tcp: fix regression in urgent data handling

Stephan Springl found that commit 1402d366019fed "tcp: introduce
tcp_try_coalesce" introduced a regression for rlogin

It turns out problem comes from TCP urgent data handling and
a change in behavior in input path.

rlogin sends two one-byte packets with URG ptr set, and when next data
frame is coalesced, we lack sk_data_ready() calls to wakeup consumer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Stephan Springl <springl-k@lar.bfw.de>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 6e38c6c23caa..d377f4854cb8 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4661,7 +4661,7 @@ queue_and_out:
 
                 if (eaten > 0)
                         kfree_skb_partial(skb, fragstolen);
-                else if (!sock_flag(sk, SOCK_DEAD))
+                if (!sock_flag(sk, SOCK_DEAD))
                         sk->sk_data_ready(sk, 0);
                 return;
         }
@@ -5556,8 +5556,7 @@ no_ack:
 #endif
                         if (eaten)
                                 kfree_skb_partial(skb, fragstolen);
-                        else
-                                sk->sk_data_ready(sk, 0);
+                        sk->sk_data_ready(sk, 0);
                         return 0;
                 }
         }