Subject: Re: [RFC bpf-next 1/2] net: bridge: add unstable br_fdb_find_port_from_ifindex helper

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Wed, 26 Jan 2022 13:03:56 +0100

Lorenzo Bianconi <[email-masked]> writes:

>> > +	rcu_read_lock();
>> 
>> This is not needed when the function is only being called from XDP...
>
> don't we need it since we do not hold the rtnl here?

No. XDP programs always run under local_bh_disable() which "counts" as
an rcu_read_lock(); I did some cleanup around this a while ago, see this
commit for a longer explanation:

782347b6bcad ("xdp: Add proper __rcu annotations to redirect map entries")

-Toke