tcp: mark tcp_congestion_ops read_mostly

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 71d5f2f..62f775c 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -405,7 +405,7 @@
 		hystart_update(sk, delay);
 }
 
-static struct tcp_congestion_ops cubictcp = {
+static struct tcp_congestion_ops cubictcp __read_mostly = {
 	.init		= bictcp_init,
 	.ssthresh	= bictcp_recalc_ssthresh,
 	.cong_avoid	= bictcp_cong_avoid,