incubator-nuttx/sched/mqueue/mq_waitirq.c

128 lines
4.3 KiB
C

/****************************************************************************
* sched/mqueue/mq_waitirq.c
*
* Copyright (C) 2007-2009, 2011, 2014, 2016 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 <sched.h>
#include <errno.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/mqueue.h>
#include "mqueue/mqueue.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxmq_wait_irq
*
* Description:
* This function is called when a signal or a timeout is received by a
* task that is waiting on a message queue -- either for a queue to
* becoming not full (on mq_send and friends) or not empty (on mq_receive
* and friends).
*
* Parameters:
* wtcb - A pointer to the TCB of the task that is waiting on a message
* queue, but has received a signal instead.
*
* Return Value:
* None
*
* Assumptions:
*
****************************************************************************/
void nxmq_wait_irq(FAR struct tcb_s *wtcb, int errcode)
{
FAR struct mqueue_inode_s *msgq;
irqstate_t flags;
/* Disable interrupts. This is necessary because an interrupt handler may
* attempt to send a message while we are doing this.
*/
flags = enter_critical_section();
/* It is possible that an interrupt/context switch beat us to the punch and
* already changed the task's state. NOTE: The operations within the if
* are safe because interrupts are always disabled with the msgwaitq,
* nwaitnotempty, and nwaitnotfull fields are modified.
*/
if (wtcb->task_state == TSTATE_WAIT_MQNOTEMPTY ||
wtcb->task_state == TSTATE_WAIT_MQNOTFULL)
{
/* Get the message queue associated with the waiter from the TCB */
msgq = wtcb->msgwaitq;
DEBUGASSERT(msgq);
wtcb->msgwaitq = NULL;
/* Decrement the count of waiters and cancel the wait */
if (wtcb->task_state == TSTATE_WAIT_MQNOTEMPTY)
{
DEBUGASSERT(msgq->nwaitnotempty > 0);
msgq->nwaitnotempty--;
}
else
{
DEBUGASSERT(msgq->nwaitnotfull > 0);
msgq->nwaitnotfull--;
}
/* Mark the errno value for the thread. */
wtcb->pterrno = errcode;
/* Restart the task. */
up_unblock_task(wtcb);
}
/* Interrupts may now be enabled. */
leave_critical_section(flags);
}