[Patch net] net: get rid of lockdep_set_class_and_subclass()

[Patch net] net: get rid of lockdep_set_class_and_subclass()

[Cong Wang]

lockdep_set_class_and_subclass() is meant to reduce
the _nested() annotations by assigning a default subclass.
For addr_list_lock, we have to compute the subclass at
run-time as the netdevice topology changes after creation.

So, we should just get rid of these
lockdep_set_class_and_subclass() and stick with our _nested()
annotations.

Fixes: 845e0ebb4408 ("net: change addr_list_lock back to static key")
Suggested-by: Taehee Yoo <ap420073@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 drivers/net/macsec.c  | 5 ++---
 drivers/net/macvlan.c | 5 ++---
 net/8021q/vlan_dev.c  | 9 ++++-----
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index e56547bfdac9..9159846b8b93 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -4052,9 +4052,8 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 		return err;
 
 	netdev_lockdep_set_classes(dev);
-	lockdep_set_class_and_subclass(&dev->addr_list_lock,
-				       &macsec_netdev_addr_lock_key,
-				       dev->lower_level);
+	lockdep_set_class(&dev->addr_list_lock,
+			  &macsec_netdev_addr_lock_key);
 
 	err = netdev_upper_dev_link(real_dev, dev, extack);
 	if (err < 0)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 6a6cc9f75307..4942f6112e51 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -880,9 +880,8 @@ static struct lock_class_key macvlan_netdev_addr_lock_key;
 static void macvlan_set_lockdep_class(struct net_device *dev)
 {
 	netdev_lockdep_set_classes(dev);
-	lockdep_set_class_and_subclass(&dev->addr_list_lock,
-				       &macvlan_netdev_addr_lock_key,
-				       dev->lower_level);
+	lockdep_set_class(&dev->addr_list_lock,
+			  &macvlan_netdev_addr_lock_key);
 }
 
 static int macvlan_init(struct net_device *dev)
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index c8d6a07e23c5..3dd7c972677b 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -503,11 +503,10 @@ static void vlan_dev_set_lockdep_one(struct net_device *dev,
 	lockdep_set_class(&txq->_xmit_lock, &vlan_netdev_xmit_lock_key);
 }
 
-static void vlan_dev_set_lockdep_class(struct net_device *dev, int subclass)
+static void vlan_dev_set_lockdep_class(struct net_device *dev)
 {
-	lockdep_set_class_and_subclass(&dev->addr_list_lock,
-				       &vlan_netdev_addr_lock_key,
-				       subclass);
+	lockdep_set_class(&dev->addr_list_lock,
+			  &vlan_netdev_addr_lock_key);
 	netdev_for_each_tx_queue(dev, vlan_dev_set_lockdep_one, NULL);
 }
 
@@ -601,7 +600,7 @@ static int vlan_dev_init(struct net_device *dev)
 
 	SET_NETDEV_DEVTYPE(dev, &vlan_type);
 
-	vlan_dev_set_lockdep_class(dev, dev->lower_level);
+	vlan_dev_set_lockdep_class(dev);
 
 	vlan->vlan_pcpu_stats = netdev_alloc_pcpu_stats(struct vlan_pcpu_stats);
 	if (!vlan->vlan_pcpu_stats)
-- 
2.27.0

Re: [Patch net] net: get rid of lockdep_set_class_and_subclass()

[David Miller]

From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Fri, 26 Jun 2020 11:24:22 -0700

> lockdep_set_class_and_subclass() is meant to reduce
> the _nested() annotations by assigning a default subclass.
> For addr_list_lock, we have to compute the subclass at
> run-time as the netdevice topology changes after creation.
> 
> So, we should just get rid of these
> lockdep_set_class_and_subclass() and stick with our _nested()
> annotations.
> 
> Fixes: 845e0ebb4408 ("net: change addr_list_lock back to static key")
> Suggested-by: Taehee Yoo <ap420073@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Applied.