[PATCHv5 net-next 2/4] net: add new helper unregister_netdevice_many_notify

[Hangbin Liu <liuhangbin@gmail.com>]

Add new helper unregister_netdevice_many_notify(), pass netlink message
header and port id, which could be used to notify userspace when flag
NLM_F_ECHO is set.

Make the unregister_netdevice_many() as a wrapper of new function
unregister_netdevice_many_notify().

Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 include/linux/netdevice.h |  2 ++
 net/core/dev.c            | 16 +++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a71d378945e3..150d7e90b2fc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3026,6 +3026,8 @@ static inline int dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
 
 int register_netdevice(struct net_device *dev);
 void unregister_netdevice_queue(struct net_device *dev, struct list_head *head);
+void unregister_netdevice_many_notify(struct list_head *head,
+				      struct nlmsghdr *nlh, u32 pid);
 void unregister_netdevice_many(struct list_head *head);
 static inline void unregister_netdevice(struct net_device *dev)
 {
diff --git a/net/core/dev.c b/net/core/dev.c
index 89cf082317dd..7e625b37880f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10779,11 +10779,14 @@ EXPORT_SYMBOL(unregister_netdevice_queue);
 /**
  *	unregister_netdevice_many - unregister many devices
  *	@head: list of devices
+ *	@nlh: netlink message header
+ *	@pid: destination netlink portid for reports
  *
  *  Note: As most callers use a stack allocated list_head,
  *  we force a list_del() to make sure stack wont be corrupted later.
  */
-void unregister_netdevice_many(struct list_head *head)
+void unregister_netdevice_many_notify(struct list_head *head,
+				      struct nlmsghdr *nlh, u32 pid)
 {
 	struct net_device *dev, *tmp;
 	LIST_HEAD(close_head);
@@ -10845,7 +10848,8 @@ void unregister_netdevice_many(struct list_head *head)
 		if (!dev->rtnl_link_ops ||
 		    dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
 			skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0,
-						     GFP_KERNEL, NULL, 0, 0, 0);
+						     GFP_KERNEL, NULL, 0,
+						     pid, nlh ? nlh->nlmsg_seq : 0);
 
 		/*
 		 *	Flush the unicast and multicast chains
@@ -10860,7 +10864,7 @@ void unregister_netdevice_many(struct list_head *head)
 			dev->netdev_ops->ndo_uninit(dev);
 
 		if (skb)
-			rtmsg_ifinfo_send(skb, dev, GFP_KERNEL, 0, NULL);
+			rtmsg_ifinfo_send(skb, dev, GFP_KERNEL, pid, nlh);
 
 		/* Notifier chain MUST detach us all upper devices. */
 		WARN_ON(netdev_has_any_upper_dev(dev));
@@ -10883,6 +10887,12 @@ void unregister_netdevice_many(struct list_head *head)
 
 	list_del(head);
 }
+EXPORT_SYMBOL(unregister_netdevice_many_notify);
+
+void unregister_netdevice_many(struct list_head *head)
+{
+	unregister_netdevice_many_notify(head, NULL, 0);
+}
 EXPORT_SYMBOL(unregister_netdevice_many);
 
 /**
-- 
2.37.2