Callers of br_fdb_find() need to hold the hash lock, which
br_fdb_find_port() doesn't do. However, since br_fdb_find_port() is not
doing any actual FDB manipulation, the hash lock is not really needed at
all. So convert to br_fdb_find_rcu(), surrounded by rcu_read_lock() /
_unlock() pair.
The device pointer copied from inside the FDB entry is then kept alive
by the RTNL lock, which br_fdb_find_port() asserts.
Fixes: 4d4fd36126d6 ("net: bridge: Publish bridge accessor functions")
Signed-off-by: Petr Machata <petrm@xxxxxxxxxxxx>
---
Notes:
Changes from v1 to v2:
- Instead of taking hash lock, take RCU lock and call br_fdb_find_rcu().
net/bridge/br_fdb.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index b19e310..502f663 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -135,9 +135,11 @@ struct net_device *br_fdb_find_port(const struct net_device *br_dev,
return NULL;
br = netdev_priv(br_dev);
- f = br_fdb_find(br, addr, vid);
+ rcu_read_lock();
+ f = br_fdb_find_rcu(br, addr, vid);
if (f && f->dst)
dev = f->dst->dev;
+ rcu_read_unlock();
return dev;
}
--
2.4.11
