[PATCH 3/3] net: Queue net_cleanup_work only if there is first net added

[Kirill Tkhai]

When llist_add() returns false, cleanup_net() hasn't made its
llist_del_all(), while the work has already been scheduled
by the first queuer. So, we may skip queue_work() in this case.

Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
---
 net/core/net_namespace.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index abf8a46e94e2..27a55236ad64 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -582,8 +582,8 @@ static DECLARE_WORK(net_cleanup_work, cleanup_net);
 void __put_net(struct net *net)
 {
        /* Cleanup the network namespace in process context */
-       llist_add(&net->cleanup_list, &cleanup_list);
-       queue_work(netns_wq, &net_cleanup_work);
+       if (llist_add(&net->cleanup_list, &cleanup_list))
+               queue_work(netns_wq, &net_cleanup_work);
 }
 EXPORT_SYMBOL_GPL(__put_net);