Subject: [PATCH 03/55] bridge: check iface upper dev when setting master via ioctl

From: Hangbin Liu <[email-masked]>
Date: Fri, 27 Apr 2018 20:59:24 +0800

[ Upstream commit e8238fc2bd7b4c3c7554fa2df067e796610212fc ]

When we set a bond slave's master to bridge via ioctl, we only check
the IFF_BRIDGE_PORT flag. Although we will find the slave's real master
at netdev_master_upper_dev_link() later, it already does some settings
and allocates some resources. It would be better to return as early
as possible.

v1 -> v2:
use netdev_master_upper_dev_get() instead of netdev_has_any_upper_dev()
to check if we have a master, because not all upper devs are masters,
e.g. vlan device.

Reported-by: [email-masked]
Signed-off-by: Hangbin Liu <[email-masked]>
Acked-by: Nikolay Aleksandrov <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/bridge/br_if.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 9ba4ed65c52b..4be5335407c5 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -509,8 +509,8 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
 		return -ELOOP;
 	}
 
-	/* Device is already being bridged */
-	if (br_port_exists(dev))
+	/* Device has master upper dev */
+	if (netdev_master_upper_dev_get(dev))
 		return -EBUSY;
 
 	/* No bridging devices that dislike that (e.g. wireless) */
-- 
2.14.3