Re: [PATCH net-next v7 03/10] net: psample: skip packet copy if no listeners

[Aaron Conole <aconole@redhat.com>]

Adrian Moreno <amorenoz@redhat.com> 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 <echaudro@redhat.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> Reviewed-by: Simon Horman <horms@kernel.org>
> Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
> ---

Reviewed-by: Aaron Conole <aconole@redhat.com>

>  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) +