team: use dynamic lockdep key instead of static key

In the current code, all team devices have same static lockdep key
and team devices could be nested so that it makes unnecessary
lockdep warning.

Test commands:
    ip link add team0 type team
    for i in {1..7}
    do
	    let A=$i-1
	    ip link add team$i type team
	    ip link set team$i master team$A
    done
    ip link del team0

Splat looks like:
[  137.406730] ============================================
[  137.412685] WARNING: possible recursive locking detected
[  137.418642] 5.3.0-rc7+ torvalds#322 Not tainted
[  137.422941] --------------------------------------------
[  137.428886] ip/1383 is trying to acquire lock:
[  137.433869] 0000000089571080 (&dev_addr_list_lock_key/1){+...}, at: dev_uc_sync_multiple+0xfa/0x1a0
[  137.444034]
[  137.444034] but task is already holding lock:
[  137.450572] 00000000d9597252 (&dev_addr_list_lock_key/1){+...}, at: dev_uc_unsync+0x10c/0x1b0
[  137.460142]
[  137.460142] other info that might help us debug this:
[  137.467458]  Possible unsafe locking scenario:
[  137.467458]
[  137.474096]        CPU0
[  137.476828]        ----
[  137.479569]   lock(&dev_addr_list_lock_key/1);
[  137.484554]   lock(&dev_addr_list_lock_key/1);
[  137.489539]
[  137.489539]  *** DEADLOCK ***
[  137.489539]
[  137.496178]  May be due to missing lock nesting notation
[  137.496178]
[  137.503789] 5 locks held by ip/1383:
[  137.507797]  #0: 00000000d497f415 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x466/0x8a0
[  137.516786]  #1: 000000008e4b4656 (&team->lock){+.+.}, at: team_uninit+0x3a/0x1a0 [team]
[  137.525882]  #2: 000000005cf248d1 (&dev_addr_list_lock_key){+...}, at: dev_uc_unsync+0x98/0x1b0
[  137.535649]  #3: 00000000d9597252 (&dev_addr_list_lock_key/1){+...}, at: dev_uc_unsync+0x10c/0x1b0
[  137.545709]  #4: 00000000bec134c3 (rcu_read_lock){....}, at: team_set_rx_mode+0x5/0x1d0 [team]
[  137.555384]
[  137.555384] stack backtrace:
[  137.560277] CPU: 0 PID: 1383 Comm: ip Not tainted 5.3.0-rc7+ torvalds#322
[  137.577826] Call Trace:
[  137.580586]  dump_stack+0x7c/0xbb
[  137.584307]  __lock_acquire+0x26a9/0x3de0
[  137.588820]  ? register_lock_class+0x14d0/0x14d0
[  137.594008]  ? register_lock_class+0x14d0/0x14d0
[  137.599194]  lock_acquire+0x164/0x3b0
[  137.603310]  ? dev_uc_sync_multiple+0xfa/0x1a0
[  137.608307]  _raw_spin_lock_nested+0x2e/0x60
[  137.613105]  ? dev_uc_sync_multiple+0xfa/0x1a0
[  137.618095]  dev_uc_sync_multiple+0xfa/0x1a0
[  137.622900]  team_set_rx_mode+0xa9/0x1d0 [team]
[  137.627993]  dev_uc_unsync+0x151/0x1b0
[  137.632205]  team_port_del+0x304/0x790 [team]
[  137.637110]  team_uninit+0xb0/0x1a0 [team]
[  137.641717]  rollback_registered_many+0x728/0xda0
[  137.647005]  ? generic_xdp_install+0x310/0x310
[  137.651994]  ? __set_pages_p+0xf4/0x150
[  137.656306]  ? check_chain_key+0x236/0x5d0
[  137.660914]  ? __nla_validate_parse+0x98/0x1ad0
[  137.666006]  unregister_netdevice_many.part.120+0x13/0x1b0
[  137.672167]  rtnl_delete_link+0xbc/0x100
[  137.676575]  ? rtnl_af_register+0xc0/0xc0
[  137.681084]  rtnl_dellink+0x2e7/0x870
[  137.685204]  ? find_held_lock+0x39/0x1d0
[  ... ]

Fixes: 3d249d4 ("net: introduce ethernet teaming device")
Signed-off-by: Taehee Yoo <[email protected]>

drivers/net/team/team.c

@@ -1607,6 +1607,34 @@ static const struct team_option team_options[] = {
 	},
 };
 
+static void team_dev_set_lockdep_one(struct net_device *dev,
+				     struct netdev_queue *txq,
+				     void *_unused)
+{
+	struct team *team = netdev_priv(dev);
+
+	lockdep_set_class(&txq->_xmit_lock, &team->xmit_lock_key);
+}
+
+static struct lock_class_key qdisc_tx_busylock_key;
+static struct lock_class_key qdisc_running_key;
+
+static void team_dev_set_lockdep_class(struct net_device *dev)
+{
+	struct team *team = netdev_priv(dev);
+
+	dev->qdisc_tx_busylock = &qdisc_tx_busylock_key;
+	dev->qdisc_running_key = &qdisc_running_key;
+
+	lockdep_register_key(&team->team_lock_key);
+	__mutex_init(&team->lock, "team->team_lock_key", &team->team_lock_key);
+
+	lockdep_register_key(&team->addr_lock_key);
+	lockdep_set_class(&dev->addr_list_lock, &team->addr_lock_key);
+
+	lockdep_register_key(&team->xmit_lock_key);
+	netdev_for_each_tx_queue(dev, team_dev_set_lockdep_one, NULL);
+}
 
 static int team_init(struct net_device *dev)
 {
@@ -1615,7 +1643,6 @@ static int team_init(struct net_device *dev)
 	int err;
 
 	team->dev = dev;
-	mutex_init(&team->lock);
 	team_set_no_mode(team);
 
 	team->pcpu_stats = netdev_alloc_pcpu_stats(struct team_pcpu_stats);
@@ -1642,7 +1669,7 @@ static int team_init(struct net_device *dev)
 		goto err_options_register;
 	netif_carrier_off(dev);
 
-	netdev_lockdep_set_classes(dev);
+	team_dev_set_lockdep_class(dev);
 
 	return 0;
 
@@ -1673,6 +1700,11 @@ static void team_uninit(struct net_device *dev)
 	team_queue_override_fini(team);
 	mutex_unlock(&team->lock);
 	netdev_change_features(dev);
+
+	lockdep_unregister_key(&team->team_lock_key);
+	lockdep_unregister_key(&team->addr_lock_key);
+	lockdep_unregister_key(&team->xmit_lock_key);
+
 }
 
 static void team_destructor(struct net_device *dev)
@@ -1967,6 +1999,23 @@ static int team_add_slave(struct net_device *dev, struct net_device *port_dev,
 	return err;
 }
 
+static void team_update_lock_key(struct net_device *dev)
+{
+	struct team *team = netdev_priv(dev);
+
+	lockdep_unregister_key(&team->team_lock_key);
+	lockdep_unregister_key(&team->addr_lock_key);
+	lockdep_unregister_key(&team->xmit_lock_key);
+
+	lockdep_register_key(&team->team_lock_key);
+	lockdep_register_key(&team->addr_lock_key);
+	lockdep_register_key(&team->xmit_lock_key);
+
+	lockdep_set_class(&team->lock, &team->team_lock_key);
+	lockdep_set_class(&dev->addr_list_lock, &team->addr_lock_key);
+	netdev_for_each_tx_queue(dev, team_dev_set_lockdep_one, NULL);
+}
+
 static int team_del_slave(struct net_device *dev, struct net_device *port_dev)
 {
 	struct team *team = netdev_priv(dev);
@@ -1976,8 +2025,12 @@ static int team_del_slave(struct net_device *dev, struct net_device *port_dev)
 	err = team_port_del(team, port_dev);
 	mutex_unlock(&team->lock);
 
-	if (!err)
-		netdev_change_features(dev);
+	if (err)
+		return err;
+
+	if (netif_is_team_master(port_dev))
+		team_update_lock_key(port_dev);
+	netdev_change_features(dev);
 
 	return err;
 }

include/linux/if_team.h

@@ -223,6 +223,11 @@ struct team {
 		atomic_t count_pending;
 		struct delayed_work dw;
 	} mcast_rejoin;
+
+	struct lock_class_key team_lock_key;
+	struct lock_class_key xmit_lock_key;
+	struct lock_class_key addr_lock_key;
+
 	long mode_priv[TEAM_MODE_PRIV_LONGS];
 };