[ 24/52] net: In unregister_netdevice_notifier unregister the netdevices.

From: Greg KH
Date: Thu May 10 2012 - 13:34:44 EST


3.3-stable review patch. If anyone has any objections, please let me know.

------------------


From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

[ Upstream commit 7d3d43dab4e978d8d9ad1acf8af15c9b1c4b0f0f ]

We already synthesize events in register_netdevice_notifier and synthesizing
events in unregister_netdevice_notifier allows to us remove the need for
special case cleanup code.

This change should be safe as it adds no new cases for existing callers
of unregiser_netdevice_notifier to handle.

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/dev.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1412,14 +1412,34 @@ EXPORT_SYMBOL(register_netdevice_notifie
* register_netdevice_notifier(). The notifier is unlinked into the
* kernel structures and may then be reused. A negative errno code
* is returned on a failure.
+ *
+ * After unregistering unregister and down device events are synthesized
+ * for all devices on the device list to the removed notifier to remove
+ * the need for special case cleanup code.
*/

int unregister_netdevice_notifier(struct notifier_block *nb)
{
+ struct net_device *dev;
+ struct net *net;
int err;

rtnl_lock();
err = raw_notifier_chain_unregister(&netdev_chain, nb);
+ if (err)
+ goto unlock;
+
+ for_each_net(net) {
+ for_each_netdev(net, dev) {
+ if (dev->flags & IFF_UP) {
+ nb->notifier_call(nb, NETDEV_GOING_DOWN, dev);
+ nb->notifier_call(nb, NETDEV_DOWN, dev);
+ }
+ nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
+ nb->notifier_call(nb, NETDEV_UNREGISTER_BATCH, dev);
+ }
+ }
+unlock:
rtnl_unlock();
return err;
}


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