ipv4: add fib_net_exit_batch()

cleanup_net() is competing with other rtnl users.

Instead of acquiring rtnl at each fib_net_exit() invocation,
add fib_net_exit_batch() so that rtnl is acquired once.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index c60e1d1ed2b0a373c0b21e250ef97bb03d92b777..54811728d90654aa341b907a9ae95cfbd75054bb 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1556,7 +1556,7 @@ static void ip_fib_net_exit(struct net *net)
 {
        int i;
 
-       rtnl_lock();
+       ASSERT_RTNL();
 #ifdef CONFIG_IP_MULTIPLE_TABLES
        RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
        RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
@@ -1581,7 +1581,7 @@ static void ip_fib_net_exit(struct net *net)
 #ifdef CONFIG_IP_MULTIPLE_TABLES
        fib4_rules_exit(net);
 #endif
-       rtnl_unlock();
+
        kfree(net->ipv4.fib_table_hash);
        fib4_notifier_exit(net);
 }
@@ -1608,7 +1608,9 @@ out:
 out_proc:
        nl_fib_lookup_exit(net);
 out_nlfl:
+       rtnl_lock();
        ip_fib_net_exit(net);
+       rtnl_unlock();
        goto out;
 }
 
@@ -1616,12 +1618,23 @@ static void __net_exit fib_net_exit(struct net *net)
 {
        fib_proc_exit(net);
        nl_fib_lookup_exit(net);
-       ip_fib_net_exit(net);
+}
+
+static void __net_exit fib_net_exit_batch(struct list_head *net_list)
+{
+       struct net *net;
+
+       rtnl_lock();
+       list_for_each_entry(net, net_list, exit_list)
+               ip_fib_net_exit(net);
+
+       rtnl_unlock();
 }
 
 static struct pernet_operations fib_net_ops = {
        .init = fib_net_init,
        .exit = fib_net_exit,
+       .exit_batch = fib_net_exit_batch,
 };
 
 void __init ip_fib_init(void)