---

yaml --- r: 376681 b: refs/heads/master c: c87a124 h: refs/heads/master i: 376679: a7040b6 v: v3
git-mirror · Jun 3, 2013 · 5173768 · 5173768
1 parent 12a741e
commit 5173768
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c802db1164f28e62c6a43132b8d290cb8113f2ac
+refs/heads/master: c87a124a5d5e8cf8e21c4363c3372bcaf53ea190
diff --git a/trunk/include/linux/rculist_nulls.h b/trunk/include/linux/rculist_nulls.h
@@ -105,9 +105,14 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
  * @head:	the head for your list.
  * @member:	the name of the hlist_nulls_node within the struct.
  *
+ * The barrier() is needed to make sure compiler doesn't cache first element [1],
+ * as this loop can be restarted [2]
+ * [1] Documentation/atomic_ops.txt around line 114
+ * [2] Documentation/RCU/rculist_nulls.txt around line 146
  */
 #define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member)			\
-	for (pos = rcu_dereference_raw(hlist_nulls_first_rcu(head));		\
+	for (({barrier();}),							\
+	     pos = rcu_dereference_raw(hlist_nulls_first_rcu(head));		\
 		(!is_a_nulls(pos)) &&						\
 		({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \
 		pos = rcu_dereference_raw(hlist_nulls_next_rcu(pos)))