/7] selftests/bpf: add two skmsg verdict tests for BPF_F_PERMANENTLY flag Liu Jian
2023-08-11  9:32 ` [PATCH bpf-next v2 6/7] selftests/bpf: add tests for verdict skmsg to itself Liu Jian
2023-08-11  9:32 ` [PATCH bpf-next v2 7/7] selftests/bpf: add tests for verdict skmsg to closed socket Liu Jian

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