[PATCH 5.4 169/191] gtp: do not confirm neighbor when do pmtu update

From: Greg Kroah-Hartman
Date: Thu Jan 02 2020 - 17:57:03 EST

From: Hangbin Liu <liuhangbin@xxxxxxxxx>

[ Upstream commit 6e9105c73f8d2163d12d5dfd762fd75483ed30f5 ]

When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

Although GTP only support ipv4 right now, and __ip_rt_update_pmtu() does not
call dst_confirm_neigh(), we still set it to false to keep consistency with
IPv6 code.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Reviewed-by: Guillaume Nault <gnault@xxxxxxxxxx>
Acked-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/gtp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -541,7 +541,7 @@ static int gtp_build_skb_ip4(struct sk_b
mtu = dst_mtu(&rt->dst);

- rt->dst.ops->update_pmtu(&rt->dst, NULL, skb, mtu, true);
+ rt->dst.ops->update_pmtu(&rt->dst, NULL, skb, mtu, false);

if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) &&
mtu < ntohs(iph->tot_len)) {