score: Simplify thread wait state handling

Remove the THREAD_WAIT_STATE_READY_AGAIN and simply use the initial value to
indicate that a thread does not wait on something.  Rename
THREAD_WAIT_FLAGS_INITIAL to THREAD_WAIT_STATE_READY.  This change is necessary
so that _Thread_Continue() can be called for threads which never waited on
something (for example dormant threads).

Update #4546.

9 files changed, 23 insertions, 38 deletions

diff --git a/cpukit/include/rtems/rtems/ratemonimpl.h b/cpukit/include/rtems/rtems/ratemonimpl.h
index 62327c5b09..d17c7fe4de 100644
--- a/cpukit/include/rtems/rtems/ratemonimpl.h
+++ b/cpukit/include/rtems/rtems/ratemonimpl.h
@@ -48,9 +48,6 @@ extern "C" {
 #define RATE_MONOTONIC_BLOCKED \
   ( THREAD_WAIT_CLASS_PERIOD | THREAD_WAIT_STATE_BLOCKED )
 
-#define RATE_MONOTONIC_READY_AGAIN \
-  ( THREAD_WAIT_CLASS_PERIOD | THREAD_WAIT_STATE_READY_AGAIN )
-
 /**
  *  @brief Allocates a period control block from
  *  the inactive chain of free period control blocks.
diff --git a/cpukit/include/rtems/score/thread.h b/cpukit/include/rtems/score/thread.h
index 23ed8e1406..c3c37eb160 100644
--- a/cpukit/include/rtems/score/thread.h
+++ b/cpukit/include/rtems/score/thread.h
@@ -404,7 +404,7 @@ typedef union {
  * The mutually exclusive wait state flags are
  * - @ref THREAD_WAIT_STATE_INTEND_TO_BLOCK,
  * - @ref THREAD_WAIT_STATE_BLOCKED, and
- * - @ref THREAD_WAIT_STATE_READY_AGAIN.
+ * - @ref THREAD_WAIT_STATE_READY.
  */
 typedef unsigned int Thread_Wait_flags;
 
diff --git a/cpukit/include/rtems/score/threadimpl.h b/cpukit/include/rtems/score/threadimpl.h
index dc41d28856..a66d1a5346 100644
--- a/cpukit/include/rtems/score/threadimpl.h
+++ b/cpukit/include/rtems/score/threadimpl.h
@@ -2217,14 +2217,18 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_cancel(
 }
 
 /**
- * @brief The initial thread wait flags value set by _Thread_Initialize().
+ * @brief Mask to get the thread wait state flags.
  */
-#define THREAD_WAIT_FLAGS_INITIAL 0x0U
+#define THREAD_WAIT_STATE_MASK 0xffU
 
 /**
- * @brief Mask to get the thread wait state flags.
+ * @brief Indicates that the thread does not wait on something.
+ *
+ * In this wait state, the wait class is zero.  This wait state is set
+ * initially by _Thread_Initialize() and after each wait operation once the
+ * thread is ready again.
  */
-#define THREAD_WAIT_STATE_MASK 0xffU
+#define THREAD_WAIT_STATE_READY 0x0U
 
 /**
  * @brief Indicates that the thread begins with the blocking operation.
@@ -2241,13 +2245,6 @@ RTEMS_INLINE_ROUTINE void _Thread_Wait_cancel(
 #define THREAD_WAIT_STATE_BLOCKED 0x2U
 
 /**
- * @brief Indicates that a condition to end the thread wait occurred.
- *
- * This could be a timeout, a signal, an event or a resource availability.
- */
-#define THREAD_WAIT_STATE_READY_AGAIN 0x4U
-
-/**
  * @brief Mask to get the thread wait class flags.
  */
 #define THREAD_WAIT_CLASS_MASK 0xff00U
diff --git a/cpukit/rtems/src/eventsurrender.c b/cpukit/rtems/src/eventsurrender.c
index 48c08e486f..0623977c8b 100644
--- a/cpukit/rtems/src/eventsurrender.c
+++ b/cpukit/rtems/src/eventsurrender.c
@@ -42,12 +42,10 @@ static bool _Event_Is_blocking_on_event(
 )
 {
   Thread_Wait_flags wait_flags;
-  Thread_Wait_flags wait_mask;
 
   wait_flags = _Thread_Wait_flags_get( the_thread );
-  wait_mask = THREAD_WAIT_CLASS_MASK | THREAD_WAIT_STATE_READY_AGAIN;
 
-  return ( wait_flags & wait_mask ) == wait_class;
+  return ( wait_flags & THREAD_WAIT_CLASS_MASK ) == wait_class;
 }
 
 static bool _Event_Is_satisfied(
@@ -88,16 +86,14 @@ rtems_status_code _Event_Surrender(
     _Event_Is_blocking_on_event( the_thread, wait_class )
       && _Event_Is_satisfied( the_thread, pending_events, &seized_events )
   ) {
-    Thread_Wait_flags ready_again;
-    bool              success;
+    bool success;
 
     _Event_Satisfy( the_thread, event, pending_events, seized_events );
 
-    ready_again = wait_class | THREAD_WAIT_STATE_READY_AGAIN;
     success = _Thread_Wait_flags_try_change_release(
       the_thread,
       wait_class | THREAD_WAIT_STATE_INTEND_TO_BLOCK,
-      ready_again
+      THREAD_WAIT_STATE_READY
     );
 
     if ( success ) {
@@ -107,7 +103,7 @@ rtems_status_code _Event_Surrender(
         _Thread_Wait_flags_get( the_thread )
           == ( wait_class | THREAD_WAIT_STATE_BLOCKED )
       );
-      _Thread_Wait_flags_set( the_thread, ready_again );
+      _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
       unblock = true;
     }
   } else {
diff --git a/cpukit/rtems/src/ratemonperiod.c b/cpukit/rtems/src/ratemonperiod.c
index 32ac688a7f..a8697abf3c 100644
--- a/cpukit/rtems/src/ratemonperiod.c
+++ b/cpukit/rtems/src/ratemonperiod.c
@@ -247,7 +247,7 @@ static rtems_status_code _Rate_monotonic_Block_while_active(
   );
   if ( !success ) {
     _Assert(
-      _Thread_Wait_flags_get( executing ) == RATE_MONOTONIC_READY_AGAIN
+      _Thread_Wait_flags_get( executing ) == THREAD_WAIT_STATE_READY
     );
     _Thread_Unblock( executing );
   }
diff --git a/cpukit/rtems/src/ratemontimeout.c b/cpukit/rtems/src/ratemontimeout.c
index b20e1e15db..375c5f081f 100644
--- a/cpukit/rtems/src/ratemontimeout.c
+++ b/cpukit/rtems/src/ratemontimeout.c
@@ -74,13 +74,13 @@ void _Rate_monotonic_Timeout( Watchdog_Control *the_watchdog )
     success = _Thread_Wait_flags_try_change_release(
       owner,
       RATE_MONOTONIC_INTEND_TO_BLOCK,
-      RATE_MONOTONIC_READY_AGAIN
+      THREAD_WAIT_STATE_READY
     );
     if ( success ) {
       unblock = false;
     } else {
       _Assert( _Thread_Wait_flags_get( owner ) == RATE_MONOTONIC_BLOCKED );
-      _Thread_Wait_flags_set( owner, RATE_MONOTONIC_READY_AGAIN );
+      _Thread_Wait_flags_set( owner, THREAD_WAIT_STATE_READY );
       unblock = true;
     }
 
diff --git a/cpukit/score/src/threadinitialize.c b/cpukit/score/src/threadinitialize.c
index 01ef479537..2682a9428c 100644
--- a/cpukit/score/src/threadinitialize.c
+++ b/cpukit/score/src/threadinitialize.c
@@ -299,7 +299,7 @@ static bool _Thread_Try_initialize(
   the_thread->Wait.operations         = &_Thread_queue_Operations_default;
   the_thread->Start.initial_priority  = config->priority;
 
-  RTEMS_STATIC_ASSERT( THREAD_WAIT_FLAGS_INITIAL == 0, Wait_flags );
+  RTEMS_STATIC_ASSERT( THREAD_WAIT_STATE_READY == 0, Wait_flags );
 
   /* POSIX Keys */
   _RBTree_Initialize_empty( &the_thread->Keys.Key_value_pairs );
diff --git a/cpukit/score/src/threadqenqueue.c b/cpukit/score/src/threadqenqueue.c
index ed6c64543c..7b42cda88c 100644
--- a/cpukit/score/src/threadqenqueue.c
+++ b/cpukit/score/src/threadqenqueue.c
@@ -41,9 +41,6 @@
 #define THREAD_QUEUE_BLOCKED \
   (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_BLOCKED)
 
-#define THREAD_QUEUE_READY_AGAIN \
-  (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_READY_AGAIN)
-
 #if defined(RTEMS_SMP)
 /*
  * A global registry of active thread queue links is used to provide deadlock
@@ -560,7 +557,7 @@ static void _Thread_queue_Force_ready_again( Thread_Control *the_thread )
    * We must set the wait flags under protection of the current thread lock,
    * otherwise a _Thread_Timeout() running on another processor may interfere.
    */
-  _Thread_Wait_flags_set( the_thread, THREAD_QUEUE_READY_AGAIN );
+  _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
   _Thread_Wait_restore_default( the_thread );
 }
 
@@ -576,13 +573,13 @@ static bool _Thread_queue_Make_ready_again( Thread_Control *the_thread )
   success = _Thread_Wait_flags_try_change_release(
     the_thread,
     THREAD_QUEUE_INTEND_TO_BLOCK,
-    THREAD_QUEUE_READY_AGAIN
+    THREAD_WAIT_STATE_READY
   );
   if ( success ) {
     unblock = false;
   } else {
     _Assert( _Thread_Wait_flags_get( the_thread ) == THREAD_QUEUE_BLOCKED );
-    _Thread_Wait_flags_set( the_thread, THREAD_QUEUE_READY_AGAIN );
+    _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
     unblock = true;
   }
 
diff --git a/cpukit/score/src/threadtimeout.c b/cpukit/score/src/threadtimeout.c
index 2f2017bebe..9431ff253d 100644
--- a/cpukit/score/src/threadtimeout.c
+++ b/cpukit/score/src/threadtimeout.c
@@ -35,9 +35,8 @@ void _Thread_Continue( Thread_Control *the_thread, Status_Control status )
 
   wait_flags = _Thread_Wait_flags_get( the_thread );
 
-  if ( ( wait_flags & THREAD_WAIT_STATE_READY_AGAIN ) == 0 ) {
+  if ( wait_flags != THREAD_WAIT_STATE_READY ) {
     Thread_Wait_flags wait_class;
-    Thread_Wait_flags ready_again;
     bool              success;
 
     _Thread_Wait_cancel( the_thread, &queue_context );
@@ -45,11 +44,10 @@ void _Thread_Continue( Thread_Control *the_thread, Status_Control status )
     the_thread->Wait.return_code = status;
 
     wait_class = wait_flags & THREAD_WAIT_CLASS_MASK;
-    ready_again = wait_class | THREAD_WAIT_STATE_READY_AGAIN;
     success = _Thread_Wait_flags_try_change_release(
       the_thread,
       wait_class | THREAD_WAIT_STATE_INTEND_TO_BLOCK,
-      ready_again
+      THREAD_WAIT_STATE_READY
     );
 
     if ( success ) {
@@ -59,7 +57,7 @@ void _Thread_Continue( Thread_Control *the_thread, Status_Control status )
         _Thread_Wait_flags_get( the_thread )
           == ( wait_class | THREAD_WAIT_STATE_BLOCKED )
       );
-      _Thread_Wait_flags_set( the_thread, ready_again );
+      _Thread_Wait_flags_set( the_thread, THREAD_WAIT_STATE_READY );
       unblock = true;
     }
   } else {