sctp: optimize the sctp_sysctl_net_register

Here, when the net is init_net, we needn't to kmemdup the ctl_table
again. So add a check for net. Also we can save some memory.

Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index d354de5..35c8923 100644 (file)
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -402,15 +402,18 @@ static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
 
 int sctp_sysctl_net_register(struct net *net)
 {
-       struct ctl_table *table;
-       int i;
+       struct ctl_table *table = sctp_net_table;
+
+       if (!net_eq(net, &init_net)) {
+               int i;
 
-       table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
-       if (!table)
-               return -ENOMEM;
+               table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
+               if (!table)
+                       return -ENOMEM;
 
-       for (i = 0; table[i].data; i++)
-               table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
+               for (i = 0; table[i].data; i++)
+                       table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
+       }
 
        net->sctp.sysctl_header = register_net_sysctl(net, "net/sctp", table);
        return 0;