From 6b724bc4300b431443f3b99520994a5aece347cd Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 12 Sep 2023 16:02:11 +0000 Subject: ipv6: lockless IPV6_MTU_DISCOVER implementation Most np->pmtudisc reads are racy. Move this 3bit field on a full byte, add annotations and make IPV6_MTU_DISCOVER setsockopt() lockless. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/ip6_output.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv6/ip6_output.c') diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index f87d8491d7e2..7e5d9eeb990f 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1436,10 +1436,10 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, v6_cork->hop_limit = ipc6->hlimit; v6_cork->tclass = ipc6->tclass; if (rt->dst.flags & DST_XFRM_TUNNEL) - mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? + mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ? READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst); else - mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? + mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ? READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst)); frag_size = READ_ONCE(np->frag_size); -- cgit