rcu: Flag need for rcu_node_tree.h and rcu_segcblist.h visibility

The rcu_node_tree.h and rcu_segcblist.h header files in the include/linux
directory might appear at first sight to be internal to the RCU
implementation.  However, the definitions in these files are needed to
determine the size of TREE SRCU's srcu_struct structure, so they must
be externally visible, which is why they live in include/linux.

This commit adds comments to this effect to those files.

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

2 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/rcu_node_tree.h b/include/linux/rcu_node_tree.h
index 4b766b61e1a0..426cee67f0e2 100644
--- a/include/linux/rcu_node_tree.h
+++ b/include/linux/rcu_node_tree.h
@@ -7,6 +7,10 @@
  * unlimited scalability while maintaining a constant level of contention
  * on the root node.
  *
+ * This seemingly RCU-private file must be available to SRCU users
+ * because the size of the TREE SRCU srcu_struct structure depends
+ * on these definitions.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
diff --git a/include/linux/rcu_segcblist.h b/include/linux/rcu_segcblist.h
index ba4d2621d9ca..c3ad00e63556 100644
--- a/include/linux/rcu_segcblist.h
+++ b/include/linux/rcu_segcblist.h
@@ -1,6 +1,10 @@
 /*
  * RCU segmented callback lists
  *
+ * This seemingly RCU-private file must be available to SRCU users
+ * because the size of the TREE SRCU srcu_struct structure depends
+ * on these definitions.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or