bridge: mdb: avoid uninitialized variable warning

A recent change to the mdb code confused the compiler to the point
where it did not realize that the port-group returned from
br_mdb_add_group() is always valid when the function returns a nonzero
return value, so we get a spurious warning:

net/bridge/br_mdb.c: In function 'br_mdb_add':
net/bridge/br_mdb.c:542:4: error: 'pg' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    __br_mdb_notify(dev, entry, RTM_NEWMDB, pg);

Slightly rearranging the code in br_mdb_add_group() makes the problem
go away, as gcc is clever enough to see that both functions check
for 'ret != 0'.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 9e8430f8d60d ("bridge: mdb: Passing the port-group pointer to br_mdb module")
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
index 30e105f57f0d9a59e1ce03de8531b90718ac8e29..74c278e0022545729641c5741bbd3d07cd6b36b5 100644 (file)
--- a/net/bridge/br_mdb.c
+++ b/net/bridge/br_mdb.c
@@ -425,8 +425,8 @@ static int br_mdb_add_group(struct net_bridge *br, struct net_bridge_port *port,
        mp = br_mdb_ip_get(mdb, group);
        if (!mp) {
                mp = br_multicast_new_group(br, port, group);
-               err = PTR_ERR(mp);
-               if (IS_ERR(mp))
+               err = PTR_ERR_OR_ZERO(mp);
+               if (err)
                        return err;
        }