| From 629737359198b16c0aadde2237db2e00c4aa4863 Mon Sep 17 00:00:00 2001 |
| From: "Yan, Zheng" <zheng.z.yan@intel.com> |
| Date: Sun, 2 Oct 2011 04:21:50 +0000 |
| Subject: tcp: properly update lost_cnt_hint during shifting |
| |
| |
| From: "Yan, Zheng" <zheng.z.yan@intel.com> |
| |
| [ 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 <zheng.z.yan@intel.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| --- |
| net/ipv4/tcp_input.c | 4 +--- |
| 1 file changed, 1 insertion(+), 3 deletions(-) |
| |
| --- a/net/ipv4/tcp_input.c |
| +++ b/net/ipv4/tcp_input.c |
| @@ -1380,9 +1380,7 @@ static int tcp_shifted_skb(struct sock * |
| |
| 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; |