From 32ae9b221e788413ce68feaae2ca39e406211a0a Mon Sep 17 00:00:00 2001 From: Marek Lindner Date: Wed, 20 Apr 2011 15:40:58 +0200 Subject: 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 Signed-off-by: Sven Eckelmann --- net/batman-adv/hard-interface.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'net/batman-adv/hard-interface.h') diff --git a/net/batman-adv/hard-interface.h b/net/batman-adv/hard-interface.h index a9ddf36e51c8..64265991460b 100644 --- a/net/batman-adv/hard-interface.h +++ b/net/batman-adv/hard-interface.h @@ -45,4 +45,22 @@ static inline void hardif_free_ref(struct hard_iface *hard_iface) 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_ */ -- cgit