/**************************************************************************** * fs/aio/aio_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 #include #include #include #include #include #include "aio/aio.h" #ifdef CONFIG_FS_AIO /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: aio_cancel * * 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 canceled. If aiocbp is NULL, then all * outstanding cancelable asynchronous I/O requests against fildes will * be canceled. * * Normal asynchronous notification will occur for asynchronous I/O * operations that are successfully canceled. If there are requests that * cannot be canceled, then the normal asynchronous completion process * will take place for those requests when they are completed. * * For requested operations that are successfully canceled, the associated * error status will be set to ECANCELED and the return status will be -1. * For requested operations that are not successfully canceled, 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 canceled. * * Returned Value: * The aio_cancel() function will return the value AIO_CANCELED if the * requested operation(s) were canceled. The value AIO_NOTCANCELED will * be returned if at least one of the requested operation(s) cannot be * canceled 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; pid_t pid; 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(); ret = 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 canceled. work_cancel() will return -ENOENT in the * first case. */ status = work_cancel(LPWORK, &aioc->aioc_work); if (status >= 0) { /* Remove the container from the list of pending transfers */ pid = aioc->aioc_pid; aioc_decant(aioc); aiocbp->aio_result = -ECANCELED; ret = AIO_CANCELED; /* Signal the client */ aio_signal(pid, aiocbp); } else { ret = AIO_NOTCANCELED; } } else { /* Can't cancel, the operation is running */ ret = AIO_NOTCANCELED; } } } 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 canceled. work_cancel() will return -ENOENT in the * first case. */ status = work_cancel(LPWORK, &aioc->aioc_work); if (status >= 0) { /* Remove the container from the list of pending transfers */ next = (FAR struct aio_container_s *)aioc->aioc_link.flink; pid = aioc->aioc_pid; aiocbp = aioc_decant(aioc); DEBUGASSERT(aiocbp); aiocbp->aio_result = -ECANCELED; if (ret != AIO_NOTCANCELED) { ret = AIO_CANCELED; } /* Signal the client */ aio_signal(pid, aiocbp); } else { ret = AIO_NOTCANCELED; } } } while (aioc); } aio_unlock(); sched_unlock(); return ret; } #endif /* CONFIG_FS_AIO */