Commit 76174004
(tcp: do not slow start when cwnd equals ssthresh )
introduced regression in TCP YeAH. Using 100ms delay 1% loss virtual
ethernet link kernel 4.2 shows bandwidth ~500KB/s for single TCP
connection and kernel 4.3 and above (including 4.8-rc4) shows bandwidth
~100KB/s.
   That is caused by stalled cwnd when cwnd equals ssthresh. This patch
fixes it by proper increasing cwnd in this case.
Signed-off-by: NArtem Germanov <agermanov@anchorfree.com>
Acked-by: NDmitry Adamushko <d.adamushko@anchorfree.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>