tcp: Fix thinko making the not-shiftable to cover S|R as well

S|R won't result in S if just SACK is received. DSACK is
another story (but it is covered correctly already).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 63c3ef6d4a1c..33902f6799c3 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1481,7 +1481,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
 
         /* Normally R but no L won't result in plain S */
         if (!dup_sack &&
-            (TCP_SKB_CB(skb)->sacked & TCPCB_TAGBITS) == TCPCB_SACKED_RETRANS)
+            (TCP_SKB_CB(skb)->sacked & (TCPCB_LOST|TCPCB_SACKED_RETRANS)) == TCPCB_SACKED_RETRANS)
                 goto fallback;
         if (!skb_can_shift(skb))
                 goto fallback;