From 6c09fa09d468d730eecd7122122175da772d3b09 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Mar 2015 08:03:06 -0800 Subject: [PATCH] tcp: align tcp_xmit_size_goal() on tcp_tso_autosize() With some mss values, it is possible tcp_xmit_size_goal() puts one segment more in TSO packet than tcp_tso_autosize(). We send then one TSO packet followed by one single MSS. It is not a serious bug, but we can do slightly better, especially for drivers using netif_set_gso_max_size() to lower gso_max_size. Using same formula avoids these corner cases and makes tcp_xmit_size_goal() a bit faster. Signed-off-by: Eric Dumazet Fixes: 605ad7f184b6 ("tcp: refine TSO autosizing") Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 9d72a0fcd928..995a2259bcfc 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -835,17 +835,13 @@ static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now, int large_allowed) { struct tcp_sock *tp = tcp_sk(sk); - u32 new_size_goal, size_goal, hlen; + u32 new_size_goal, size_goal; if (!large_allowed || !sk_can_gso(sk)) return mss_now; - /* Maybe we should/could use sk->sk_prot->max_header here ? */ - hlen = inet_csk(sk)->icsk_af_ops->net_header_len + - inet_csk(sk)->icsk_ext_hdr_len + - tp->tcp_header_len; - - new_size_goal = sk->sk_gso_max_size - 1 - hlen; + /* Note : tcp_tso_autosize() will eventually split this later */ + new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER; new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal); /* We try hard to avoid divides here */ -- 2.30.2