[rtems commit] score: PR2179: Fix initially locked PI mutex

[Sebastian Huber]

Module:    rtems
Branch:    4.10
Commit:    a62a3c32b1788f8d1dd318b5e36acc1cf16daf69
Changeset: http://git.rtems.org/rtems/commit/?id=a62a3c32b1788f8d1dd318b5e36acc1cf16daf69

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Tue Aug 19 17:43:36 2014 +0200

score: PR2179: Fix initially locked PI mutex

---

 cpukit/score/src/coremutex.c     |   14 ++++++++++----
 testsuites/sptests/sp51/init.c   |   36 ++++++++++++++++++++++++++++++++++++
 testsuites/sptests/sp51/sp51.doc |    3 +++
 3 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/cpukit/score/src/coremutex.c b/cpukit/score/src/coremutex.c
index 9745f82..261e18e 100644
--- a/cpukit/score/src/coremutex.c
+++ b/cpukit/score/src/coremutex.c
@@ -59,14 +59,19 @@ CORE_mutex_Status _CORE_mutex_Initialize(
   the_mutex->blocked_count = 0;
 
   if ( initial_lock == CORE_MUTEX_LOCKED ) {
+    bool is_priority_ceiling =
+     _CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes );
+
     the_mutex->nest_count = 1;
     the_mutex->holder     = _Thread_Executing;
     the_mutex->holder_id  = _Thread_Executing->Object.id;
-    if ( _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) ||
-         _CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ) {
+
+    if (  is_priority_ceiling ||
+         _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) ) {
       Priority_Control ceiling = the_mutex->Attributes.priority_ceiling;
 
-      if ( _Thread_Executing->current_priority < ceiling )
+      if ( is_priority_ceiling &&
+           _Thread_Executing->current_priority < ceiling )
        return CORE_MUTEX_STATUS_CEILING_VIOLATED;
 #ifdef __RTEMS_STRICT_ORDER_MUTEX__
        _Chain_Prepend_unprotected( &_Thread_Executing->lock_mutex,
@@ -75,7 +80,8 @@ CORE_mutex_Status _CORE_mutex_Initialize(
 #endif
 
       _Thread_Executing->resource_count++;
-      _Thread_Change_priority( _Thread_Executing, ceiling, false );
+      if ( is_priority_ceiling )
+        _Thread_Change_priority( _Thread_Executing, ceiling, false );
     }
   } else {
     the_mutex->nest_count = 0;
diff --git a/testsuites/sptests/sp51/init.c b/testsuites/sptests/sp51/init.c
index 8f34cab..82deb53 100644
--- a/testsuites/sptests/sp51/init.c
+++ b/testsuites/sptests/sp51/init.c
@@ -11,6 +11,40 @@
 
 #include <tmacros.h>
 
+static void test_create_initially_locked_prio_inherit_sema(void)
+{
+  rtems_status_code   sc;
+  rtems_id            id;
+  rtems_task_priority prio_a;
+  rtems_task_priority prio_b;
+  rtems_task_priority prio_ceiling = 0;
+
+  sc = rtems_task_set_priority(RTEMS_SELF, RTEMS_CURRENT_PRIORITY, &prio_a);
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+  rtems_test_assert(prio_a != prio_ceiling);
+
+  sc = rtems_semaphore_create(
+    rtems_build_name( 'S', 'E', 'M', 'A' ),
+    0,
+    RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_INHERIT_PRIORITY,
+    prio_ceiling,
+    &id
+  );
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+  sc = rtems_task_set_priority(RTEMS_SELF, RTEMS_CURRENT_PRIORITY, &prio_b);
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+  rtems_test_assert(prio_a == prio_b);
+
+  sc = rtems_semaphore_release(id);
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+  sc = rtems_semaphore_delete(id);
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+}
+
 rtems_task Init(
   rtems_task_argument argument
 )
@@ -50,6 +84,8 @@ rtems_task Init(
   sc = rtems_semaphore_release( mutex );
   directive_failed( sc, "rtems_semaphore_release" );
 
+  test_create_initially_locked_prio_inherit_sema();
+
   puts( "*** END OF TEST 51 ***" );
   rtems_test_exit( 0 );
 }
diff --git a/testsuites/sptests/sp51/sp51.doc b/testsuites/sptests/sp51/sp51.doc
index bbf162a..fee5cf3 100644
--- a/testsuites/sptests/sp51/sp51.doc
+++ b/testsuites/sptests/sp51/sp51.doc
@@ -26,3 +26,6 @@ concepts:
 
 + Ensure the when the binary semaphore lock fails to acquire the mutex,
   it is an error to release it since the lock failed.
+
++ Verify that creation of an initially locked priority inheritance mutex does
+  not change the priority of the executing thread.