doc: Converted NMI-RCU.txt to NMI-RCU.rst.

This patch converts NMI-RCU from txt to rst format.
Also adds NMI-RCU in the index.rst file.

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
[ paulmck: Apply feedback from Phong Tran. ]
Tested-by: Phong Tran <tranmanphong@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/Documentation/RCU/NMI-RCU.txt b/Documentation/RCU/NMI-RCU.rst
similarity index 73%
rename from Documentation/RCU/NMI-RCU.txt
rename to Documentation/RCU/NMI-RCU.rst
index 881353f..1809583 100644 (file)
--- a/Documentation/RCU/NMI-RCU.txt
+++ b/Documentation/RCU/NMI-RCU.rst
@@ -1,4 +1,7 @@
+.. _NMI_rcu_doc:
+
 Using RCU to Protect Dynamic NMI Handlers
+=========================================
 
 
 Although RCU is usually used to protect read-mostly data structures,
@@ -9,7 +12,7 @@ work in "arch/x86/oprofile/nmi_timer_int.c" and in
 "arch/x86/kernel/traps.c".
 
 The relevant pieces of code are listed below, each followed by a
-brief explanation.
+brief explanation::
 
        static int dummy_nmi_callback(struct pt_regs *regs, int cpu)
        {
@@ -18,12 +21,12 @@ brief explanation.
 
 The dummy_nmi_callback() function is a "dummy" NMI handler that does
 nothing, but returns zero, thus saying that it did nothing, allowing
-the NMI handler to take the default machine-specific action.
+the NMI handler to take the default machine-specific action::
 
        static nmi_callback_t nmi_callback = dummy_nmi_callback;
 
 This nmi_callback variable is a global function pointer to the current
-NMI handler.
+NMI handler::
 
        void do_nmi(struct pt_regs * regs, long error_code)
        {
@@ -53,11 +56,12 @@ anyway.  However, in practice it is a good documentation aid, particularly
 for anyone attempting to do something similar on Alpha or on systems
 with aggressive optimizing compilers.
 
-Quick Quiz:  Why might the rcu_dereference_sched() be necessary on Alpha,
-            given that the code referenced by the pointer is read-only?
+Quick Quiz:
+               Why might the rcu_dereference_sched() be necessary on Alpha, given that the code referenced by the pointer is read-only?
 
+:ref:`Answer to Quick Quiz <answer_quick_quiz_NMI>`
 
-Back to the discussion of NMI and RCU...
+Back to the discussion of NMI and RCU::
 
        void set_nmi_callback(nmi_callback_t callback)
        {
@@ -68,7 +72,7 @@ The set_nmi_callback() function registers an NMI handler.  Note that any
 data that is to be used by the callback must be initialized up -before-
 the call to set_nmi_callback().  On architectures that do not order
 writes, the rcu_assign_pointer() ensures that the NMI handler sees the
-initialized values.
+initialized values::
 
        void unset_nmi_callback(void)
        {
@@ -82,7 +86,7 @@ up any data structures used by the old NMI handler until execution
 of it completes on all other CPUs.
 
 One way to accomplish this is via synchronize_rcu(), perhaps as
-follows:
+follows::
 
        unset_nmi_callback();
        synchronize_rcu();
@@ -98,24 +102,23 @@ to free up the handler's data as soon as synchronize_rcu() returns.
 Important note: for this to work, the architecture in question must
 invoke nmi_enter() and nmi_exit() on NMI entry and exit, respectively.
 
+.. _answer_quick_quiz_NMI:
 
-Answer to Quick Quiz
-
-       Why might the rcu_dereference_sched() be necessary on Alpha, given
-       that the code referenced by the pointer is read-only?
+Answer to Quick Quiz:
+       Why might the rcu_dereference_sched() be necessary on Alpha, given that the code referenced by the pointer is read-only?
 
-       Answer: The caller to set_nmi_callback() might well have
-               initialized some data that is to be used by the new NMI
-               handler.  In this case, the rcu_dereference_sched() would
-               be needed, because otherwise a CPU that received an NMI
-               just after the new handler was set might see the pointer
-               to the new NMI handler, but the old pre-initialized
-               version of the handler's data.
+       The caller to set_nmi_callback() might well have
+       initialized some data that is to be used by the new NMI
+       handler.  In this case, the rcu_dereference_sched() would
+       be needed, because otherwise a CPU that received an NMI
+       just after the new handler was set might see the pointer
+       to the new NMI handler, but the old pre-initialized
+       version of the handler's data.
 
-               This same sad story can happen on other CPUs when using
-               a compiler with aggressive pointer-value speculation
-               optimizations.
+       This same sad story can happen on other CPUs when using
+       a compiler with aggressive pointer-value speculation
+       optimizations.
 
-               More important, the rcu_dereference_sched() makes it
-               clear to someone reading the code that the pointer is
-               being protected by RCU-sched.
+       More important, the rcu_dereference_sched() makes it
+       clear to someone reading the code that the pointer is
+       being protected by RCU-sched.

diff --git a/Documentation/RCU/index.rst b/Documentation/RCU/index.rst
index 8d20d44..627128c 100644 (file)
--- a/Documentation/RCU/index.rst
+++ b/Documentation/RCU/index.rst
@@ -10,6 +10,7 @@ RCU concepts
    arrayRCU
    rcu
    listRCU
+   NMI-RCU
    UP
 
    Design/Memory-Ordering/Tree-RCU-Memory-Ordering