score: Avoid Giant lock for barriers

Use _Thread_queue_Flush_critical() to atomically release the barrier.

Update #2555.

1 files changed, 27 insertions, 26 deletions

diff --git a/cpukit/score/src/corebarrierwait.c b/cpukit/score/src/corebarrierwait.c
index 11495e5e69..4a924b28dd 100644
--- a/cpukit/score/src/corebarrierwait.c
+++ b/cpukit/score/src/corebarrierwait.c
@@ -19,44 +19,45 @@
 #endif
 
 #include <rtems/score/corebarrierimpl.h>
-#include <rtems/score/isrlevel.h>
 #include <rtems/score/statesimpl.h>
-#include <rtems/score/threadqimpl.h>
 
 void _CORE_barrier_Do_seize(
   CORE_barrier_Control    *the_barrier,
   Thread_Control          *executing,
   bool                     wait,
-  Watchdog_Interval        timeout
+  Watchdog_Interval        timeout,
 #if defined(RTEMS_MULTIPROCESSING)
-  ,
   Thread_queue_MP_callout  mp_callout,
-  Objects_Id               mp_id
+  Objects_Id               mp_id,
 #endif
+  ISR_lock_Context        *lock_context
 )
 {
-  ISR_lock_Context lock_context;
+  uint32_t number_of_waiting_threads;
 
   executing->Wait.return_code = CORE_BARRIER_STATUS_SUCCESSFUL;
-  _Thread_queue_Acquire( &the_barrier->Wait_queue, &lock_context );
-  the_barrier->number_of_waiting_threads++;
-  if ( _CORE_barrier_Is_automatic( &the_barrier->Attributes ) ) {
-    if ( the_barrier->number_of_waiting_threads ==
-	 the_barrier->Attributes.maximum_count) {
-      executing->Wait.return_code = CORE_BARRIER_STATUS_AUTOMATICALLY_RELEASED;
-      _Thread_queue_Release( &the_barrier->Wait_queue, &lock_context );
-      _CORE_barrier_Surrender( the_barrier, mp_callout, mp_id );
-      return;
-    }
-  }
 
-  _Thread_queue_Enqueue_critical(
-    &the_barrier->Wait_queue.Queue,
-    CORE_BARRIER_TQ_OPERATIONS,
-    executing,
-    STATES_WAITING_FOR_BARRIER,
-    timeout,
-    CORE_BARRIER_TIMEOUT,
-    &lock_context
-  );
+  _CORE_barrier_Acquire_critical( the_barrier, lock_context );
+
+  number_of_waiting_threads = the_barrier->number_of_waiting_threads;
+  ++number_of_waiting_threads;
+
+  if (
+    _CORE_barrier_Is_automatic( &the_barrier->Attributes )
+      && number_of_waiting_threads == the_barrier->Attributes.maximum_count
+  ) {
+    executing->Wait.return_code = CORE_BARRIER_STATUS_AUTOMATICALLY_RELEASED;
+    _CORE_barrier_Surrender( the_barrier, mp_callout, mp_id, lock_context );
+  } else {
+    the_barrier->number_of_waiting_threads = number_of_waiting_threads;
+    _Thread_queue_Enqueue_critical(
+      &the_barrier->Wait_queue.Queue,
+      CORE_BARRIER_TQ_OPERATIONS,
+      executing,
+      STATES_WAITING_FOR_BARRIER,
+      timeout,
+      CORE_BARRIER_TIMEOUT,
+      lock_context
+    );
+  }
 }