From 8f26fb1c1ed81c33f5d87c5936f4d9d1b4118918 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 15 Oct 2013 12:24:54 -0700 Subject: [PATCH] tcp: remove the sk_can_gso() check from tcp_set_skb_tso_segs() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit sk_can_gso() should only be used as a hint in tcp_sendmsg() to build GSO packets in the first place. (As a performance hint) Once we have GSO packets in write queue, we can not decide they are no longer GSO only because flow now uses a route which doesn't handle TSO/GSO. Core networking stack handles the case very well for us, all we need is keeping track of packet counts in MSS terms, regardless of segmentation done later (in GSO or hardware) Right now, if tcp_fragment() splits a GSO packet in two parts, @left and @right, and route changed through a non GSO device, both @left and @right have pcount set to 1, which is wrong, and leads to incorrect packet_count tracking. This problem was added in commit d5ac99a648 ("[TCP]: skb pcount with MTU discovery") Signed-off-by: Eric Dumazet Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Reported-by: Maciej Żenczykowski Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 8fad1c155688..d46f2143305c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -989,8 +989,7 @@ static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb, /* Make sure we own this skb before messing gso_size/gso_segs */ WARN_ON_ONCE(skb_cloned(skb)); - if (skb->len <= mss_now || !sk_can_gso(sk) || - skb->ip_summed == CHECKSUM_NONE) { + if (skb->len <= mss_now || skb->ip_summed == CHECKSUM_NONE) { /* Avoid the costly divide in the normal * non-TSO case. */