[linux-next] LinuxNextTracking branch, master, updated. next-20160118

batman at open-mesh.org batman at open-mesh.org
Tue Jan 19 00:15:45 CET 2016


The following commit has been merged in the master branch:
commit 2baa753c276f27f8e844637561ad597867aa6fb6
Author: Sven Eckelmann <sven at narfation.org>
Date:   Tue Jan 5 12:06:22 2016 +0100

    batman-adv: Drop immediate batadv_neigh_node free function
    
    It is not allowed to free the memory of an object which is part of a list
    which is protected by rcu-read-side-critical sections without making sure
    that no other context is accessing the object anymore. This usually happens
    by removing the references to this object and then waiting until the rcu
    grace period is over and no one (allowedly) accesses it anymore.
    
    But the _now functions ignore this completely. They free the object
    directly even when a different context still tries to access it. This has
    to be avoided and thus these functions must be removed and all functions
    have to use batadv_neigh_node_free_ref.
    
    Fixes: 89652331c00f ("batman-adv: split tq information in neigh_node struct")
    Signed-off-by: Sven Eckelmann <sven at narfation.org>
    Signed-off-by: Marek Lindner <mareklindner at neomailbox.ch>
    Signed-off-by: Antonio Quartulli <a at unstable.cc>

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 6929acc..78fd4ea 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -285,20 +285,8 @@ static void batadv_neigh_node_free_rcu(struct rcu_head *rcu)
 }
 
 /**
- * batadv_neigh_node_free_ref_now - decrement the neighbors refcounter
- *  and possibly free it (without rcu callback)
- * @neigh_node: neigh neighbor to free
- */
-static void
-batadv_neigh_node_free_ref_now(struct batadv_neigh_node *neigh_node)
-{
-	if (atomic_dec_and_test(&neigh_node->refcount))
-		batadv_neigh_node_free_rcu(&neigh_node->rcu);
-}
-
-/**
  * batadv_neigh_node_free_ref - decrement the neighbors refcounter
- *  and possibly free it
+ *  and possibly release it
  * @neigh_node: neigh neighbor to free
  */
 void batadv_neigh_node_free_ref(struct batadv_neigh_node *neigh_node)
@@ -733,24 +721,23 @@ int batadv_hardif_neigh_seq_print_text(struct seq_file *seq, void *offset)
 }
 
 /**
- * batadv_orig_ifinfo_free_rcu - free the orig_ifinfo object
- * @rcu: rcu pointer of the orig_ifinfo object
+ * batadv_orig_ifinfo_release - release orig_ifinfo from lists and queue for
+ *  free after rcu grace period
+ * @orig_ifinfo: the orig_ifinfo object to release
  */
-static void batadv_orig_ifinfo_free_rcu(struct rcu_head *rcu)
+static void batadv_orig_ifinfo_release(struct batadv_orig_ifinfo *orig_ifinfo)
 {
-	struct batadv_orig_ifinfo *orig_ifinfo;
 	struct batadv_neigh_node *router;
 
-	orig_ifinfo = container_of(rcu, struct batadv_orig_ifinfo, rcu);
-
 	if (orig_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
-		batadv_hardif_free_ref_now(orig_ifinfo->if_outgoing);
+		batadv_hardif_free_ref(orig_ifinfo->if_outgoing);
 
 	/* this is the last reference to this object */
 	router = rcu_dereference_protected(orig_ifinfo->router, true);
 	if (router)
-		batadv_neigh_node_free_ref_now(router);
-	kfree(orig_ifinfo);
+		batadv_neigh_node_free_ref(router);
+
+	kfree_rcu(orig_ifinfo, rcu);
 }
 
 /**
@@ -761,7 +748,7 @@ static void batadv_orig_ifinfo_free_rcu(struct rcu_head *rcu)
 void batadv_orig_ifinfo_free_ref(struct batadv_orig_ifinfo *orig_ifinfo)
 {
 	if (atomic_dec_and_test(&orig_ifinfo->refcount))
-		call_rcu(&orig_ifinfo->rcu, batadv_orig_ifinfo_free_rcu);
+		batadv_orig_ifinfo_release(orig_ifinfo);
 }
 
 /**

-- 
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