From f51048c3e07b68c90b21a77541fc4b208f9244d7 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Thu, 6 Jul 2017 15:01:57 -0700 Subject: [PATCH] bonding: avoid NETDEV_CHANGEMTU event when unregistering slave As Hongjun/Nicolas summarized in their original patch: " When a device changes from one netns to another, it's first unregistered, then the netns reference is updated and the dev is registered in the new netns. Thus, when a slave moves to another netns, it is first unregistered. This triggers a NETDEV_UNREGISTER event which is caught by the bonding driver. The driver calls bond_release(), which calls dev_set_mtu() and thus triggers NETDEV_CHANGEMTU (the device is still in the old netns). " This is a very special case, because the device is being unregistered no one should still care about the NETDEV_CHANGEMTU event triggered at this point, we can avoid broadcasting this event on this path, and avoid touching inetdev_event()/addrconf_notify() path. It requires to export __dev_set_mtu() to bonding driver. Reported-by: Hongjun Li Reported-by: Nicolas Dichtel Cc: Jay Vosburgh Cc: Veaceslav Falico Cc: Andy Gospodarek Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 15 +++++++++------ include/linux/netdevice.h | 1 + net/core/dev.c | 3 ++- 3 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 2865f31c6076..14ff622190a5 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1820,7 +1820,7 @@ err_undo_flags: */ static int __bond_release_one(struct net_device *bond_dev, struct net_device *slave_dev, - bool all) + bool all, bool unregister) { struct bonding *bond = netdev_priv(bond_dev); struct slave *slave, *oldcurrent; @@ -1965,7 +1965,10 @@ static int __bond_release_one(struct net_device *bond_dev, dev_set_mac_address(slave_dev, (struct sockaddr *)&ss); } - dev_set_mtu(slave_dev, slave->original_mtu); + if (unregister) + __dev_set_mtu(slave_dev, slave->original_mtu); + else + dev_set_mtu(slave_dev, slave->original_mtu); slave_dev->priv_flags &= ~IFF_BONDING; @@ -1977,7 +1980,7 @@ static int __bond_release_one(struct net_device *bond_dev, /* A wrapper used because of ndo_del_link */ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev) { - return __bond_release_one(bond_dev, slave_dev, false); + return __bond_release_one(bond_dev, slave_dev, false, false); } /* First release a slave and then destroy the bond if no more slaves are left. @@ -1989,7 +1992,7 @@ static int bond_release_and_destroy(struct net_device *bond_dev, struct bonding *bond = netdev_priv(bond_dev); int ret; - ret = bond_release(bond_dev, slave_dev); + ret = __bond_release_one(bond_dev, slave_dev, false, true); if (ret == 0 && !bond_has_slaves(bond)) { bond_dev->priv_flags |= IFF_DISABLE_NETPOLL; netdev_info(bond_dev, "Destroying bond %s\n", @@ -3060,7 +3063,7 @@ static int bond_slave_netdev_event(unsigned long event, if (bond_dev->type != ARPHRD_ETHER) bond_release_and_destroy(bond_dev, slave_dev); else - bond_release(bond_dev, slave_dev); + __bond_release_one(bond_dev, slave_dev, false, true); break; case NETDEV_UP: case NETDEV_CHANGE: @@ -4252,7 +4255,7 @@ static void bond_uninit(struct net_device *bond_dev) /* Release the bonded slaves */ bond_for_each_slave(bond, slave, iter) - __bond_release_one(bond_dev, slave->dev, true); + __bond_release_one(bond_dev, slave->dev, true, true); netdev_info(bond_dev, "Released all slaves\n"); arr = rtnl_dereference(bond->slave_arr); diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index e48ee2eaaa3e..779b23595596 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3284,6 +3284,7 @@ void __dev_notify_flags(struct net_device *, unsigned int old_flags, int dev_change_name(struct net_device *, const char *); int dev_set_alias(struct net_device *, const char *, size_t); int dev_change_net_namespace(struct net_device *, struct net *, const char *); +int __dev_set_mtu(struct net_device *, int); int dev_set_mtu(struct net_device *, int); void dev_set_group(struct net_device *, int); int dev_set_mac_address(struct net_device *, struct sockaddr *); diff --git a/net/core/dev.c b/net/core/dev.c index 7098fba52be1..02440518dd69 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6765,7 +6765,7 @@ int dev_change_flags(struct net_device *dev, unsigned int flags) } EXPORT_SYMBOL(dev_change_flags); -static int __dev_set_mtu(struct net_device *dev, int new_mtu) +int __dev_set_mtu(struct net_device *dev, int new_mtu) { const struct net_device_ops *ops = dev->netdev_ops; @@ -6775,6 +6775,7 @@ static int __dev_set_mtu(struct net_device *dev, int new_mtu) dev->mtu = new_mtu; return 0; } +EXPORT_SYMBOL(__dev_set_mtu); /** * dev_set_mtu - Change maximum transfer unit -- 2.20.1