netdev - [PATCH 1/1] tcp: Honor the eor bit in tcp_mtu

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Date:   Mon,  5 Feb 2018 17:11:26 +0200
From:   Ilya Lesokhin <ilyal@...lanox.com>
To:     netdev@...r.kernel.org, kafai@...com
Cc:     borisp@...lanox.com, Ilya Lesokhin <ilyal@...lanox.com>
Subject: [PATCH 1/1] tcp: Honor the eor bit in tcp_mtu_probe

Avoid SKB coalescing if eor bit is set in one of the relevant
SKBs.

Fixes: c134ecb87817 ("tcp: Make use of MSG_EOR in tcp_sendmsg")
Signed-off-by: Ilya Lesokhin <ilyal@...lanox.com>
---
 net/ipv4/tcp_output.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e9f985e42405..c8cc679f1779 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2099,6 +2099,17 @@ static int tcp_mtu_probe(struct sock *sk)
 			return 0;
 	}
 
+	len = probe_size;
+	tcp_for_write_queue_from_safe(skb, next, sk) {
+		if (len <= skb->len)
+			break;
+
+		if (unlikely(TCP_SKB_CB(skb)->eor))
+			return -1;
+
+		len -= skb->len;
+	}
+
 	/* We're allowed to probe.  Build it now. */
 	nskb = sk_stream_alloc_skb(sk, probe_size, GFP_ATOMIC, false);
 	if (!nskb)
-- 
2.15.0.317.g14c63a9