doc/RCU/rcu: Use ':ref:' for links to other docs

Signed-off-by: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

Documentation/RCU/rcu.rst

@@ -11,8 +11,8 @@ must be long enough that any readers accessing the item being deleted have
 since dropped their references.  For example, an RCU-protected deletion
 from a linked list would first remove the item from the list, wait for
 a grace period to elapse, then free the element.  See the
-Documentation/RCU/listRCU.rst file for more information on using RCU with
-linked lists.
+:ref:`Documentation/RCU/listRCU.rst <list_rcu_doc>` for more information on
+using RCU with linked lists.
 
 Frequently Asked Questions
 --------------------------
@@ -50,7 +50,7 @@ Frequently Asked Questions
 - If I am running on a uniprocessor kernel, which can only do one
   thing at a time, why should I wait for a grace period?
 
-  See the Documentation/RCU/UP.rst file for more information.
+  See :ref:`Documentation/RCU/UP.rst <up_doc>` for more information.
 
 - How can I see where RCU is currently used in the Linux kernel?
 
@@ -68,9 +68,9 @@ Frequently Asked Questions
 
 - Why the name "RCU"?
 
-  "RCU" stands for "read-copy update".  The file Documentation/RCU/listRCU.rst
-  has more information on where this name came from, search for
-  "read-copy update" to find it.
+  "RCU" stands for "read-copy update".
+  :ref:`Documentation/RCU/listRCU.rst <list_rcu_doc>` has more information on where
+  this name came from, search for "read-copy update" to find it.
 
 - I hear that RCU is patented?  What is with that?