[rtems commit] score: Delete _CORE_message_queue_Flush_support()
Sebastian Huber
sebh at rtems.org
Wed May 20 07:12:03 UTC 2015
Module: rtems
Branch: master
Commit: c654b52517c2d255aa98eed347edeba60dc854d0
Changeset: http://git.rtems.org/rtems/commit/?id=c654b52517c2d255aa98eed347edeba60dc854d0
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Thu Apr 30 13:18:45 2015 +0200
score: Delete _CORE_message_queue_Flush_support()
Check the number of pending messages in _CORE_message_queue_Flush() to
avoid race conditions.
---
cpukit/score/Makefile.am | 2 +-
cpukit/score/include/rtems/score/coremsgimpl.h | 17 ------
cpukit/score/src/coremsgclose.c | 3 +-
cpukit/score/src/coremsgflush.c | 72 ++++++++++++++++++----
cpukit/score/src/coremsgflushsupp.c | 84 --------------------------
5 files changed, 62 insertions(+), 116 deletions(-)
diff --git a/cpukit/score/Makefile.am b/cpukit/score/Makefile.am
index 19d3237..6d4414c 100644
--- a/cpukit/score/Makefile.am
+++ b/cpukit/score/Makefile.am
@@ -158,7 +158,7 @@ libscore_a_SOURCES += src/corebarrier.c src/corebarrierrelease.c \
## CORE_MESSAGE_QUEUE_C_FILES
libscore_a_SOURCES += src/coremsg.c src/coremsgbroadcast.c \
src/coremsgclose.c src/coremsgflush.c src/coremsgflushwait.c \
- src/coremsginsert.c src/coremsgflushsupp.c src/coremsgseize.c \
+ src/coremsginsert.c src/coremsgseize.c \
src/coremsgsubmit.c
## CORE_MUTEX_C_FILES
diff --git a/cpukit/score/include/rtems/score/coremsgimpl.h b/cpukit/score/include/rtems/score/coremsgimpl.h
index cedf276..1f67969 100644
--- a/cpukit/score/include/rtems/score/coremsgimpl.h
+++ b/cpukit/score/include/rtems/score/coremsgimpl.h
@@ -179,23 +179,6 @@ uint32_t _CORE_message_queue_Flush(
CORE_message_queue_Control *the_message_queue
);
-/**
- * @brief Flush all outstanding messages.
- *
- * This routine flushes all outstanding messages and returns
- * them to the inactive message chain.
- *
- * @param[in] the_message_queue points to the message queue to flush
- *
- * @retval This method returns the number of pending messages flushed.
- *
- * - INTERRUPT LATENCY:
- * + single case
- */
-uint32_t _CORE_message_queue_Flush_support(
- CORE_message_queue_Control *the_message_queue
-);
-
#if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API)
/**
* @brief Flush waiting threads.
diff --git a/cpukit/score/src/coremsgclose.c b/cpukit/score/src/coremsgclose.c
index 17ecc44..d808a4e 100644
--- a/cpukit/score/src/coremsgclose.c
+++ b/cpukit/score/src/coremsgclose.c
@@ -49,8 +49,7 @@ void _CORE_message_queue_Close(
* the flush satisfying any blocked senders as a side-effect.
*/
- if ( the_message_queue->number_of_pending_messages != 0 )
- (void) _CORE_message_queue_Flush_support( the_message_queue );
+ (void) _CORE_message_queue_Flush( the_message_queue );
(void) _Workspace_Free( the_message_queue->message_buffers );
diff --git a/cpukit/score/src/coremsgflush.c b/cpukit/score/src/coremsgflush.c
index 51f6c8d..05683f0 100644
--- a/cpukit/score/src/coremsgflush.c
+++ b/cpukit/score/src/coremsgflush.c
@@ -1,8 +1,9 @@
/**
- * @file
+ * @file
*
- * @brief Flush Pending Messages
- * @ingroup ScoreMessageQueue
+ * @brief Flush Messages Routine
+ *
+ * @ingroup ScoreMessageQueue
*/
/*
@@ -18,19 +19,66 @@
#include "config.h"
#endif
-#include <rtems/system.h>
-#include <rtems/score/chain.h>
-#include <rtems/score/isr.h>
#include <rtems/score/coremsgimpl.h>
-#include <rtems/score/thread.h>
-#include <rtems/score/wkspace.h>
+#include <rtems/score/isr.h>
uint32_t _CORE_message_queue_Flush(
CORE_message_queue_Control *the_message_queue
)
{
- if ( the_message_queue->number_of_pending_messages != 0 )
- return _CORE_message_queue_Flush_support( the_message_queue );
- else
- return 0;
+ ISR_Level level;
+ Chain_Node *inactive_head;
+ Chain_Node *inactive_first;
+ Chain_Node *message_queue_first;
+ Chain_Node *message_queue_last;
+ uint32_t count;
+
+ /*
+ * Currently, RTEMS supports no API that has both flush and blocking
+ * sends. Thus, this routine assumes that there are no senders
+ * blocked waiting to send messages. In the event, that an API is
+ * added that can flush a message queue when threads are blocked
+ * waiting to send, there are two basic behaviors envisioned:
+ *
+ * (1) The thread queue of pending senders is a logical extension
+ * of the pending message queue. In this case, it should be
+ * flushed using the _Thread_queue_Flush() service with a status
+ * such as CORE_MESSAGE_QUEUE_SENDER_FLUSHED (which currently does
+ * not exist). This can be implemented without changing the "big-O"
+ * of the message flushing part of the routine.
+ *
+ * (2) Only the actual messages queued should be purged. In this case,
+ * the blocked sender threads must be allowed to send their messages.
+ * In this case, the implementation will be forced to individually
+ * dequeue the senders and queue their messages. This will force
+ * this routine to have "big O(n)" where n is the number of blocked
+ * senders. If there are more messages pending than senders blocked,
+ * then the existing flush code can be used to dispose of the remaining
+ * pending messages.
+ *
+ * For now, though, we are very happy to have a small routine with
+ * fixed execution time that only deals with pending messages.
+ */
+
+ _ISR_Disable( level );
+
+ count = the_message_queue->number_of_pending_messages;
+ if ( count != 0 ) {
+ the_message_queue->number_of_pending_messages = 0;
+
+ inactive_head = _Chain_Head( &the_message_queue->Inactive_messages );
+ inactive_first = inactive_head->next;
+ message_queue_first = _Chain_First( &the_message_queue->Pending_messages );
+ message_queue_last = _Chain_Last( &the_message_queue->Pending_messages );
+
+ inactive_head->next = message_queue_first;
+ message_queue_last->next = inactive_first;
+ inactive_first->previous = message_queue_last;
+ message_queue_first->previous = inactive_head;
+
+ _Chain_Initialize_empty( &the_message_queue->Pending_messages );
+ }
+
+ _ISR_Enable( level );
+ return count;
}
diff --git a/cpukit/score/src/coremsgflushsupp.c b/cpukit/score/src/coremsgflushsupp.c
deleted file mode 100644
index 041972f..0000000
--- a/cpukit/score/src/coremsgflushsupp.c
+++ /dev/null
@@ -1,84 +0,0 @@
-/**
- * @file
- *
- * @brief Flush Messages Support Routine
- *
- * @ingroup ScoreMessageQueue
- */
-
-/*
- * COPYRIGHT (c) 1989-1999.
- * On-Line Applications Research Corporation (OAR).
- *
- * The license and distribution terms for this file may be
- * found in the file LICENSE in this distribution or at
- * http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <rtems/system.h>
-#include <rtems/score/chain.h>
-#include <rtems/score/isr.h>
-#include <rtems/score/coremsgimpl.h>
-#include <rtems/score/thread.h>
-#include <rtems/score/wkspace.h>
-
-uint32_t _CORE_message_queue_Flush_support(
- CORE_message_queue_Control *the_message_queue
-)
-{
- ISR_Level level;
- Chain_Node *inactive_head;
- Chain_Node *inactive_first;
- Chain_Node *message_queue_first;
- Chain_Node *message_queue_last;
- uint32_t count;
-
- /*
- * Currently, RTEMS supports no API that has both flush and blocking
- * sends. Thus, this routine assumes that there are no senders
- * blocked waiting to send messages. In the event, that an API is
- * added that can flush a message queue when threads are blocked
- * waiting to send, there are two basic behaviors envisioned:
- *
- * (1) The thread queue of pending senders is a logical extension
- * of the pending message queue. In this case, it should be
- * flushed using the _Thread_queue_Flush() service with a status
- * such as CORE_MESSAGE_QUEUE_SENDER_FLUSHED (which currently does
- * not exist). This can be implemented without changing the "big-O"
- * of the message flushing part of the routine.
- *
- * (2) Only the actual messages queued should be purged. In this case,
- * the blocked sender threads must be allowed to send their messages.
- * In this case, the implementation will be forced to individually
- * dequeue the senders and queue their messages. This will force
- * this routine to have "big O(n)" where n is the number of blocked
- * senders. If there are more messages pending than senders blocked,
- * then the existing flush code can be used to dispose of the remaining
- * pending messages.
- *
- * For now, though, we are very happy to have a small routine with
- * fixed execution time that only deals with pending messages.
- */
-
- _ISR_Disable( level );
- inactive_head = _Chain_Head( &the_message_queue->Inactive_messages );
- inactive_first = inactive_head->next;
- message_queue_first = _Chain_First( &the_message_queue->Pending_messages );
- message_queue_last = _Chain_Last( &the_message_queue->Pending_messages );
-
- inactive_head->next = message_queue_first;
- message_queue_last->next = inactive_first;
- inactive_first->previous = message_queue_last;
- message_queue_first->previous = inactive_head;
-
- _Chain_Initialize_empty( &the_message_queue->Pending_messages );
-
- count = the_message_queue->number_of_pending_messages;
- the_message_queue->number_of_pending_messages = 0;
- _ISR_Enable( level );
- return count;
-}
More information about the vc
mailing list