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

batman at open-mesh.org batman at open-mesh.org
Tue Jan 19 00:15:46 CET 2016


The following commit has been merged in the master branch:
commit ae3e1e36e3cb6c686a7a2725af20ca86aa46d62a
Author: Sven Eckelmann <sven at narfation.org>
Date:   Tue Jan 5 12:06:24 2016 +0100

    batman-adv: Drop immediate neigh_ifinfo 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_ifinfo_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 0b7ab38e..f683335 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -163,42 +163,28 @@ err:
 }
 
 /**
- * batadv_neigh_ifinfo_free_rcu - free the neigh_ifinfo object
- * @rcu: rcu pointer of the neigh_ifinfo object
- */
-static void batadv_neigh_ifinfo_free_rcu(struct rcu_head *rcu)
-{
-	struct batadv_neigh_ifinfo *neigh_ifinfo;
-
-	neigh_ifinfo = container_of(rcu, struct batadv_neigh_ifinfo, rcu);
-
-	if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
-		batadv_hardif_free_ref_now(neigh_ifinfo->if_outgoing);
-
-	kfree(neigh_ifinfo);
-}
-
-/**
- * batadv_neigh_ifinfo_free_now - decrement the refcounter and possibly free
- *  the neigh_ifinfo (without rcu callback)
+ * batadv_neigh_ifinfo_release - release neigh_ifinfo from lists and queue for
+ *  free after rcu grace period
  * @neigh_ifinfo: the neigh_ifinfo object to release
  */
 static void
-batadv_neigh_ifinfo_free_ref_now(struct batadv_neigh_ifinfo *neigh_ifinfo)
+batadv_neigh_ifinfo_release(struct batadv_neigh_ifinfo *neigh_ifinfo)
 {
-	if (atomic_dec_and_test(&neigh_ifinfo->refcount))
-		batadv_neigh_ifinfo_free_rcu(&neigh_ifinfo->rcu);
+	if (neigh_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
+		batadv_hardif_free_ref(neigh_ifinfo->if_outgoing);
+
+	kfree_rcu(neigh_ifinfo, rcu);
 }
 
 /**
- * batadv_neigh_ifinfo_free_ref - decrement the refcounter and possibly free
+ * batadv_neigh_ifinfo_free_ref - decrement the refcounter and possibly release
  *  the neigh_ifinfo
  * @neigh_ifinfo: the neigh_ifinfo object to release
  */
 void batadv_neigh_ifinfo_free_ref(struct batadv_neigh_ifinfo *neigh_ifinfo)
 {
 	if (atomic_dec_and_test(&neigh_ifinfo->refcount))
-		call_rcu(&neigh_ifinfo->rcu, batadv_neigh_ifinfo_free_rcu);
+		batadv_neigh_ifinfo_release(neigh_ifinfo);
 }
 
 /**
@@ -245,7 +231,7 @@ static void batadv_neigh_node_free_rcu(struct rcu_head *rcu)
 
 	hlist_for_each_entry_safe(neigh_ifinfo, node_tmp,
 				  &neigh_node->ifinfo_list, list) {
-		batadv_neigh_ifinfo_free_ref_now(neigh_ifinfo);
+		batadv_neigh_ifinfo_free_ref(neigh_ifinfo);
 	}
 
 	hardif_neigh = batadv_hardif_neigh_get(neigh_node->if_incoming,

-- 
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