datapath: don't unlock mutex when changing the user_features fails

Upstream commit:
    commit 4c76bf696a608ea5cc555fe97ec59a9033236604
    Author: Tonghao Zhang <xiangxia.m.yue@gmail.com>
    Date:   Fri Nov 1 22:23:53 2019 +0800

    net: openvswitch: don't unlock mutex when changing the user_features fails

    Unlocking of a not locked mutex is not allowed.
    Other kernel thread may be in critical section while
    we unlock it because of setting user_feature fail.

    Fixes: 95a7233c4 ("net: openvswitch: Set OvS recirc_id from tc chain index")
    Cc: Paul Blakey <paulb@mellanox.com>
    Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
    Tested-by: Greg Rose <gvrose8192@gmail.com>
    Acked-by: William Tu <u9012063@gmail.com>
    Acked-by: Pravin B Shelar <pshelar@ovn.org>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Reviewed-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

datapath/datapath.c

@@ -1746,6 +1746,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
 				ovs_dp_reset_user_features(skb, info);
 		}
 
+		ovs_unlock();
 		goto err_destroy_meters;
 	}
 
@@ -1762,7 +1763,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
 	return 0;
 
 err_destroy_meters:
-	ovs_unlock();
 	ovs_meters_exit(dp);
 err_destroy_ports_array:
 	kfree(dp->ports);