From: ebiederm@xmission•com (Eric W. Biederman)
To: David Miller <davem@davemloft•net>
Cc: <netdev@vger•kernel.org>, Arnd Bergmann <arnd@arnd•de>,
Jason Wang <jasowang@redhat•com>,
"Michael S. Tsirkin" <mst@redhat•com>,
Ian Campbell <ian.campbell@citrix•com>,
Shirly Ma <mashirley@us•ibm.com>
Subject: [PATCH 4/5] macvtap: Rewrite macvtap_newlink so the error handling works.
Date: Thu, 20 Oct 2011 07:28:46 -0700 [thread overview]
Message-ID: <m1botbu481.fsf_-_@fess.ebiederm.org> (raw)
In-Reply-To: <m1hb33u4ab.fsf_-_@fess.ebiederm.org> (Eric W. Biederman's message of "Thu, 20 Oct 2011 07:27:24 -0700")
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>
---
drivers/net/macvtap.c | 73 +++++++++++++++++++++++++++++++++----------------
1 files changed, 49 insertions(+), 24 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 515aa87..25689e9 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);
--
1.7.2.5
next prev parent reply other threads:[~2011-10-20 14:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-20 14:24 [PATCH 0/5] macvtap fixes Eric W. Biederman
2011-10-20 14:26 ` [PATCH 1/5] macvtap: Close a race between macvtap_open and macvtap_dellink Eric W. Biederman
2011-10-20 14:26 ` [PATCH 2/5] macvtap: Fix macvtap_open races in the zero copy enable code Eric W. Biederman
2011-10-20 14:27 ` [PATCH 3/5] macvtap: Don't leak unreceived packets when we delete a macvtap device Eric W. Biederman
2011-10-20 14:28 ` Eric W. Biederman [this message]
2011-10-20 14:29 ` [PATCH 5/5] macvtap: Fix the minor device number allocation Eric W. Biederman
2011-10-21 6:56 ` [PATCH 0/5] macvtap fixes David Miller
2011-10-24 6:31 ` Michael S. Tsirkin
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