net: sched: refactor police action helpers to require tcf_lock

In order to remove rtnl lock dependency from flow_action representation
translator, change rcu_dereference_bh_rtnl() to rcu_dereference_protected()
in police action helpers that provide external access to rate and burst
values. This is safe to do because the functions are not called from
anywhere else outside flow_action infrastructure which was modified to
obtain tcf_lock when accessing action data in one of previous patches in
the series.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tc_act/tc_police.h

@@ -54,7 +54,8 @@ static inline u64 tcf_police_rate_bytes_ps(const struct tc_action *act)
 	struct tcf_police *police = to_police(act);
 	struct tcf_police_params *params;
 
-	params = rcu_dereference_bh_rtnl(police->params);
+	params = rcu_dereference_protected(police->params,
+					   lockdep_is_held(&police->tcf_lock));
 	return params->rate.rate_bytes_ps;
 }
 
@@ -63,7 +64,8 @@ static inline s64 tcf_police_tcfp_burst(const struct tc_action *act)
 	struct tcf_police *police = to_police(act);
 	struct tcf_police_params *params;
 
-	params = rcu_dereference_bh_rtnl(police->params);
+	params = rcu_dereference_protected(police->params,
+					   lockdep_is_held(&police->tcf_lock));
 	return params->tcfp_burst;
 }