nuttx/libs/libc/wqueue/work_cancel.c

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/****************************************************************************
* libs/libc/wqueue/work_cancel.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <queue.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include "wqueue/wqueue.h"
#if defined(CONFIG_LIBC_USRWORK) && !defined(__KERNEL__)
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_qcancel
*
* Description:
* Cancel previously queued work. This removes work from the work queue.
* After work has been cancelled, it may be requeued by calling
* work_queue() again.
*
* Input Parameters:
* wqueue - The work queue
* work - The previously queue work structure to cancel
*
* Returned Value:
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* Zero (OK) on success, a negated errno on failure. This error may be
* reported:
*
* -ENOENT - There is no such work queued.
* -EINVAL - An invalid work queue was specified
*
****************************************************************************/
static int work_qcancel(FAR struct usr_wqueue_s *wqueue,
FAR struct work_s *work)
{
FAR sq_entry_t *prev = NULL;
FAR sq_entry_t *curr;
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int ret = -ENOENT;
int semcount;
DEBUGASSERT(work != NULL);
/* Get exclusive access to the work queue */
while (_SEM_WAIT(&wqueue->lock) < 0);
/* 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.
*/
if (work->worker != NULL)
{
/* Search the work activelist for the target work. We can't
* use sq_rem to do this because there are additional operations that
* need to be done.
*/
curr = wqueue->q.head;
while (curr && curr != &work->u.s.sq)
{
prev = curr;
curr = curr->flink;
}
/* Check if the work was found in the list. If not, then an OS
* error has occurred because the work is marked active!
*/
DEBUGASSERT(curr);
/* Now, remove the work from the work queue */
if (prev)
{
/* Remove the work from mid- or end-of-queue */
sq_remafter(prev, &wqueue->q);
}
else
{
/* Remove the work at the head of the queue */
sq_remfirst(&wqueue->q);
_SEM_GETVALUE(&wqueue->wake, &semcount);
if (semcount < 1)
{
_SEM_POST(&wqueue->wake);
}
}
work->worker = NULL;
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ret = OK;
}
_SEM_POST(&wqueue->lock);
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return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: work_cancel
*
* Description:
* Cancel previously queued user-mode work. This removes work from the
* user mode work queue. After work has been cancelled, it may be
* requeued by calling work_queue() again.
*
* Input Parameters:
* qid - The work queue ID (must be USRWORK)
* work - The previously queued work structure to cancel
*
* Returned Value:
* Zero (OK) on success, a negated errno on failure. This error may be
* reported:
*
* -ENOENT - There is no such work queued.
*
****************************************************************************/
int work_cancel(int qid, FAR struct work_s *work)
{
if (qid == USRWORK)
{
return work_qcancel(&g_usrwork, work);
}
else
{
return -EINVAL;
}
}
#endif /* CONFIG_LIBC_USRWORK && !__KERNEL__ */