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From: David Miller <davem@davemloft.net>
To: liuhangbin@gmail.com
Cc: netdev@vger.kernel.org, ja@ssi.bg, marcelo.leitner@gmail.com,
	dsahern@gmail.com, edumazet@google.com
Subject: Re: [PATCHv2 net] ipv6/route: should not update neigh confirm time during PMTU update
Date: Mon, 02 Dec 2019 18:47:04 -0800 (PST)	[thread overview]
Message-ID: <20191202.184704.723174427717421022.davem@davemloft.net> (raw)
In-Reply-To: <20191203021137.26809-1-liuhangbin@gmail.com>

From: Hangbin Liu <liuhangbin@gmail.com>
Date: Tue,  3 Dec 2019 10:11:37 +0800

> Fix it by removing the dst_confirm_neigh() in __ip6_rt_update_pmtu() as
> there is no two-way communication during PMTU update.
> 
> v2: remove dst_confirm_neigh directly as David Miller pointed out.

That's not what I said.

I said that this interface is designed for situations where the neigh
update is appropriate, and that's what happens for most callers _except_
these tunnel cases.

The tunnel use is the exception and invoking the interface
inappropriately.

It is important to keep the neigh reachability fresh for TCP flows so
you cannot remove this dst_confirm_neigh() call.

Instead, make a new interface that the tunnel use cases can call into
to elide the neigh update.

Yes, this means you will have too update all of the tunnel callers
into these calls chains but that's the price we have to pay in this
situation unfortunately.

  reply	other threads:[~2019-12-03  2:47 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-22  6:19 [PATCH net] ipv6/route: only update neigh confirm time if pmtu changed Hangbin Liu
2019-11-22 18:04 ` David Miller
2019-11-26  9:17   ` Hangbin Liu
2019-12-03  2:11 ` [PATCHv2 net] ipv6/route: should not update neigh confirm time during PMTU update Hangbin Liu
2019-12-03  2:47   ` David Miller [this message]
2019-12-03 10:15     ` Hangbin Liu
2019-12-03 10:25       ` Hangbin Liu
2019-12-03 19:58         ` David Miller
2019-12-10  3:36           ` Hangbin Liu
2019-12-10 17:00             ` Guillaume Nault
2019-12-18 11:53   ` [PATCH net-next 0/8] disable neigh update for tunnels during pmtu update Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 1/8] net: add bool confirm_neigh parameter for dst_ops.update_pmtu Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 2/8] ip6_gre: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 3/8] gtp: " Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 4/8] net/dst: add new function skb_dst_update_pmtu_no_confirm Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 5/8] tunnel: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-19 17:47       ` Guillaume Nault
2019-12-20  2:36         ` Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 6/8] vti: " Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 7/8] sit: " Hangbin Liu
2019-12-18 11:53     ` [PATCH net-next 8/8] net/dst: do not confirm neighbor for vxlan and geneve " Hangbin Liu
2019-12-19 17:49       ` Guillaume Nault
2019-12-18 12:01     ` [PATCH net-next 0/8] disable neigh update for tunnels during " Hangbin Liu
2019-12-19 17:57       ` Guillaume Nault
2019-12-20  2:48         ` Hangbin Liu
2019-12-19 17:53     ` Guillaume Nault
2019-12-20  3:25     ` [PATCHv4 net " Hangbin Liu
2019-12-20  3:25       ` [PATCHv4 net 1/8] net: add bool confirm_neigh parameter for dst_ops.update_pmtu Hangbin Liu
2019-12-20  3:25       ` [PATCHv4 net 2/8] ip6_gre: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-20  3:25       ` [PATCHv4 net 3/8] gtp: " Hangbin Liu
2019-12-21 18:35         ` Guillaume Nault
2019-12-20  3:25       ` [PATCHv4 net 4/8] net/dst: add new function skb_dst_update_pmtu_no_confirm Hangbin Liu
2019-12-20  3:25       ` [PATCHv4 net 5/8] tunnel: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-21 18:43         ` Guillaume Nault
2019-12-20  3:25       ` [PATCHv4 net 6/8] vti: " Hangbin Liu
2019-12-21 18:30         ` Guillaume Nault
2019-12-20  3:25       ` [PATCHv4 net 7/8] sit: " Hangbin Liu
2019-12-20  3:25       ` [PATCHv4 net 8/8] net/dst: do not confirm neighbor for vxlan and geneve " Hangbin Liu
2019-12-21 18:38         ` Guillaume Nault
2019-12-20 16:14       ` [PATCHv4 net 0/8] disable neigh update for tunnels during " David Ahern
2019-12-22  2:51       ` [PATCHv5 " Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 1/8] net: add bool confirm_neigh parameter for dst_ops.update_pmtu Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 2/8] ip6_gre: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 3/8] gtp: " Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 4/8] net/dst: add new function skb_dst_update_pmtu_no_confirm Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 5/8] tunnel: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 6/8] vti: " Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 7/8] sit: " Hangbin Liu
2019-12-22  2:51         ` [PATCHv5 net 8/8] net/dst: do not confirm neighbor for vxlan and geneve " Hangbin Liu
2019-12-22 22:10         ` [PATCHv5 net 0/8] disable neigh update for tunnels during " Guillaume Nault
2019-12-25  6:30         ` David Miller

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