batman-adv: Initialize gw sel_class via batadv_algo

The gateway selection class variable is shared between different algorithm
versions. But the interpretation of the content is algorithm specific. The
initialization is therefore also algorithm specific.

But this was implemented incorrectly and the initialization for BATMAN_V
always overwrote the value previously written for BATMAN_IV. This could
only be avoided when BATMAN_V was disabled during compile time.

Using a special batadv_algo hook for this initialization avoids this
problem.

Fixes: 50164d8f500f ("batman-adv: B.A.T.M.A.N. V - implement GW selection logic")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
diff --git a/net/batman-adv/gateway_common.c b/net/batman-adv/gateway_common.c
index 2118481..3e3f91a 100644
--- a/net/batman-adv/gateway_common.c
+++ b/net/batman-adv/gateway_common.c
@@ -253,6 +253,11 @@ static void batadv_gw_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
  */
 void batadv_gw_init(struct batadv_priv *bat_priv)
 {
+	if (bat_priv->algo_ops->gw.init_sel_class)
+		bat_priv->algo_ops->gw.init_sel_class(bat_priv);
+	else
+		atomic_set(&bat_priv->gw.sel_class, 1);
+
 	batadv_tvlv_handler_register(bat_priv, batadv_gw_tvlv_ogm_handler_v1,
 				     NULL, BATADV_TVLV_GW, 1,
 				     BATADV_TVLV_HANDLER_OGM_CIFNOTFND);