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 <hongjun.li@6wind.com>
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 7098fba..0244051 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