netns: Register net/core/ sysctls at read-only root.

Most of the net/core/xxx sysctls are read-only now, but this
goal is achieved with excessive memory consumption in each
namespace - the whole table is cloned and most of the entries
in it are ~= 0222.

Split it into two parts and register (the largest) one at the
read-only root.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 5fc801057244b797aafce24665147987cdd877ef..a570e2af22cb78d0994d41d19e83a29a5e7c5527 100644 (file)
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -124,14 +124,6 @@ static struct ctl_table net_core_table[] = {
        },
 #endif /* CONFIG_XFRM */
 #endif /* CONFIG_NET */
-       {
-               .ctl_name       = NET_CORE_SOMAXCONN,
-               .procname       = "somaxconn",
-               .data           = &init_net.core.sysctl_somaxconn,
-               .maxlen         = sizeof(int),
-               .mode           = 0644,
-               .proc_handler   = &proc_dointvec
-       },
        {
                .ctl_name       = NET_CORE_BUDGET,
                .procname       = "netdev_budget",
@@ -151,6 +143,18 @@ static struct ctl_table net_core_table[] = {
        { .ctl_name = 0 }
 };
 
+static struct ctl_table netns_core_table[] = {
+       {
+               .ctl_name       = NET_CORE_SOMAXCONN,
+               .procname       = "somaxconn",
+               .data           = &init_net.core.sysctl_somaxconn,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = &proc_dointvec
+       },
+       { .ctl_name = 0 }
+};
+
 static __net_initdata struct ctl_path net_core_path[] = {
        { .procname = "net", .ctl_name = CTL_NET, },
        { .procname = "core", .ctl_name = NET_CORE, },
@@ -159,23 +163,17 @@ static __net_initdata struct ctl_path net_core_path[] = {
 
 static __net_init int sysctl_core_net_init(struct net *net)
 {
-       struct ctl_table *tbl, *tmp;
+       struct ctl_table *tbl;
 
        net->core.sysctl_somaxconn = SOMAXCONN;
 
-       tbl = net_core_table;
+       tbl = netns_core_table;
        if (net != &init_net) {
-               tbl = kmemdup(tbl, sizeof(net_core_table), GFP_KERNEL);
+               tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);
                if (tbl == NULL)
                        goto err_dup;
 
-               for (tmp = tbl; tmp->procname; tmp++) {
-                       if (tmp->data >= (void *)&init_net &&
-                                       tmp->data < (void *)(&init_net + 1))
-                               tmp->data += (char *)net - (char *)&init_net;
-                       else
-                               tmp->mode &= ~0222;
-               }
+               tbl[0].data = &net->core.sysctl_somaxconn;
        }
 
        net->core.sysctl_hdr = register_net_sysctl_table(net,
@@ -186,7 +184,7 @@ static __net_init int sysctl_core_net_init(struct net *net)
        return 0;
 
 err_reg:
-       if (tbl != net_core_table)
+       if (tbl != netns_core_table)
                kfree(tbl);
 err_dup:
        return -ENOMEM;
@@ -198,7 +196,7 @@ static __net_exit void sysctl_core_net_exit(struct net *net)
 
        tbl = net->core.sysctl_hdr->ctl_table_arg;
        unregister_net_sysctl_table(net->core.sysctl_hdr);
-       BUG_ON(tbl == net_core_table);
+       BUG_ON(tbl == netns_core_table);
        kfree(tbl);
 }
 
@@ -209,6 +207,7 @@ static __net_initdata struct pernet_operations sysctl_core_ops = {
 
 static __init int sysctl_core_init(void)
 {
+       register_net_sysctl_rotable(net_core_path, net_core_table);
        return register_pernet_subsys(&sysctl_core_ops);
 }