[PATCH v2 1/1] tcp: Honor the eor bit in tcp_mtu_probe

[Ilya Lesokhin]

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 <il...@mellanox.com>
---
 net/ipv4/tcp_output.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e9f985e42405..70c5bb4958c3 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)
@@ -2134,6 +2145,7 @@ static int tcp_mtu_probe(struct sock *sk)
                        /* We've eaten all the data from this skb.
                         * Throw it away. */
                        TCP_SKB_CB(nskb)->tcp_flags |= 
TCP_SKB_CB(skb)->tcp_flags;
+                       TCP_SKB_CB(nskb)->eor = TCP_SKB_CB(skb)->eor;
                        tcp_unlink_write_queue(skb, sk);
                        sk_wmem_free_skb(sk, skb);
                } else {
-- 
2.15.0.317.g14c63a9