[PATCH] Yet another RCU documentation update

Update RCU documentation based on discussions and review of RCU-based tree
patches.  Add an introductory whatisRCU.txt file.

Signed-off-by: <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/Documentation/RCU/rcu.txt b/Documentation/RCU/rcu.txt
index eb44400..6fa0922 100644
--- a/Documentation/RCU/rcu.txt
+++ b/Documentation/RCU/rcu.txt
@@ -64,6 +64,54 @@
 	Of these, one was allowed to lapse by the assignee, and the
 	others have been contributed to the Linux kernel under GPL.
 
+o	I hear that RCU needs work in order to support realtime kernels?
+
+	Yes, work in progress.
+
 o	Where can I find more information on RCU?
 
 	See the RTFP.txt file in this directory.
+	Or point your browser at http://www.rdrop.com/users/paulmck/RCU/.
+
+o	What are all these files in this directory?
+
+
+	NMI-RCU.txt
+
+		Describes how to use RCU to implement dynamic
+		NMI handlers, which can be revectored on the fly,
+		without rebooting.
+
+	RTFP.txt
+
+		List of RCU-related publications and web sites.
+
+	UP.txt
+
+		Discussion of RCU usage in UP kernels.
+
+	arrayRCU.txt
+
+		Describes how to use RCU to protect arrays, with
+		resizeable arrays whose elements reference other
+		data structures being of the most interest.
+
+	checklist.txt
+
+		Lists things to check for when inspecting code that
+		uses RCU.
+
+	listRCU.txt
+
+		Describes how to use RCU to protect linked lists.
+		This is the simplest and most common use of RCU
+		in the Linux kernel.
+
+	rcu.txt
+
+		You are reading it!
+
+	whatisRCU.txt
+
+		Overview of how the RCU implementation works.  Along
+		the way, presents a conceptual view of RCU.