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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v7 03/10] net: psample: skip packet copy if no listeners In-Reply-To: <20240630195740.1469727-4-amorenoz@redhat.com> (Adrian Moreno's message of "Sun, 30 Jun 2024 21:57:24 +0200") References: <20240630195740.1469727-1-amorenoz@redhat.com> <20240630195740.1469727-4-amorenoz@redhat.com> Date: Mon, 01 Jul 2024 14:07:32 -0400 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Adrian Moreno writes: > If nobody is listening on the multicast group, generating the sample, > which involves copying packet data, seems completely unnecessary. > > Return fast in this case. > > Acked-by: Eelco Chaudron > Reviewed-by: Ido Schimmel > Reviewed-by: Simon Horman > Signed-off-by: Adrian Moreno > --- Reviewed-by: Aaron Conole > net/psample/psample.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/psample/psample.c b/net/psample/psample.c > index b37488f426bc..1c76f3e48dcd 100644 > --- a/net/psample/psample.c > +++ b/net/psample/psample.c > @@ -376,6 +376,10 @@ void psample_sample_packet(struct psample_group *group, struct sk_buff *skb, > void *data; > int ret; > > + if (!genl_has_listeners(&psample_nl_family, group->net, > + PSAMPLE_NL_MCGRP_SAMPLE)) > + return; > + > meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) + > (out_ifindex ? nla_total_size(sizeof(u16)) : 0) + > (md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) +