Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  Revert "net: Make accesses to ->br_port safe for sparse RCU"
  mce: convert to rcu_dereference_index_check()
  net: Make accesses to ->br_port safe for sparse RCU
  vfs: add fs.h to define struct file
  lockdep: Add an in_workqueue_context() lockdep-based test function
  rcu: add __rcu API for later sparse checking
  rcu: add an rcu_dereference_index_check()
  tree/tiny rcu: Add debug RCU head objects
  mm: remove all rcu head initializations
  fs: remove all rcu head initializations, except on_stack initializations
  powerpc: remove all rcu head initializations

1 files changed, 15 insertions, 0 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 327d2deb4451..59fef1531dd2 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -68,6 +68,21 @@ struct workqueue_struct {
 #endif
 };
 
+#ifdef CONFIG_LOCKDEP
+/**
+ * in_workqueue_context() - in context of specified workqueue?
+ * @wq: the workqueue of interest
+ *
+ * Checks lockdep state to see if the current task is executing from
+ * within a workqueue item.  This function exists only if lockdep is
+ * enabled.
+ */
+int in_workqueue_context(struct workqueue_struct *wq)
+{
+        return lock_is_held(&wq->lockdep_map);
+}
+#endif
+
 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 
 static struct debug_obj_descr work_debug_descr;