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From: Martin KaFai Lau <kafai@fb.com>
Subject: Re: [RFC PATCH net 3/4] ipv6: datagram: Update dst cache of a
 connected datagram sk during pmtu update
Date: Tue, 5 Apr 2016 17:11:41 -0700
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Cc: netdev <netdev@vger.kernel.org>,
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To: Cong Wang <xiyou.wangcong@gmail.com>
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On Mon, Apr 04, 2016 at 01:45:02PM -0700, Cong Wang wrote:
> I see your point, but calling __ip6_datagram_connect() seems overkill
> here, we don't need to update so many things in the pmtu update context,
> at least IPv4 doesn't do that either. I don't think you have to do that.
>
> So why just updating the dst cache (also some addr cache) here is not
> enough?
I am not sure I understand.  I could be missing something.

This patch uses ip6_datagram_dst_update() to do the route lookup and
sk->sk_dst_cache update.  ip6_datagram_dst_update() is
created in the first two refactoring patches and is also used by
__ip6_datagram_connect().

Which operations in ip6_datagram_dst_update() could be saved
during the pmtu update?