netdev - [PATCH net-next] tcp: do not clear again skb->csum in tcp_init_nondata

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Date:   Fri, 03 Nov 2017 06:18:59 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>,
        Neal Cardwell <ncardwell@...gle.com>
Subject: [PATCH net-next] tcp: do not clear again skb->csum in
 tcp_init_nondata_skb()

From: Eric Dumazet <edumazet@...gle.com>

tcp_init_nondata_skb() is fed with freshly allocated skbs.
They already have a cleared csum field, no need to clear it again.

This is based on Neal review on commit 3b11775033dc ("tcp: do not mangle
skb->cb[] in tcp_make_synack()"), noticing I did not clear skb->csum.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: Neal Cardwell <ncardwell@...gle.com>
---
 net/ipv4/tcp_output.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 822962ece2840824db3d89993f6889780cd2ab99..0b8062274ed2bf1c2781fe7e88f0de97f6ab6e55 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -381,7 +381,6 @@ static void tcp_ecn_send(struct sock *sk, struct sk_buff *skb,
 static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
 {
 	skb->ip_summed = CHECKSUM_PARTIAL;
-	skb->csum = 0;
 
 	TCP_SKB_CB(skb)->tcp_flags = flags;
 	TCP_SKB_CB(skb)->sacked = 0;