[PATCH v4 net-next 07/15] ipv4: add __unregister_nexthop_notifier()

[Eric Dumazet <edumazet@google.com>]

unregister_nexthop_notifier() assumes the caller does not hold rtnl.

We need in the following patch to use it from a context
already holding rtnl.

Add __unregister_nexthop_notifier().

unregister_nexthop_notifier() becomes a wrapper.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/nexthop.h |  1 +
 net/ipv4/nexthop.c    | 19 +++++++++++++------
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/net/nexthop.h b/include/net/nexthop.h
index d92046a4a078250eec528f3cb2c3ab557decad03..6647ad509faa02a9a13d58f3405c4a540abc5077 100644
--- a/include/net/nexthop.h
+++ b/include/net/nexthop.h
@@ -218,6 +218,7 @@ struct nh_notifier_info {
 
 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
 			      struct netlink_ext_ack *extack);
+int __unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 7270a8631406c508eebf85c42eb29a5268d7d7cf..70509da4f0806d25b3707835c08888d5e57b782e 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -3631,17 +3631,24 @@ int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
 }
 EXPORT_SYMBOL(register_nexthop_notifier);
 
-int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb)
+int __unregister_nexthop_notifier(struct net *net, struct notifier_block *nb)
 {
 	int err;
 
-	rtnl_lock();
 	err = blocking_notifier_chain_unregister(&net->nexthop.notifier_chain,
 						 nb);
-	if (err)
-		goto unlock;
-	nexthops_dump(net, nb, NEXTHOP_EVENT_DEL, NULL);
-unlock:
+	if (!err)
+		nexthops_dump(net, nb, NEXTHOP_EVENT_DEL, NULL);
+	return err;
+}
+EXPORT_SYMBOL(__unregister_nexthop_notifier);
+
+int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb)
+{
+	int err;
+
+	rtnl_lock();
+	err = __unregister_nexthop_notifier(net, nb);
 	rtnl_unlock();
 	return err;
 }
-- 
2.43.0.594.gd9cf4e227d-goog