batman-adv: use rcu_replace_pointer() where appropriate

In commit a63fc6b7 ("rcu: Upgrade rcu_swap_protected() to
rcu_replace_pointer()") a new helper macro named rcu_replace_pointer() was
introduced to simplify code requiring to switch an rcu pointer to a new
value while extracting the old one.

Use rcu_replace_pointer() where appropriate to make code slimer.
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/gateway_client.c

@@ -146,8 +146,8 @@ static void batadv_gw_select(struct batadv_priv *bat_priv,
 	if (new_gw_node)
 		kref_get(&new_gw_node->refcount);
 
-	curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
-	rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node);
+	curr_gw_node = rcu_replace_pointer(bat_priv->gw.curr_gw, new_gw_node,
+					   true);
 
 	if (curr_gw_node)
 		batadv_gw_node_put(curr_gw_node);

net/batman-adv/hard-interface.c

@@ -473,8 +473,8 @@ static void batadv_primary_if_select(struct batadv_priv *bat_priv,
 	if (new_hard_iface)
 		kref_get(&new_hard_iface->refcount);
 
-	curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1);
-	rcu_assign_pointer(bat_priv->primary_if, new_hard_iface);
+	curr_hard_iface = rcu_replace_pointer(bat_priv->primary_if,
+					      new_hard_iface, 1);
 
 	if (!new_hard_iface)
 		goto out;

net/batman-adv/routing.c

@@ -71,13 +71,13 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
 	 * the code needs to ensure the curr_router variable contains a pointer
 	 * to the replaced best neighbor.
 	 */
-	curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
 
 	/* increase refcount of new best neighbor */
 	if (neigh_node)
 		kref_get(&neigh_node->refcount);
 
-	rcu_assign_pointer(orig_ifinfo->router, neigh_node);
+	curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node,
+					  true);
 	spin_unlock_bh(&orig_node->neigh_list_lock);
 	batadv_orig_ifinfo_put(orig_ifinfo);