tcp: Namespace-ify sysctl_tcp_limit_output_bytes

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -146,6 +146,7 @@ struct netns_ipv4 {
 	int sysctl_tcp_moderate_rcvbuf;
 	int sysctl_tcp_tso_win_divisor;
 	int sysctl_tcp_workaround_signed_windows;
+	int sysctl_tcp_limit_output_bytes;
 	struct inet_timewait_death_row tcp_death_row;
 	int sysctl_max_syn_backlog;
 	int sysctl_tcp_fastopen;

include/net/tcp.h

@@ -250,7 +250,6 @@ extern int sysctl_tcp_rmem[3];
 
 #define TCP_RACK_LOSS_DETECTION  0x1 /* Use RACK to detect losses */
 
-extern int sysctl_tcp_limit_output_bytes;
 extern int sysctl_tcp_challenge_ack_limit;
 extern int sysctl_tcp_min_tso_segs;
 extern int sysctl_tcp_min_rtt_wlen;

net/ipv4/sysctl_net_ipv4.c

@@ -457,13 +457,6 @@ static struct ctl_table ipv4_table[] = {
 		.maxlen		= TCP_CA_NAME_MAX,
 		.proc_handler	= proc_tcp_congestion_control,
 	},
-	{
-		.procname	= "tcp_limit_output_bytes",
-		.data		= &sysctl_tcp_limit_output_bytes,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec
-	},
 	{
 		.procname	= "tcp_challenge_ack_limit",
 		.data		= &sysctl_tcp_challenge_ack_limit,
@@ -1145,6 +1138,13 @@ static struct ctl_table ipv4_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+	{
+		.procname	= "tcp_limit_output_bytes",
+		.data		= &init_net.ipv4.sysctl_tcp_limit_output_bytes,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
 	{ }
 };
 

net/ipv4/tcp_ipv4.c

@@ -2499,6 +2499,8 @@ static int __net_init tcp_sk_init(struct net *net)
 	 * which are too large can cause TCP streams to be bursty.
 	 */
 	net->ipv4.sysctl_tcp_tso_win_divisor = 3;
+	/* Default TSQ limit of four TSO segments */
+	net->ipv4.sysctl_tcp_limit_output_bytes = 262144;
 
 	net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
 	spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);

net/ipv4/tcp_output.c

@@ -45,9 +45,6 @@
 
 #include <trace/events/tcp.h>
 
-/* Default TSQ limit of four TSO segments */
-int sysctl_tcp_limit_output_bytes __read_mostly = 262144;
-
 static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 			   int push_one, gfp_t gfp);
 
@@ -2215,7 +2212,8 @@ static bool tcp_small_queue_check(struct sock *sk, const struct sk_buff *skb,
 	unsigned int limit;
 
 	limit = max(2 * skb->truesize, sk->sk_pacing_rate >> 10);
-	limit = min_t(u32, limit, sysctl_tcp_limit_output_bytes);
+	limit = min_t(u32, limit,
+		      sock_net(sk)->ipv4.sysctl_tcp_limit_output_bytes);
 	limit <<= factor;
 
 	if (refcount_read(&sk->sk_wmem_alloc) > limit) {