team: introduce random mode

As suggested by Eric Dumazet, allow user to select mode which chooses
TX port randomly. Functionality should be more of less similar to
round-robin mode with even lower overhead.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if_team.h b/include/linux/if_team.h
index 3283def..4474557 100644
--- a/include/linux/if_team.h
+++ b/include/linux/if_team.h
@@ -240,6 +240,26 @@
 	return NULL;
 }
 
+static inline struct team_port *
+team_get_first_port_txable_rcu(struct team *team, struct team_port *port)
+{
+	struct team_port *cur;
+
+	if (likely(team_port_txable(port)))
+		return port;
+	cur = port;
+	list_for_each_entry_continue_rcu(cur, &team->port_list, list)
+		if (team_port_txable(port))
+			return cur;
+	list_for_each_entry_rcu(cur, &team->port_list, list) {
+		if (cur == port)
+			break;
+		if (team_port_txable(port))
+			return cur;
+	}
+	return NULL;
+}
+
 extern int team_options_register(struct team *team,
 				 const struct team_option *option,
 				 size_t option_count);