batman-adv: Place kref_get for softif_vlan near use

It is hard to understand why the refcnt is increased when it isn't done
near the actual place the new reference is used. So using kref_get right
before the place which requires the reference and in the same function
helps to avoid accidental problems caused by incorrect reference counting.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index e508bf5..49e16b6 100644 (file)
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -594,6 +594,7 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
        }
 
        spin_lock_bh(&bat_priv->softif_vlan_list_lock);
+       kref_get(&vlan->refcount);
        hlist_add_head_rcu(&vlan->list, &bat_priv->softif_vlan_list);
        spin_unlock_bh(&bat_priv->softif_vlan_list_lock);
 
@@ -604,6 +605,9 @@ int batadv_softif_create_vlan(struct batadv_priv *bat_priv, unsigned short vid)
                            bat_priv->soft_iface->dev_addr, vid,
                            BATADV_NULL_IFINDEX, BATADV_NO_MARK);
 
+       /* don't return reference to new softif_vlan */
+       batadv_softif_vlan_put(vlan);
+
        return 0;
 }