87 lines
2.6 KiB
C
87 lines
2.6 KiB
C
/****************************************************************************
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* mm/iob/iob_remove_queue.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 <debug.h>
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#include <nuttx/irq.h>
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#include <nuttx/arch.h>
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#include <nuttx/mm/iob.h>
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#include "iob.h"
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#if CONFIG_IOB_NCHAINS > 0
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: iob_remove_queue
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*
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* Description:
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* Remove and return one I/O buffer chain from the head of a queue.
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*
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* Returned Value:
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* Returns a reference to the I/O buffer chain at the head of the queue.
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*
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****************************************************************************/
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FAR struct iob_s *iob_remove_queue(FAR struct iob_queue_s *iobq)
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{
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FAR struct iob_qentry_s *qentry;
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FAR struct iob_s *iob = NULL;
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/* Remove the I/O buffer chain from the head of the queue */
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irqstate_t flags = spin_lock_irqsave(&g_iob_lock);
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qentry = iobq->qh_head;
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if (qentry)
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{
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iobq->qh_head = qentry->qe_flink;
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if (!iobq->qh_head)
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{
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iobq->qh_tail = NULL;
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}
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spin_unlock_irqrestore(&g_iob_lock, flags);
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/* Extract the I/O buffer chain from the container and free the
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* container.
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*/
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iob = qentry->qe_head;
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iob_free_qentry(qentry);
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}
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else
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{
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spin_unlock_irqrestore(&g_iob_lock, flags);
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}
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return iob;
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}
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#endif /* CONFIG_IOB_NCHAINS > 0 */
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