rcu: create rcu_my_thread_group_empty() wrapper

Some RCU-lockdep splat repairs need to know whether they are running
in a single-threaded process.  Unfortunately, the thread_group_empty()
primitive is defined in sched.h, and can induce #include hell.  This
commit therefore introduces a rcu_my_thread_group_empty() wrapper that
is defined in rcupdate.c, thus avoiding the need to include sched.h
everywhere.

Signed-off-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 07db2fe..db266bb 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -190,6 +190,8 @@ static inline int rcu_read_lock_sched_held(void)
 
 #ifdef CONFIG_PROVE_RCU
 
+extern int rcu_my_thread_group_empty(void);
+
 /**
  * rcu_dereference_check - rcu_dereference with debug checking
  * @p: The pointer to read, prior to dereferencing

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 03a7ea1..49d808e 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -122,3 +122,14 @@ void wakeme_after_rcu(struct rcu_head  *head)
        rcu = container_of(head, struct rcu_synchronize, head);
        complete(&rcu->completion);
 }
+
+#ifdef CONFIG_PROVE_RCU
+/*
+ * wrapper function to avoid #include problems.
+ */
+int rcu_my_thread_group_empty(void)
+{
+       return thread_group_empty(current);
+}
+EXPORT_SYMBOL_GPL(rcu_my_thread_group_empty);
+#endif /* #ifdef CONFIG_PROVE_RCU */