nexthop: convert nexthop_net_exit_batch to exit_batch_rtnl method

exit_batch_rtnl() is called while RTNL is held.

This saves one rtnl_lock()/rtnl_unlock() pair.

We also need to create nexthop_net_exit()
to make sure net->nexthop.devhash is not freed too soon,
otherwise we will not be able to unregister netdev
from exit_batch_rtnl() methods.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20240206144313.2050392-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index bbff68b5b5d4a1d835c9785fbe84f4cab32a1db0..7270a8631406c508eebf85c42eb29a5268d7d7cf 100644 (file)
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -3737,16 +3737,20 @@ out:
 }
 EXPORT_SYMBOL(nexthop_res_grp_activity_update);
 
-static void __net_exit nexthop_net_exit_batch(struct list_head *net_list)
+static void __net_exit nexthop_net_exit_batch_rtnl(struct list_head *net_list,
+                                                  struct list_head *dev_to_kill)
 {
        struct net *net;
 
-       rtnl_lock();
-       list_for_each_entry(net, net_list, exit_list) {
+       ASSERT_RTNL();
+       list_for_each_entry(net, net_list, exit_list)
                flush_all_nexthops(net);
-               kfree(net->nexthop.devhash);
-       }
-       rtnl_unlock();
+}
+
+static void __net_exit nexthop_net_exit(struct net *net)
+{
+       kfree(net->nexthop.devhash);
+       net->nexthop.devhash = NULL;
 }
 
 static int __net_init nexthop_net_init(struct net *net)
@@ -3764,7 +3768,8 @@ static int __net_init nexthop_net_init(struct net *net)
 
 static struct pernet_operations nexthop_net_ops = {
        .init = nexthop_net_init,
-       .exit_batch = nexthop_net_exit_batch,
+       .exit = nexthop_net_exit,
+       .exit_batch_rtnl = nexthop_net_exit_batch_rtnl,
 };
 
 static int __init nexthop_init(void)