On Tue, Aug 27, 2019 at 4:07 PM Eric Dumazet <eduma...@google.com> wrote: > > On Tue, Aug 27, 2019 at 9:09 PM Willem de Bruijn > <willemdebruijn.ker...@gmail.com> wrote: > > > > From: Willem de Bruijn <will...@google.com> > > > > TCP associates tx timestamp requests with a byte in the bytestream. > > If merging skbs in tcp_mtu_probe, migrate the tstamp request. > > > > Similar to MSG_EOR, do not allow moving a timestamp from any segment > > in the probe but the last. This to avoid merging multiple timestamps. > > > > Tested with the packetdrill script at > > https://github.com/wdebruij/packetdrill/commits/mtu_probe-1 > > > > Link: http://patchwork.ozlabs.org/patch/1143278/#2232897 > > Fixes: 4ed2d765dfac ("net-timestamp: TCP timestamping") > > Signed-off-by: Willem de Bruijn <will...@google.com> > > --- > > net/ipv4/tcp_output.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > > index 5c46bc4c7e8d..42abc9bd687a 100644 > > --- a/net/ipv4/tcp_output.c > > +++ b/net/ipv4/tcp_output.c > > @@ -2053,7 +2053,7 @@ static bool tcp_can_coalesce_send_queue_head(struct > > sock *sk, int len) > > if (len <= skb->len) > > break; > > > > - if (unlikely(TCP_SKB_CB(skb)->eor)) > > + if (unlikely(TCP_SKB_CB(skb)->eor) || > > tcp_has_tx_tstamp(skb)) > > return false; > > > > len -= skb->len; > > @@ -2170,6 +2170,7 @@ static int tcp_mtu_probe(struct sock *sk) > > * we need to propagate it to the new skb. > > */ > > TCP_SKB_CB(nskb)->eor = TCP_SKB_CB(skb)->eor; > > + tcp_skb_collapse_tstamp(nskb, skb); > > nit: maybe rename tcp_skb_collapse_tstamp() to tcp_skb_tstamp_copy() > or something ? > > Its name came from the fact that it was only used from > tcp_collapse_retrans(), but it will no > longer be the case after your fix.
Sure, that's more descriptive. One caveat, the function is exposed in a header, so it's a bit more churn. If you don't mind that, I'll send the v2.
