218 lines
7.5 KiB
C
218 lines
7.5 KiB
C
/****************************************************************************
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* fs/aio/aio_cancel.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <aio.h>
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#include <sched.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/wqueue.h>
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#include "aio/aio.h"
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#ifdef CONFIG_FS_AIO
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: aio_cancel
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*
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* Description:
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* The aio_cancel() function attempts to cancel one or more asynchronous
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* I/O requests currently outstanding against file descriptor 'fildes'.
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* The aiocbp argument points to the asynchronous I/O control block for
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* a particular request to be canceled. If aiocbp is NULL, then all
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* outstanding cancelable asynchronous I/O requests against fildes will
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* be canceled.
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*
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* Normal asynchronous notification will occur for asynchronous I/O
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* operations that are successfully canceled. If there are requests that
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* cannot be canceled, then the normal asynchronous completion process
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* will take place for those requests when they are completed.
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*
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* For requested operations that are successfully canceled, the associated
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* error status will be set to ECANCELED and the return status will be -1.
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* For requested operations that are not successfully canceled, the aiocbp
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* will not be modified by aio_cancel().
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*
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* Input Parameters:
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* fildes - Not used in this implementation
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* aiocbp - Points to the asynchronous I/O control block for a particular
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* request to be canceled.
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*
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* Returned Value:
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* The aio_cancel() function will return the value AIO_CANCELED if the
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* requested operation(s) were canceled. The value AIO_NOTCANCELED will
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* be returned if at least one of the requested operation(s) cannot be
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* canceled because it is in progress. In this case, the state of the
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* other operations, if any, referenced in the call to aio_cancel() is
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* not indicated by the return value of aio_cancel(). The application
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* may determine the state of affairs for these operations by using
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* aio_error(). The value AIO_ALLDONE is returned if all of the
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* operations have already completed. Otherwise, the function will return
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* -1 and set errno to indicate the error.
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*
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****************************************************************************/
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int aio_cancel(int fildes, FAR struct aiocb *aiocbp)
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{
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FAR struct aio_container_s *aioc;
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FAR struct aio_container_s *next;
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pid_t pid;
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int status;
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int ret;
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/* Check if a non-NULL aiocbp was provided */
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/* Lock the scheduler so that no I/O events can complete on the worker
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* thread until we set complete this operation.
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*/
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ret = AIO_ALLDONE;
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sched_lock();
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ret = aio_lock();
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if (aiocbp)
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{
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/* Check if the I/O has completed */
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if (aiocbp->aio_result == -EINPROGRESS)
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{
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/* No.. Find the container for this AIO control block */
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for (aioc = (FAR struct aio_container_s *)g_aio_pending.head;
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aioc && aioc->aioc_aiocbp != aiocbp;
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aioc = (FAR struct aio_container_s *)aioc->aioc_link.flink);
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/* Did we find a container for this fildes? We should; the
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* aio_result says that the transfer is pending. If not we return
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* AIO_ALLDONE.
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*/
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if (aioc)
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{
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/* Yes... attempt to cancel the I/O. There are two
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* possibilities:* (1) the work has already been started and
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* is no longer queued, or (2) the work has not been started
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* and is still in the work queue. Only the second case can
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* be canceled. work_cancel() will return -ENOENT in the
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* first case.
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*/
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status = work_cancel(LPWORK, &aioc->aioc_work);
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if (status >= 0)
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{
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/* Remove the container from the list of pending transfers */
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pid = aioc->aioc_pid;
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aioc_decant(aioc);
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aiocbp->aio_result = -ECANCELED;
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ret = AIO_CANCELED;
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/* Signal the client */
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aio_signal(pid, aiocbp);
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}
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else
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{
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ret = AIO_NOTCANCELED;
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}
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}
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else
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{
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/* Can't cancel, the operation is running */
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ret = AIO_NOTCANCELED;
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}
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}
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}
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else
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{
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/* No aiocbp.. cancel all outstanding I/O for the fildes */
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next = (FAR struct aio_container_s *)g_aio_pending.head;
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do
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{
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/* Find the next container with this AIO control block */
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for (aioc = next;
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aioc && aioc->aioc_aiocbp->aio_fildes != fildes;
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aioc = (FAR struct aio_container_s *)aioc->aioc_link.flink);
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/* Did we find the container? We should; the aio_result says
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* that the transfer is pending. If not we return AIO_ALLDONE.
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*/
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if (aioc)
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{
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/* Yes... attempt to cancel the I/O. There are two
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* possibilities:* (1) the work has already been started and
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* is no longer queued, or (2) the work has not been started
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* and is still in the work queue. Only the second case can
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* be canceled. work_cancel() will return -ENOENT in the
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* first case.
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*/
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status = work_cancel(LPWORK, &aioc->aioc_work);
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if (status >= 0)
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{
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/* Remove the container from the list of pending transfers */
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next =
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(FAR struct aio_container_s *)aioc->aioc_link.flink;
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pid = aioc->aioc_pid;
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aiocbp = aioc_decant(aioc);
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DEBUGASSERT(aiocbp);
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aiocbp->aio_result = -ECANCELED;
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if (ret != AIO_NOTCANCELED)
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{
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ret = AIO_CANCELED;
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}
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/* Signal the client */
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aio_signal(pid, aiocbp);
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}
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else
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{
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ret = AIO_NOTCANCELED;
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}
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}
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}
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while (aioc);
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}
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aio_unlock();
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sched_unlock();
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return ret;
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}
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#endif /* CONFIG_FS_AIO */
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