From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH 4/5] macvtap: Rewrite macvtap_newlink so the error handling works. Date: Thu, 20 Oct 2011 07:28:46 -0700 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: , Arnd Bergmann , Jason Wang , "Michael S. Tsirkin" , Ian Campbell , Shirly Ma To: David Miller Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:58260 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752983Ab1JTO2P (ORCPT ); Thu, 20 Oct 2011 10:28:15 -0400 In-Reply-To: (Eric W. Biederman's message of "Thu, 20 Oct 2011 07:27:24 -0700") Sender: netdev-owner@vger.kernel.org List-ID: 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 --- 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