nuttx/mm/mm_heap/mm_addfreechunk.c

/****************************************************************************
 * mm/mm_heap/mm_addfreechunk.c
 *
 *   Copyright (C) 2007, 2009, 2013 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 <nuttx/mm/mm.h>

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

/****************************************************************************
 * Name: mm_addfreechunk
 *
 * Description:
 *   Add a free chunk to the node next.  It is assumed that the caller holds
 *   the mm semaphore
 *
 ****************************************************************************/

void mm_addfreechunk(FAR struct mm_heap_s *heap, FAR struct mm_freenode_s *node)
{
  FAR struct mm_freenode_s *next;
  FAR struct mm_freenode_s *prev;

  /* Convert the size to a nodelist index */

  int ndx = mm_size2ndx(node->size);

  /* Now put the new node into the next */

  for (prev = &heap->mm_nodelist[ndx], next = heap->mm_nodelist[ndx].flink;
       next && next->size && next->size < node->size;
       prev = next, next = next->flink);

  /* Does it go in mid next or at the end? */

  prev->flink = node;
  node->blink = prev;
  node->flink = next;

  if (next)
    {
      /* The new node goes between prev and next */

      next->blink = node;
    }
}