52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
/* wait queue for multiple fibers on nanokernel objects */
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/*
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* Copyright (c) 2015 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <wait_q.h>
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/*
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* Remove first fiber from a wait queue and put it on the ready queue, knowing
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* that the wait queue is not empty.
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*/
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static struct tcs *_nano_wait_q_remove_no_check(struct _nano_queue *wait_q)
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{
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struct tcs *tcs = wait_q->head;
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if (wait_q->tail == wait_q->head) {
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_nano_wait_q_reset(wait_q);
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} else {
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wait_q->head = tcs->link;
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}
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tcs->link = 0;
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_nano_fiber_ready(tcs);
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return tcs;
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}
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/*
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* Remove first fiber from a wait queue and put it on the ready queue.
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* Abort and return NULL if the wait queue is empty.
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*/
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struct tcs *_nano_wait_q_remove(struct _nano_queue *wait_q)
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{
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return wait_q->head ? _nano_wait_q_remove_no_check(wait_q) : NULL;
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}
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