team: remove synchronize_rcu() called during port disable

Check the unlikely case of team->en_port_count == 0 before modulo
operation.

Signed-off-by: Jiri Pirko <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/team/team.c

···
 	team->mode = &__team_no_mode;
 }
 
-static void __team_adjust_ops(struct team *team, int en_port_count)
+static void team_adjust_ops(struct team *team)
 {
 	/*
 	 * To avoid checks in rx/tx skb paths, ensure here that non-null and
 	 * correct ops are always set.
 	 */
 
-	if (!en_port_count || !team_is_mode_set(team) ||
+	if (!team->en_port_count || !team_is_mode_set(team) ||
 	    !team->mode->ops->transmit)
 		team->ops.transmit = team_dummy_transmit;
 	else
 		team->ops.transmit = team->mode->ops->transmit;
 
-	if (!en_port_count || !team_is_mode_set(team) ||
+	if (!team->en_port_count || !team_is_mode_set(team) ||
 	    !team->mode->ops->receive)
 		team->ops.receive = team_dummy_receive;
 	else
 		team->ops.receive = team->mode->ops->receive;
-}
-
-static void team_adjust_ops(struct team *team)
-{
-	__team_adjust_ops(team, team->en_port_count);
 }
 
 /*
···
 	hlist_del_rcu(&port->hlist);
 	__reconstruct_port_hlist(team, port->index);
 	port->index = -1;
-	team_queue_override_port_del(team, port);
-	__team_adjust_ops(team, team->en_port_count - 1);
-	/*
-	 * Wait until readers see adjusted ops. This ensures that
-	 * readers never see team->en_port_count == 0
-	 */
-	synchronize_rcu();
 	team->en_port_count--;
+	team_queue_override_port_del(team, port);
+	team_adjust_ops(team);
 }
 
 #define TEAM_VLAN_FEATURES (NETIF_F_ALL_CSUM | NETIF_F_SG | \

drivers/net/team/team_mode_loadbalance.c

···
 						struct sk_buff *skb,
 						unsigned char hash)
 {
-	int port_index;
+	int port_index = team_num_to_port_index(team, hash);
 
-	port_index = hash % team->en_port_count;
 	return team_get_port_by_index_rcu(team, port_index);
 }
 

drivers/net/team/team_mode_roundrobin.c

···
 	struct team_port *port;
 	int port_index;
 
-	port_index = rr_priv(team)->sent_packets++ % team->en_port_count;
+	port_index = team_num_to_port_index(team,
+					    rr_priv(team)->sent_packets++);
 	port = team_get_port_by_index_rcu(team, port_index);
 	port = team_get_first_port_txable_rcu(team, port);
 	if (unlikely(!port))

include/linux/if_team.h

···
 			return port;
 	return NULL;
 }
+
+static inline int team_num_to_port_index(struct team *team, int num)
+{
+	int en_port_count = ACCESS_ONCE(team->en_port_count);
+
+	if (unlikely(!en_port_count))
+		return 0;
+	return num % en_port_count;
+}
+
 static inline struct team_port *team_get_port_by_index_rcu(struct team *team,
 							   int port_index)
 {