From 72822225bd41320a98f5d7cde38317766e18983f Mon Sep 17 00:00:00 2001 From: Linus Lüssing Date: Mon, 15 Apr 2013 21:43:29 +0800 Subject: batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit rcu_barrier() only waits for the currently scheduled rcu functions to finish - it won't wait for any function scheduled via another call_rcu() within an rcu scheduled function. Unfortunately our batadv_tt_orig_list_entry_free_ref() does just that, via a batadv_orig_node_free_ref() call, leading to our rcu_barrier() call potentially missing such a batadv_orig_node_free_ref(). This patch fixes this issue by calling the batadv_orig_node_free_rcu() directly from the rcu callback, removing the unnecessary, additional call_rcu() layer here. Signed-off-by: Linus Lüssing Signed-off-by: Marek Lindner Acked-by: Antonio Quartulli --- net/batman-adv/originator.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'net/batman-adv/originator.c') diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index 2f3452546636..fad1a2093e15 100644 --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -156,12 +156,28 @@ static void batadv_orig_node_free_rcu(struct rcu_head *rcu) kfree(orig_node); } +/** + * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly + * schedule an rcu callback for freeing it + * @orig_node: the orig node to free + */ void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node) { if (atomic_dec_and_test(&orig_node->refcount)) call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu); } +/** + * batadv_orig_node_free_ref_now - decrement the orig node refcounter and + * possibly free it (without rcu callback) + * @orig_node: the orig node to free + */ +void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node) +{ + if (atomic_dec_and_test(&orig_node->refcount)) + batadv_orig_node_free_rcu(&orig_node->rcu); +} + void batadv_originator_free(struct batadv_priv *bat_priv) { struct batadv_hashtable *hash = bat_priv->orig_hash; -- cgit v1.2.3