tcp: Namespace-ify sysctl_tcp_workaround_signed_windows

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 60df3ab..5bbed67 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -45,11 +45,6 @@
 
 #include <trace/events/tcp.h>
 
-/* People can turn this on to work with those rare, broken TCPs that
- * interpret the window field as a signed quantity.
- */
-int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
-
 /* Default TSQ limit of four TSO segments */
 int sysctl_tcp_limit_output_bytes __read_mostly = 262144;
 
@@ -196,7 +191,7 @@ u32 tcp_default_init_rwnd(u32 mss)
  * be a multiple of mss if possible. We assume here that mss >= 1.
  * This MUST be enforced by all callers.
  */
-void tcp_select_initial_window(int __space, __u32 mss,
+void tcp_select_initial_window(const struct sock *sk, int __space, __u32 mss,
 			       __u32 *rcv_wnd, __u32 *window_clamp,
 			       int wscale_ok, __u8 *rcv_wscale,
 			       __u32 init_rcv_wnd)
@@ -220,7 +215,7 @@ void tcp_select_initial_window(int __space, __u32 mss,
 	 * which we interpret as a sign the remote TCP is not
 	 * misinterpreting the window field as a signed quantity.
 	 */
-	if (sysctl_tcp_workaround_signed_windows)
+	if (sock_net(sk)->ipv4.sysctl_tcp_workaround_signed_windows)
 		(*rcv_wnd) = min(space, MAX_TCP_WINDOW);
 	else
 		(*rcv_wnd) = space;
@@ -280,7 +275,8 @@ static u16 tcp_select_window(struct sock *sk)
 	/* Make sure we do not exceed the maximum possible
 	 * scaled window.
 	 */
-	if (!tp->rx_opt.rcv_wscale && sysctl_tcp_workaround_signed_windows)
+	if (!tp->rx_opt.rcv_wscale &&
+	    sock_net(sk)->ipv4.sysctl_tcp_workaround_signed_windows)
 		new_win = min(new_win, MAX_TCP_WINDOW);
 	else
 		new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale));
@@ -3349,7 +3345,7 @@ static void tcp_connect_init(struct sock *sk)
 	if (rcv_wnd == 0)
 		rcv_wnd = dst_metric(dst, RTAX_INITRWND);
 
-	tcp_select_initial_window(tcp_full_space(sk),
+	tcp_select_initial_window(sk, tcp_full_space(sk),
 				  tp->advmss - (tp->rx_opt.ts_recent_stamp ? tp->tcp_header_len - sizeof(struct tcphdr) : 0),
 				  &tp->rcv_wnd,
 				  &tp->window_clamp,