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/*
* Region Manager
*
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#ifdef RTEMS_REGION_SHRED_ON_FREE
#include <string.h>
#ifndef RTEMS_REGION_FREE_SHRED_PATTERN
#define RTEMS_REGION_FREE_SHRED_PATTERN 0x00
#endif
#endif
#include <rtems/system.h>
#include <rtems/rtems/status.h>
#include <rtems/rtems/support.h>
#include <rtems/score/object.h>
#include <rtems/rtems/options.h>
#include <rtems/rtems/region.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/apimutex.h>
/*PAGE
*
* rtems_region_return_segment
*
* This directive will return a segment to its region.
*
* Input parameters:
* id - region id
* segment - pointer to segment address
*
* Output parameters:
* RTEMS_SUCCESSFUL - if successful
* error code - if unsuccessful
*/
rtems_status_code rtems_region_return_segment(
Objects_Id id,
void *segment
)
{
register Region_Control *the_region;
Thread_Control *the_thread;
Objects_Locations location;
void **the_segment;
#ifdef RTEMS_REGION_FREE_SHRED_PATTERN
uint32_t size;
#endif
int status;
_RTEMS_Lock_allocator();
the_region = _Region_Get( id, &location );
switch ( location ) {
case OBJECTS_REMOTE: /* this error cannot be returned */
_RTEMS_Unlock_allocator();
return RTEMS_INTERNAL_ERROR;
case OBJECTS_ERROR:
_RTEMS_Unlock_allocator();
return RTEMS_INVALID_ID;
case OBJECTS_LOCAL:
_Region_Debug_Walk( the_region, 3 );
#ifdef RTEMS_REGION_FREE_SHRED_PATTERN
if ( _Heap_Size_of_user_area( &the_region->Memory, segment, &size ) ) {
memset(segment, (RTEMS_REGION_FREE_SHRED_PATTERN & 0xFF), size);
} else {
_RTEMS_Unlock_allocator();
return RTEMS_INVALID_ADDRESS;
}
#endif
status = _Region_Free_segment( the_region, segment );
_Region_Debug_Walk( the_region, 4 );
if ( !status ) {
_RTEMS_Unlock_allocator();
return RTEMS_INVALID_ADDRESS;
}
the_region->number_of_used_blocks -= 1;
/*
* Switch from using the memory allocation mutex to using a
* dispatching disabled critical section. We have to do this
* because this thread may unblock one or more threads that were
* waiting on memory.
*
* NOTE: The following loop is O(n) where n is the number of
* threads whose memory request is satisfied.
*/
_RTEMS_Unlock_allocator();
_Thread_Disable_dispatch();
for ( ; ; ) {
the_thread = _Thread_queue_First( &the_region->Wait_queue );
if ( the_thread == NULL )
break;
the_segment = (void **) _Region_Allocate_segment(
the_region,
the_thread->Wait.count
);
if ( the_segment == NULL )
break;
*(void **)the_thread->Wait.return_argument = the_segment;
the_region->number_of_used_blocks += 1;
_Thread_queue_Extract( &the_region->Wait_queue, the_thread );
the_thread->Wait.return_code = RTEMS_SUCCESSFUL;
}
_Thread_Enable_dispatch();
return RTEMS_SUCCESSFUL;
}
return RTEMS_INTERNAL_ERROR; /* unreached - only to remove warnings */
}
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