netdev - [PATCH v3 net-next 04/15] bonding: use exit_batch

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Message-ID: <20240205124752.811108-5-edumazet@google.com>
Date: Mon,  5 Feb 2024 12:47:41 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Antoine Tenart <atenart@...nel.org>, netdev@...r.kernel.org, eric.dumazet@...il.com, 
	Eric Dumazet <edumazet@...gle.com>, Jay Vosburgh <j.vosburgh@...il.com>, 
	Andy Gospodarek <andy@...yhouse.net>
Subject: [PATCH v3 net-next 04/15] 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@...gle.com>
Cc: Antoine Tenart <atenart@...nel.org>
Acked-by: Jay Vosburgh <j.vosburgh@...il.com>
Cc: Andy Gospodarek <andy@...yhouse.net>
---
 drivers/net/bonding/bond_main.c | 37 +++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 4e0600c7b050f21c82a8862e224bb055e95d5039..a5e3d000ebd85c09beba379a2e6a7f69a0fd4c88 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -6415,28 +6415,41 @@ 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);
@@ -6446,6 +6459,8 @@ 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),
-- 
2.43.0.594.gd9cf4e227d-goog