tcp: Namespace-ify sysctl_tcp_rmem and sysctl_tcp_wmem

Note that when a new netns is created, it inherits its
sysctl_tcp_rmem and sysctl_tcp_wmem from initial netns.

This change is needed so that we can refine TCP rcvbuf autotuning,
to take RTT into consideration.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index a82b440..ef0ff33 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -441,22 +441,6 @@ static struct ctl_table ipv4_table[] = {
 		.proc_handler	= proc_doulongvec_minmax,
 	},
 	{
-		.procname	= "tcp_wmem",
-		.data		= &sysctl_tcp_wmem,
-		.maxlen		= sizeof(sysctl_tcp_wmem),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-	},
-	{
-		.procname	= "tcp_rmem",
-		.data		= &sysctl_tcp_rmem,
-		.maxlen		= sizeof(sysctl_tcp_rmem),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-	},
-	{
 		.procname	= "tcp_low_latency",
 		.data		= &sysctl_tcp_low_latency,
 		.maxlen		= sizeof(int),
@@ -1164,6 +1148,22 @@ static struct ctl_table ipv4_net_table[] = {
 		.extra1		= &zero,
 		.extra2		= &thousand,
 	},
+	{
+		.procname	= "tcp_wmem",
+		.data		= &init_net.ipv4.sysctl_tcp_wmem,
+		.maxlen		= sizeof(init_net.ipv4.sysctl_tcp_wmem),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
+	},
+	{
+		.procname	= "tcp_rmem",
+		.data		= &init_net.ipv4.sysctl_tcp_rmem,
+		.maxlen		= sizeof(init_net.ipv4.sysctl_tcp_rmem),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
+	},
 	{ }
 };