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authorEric W. Biederman <ebiederm@xmission.com>2011-10-20 04:28:46 +0000
committerDavid S. Miller <davem@davemloft.net>2011-10-21 02:53:07 -0400
commit9bf1907f4293d61d5a283d18c4ad28d048261797 (patch)
treea234645761a946931ae3c0e3ba1088ebec455325
parent2259fef0bb80a8fc842b5690b89a640464df2859 (diff)
macvtap: Rewrite macvtap_newlink so the error handling works.
Place macvlan_common_newlink at the end of macvtap_newlink because failing in newlink after registering your network device is not supported. Move device_create into a netdevice creation notifier. The network device notifier is the only hook that is called after the network device has been registered with the device layer and before register_network_device returns success. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/macvtap.c73
1 files changed, 49 insertions, 24 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 515aa873929..25689e9df3b 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -280,34 +280,16 @@ static int macvtap_newlink(struct net *src_net,
struct nlattr *tb[],
struct nlattr *data[])
{
- struct device *classdev;
- dev_t devt;
- int err;
-
- err = macvlan_common_newlink(src_net, dev, tb, data,
- macvtap_receive, macvtap_forward);
- if (err)
- goto out;
-
- devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);
-
- classdev = device_create(macvtap_class, &dev->dev, devt,
- dev, "tap%d", dev->ifindex);
- if (IS_ERR(classdev)) {
- err = PTR_ERR(classdev);
- macvtap_del_queues(dev);
- }
-
-out:
- return err;
+ /* Don't put anything that may fail after macvlan_common_newlink
+ * because we can't undo what it does.
+ */
+ return macvlan_common_newlink(src_net, dev, tb, data,
+ macvtap_receive, macvtap_forward);
}
static void macvtap_dellink(struct net_device *dev,
struct list_head *head)
{
- device_destroy(macvtap_class,
- MKDEV(MAJOR(macvtap_major), dev->ifindex));
-
macvtap_del_queues(dev);
macvlan_dellink(dev, head);
}
@@ -975,6 +957,42 @@ struct socket *macvtap_get_socket(struct file *file)
}
EXPORT_SYMBOL_GPL(macvtap_get_socket);
+static int macvtap_device_event(struct notifier_block *unused,
+ unsigned long event, void *ptr)
+{
+ struct net_device *dev = ptr;
+ struct device *classdev;
+ dev_t devt;
+
+ if (dev->rtnl_link_ops != &macvtap_link_ops)
+ return NOTIFY_DONE;
+
+
+ switch (event) {
+ case NETDEV_REGISTER:
+ /* Create the device node here after the network device has
+ * been registered but before register_netdevice has
+ * finished running.
+ */
+ devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);
+ classdev = device_create(macvtap_class, &dev->dev, devt,
+ dev, "tap%d", dev->ifindex);
+ if (IS_ERR(classdev))
+ return notifier_from_errno(PTR_ERR(classdev));
+ break;
+ case NETDEV_UNREGISTER:
+ devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);
+ device_destroy(macvtap_class, devt);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block macvtap_notifier_block __read_mostly = {
+ .notifier_call = macvtap_device_event,
+};
+
static int macvtap_init(void)
{
int err;
@@ -995,12 +1013,18 @@ static int macvtap_init(void)
goto out3;
}
- err = macvlan_link_register(&macvtap_link_ops);
+ err = register_netdevice_notifier(&macvtap_notifier_block);
if (err)
goto out4;
+ err = macvlan_link_register(&macvtap_link_ops);
+ if (err)
+ goto out5;
+
return 0;
+out5:
+ unregister_netdevice_notifier(&macvtap_notifier_block);
out4:
class_unregister(macvtap_class);
out3:
@@ -1015,6 +1039,7 @@ module_init(macvtap_init);
static void macvtap_exit(void)
{
rtnl_link_unregister(&macvtap_link_ops);
+ unregister_netdevice_notifier(&macvtap_notifier_block);
class_unregister(macvtap_class);
cdev_del(&macvtap_cdev);
unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);