[PATCH net 2/2] net: remove type_check from dev_get_nest_level()
From: Sabrina Dubroca <sd@queasysnail.net>
Date: 2016-08-12 14:11:16
Subsystem:
networking drivers, networking [general], networking [macsec], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Sabrina Dubroca, Linus Torvalds
The idea for type_check in dev_get_nest_level() was to count the number of nested devices of the same type (currently, only macvlan or vlan devices). This prevented the false positive lockdep warning on configurations such as: eth0 <--- macvlan0 <--- vlan0 <--- macvlan1 However, this doesn't prevent a warning on a configuration such as: eth0 <--- macvlan0 <--- vlan0 eth1 <--- vlan1 <--- macvlan1 In this case, all the locks end up with a nesting subclass of 1, so lockdep thinks that there is still a deadlock: - in the first case we have (macvlan_netdev_addr_lock_key, 1) and then take (vlan_netdev_xmit_lock_key, 1) - in the second case, we have (vlan_netdev_xmit_lock_key, 1) and then take (macvlan_netdev_addr_lock_key, 1) By removing the linktype check in dev_get_nest_level() and always incrementing the nesting depth, lockdep considers this configuration valid. Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> --- drivers/net/macsec.c | 2 +- drivers/net/macvlan.c | 2 +- include/linux/netdevice.h | 3 +-- net/8021q/vlan.c | 2 +- net/core/dev.c | 10 +++------- 5 files changed, 7 insertions(+), 12 deletions(-)
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 2043e8c97a81..351e701eb043 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c@@ -3201,7 +3201,7 @@ static int macsec_newlink(struct net *net, struct net_device *dev, dev_hold(real_dev); - macsec->nest_level = dev_get_nest_level(real_dev, netif_is_macsec) + 1; + macsec->nest_level = dev_get_nest_level(real_dev) + 1; netdev_lockdep_set_classes(dev); lockdep_set_class_and_subclass(&dev->addr_list_lock, &macsec_netdev_addr_lock_key,
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index cd9b53834bf6..3234fcdea317 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c@@ -1315,7 +1315,7 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev, vlan->dev = dev; vlan->port = port; vlan->set_features = MACVLAN_FEATURES; - vlan->nest_level = dev_get_nest_level(lowerdev, netif_is_macvlan) + 1; + vlan->nest_level = dev_get_nest_level(lowerdev) + 1; vlan->mode = MACVLAN_MODE_VEPA; if (data && data[IFLA_MACVLAN_MODE])
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 076df5360ba5..3a788bf0affd 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -3891,8 +3891,7 @@ void netdev_default_l2upper_neigh_destroy(struct net_device *dev, extern u8 netdev_rss_key[NETDEV_RSS_KEY_LEN] __read_mostly; void netdev_rss_key_fill(void *buffer, size_t len); -int dev_get_nest_level(struct net_device *dev, - bool (*type_check)(const struct net_device *dev)); +int dev_get_nest_level(struct net_device *dev); int skb_checksum_help(struct sk_buff *skb); struct sk_buff *__skb_gso_segment(struct sk_buff *skb, netdev_features_t features, bool tx_path);
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 82a116ba590e..8de138d3306b 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c@@ -169,7 +169,7 @@ int register_vlan_dev(struct net_device *dev) if (err < 0) goto out_uninit_mvrp; - vlan->nest_level = dev_get_nest_level(real_dev, is_vlan_dev) + 1; + vlan->nest_level = dev_get_nest_level(real_dev) + 1; err = register_netdevice(dev); if (err < 0) goto out_uninit_mvrp;
diff --git a/net/core/dev.c b/net/core/dev.c
index 4ce07dc25573..dd6ce598de89 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -6045,8 +6045,7 @@ void *netdev_lower_dev_get_private(struct net_device *dev, EXPORT_SYMBOL(netdev_lower_dev_get_private); -int dev_get_nest_level(struct net_device *dev, - bool (*type_check)(const struct net_device *dev)) +int dev_get_nest_level(struct net_device *dev) { struct net_device *lower = NULL; struct list_head *iter;
@@ -6056,15 +6055,12 @@ int dev_get_nest_level(struct net_device *dev, ASSERT_RTNL(); netdev_for_each_lower_dev(dev, lower, iter) { - nest = dev_get_nest_level(lower, type_check); + nest = dev_get_nest_level(lower); if (max_nest < nest) max_nest = nest; } - if (type_check(dev)) - max_nest++; - - return max_nest; + return max_nest + 1; } EXPORT_SYMBOL(dev_get_nest_level);
--
2.9.2