incubator-nuttx/sched/sched_free.c

/************************************************************
 * sched_free.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 <sys/types.h>
#include <nuttx/kmalloc.h>
#include <queue.h>
#include <assert.h>
#include <nuttx/arch.h>
#include "os_internal.h"

/************************************************************
 * Definitions
 ************************************************************/

/************************************************************
 * Private Type Declarations
 ************************************************************/

/************************************************************
 * Global Variables
 ************************************************************/

/************************************************************
 * Private Variables
 ************************************************************/

/************************************************************
 * Private Function Prototypes
 ************************************************************/

/************************************************************
 * Public Functions
 ************************************************************/

/************************************************************
 * Name: sched_free
 *
 * Description:
 *   This function performs deallocations that
 *   the operating system may need to make.  This special
 *   interface to free is used to handling corner cases
 *   where the operating system may have to perform deallocations
 *   from within an interrupt handler.
 *
 ************************************************************/

void sched_free(FAR void *address)
{
  /* Check if this is an attempt to deallocate memory from
   * an exception handler.  If this function is called from the
   * IDLE task, then we must have exclusive access to the memory
   * manager to do this.
   */

  if (up_interrupt_context() || mm_trysemaphore() != 0)
    {
      /* Yes.. Delay the deallocation until a more appropriate time. */

      irqstate_t saved_state = irqsave();
      sq_addlast((FAR sq_entry_t*)address, (sq_queue_t*)&g_delayeddeallocations);
      irqrestore(saved_state);
    }
  else
    {
      /* No.. just deallocate the memory now. */

      kfree(address);
      mm_givesemaphore();
    }
}