net: Introduce unregister_netdevice_queue()

This patchs adds an unreg_list anchor to struct net_device, and
introduces an unregister_netdevice_queue() function, able to queue
a net_device to a list instead of immediately unregister it.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 8 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 83800091a31a..0ded0a4768a0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -683,6 +683,7 @@ struct net_device
 
         struct list_head        dev_list;
         struct list_head        napi_list;
+        struct list_head        unreg_list;
 
         /* Net device features */
         unsigned long           features;
@@ -1116,7 +1117,13 @@ extern int		dev_close(struct net_device *dev);
 extern void             dev_disable_lro(struct net_device *dev);
 extern int              dev_queue_xmit(struct sk_buff *skb);
 extern int              register_netdevice(struct net_device *dev);
-extern void             unregister_netdevice(struct net_device *dev);
+extern void             unregister_netdevice_queue(struct net_device *dev,
+                                                   struct list_head *head);
+static inline void unregister_netdevice(struct net_device *dev)
+{
+        unregister_netdevice_queue(dev, NULL);
+}
+
 extern void             free_netdev(struct net_device *dev);
 extern void             synchronize_net(void);
 extern int              register_netdevice_notifier(struct notifier_block *nb);
diff --git a/net/core/dev.c b/net/core/dev.c
index 950c13fa60d2..ff94e2b8df7f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5245,25 +5245,31 @@ void synchronize_net(void)
 EXPORT_SYMBOL(synchronize_net);
 
 /**
- *      unregister_netdevice - remove device from the kernel
+ *      unregister_netdevice_queue - remove device from the kernel
  *      @dev: device
- *
+ *      @head: list
+
  *      This function shuts down a device interface and removes it
  *      from the kernel tables.
+ *      If head not NULL, device is queued to be unregistered later.
  *
  *      Callers must hold the rtnl semaphore.  You may want
  *      unregister_netdev() instead of this.
  */
 
-void unregister_netdevice(struct net_device *dev)
+void unregister_netdevice_queue(struct net_device *dev, struct list_head *head)
 {
         ASSERT_RTNL();
 
-        rollback_registered(dev);
-        /* Finish processing unregister after unlock */
-        net_set_todo(dev);
+        if (head) {
+                list_add_tail(&dev->unreg_list, head);
+        } else {
+                rollback_registered(dev);
+                /* Finish processing unregister after unlock */
+                net_set_todo(dev);
+        }
 }
-EXPORT_SYMBOL(unregister_netdevice);
+EXPORT_SYMBOL(unregister_netdevice_queue);
 
 /**
  *      unregister_netdev - remove device from the kernel