nuttx/sched/work_cancel.c
patacongo bf7555cc4a Fix a potential race condition
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2234 42af7a65-404d-4744-a932-0658087f49c3
2009-11-06 13:42:49 +00:00

113 lines
4.3 KiB
C
Executable File

/****************************************************************************
* sched/work_cancel.c
*
* Copyright (C) 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <queue.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include "work_internal.h"
#ifdef CONFIG_SCHED_WORKQUEUE
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: work_cancel
*
* Description:
* Cancel previously queued work. This removes work from the work queue.
* After work has been canceled, it may be re-queue by calling work_queue()
* again.
*
* Input parameters:
* work - The previously queue work structure to cancel
*
* Returned Value:
* Zero on success, a negated errno on failure
*
****************************************************************************/
int work_cancel(struct work_s *work)
{
irqstate_t flags;
DEBUGASSERT(work != NULL);
/* Cancelling the work is simply a matter of removing the work structure
* from the work queue. This must be done with interrupts disabled because
* new work is typically added to the work queue from interrupt handlers.
*/
flags = irqsave();
DEBUGASSERT(work->dq.flink || (FAR dq_entry_t *)work == g_work.head);
DEBUGASSERT(work->dq.blink || (FAR dq_entry_t *)work == g_work.tail);
dq_rem((FAR dq_entry_t *)work, &g_work);
irqrestore(flags);
return OK;
}
#endif /* CONFIG_SCHED_WORKQUEUE */