[PATCH AUTOSEL for 4.9 202/293] bridge: allow ext learned entries to change ports

[Sasha Levin]

From: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit 7597b266c56feaad7d4e6e65822766e929407da2 ]

current code silently ignores change of port in the request
message. This patch makes sure the port is modified and
notification is sent to userspace.

Fixes: cf6b8e1eedff ("bridge: add API to notify bridge driver of learned FBD on offloaded device")
Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 net/bridge/br_fdb.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 6b43c8c88f19..f32b8138f9c8 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -1101,8 +1101,9 @@ void br_fdb_unsync_static(struct net_bridge *br, struct net_bridge_port *p)
 int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
 			      const unsigned char *addr, u16 vid)
 {
-	struct hlist_head *head;
 	struct net_bridge_fdb_entry *fdb;
+	struct hlist_head *head;
+	bool modified = false;
 	int err = 0;
 
 	ASSERT_RTNL();
@@ -1118,14 +1119,25 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
 		}
 		fdb->added_by_external_learn = 1;
 		fdb_notify(br, fdb, RTM_NEWNEIGH);
-	} else if (fdb->added_by_external_learn) {
-		/* Refresh entry */
-		fdb->updated = fdb->used = jiffies;
-	} else if (!fdb->added_by_user) {
-		/* Take over SW learned entry */
-		fdb->added_by_external_learn = 1;
+	} else {
 		fdb->updated = jiffies;
-		fdb_notify(br, fdb, RTM_NEWNEIGH);
+
+		if (fdb->dst != p) {
+			fdb->dst = p;
+			modified = true;
+		}
+
+		if (fdb->added_by_external_learn) {
+			/* Refresh entry */
+			fdb->used = jiffies;
+		} else if (!fdb->added_by_user) {
+			/* Take over SW learned entry */
+			fdb->added_by_external_learn = 1;
+			modified = true;
+		}
+
+		if (modified)
+			fdb_notify(br, fdb, RTM_NEWNEIGH);
 	}
 
 err_unlock:
-- 
2.15.1