diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 9a8970b..98e0fd2 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -438,6 +438,7 @@
 	NET_CIPSOV4_RBM_STRICTVALID=121,
 	NET_TCP_AVAIL_CONG_CONTROL=122,
 	NET_TCP_ALLOWED_CONG_CONTROL=123,
+	NET_TCP_MAX_SSTHRESH=124,
 };
 
 enum {
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 7fd6b77..6d09f50 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -230,6 +230,7 @@
 extern int sysctl_tcp_base_mss;
 extern int sysctl_tcp_workaround_signed_windows;
 extern int sysctl_tcp_slow_start_after_idle;
+extern int sysctl_tcp_max_ssthresh;
 
 extern atomic_t tcp_memory_allocated;
 extern atomic_t tcp_sockets_allocated;