Merge 4.16-rc6 into tty-next

We want the serial/tty fixes in here as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index d4362befe7e2..2cedf520cb28 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6396,6 +6396,7 @@ static int __netdev_upper_dev_link(struct net_device *dev,
                 .linking = true,
                 .upper_info = upper_info,
         };
+        struct net_device *master_dev;
         int ret = 0;
 
         ASSERT_RTNL();
@@ -6407,11 +6408,14 @@ static int __netdev_upper_dev_link(struct net_device *dev,
         if (netdev_has_upper_dev(upper_dev, dev))
                 return -EBUSY;
 
-        if (netdev_has_upper_dev(dev, upper_dev))
-                return -EEXIST;
-
-        if (master && netdev_master_upper_dev_get(dev))
-                return -EBUSY;
+        if (!master) {
+                if (netdev_has_upper_dev(dev, upper_dev))
+                        return -EEXIST;
+        } else {
+                master_dev = netdev_master_upper_dev_get(dev);
+                if (master_dev)
+                        return master_dev == upper_dev ? -EEXIST : -EBUSY;
+        }
 
         ret = call_netdevice_notifiers_info(NETDEV_PRECHANGEUPPER,
                                             &changeupper_info.info);