ipv4: Namespaceify tcp_notsent_lowat sysctl knob

Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -106,6 +106,7 @@ struct netns_ipv4 {
 	int sysctl_tcp_retries2;
 	int sysctl_tcp_orphan_retries;
 	int sysctl_tcp_fin_timeout;
+	unsigned int sysctl_tcp_notsent_lowat;
 
 	struct ping_group_range ping_group_range;
 

include/net/tcp.h

@@ -267,7 +267,6 @@ extern int sysctl_tcp_thin_dupack;
 extern int sysctl_tcp_early_retrans;
 extern int sysctl_tcp_limit_output_bytes;
 extern int sysctl_tcp_challenge_ack_limit;
-extern unsigned int sysctl_tcp_notsent_lowat;
 extern int sysctl_tcp_min_tso_segs;
 extern int sysctl_tcp_min_rtt_wlen;
 extern int sysctl_tcp_autocorking;
@@ -1682,7 +1681,8 @@ void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
 
 static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
 {
-	return tp->notsent_lowat ?: sysctl_tcp_notsent_lowat;
+	struct net *net = sock_net((struct sock *)tp);
+	return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat;
 }
 
 static inline bool tcp_stream_memory_free(const struct sock *sk)

net/ipv4/sysctl_net_ipv4.c

@@ -455,13 +455,6 @@ static struct ctl_table ipv4_table[] = {
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &one,
 	},
-	{
-		.procname	= "tcp_notsent_lowat",
-		.data		= &sysctl_tcp_notsent_lowat,
-		.maxlen		= sizeof(sysctl_tcp_notsent_lowat),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
-	},
 	{
 		.procname	= "tcp_rmem",
 		.data		= &sysctl_tcp_rmem,
@@ -960,6 +953,13 @@ static struct ctl_table ipv4_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
+	{
+		.procname	= "tcp_notsent_lowat",
+		.data		= &init_net.ipv4.sysctl_tcp_notsent_lowat,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
 	{ }
 };
 

net/ipv4/tcp_ipv4.c

@@ -2395,6 +2395,7 @@ static int __net_init tcp_sk_init(struct net *net)
 	net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
 	net->ipv4.sysctl_tcp_orphan_retries = 0;
 	net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT;
+	net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX;
 
 	return 0;
 fail:

net/ipv4/tcp_output.c

@@ -62,9 +62,6 @@ int sysctl_tcp_tso_win_divisor __read_mostly = 3;
 /* By default, RFC2861 behavior.  */
 int sysctl_tcp_slow_start_after_idle __read_mostly = 1;
 
-unsigned int sysctl_tcp_notsent_lowat __read_mostly = UINT_MAX;
-EXPORT_SYMBOL(sysctl_tcp_notsent_lowat);
-
 static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
 			   int push_one, gfp_t gfp);