4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ilya Lesokhin <ilyal@xxxxxxxxxxxx>
[ Upstream commit 808cf9e38cd7923036a99f459ccc8cf2955e47af ]
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@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_output.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1907,6 +1907,24 @@ static inline void tcp_mtu_check_reprobe
}
}
+static bool tcp_can_coalesce_send_queue_head(struct sock *sk, int len)
+{
+ struct sk_buff *skb, *next;
+
+ skb = tcp_send_head(sk);
+ tcp_for_write_queue_from_safe(skb, next, sk) {
+ if (len <= skb->len)
+ break;
+
+ if (unlikely(TCP_SKB_CB(skb)->eor))
+ return false;
+
+ len -= skb->len;
+ }
+
+ return true;
+}
+
/* Create a new MTU probe if we are ready.
* MTU probe is regularly attempting to increase the path MTU by
* deliberately sending larger packets. This discovers routing
@@ -1979,6 +1997,9 @@ static int tcp_mtu_probe(struct sock *sk
return 0;
}
+ if (!tcp_can_coalesce_send_queue_head(sk, probe_size))
+ return -1;
+
/* We're allowed to probe. Build it now. */
nskb = sk_stream_alloc_skb(sk, probe_size, GFP_ATOMIC, false);
if (!nskb)
@@ -2014,6 +2035,10 @@ 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;
+ /* If this is the last SKB we copy and eor is set
+ * we need to propagate it to the new skb.
+ */
+ TCP_SKB_CB(nskb)->eor = TCP_SKB_CB(skb)->eor;
tcp_unlink_write_queue(skb, sk);
sk_wmem_free_skb(sk, skb);
} else {