From b00654416d4baccf2269ec888e55d6df069cd36f Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Sun, 2 Oct 2011 04:21:50 +0000 Subject: [PATCH] tcp: properly update lost_cnt_hint during shifting [ Upstream commit 1e5289e121372a3494402b1b131b41bfe1cf9b7f ] lost_skb_hint is used by tcp_mark_head_lost() to mark the first unhandled skb. lost_cnt_hint is the number of packets or sacked packets before the lost_skb_hint; When shifting a skb that is before the lost_skb_hint, if tcp_is_fack() is ture, the skb has already been counted in the lost_cnt_hint; if tcp_is_fack() is false, tcp_sacktag_one() will increase the lost_cnt_hint. So tcp_shifted_skb() does not need to adjust the lost_cnt_hint by itself. When shifting a skb that is equal to lost_skb_hint, the shifted packets will not be counted by tcp_mark_head_lost(). So tcp_shifted_skb() should adjust the lost_cnt_hint even tcp_is_fack(tp) is true. Signed-off-by: Zheng Yan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index b6771f9..c68040f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1380,9 +1380,7 @@ static int tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, BUG_ON(!pcount); - /* Tweak before seqno plays */ - if (!tcp_is_fack(tp) && tcp_is_sack(tp) && tp->lost_skb_hint && - !before(TCP_SKB_CB(tp->lost_skb_hint)->seq, TCP_SKB_CB(skb)->seq)) + if (skb == tp->lost_skb_hint) tp->lost_cnt_hint += pcount; TCP_SKB_CB(prev)->end_seq += shifted; -- 2.7.4