tcp: Namespace-ify sysctl_tcp_default_congestion_control

Make default TCP default congestion control to a per namespace
value. This changes default congestion control to a pointer to congestion ops
(rather than implicit as first element of available lsit).

The congestion control setting of new namespaces is inherited
from the current setting of the root namespace.

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

1 files changed, 11 insertions, 8 deletions

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index ef0ff3357a44..93e172118a94 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -201,6 +201,8 @@ static int ipv4_ping_group_range(struct ctl_table *table, int write,
 static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
                                        void __user *buffer, size_t *lenp, loff_t *ppos)
 {
+        struct net *net = container_of(ctl->data, struct net,
+                                       ipv4.tcp_congestion_control);
         char val[TCP_CA_NAME_MAX];
         struct ctl_table tbl = {
                 .data = val,
@@ -208,11 +210,11 @@ static int proc_tcp_congestion_control(struct ctl_table *ctl, int write,
         };
         int ret;
 
-        tcp_get_default_congestion_control(val);
+        tcp_get_default_congestion_control(net, val);
 
         ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
         if (write && ret == 0)
-                ret = tcp_set_default_congestion_control(val);
+                ret = tcp_set_default_congestion_control(net, val);
         return ret;
 }
 
@@ -447,12 +449,6 @@ static struct ctl_table ipv4_table[] = {
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec
         },
-        {
-                .procname       = "tcp_congestion_control",
-                .mode           = 0644,
-                .maxlen         = TCP_CA_NAME_MAX,
-                .proc_handler   = proc_tcp_congestion_control,
-        },
 #ifdef CONFIG_NETLABEL
         {
                 .procname       = "cipso_cache_enable",
@@ -764,6 +760,13 @@ static struct ctl_table ipv4_net_table[] = {
         },
 #endif
         {
+                .procname       = "tcp_congestion_control",
+                .data           = &init_net.ipv4.tcp_congestion_control,
+                .mode           = 0644,
+                .maxlen         = TCP_CA_NAME_MAX,
+                .proc_handler   = proc_tcp_congestion_control,
+        },
+        {
                 .procname       = "tcp_keepalive_time",
                 .data           = &init_net.ipv4.sysctl_tcp_keepalive_time,
                 .maxlen         = sizeof(int),