Subject: Re: [PATCH net-next] tcp: fix build fong CONFIG_MPTCP=n

From: Florian Westphal <[email-masked]>
Date: Sat, 1 Aug 2020 11:29:43 +0200

Florian Westphal <[email-masked]> wrote:
> Eric Dumazet <[email-masked]> wrote:
> > Fixes these errors:
> > 
> > net/ipv4/syncookies.c: In function 'tcp_get_cookie_sock':
> > net/ipv4/syncookies.c:216:19: error: 'struct tcp_request_sock' has no
> > member named 'drop_req'
> >   216 |   if (tcp_rsk(req)->drop_req) {
> >       |                   ^~
> > net/ipv4/syncookies.c: In function 'cookie_tcp_reqsk_alloc':
> > net/ipv4/syncookies.c:289:27: warning: unused variable 'treq'
> > [-Wunused-variable]
> >   289 |  struct tcp_request_sock *treq;
> >       |                           ^~~~
> 
> Ugh, sorry about this.
> 
> > make[3]: *** [scripts/Makefile.build:280: net/ipv4/syncookies.o] Error 1
> > make[3]: *** Waiting for unfinished jobs....
> >
> > Fixes: 9466a1ccebbe ("mptcp: enable JOIN requests even if cookies are in use")
> > Signed-off-by: Eric Dumazet <[email-masked]>
> > Cc: Florian Westphal <[email-masked]>
> > ---
> >  net/ipv4/syncookies.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
> > index 11b20474be8310d7070750a1c7b4013f2fba2f55..f0794f0232bae749244fff35d8b96b1f561a5e87 100644
> > --- a/net/ipv4/syncookies.c
> > +++ b/net/ipv4/syncookies.c
> > @@ -213,7 +213,7 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
> >  		tcp_sk(child)->tsoffset = tsoff;
> >  		sock_rps_save_rxhash(child, skb);
> >  
> > -		if (tcp_rsk(req)->drop_req) {
> > +		if (rsk_drop_req(req)) {
> 
> This hunk breaks join self test for mptcp, but it should not. Looks like
> cookie path missed a ->is_mptcp = 1 somewhere.  Investigating.

I take that back, the failure is spurious, also sometimes occurs with
no-cookie part of test and also happens with a checkout before the
syncookie patches got merged.  I will take another look at this on
Monday.  No need to hold up this fix, so

Acked-by: Florian Westphal <[email-masked]>