bonding: use exit_batch_rtnl() method

exit_batch_rtnl() is called while RTNL is held,
and devices to be unregistered can be queued in the dev_kill_list.

This saves one rtnl_lock()/rtnl_unlock() pair,
and one unregister_netdevice_many() call.

v2: Added bond_net_pre_exit() method to make sure bond_destroy_sysfs()
    is called before we unregister the devices in bond_net_exit_batch_rtnl
 (Antoine Tenart : https://lore.kernel.org/netdev/170688415193.5216.10499830272732622816@kwain/)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20240206144313.2050392-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index ae9d32c0faf40ca32884f3c7e69b320e1e02c8d0..cb67ece47328cc50c6158cc0408d1820ef8c6dd4 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -6416,28 +6416,41 @@ static int __net_init bond_net_init(struct net *net)
        return 0;
 }
 
-static void __net_exit bond_net_exit_batch(struct list_head *net_list)
+/* According to commit 69b0216ac255 ("bonding: fix bonding_masters
+ * race condition in bond unloading") we need to remove sysfs files
+ * before we remove our devices (done later in bond_net_exit_batch_rtnl())
+ */
+static void __net_exit bond_net_pre_exit(struct net *net)
+{
+       struct bond_net *bn = net_generic(net, bond_net_id);
+
+       bond_destroy_sysfs(bn);
+}
+
+static void __net_exit bond_net_exit_batch_rtnl(struct list_head *net_list,
+                                               struct list_head *dev_kill_list)
 {
        struct bond_net *bn;
        struct net *net;
-       LIST_HEAD(list);
-
-       list_for_each_entry(net, net_list, exit_list) {
-               bn = net_generic(net, bond_net_id);
-               bond_destroy_sysfs(bn);
-       }
 
        /* Kill off any bonds created after unregistering bond rtnl ops */
-       rtnl_lock();
        list_for_each_entry(net, net_list, exit_list) {
                struct bonding *bond, *tmp_bond;
 
                bn = net_generic(net, bond_net_id);
                list_for_each_entry_safe(bond, tmp_bond, &bn->dev_list, bond_list)
-                       unregister_netdevice_queue(bond->dev, &list);
+                       unregister_netdevice_queue(bond->dev, dev_kill_list);
        }
-       unregister_netdevice_many(&list);
-       rtnl_unlock();
+}
+
+/* According to commit 23fa5c2caae0 ("bonding: destroy proc directory
+ * only after all bonds are gone") bond_destroy_proc_dir() is called
+ * after bond_net_exit_batch_rtnl() has completed.
+ */
+static void __net_exit bond_net_exit_batch(struct list_head *net_list)
+{
+       struct bond_net *bn;
+       struct net *net;
 
        list_for_each_entry(net, net_list, exit_list) {
                bn = net_generic(net, bond_net_id);
@@ -6447,6 +6460,8 @@ static void __net_exit bond_net_exit_batch(struct list_head *net_list)
 
 static struct pernet_operations bond_net_ops = {
        .init = bond_net_init,
+       .pre_exit = bond_net_pre_exit,
+       .exit_batch_rtnl = bond_net_exit_batch_rtnl,
        .exit_batch = bond_net_exit_batch,
        .id   = &bond_net_id,
        .size = sizeof(struct bond_net),