source: rtems/c/src/exec/rtems/src/semrelease.c @ 5870ac55

4.104.114.84.95
Last change on this file since 5870ac55 was 5870ac55, checked in by Joel Sherrill <joel.sherrill@…>, on Jan 5, 2000 at 10:19:21 PM

Added support for simple binary semaphores in addition to the high
power binary/mutex style semaphores already supported by RTEMS. This
was done at the request of Eric Norum <eric@…> in support
of his effort to port EPICS to RTEMS. This change consisted of
changing the nesting_allowed boolean into a lock_nesting_behavior
enumerated value as well as allowing the core mutex object to optionally
support ensuring that the holder of a binary semaphore released it.
Finally, a more subtle enhancement was to allow the non-holder to release
a priority inheritance/ceiling mutex and still allow the holding task
to return to its original priority.

  • Property mode set to 100644
File size: 3.1 KB
Line 
1/*
2 *  Semaphore Manager
3 *
4 *  DESCRIPTION:
5 *
6 *  This package is the implementation of the Semaphore Manager.
7 *  This manager utilizes standard Dijkstra counting semaphores to provide
8 *  synchronization and mutual exclusion capabilities.
9 *
10 *  Directives provided are:
11 *
12 *     + create a semaphore
13 *     + get an ID of a semaphore
14 *     + delete a semaphore
15 *     + acquire a semaphore
16 *     + release a semaphore
17 *
18 *  COPYRIGHT (c) 1989-1999.
19 *  On-Line Applications Research Corporation (OAR).
20 *
21 *  The license and distribution terms for this file may be
22 *  found in the file LICENSE in this distribution or at
23 *  http://www.OARcorp.com/rtems/license.html.
24 *
25 *  $Id$
26 */
27
28#include <rtems/system.h>
29#include <rtems/rtems/status.h>
30#include <rtems/rtems/support.h>
31#include <rtems/rtems/attr.h>
32#include <rtems/score/isr.h>
33#include <rtems/score/object.h>
34#include <rtems/rtems/options.h>
35#include <rtems/rtems/sem.h>
36#include <rtems/score/coremutex.h>
37#include <rtems/score/coresem.h>
38#include <rtems/score/states.h>
39#include <rtems/score/thread.h>
40#include <rtems/score/threadq.h>
41#if defined(RTEMS_MULTIPROCESSING)
42#include <rtems/score/mpci.h>
43#endif
44#include <rtems/score/sysstate.h>
45
46#include <rtems/score/interr.h>
47
48/*PAGE
49 *
50 *  rtems_semaphore_release
51 *
52 *  This directive allows a thread to release a semaphore.
53 *
54 *  Input parameters:
55 *    id - semaphore id
56 *
57 *  Output parameters:
58 *    RTEMS_SUCCESSFUL - if successful
59 *    error code        - if unsuccessful
60 */
61
62rtems_status_code rtems_semaphore_release(
63  Objects_Id id
64)
65{
66  register Semaphore_Control *the_semaphore;
67  Objects_Locations           location;
68  CORE_mutex_Status           mutex_status;
69  CORE_semaphore_Status       semaphore_status;
70
71  the_semaphore = _Semaphore_Get( id, &location );
72  switch ( location ) {
73
74    case OBJECTS_REMOTE:
75#if defined(RTEMS_MULTIPROCESSING)
76      return _Semaphore_MP_Send_request_packet(
77        SEMAPHORE_MP_RELEASE_REQUEST,
78        id,
79        0,                               /* Not used */
80        MPCI_DEFAULT_TIMEOUT
81      );
82#endif
83
84    case OBJECTS_ERROR:
85      return RTEMS_INVALID_ID;
86
87    case OBJECTS_LOCAL:
88      if ( !_Attributes_Is_counting_semaphore(the_semaphore->attribute_set) ) {
89        mutex_status = _CORE_mutex_Surrender(
90                         &the_semaphore->Core_control.mutex,
91                         id,
92#if defined(RTEMS_MULTIPROCESSING)
93                         _Semaphore_Core_mutex_mp_support
94#else
95                         NULL
96#endif
97                       );
98        _Thread_Enable_dispatch();
99        return _Semaphore_Translate_core_mutex_return_code( mutex_status );
100      }
101      else
102        semaphore_status = _CORE_semaphore_Surrender(
103                             &the_semaphore->Core_control.semaphore,
104                             id,
105#if defined(RTEMS_MULTIPROCESSING)
106                             _Semaphore_Core_semaphore_mp_support
107#else
108                             NULL
109#endif
110                           );
111        _Thread_Enable_dispatch();
112        return
113          _Semaphore_Translate_core_semaphore_return_code( semaphore_status );
114  }
115
116  return RTEMS_INTERNAL_ERROR;   /* unreached - only to remove warnings */
117}
Note: See TracBrowser for help on using the repository browser.