b08a86171f
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3
123 lines
4.4 KiB
C
123 lines
4.4 KiB
C
/************************************************************
|
|
* sched_unlock.c
|
|
*
|
|
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
|
|
*
|
|
* 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 Gregory Nutt 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 <sys/types.h>
|
|
#include <nuttx/arch.h>
|
|
#include "os_internal.h"
|
|
|
|
/************************************************************
|
|
* Definitions
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Private Type Declarations
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Global Variables
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Private Variables
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Private Function Prototypes
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Private Functionss
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Public Functions
|
|
************************************************************/
|
|
|
|
/************************************************************
|
|
* Name: sched_unlock
|
|
*
|
|
* Description: This function decrements the preemption lock
|
|
* count. Typically this is paired with sched_lock() and
|
|
* concludes a critical section of code. Preemption will not
|
|
* be unlocked until sched_unlock() has been called as many
|
|
* times as sched_lock(). When the lockcount is decremented
|
|
* to zero, any tasks that were eligible to preempt the
|
|
* current task will execute.
|
|
************************************************************/
|
|
|
|
STATUS sched_unlock(void)
|
|
{
|
|
_TCB *rtcb = (_TCB*)g_readytorun.head;
|
|
|
|
/* Check for some special cases: (1) rtcb may be NULL only during
|
|
* early boot-up phases, and (2) sched_unlock() should have no
|
|
* effect if called from the interrupt level.
|
|
*/
|
|
|
|
if (rtcb && !up_interrupt_context())
|
|
{
|
|
/* Decrement the preemption lock counter */
|
|
|
|
if (rtcb->lockcount)
|
|
{
|
|
rtcb->lockcount--;
|
|
}
|
|
|
|
/* Check if the lock counter has decremented to zero. If so,
|
|
* then pre-emption has been re-enabled.
|
|
*/
|
|
|
|
if (rtcb->lockcount <= 0)
|
|
{
|
|
rtcb->lockcount = 0;
|
|
|
|
/* Release any ready-to-run tasks that have collected in
|
|
* g_pendingtasks.
|
|
*/
|
|
|
|
if (g_pendingtasks.head)
|
|
{
|
|
up_release_pending();
|
|
}
|
|
}
|
|
}
|
|
return OK;
|
|
}
|