On Tue, Apr 05, 2016 at 07:56:54PM -0400, David Miller wrote: > From: Cong Wang <xiyou.wangc...@gmail.com> > Date: Mon, 4 Apr 2016 13:45:02 -0700 > > > On Sat, Apr 2, 2016 at 7:33 PM, Martin KaFai Lau <ka...@fb.com> wrote: > >> One thing to note is that this patch uses the addresses from the sk > >> instead of iph when updating sk->sk_dst_cache. It is basically the > >> same logic that the __ip6_datagram_connect() is doing, so some > >> refactoring works in the first two patches. > >> > >> AFAIK, a UDP socket can become connected after sending out some > >> datagrams in un-connected state. or It can be connected > >> multiple times to different destinations. I did some quick > >> tests but I could be wrong. > >> > >> I am thinking if there could be a chance that the skb->data, which > >> has the original outgoing iph, is not related to the current > >> connected address. If it is possible, we have to specifically > >> use the addresses in the sk instead of skb->data (i.e. iph) when > >> updating the sk->sk_dst_cache. > >> > >> If we need to use the sk addresses (and other info) to find out a > >> new dst for a connected udp socket, it is better not doing it while > >> the userland is connecting to somewhere else. > >> > >> If the above case is impossible, we can keep using the info from iph to > >> do the dst update for a connected-udp sk without taking the lock. > > > > 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 think we are steadily getting closer to a version of this fix that > we have some agreement on, right? > > Martin can you address Cong's feedback and spin another version of this > series? Dave, I will spin v2 shortly with some minor changes.
Cong, I believe the loose ends have been tied up after the last email thread since last Thursday?
