net: Allow fib_rule_unregister to batch

Refactor the code so fib_rules_register always takes a template instead
of the actual fib_rules_ops structure that will be used.  This is
required for network namespace support so 2 out of the 3 callers already
do this, it allows the error handling to be made common, and it allows
fib_rules_unregister to free the template for hte caller.

Modify fib_rules_unregister to use call_rcu instead of syncrhonize_rcu
to allw multiple namespaces to be cleaned up in the same rcu grace
period.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 15 deletions

diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 3b38f49f2c28..b7aa7c64cc4a 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -264,16 +264,14 @@ static struct fib_rules_ops fib6_rules_ops_template = {
 
 static int fib6_rules_net_init(struct net *net)
 {
+        struct fib_rules_ops *ops;
         int err = -ENOMEM;
 
-        net->ipv6.fib6_rules_ops = kmemdup(&fib6_rules_ops_template,
-                                           sizeof(*net->ipv6.fib6_rules_ops),
-                                           GFP_KERNEL);
-        if (!net->ipv6.fib6_rules_ops)
-                goto out;
+        ops = fib_rules_register(&fib6_rules_ops_template, net);
+        if (IS_ERR(ops))
+                return PTR_ERR(ops);
+        net->ipv6.fib6_rules_ops = ops;
 
-        net->ipv6.fib6_rules_ops->fro_net = net;
-        INIT_LIST_HEAD(&net->ipv6.fib6_rules_ops->rules_list);
 
         err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
                                    RT6_TABLE_LOCAL, 0);
@@ -283,25 +281,19 @@ static int fib6_rules_net_init(struct net *net)
         err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
                                    0x7FFE, RT6_TABLE_MAIN, 0);
         if (err)
-                goto out_fib6_default_rule_add;
+                goto out_fib6_rules_ops;
 
-        err = fib_rules_register(net->ipv6.fib6_rules_ops);
-        if (err)
-                goto out_fib6_default_rule_add;
 out:
         return err;
 
-out_fib6_default_rule_add:
-        fib_rules_cleanup_ops(net->ipv6.fib6_rules_ops);
 out_fib6_rules_ops:
-        kfree(net->ipv6.fib6_rules_ops);
+        fib_rules_unregister(ops);
         goto out;
 }
 
 static void fib6_rules_net_exit(struct net *net)
 {
         fib_rules_unregister(net->ipv6.fib6_rules_ops);
-        kfree(net->ipv6.fib6_rules_ops);
 }
 
 static struct pernet_operations fib6_rules_net_ops = {