4.9-stable review patch. If anyone has any objections, please let me know.
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From: Ilya Lesokhin ilyal@mellanox.com
[ 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@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 {