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nuttx-bb/nuttx/fs/aio/aio_cancel.c

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/****************************************************************************
* fs/aio/aio_cancel.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <aio.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/wqueue.h>
#include "aio/aio.h"
#ifdef CONFIG_FS_AIO
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: aio_read
*
* Description:
* The aio_cancel() function attempts to cancel one or more asynchronous
* I/O requests currently outstanding against file descriptor 'fildes'.
* The aiocbp argument points to the asynchronous I/O control block for
* a particular request to be cancelled. If aiocbp is NULL, then all
* outstanding cancelable asynchronous I/O requests against fildes will
* be cancelled.
*
* Normal asynchronous notification will occur for asynchronous I/O
* operations that are successfully cancelled. If there are requests that
* cannot be cancelled, then the normal asynchronous completion process
* will take place for those requests when they are completed.
*
* For requested operations that are successfully cancelled, the associated
* error status will be set to ECANCELED and the return status will be -1.
* For requested operations that are not successfully cancelled, the aiocbp
* will not be modified by aio_cancel().
*
* Input Parameters:
* fildes - Not used in this implementation
* aiocbp - Points to the asynchronous I/O control block for a particular
* request to be cancelled.
*
* Returned Value:
* The aio_cancel() function will return the value AIO_CANCELED if the
* requested operation(s) were cancelled. The value AIO_NOTCANCELED will
* be returned if at least one of the requested operation(s) cannot be
* cancelled because it is in progress. In this case, the state of the
* other operations, if any, referenced in the call to aio_cancel() is
* not indicated by the return value of aio_cancel(). The application
* may determine the state of affairs for these operations by using
* aio_error(). The value AIO_ALLDONE is returned if all of the
* operations have already completed. Otherwise, the function will return
* -1 and set errno to indicate the error.
*
****************************************************************************/
int aio_cancel(int fildes, FAR struct aiocb *aiocbp)
{
FAR struct aio_container_s *aioc;
FAR struct aio_container_s *next;
int status;
int ret;
/* Check if a non-NULL aiocbp was provided */
/* Lock the scheduler so that no I/O events can complete on the worker
* thread until we set complete this operation.
*/
ret = AIO_ALLDONE;
sched_lock();
aio_lock();
if (aiocbp)
{
/* Check if the I/O has completed */
if (aiocbp->aio_result == -EINPROGRESS)
{
/* No.. Find the container for this AIO control block */
for (aioc = (FAR struct aio_container_s *)g_aio_pending.head;
aioc && aioc->aioc_aiocbp != aiocbp;
aioc = (FAR struct aio_container_s *)aioc->aioc_link.flink);
/* Did we find a container for this fildes? We should; the aio_result says
* that the transfer is pending. If not we return AIO_ALLDONE.
*/
if (aioc)
{
/* Yes... attempt to cancel the I/O. There are two
* possibilities:* (1) the work has already been started and
* is no longer queued, or (2) the work has not been started
* and is still in the work queue. Only the second case can
* be cancelled. work_cancel() will return -ENOENT in the
* first case.
*/
status = work_cancel(LPWORK, &aioc->aioc_work);
if (status >= 0)
{
aiocbp->aio_result = -ECANCELED;
ret = AIO_CANCELED;
}
else
{
ret = AIO_NOTCANCELED;
}
/* Remove the container from the list of pending transfers */
(void)aioc_decant(aioc);
}
}
}
else
{
/* No aiocbp.. cancel all outstanding I/O for the fildes */
next = (FAR struct aio_container_s *)g_aio_pending.head;
do
{
/* Find the next container with this AIO control block */
for (aioc = next;
aioc && aioc->aioc_aiocbp->aio_fildes != fildes;
aioc = (FAR struct aio_container_s *)aioc->aioc_link.flink);
/* Did we find the container? We should; the aio_result says
* that the transfer is pending. If not we return AIO_ALLDONE.
*/
if (aioc)
{
/* Yes... attempt to cancel the I/O. There are two
* possibilities:* (1) the work has already been started and
* is no longer queued, or (2) the work has not been started
* and is still in the work queue. Only the second case can
* be cancelled. work_cancel() will return -ENOENT in the
* first case.
*/
status = work_cancel(LPWORK, &aioc->aioc_work);
/* Remove the container from the list of pending transfers */
next = (FAR struct aio_container_s *)aioc->aioc_link.flink;
aiocbp = aioc_decant(aioc);
DEBUGASSERT(aiocbp);
if (status >= 0)
{
aiocbp->aio_result = -ECANCELED;
if (ret != AIO_NOTCANCELED)
{
ret = AIO_CANCELED;
}
}
else
{
ret = AIO_NOTCANCELED;
}
}
}
while (aioc);
}
aio_unlock();
sched_unlock();
return ret;
}
#endif /* CONFIG_FS_AIO */
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