batman-adv: Make bat_priv->primary_if an rcu protected pointer
The rcu protected macros rcu_dereference() and rcu_assign_pointer()
for the bat_priv->primary_if need to be used, as well as spin/rcu locking.
Otherwise we might end up using a primary_if pointer pointing to already
freed memory.
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
diff --git a/net/batman-adv/hard-interface.h b/net/batman-adv/hard-interface.h
index a9ddf36..6426599 100644
--- a/net/batman-adv/hard-interface.h
+++ b/net/batman-adv/hard-interface.h
@@ -45,4 +45,22 @@
call_rcu(&hard_iface->rcu, hardif_free_rcu);
}
+static inline struct hard_iface *primary_if_get_selected(
+ struct bat_priv *bat_priv)
+{
+ struct hard_iface *hard_iface;
+
+ rcu_read_lock();
+ hard_iface = rcu_dereference(bat_priv->primary_if);
+ if (!hard_iface)
+ goto out;
+
+ if (!atomic_inc_not_zero(&hard_iface->refcount))
+ hard_iface = NULL;
+
+out:
+ rcu_read_unlock();
+ return hard_iface;
+}
+
#endif /* _NET_BATMAN_ADV_HARD_INTERFACE_H_ */