tcp: fix comment for tp->highest_sack

There was an off-by-one error in the comments describing the
highest_sack field in struct tcp_sock. The comments previously claimed
that it was the "start sequence of the highest skb with SACKed
bit". This commit fixes the comments to note that it is the "start
sequence of the skb just *after* the highest skb with SACKed bit".

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 46a85c9e1f2..3c7ffdb40dc 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -412,7 +412,8 @@ struct tcp_sock {
 
         struct tcp_sack_block recv_sack_cache[4];
 
-        struct sk_buff *highest_sack;   /* highest skb with SACK received
+        struct sk_buff *highest_sack;   /* skb just after the highest
+                                         * skb with SACKed bit set
                                          * (validity guaranteed only if
                                          * sacked_out > 0)
                                          */