Resync new repository with old repo r5166

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5153 42af7a65-404d-4744-a932-0658087f49c3
2026-11-07 02:41:37 +08:00 · 2012-09-17 18:18:44 +00:00
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+/****************************************************************************
+ * sched/pthread_mutexunlock.c
+ *
+ *   Copyright (C) 2007-2009 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 <unistd.h>
+#include <pthread.h>
+#include <sched.h>
+#include <errno.h>
+#include <debug.h>
+
+#include "pthread_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: pthread_mutex_unlock
+ *
+ * Description:
+ *   The pthread_mutex_unlock() function releases the mutex object referenced
+ *   by mutex. The manner in which a mutex is released is dependent upon the
+ *   mutex's type attribute. If there are threads blocked on the mutex object
+ *   referenced by mutex when pthread_mutex_unlock() is called, resulting in
+ *   the mutex becoming available, the scheduling policy is used to determine
+ *   which thread shall acquire the mutex. (In the case of PTHREAD_MUTEX_RECURSIVE
+ *   mutexes, the mutex becomes available when the count reaches zero and the
+ *   calling thread no longer has any locks on this mutex).
+ *
+ *   If a signal is delivered to a thread waiting for a mutex, upon return from
+ *   the signal handler the thread resumes waiting for the mutex as if it was
+ *   not interrupted.
+ *
+ * Parameters:
+ *   None
+ *
+ * Return Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+int pthread_mutex_unlock(FAR pthread_mutex_t *mutex)
+{
+  int ret = OK;
+
+  sdbg("mutex=0x%p\n", mutex);
+
+  if (!mutex)
+    {
+      ret = EINVAL;
+    }
+  else
+    {
+      /* Make sure the semaphore is stable while we make the following
+       * checks.  This all needs to be one atomic action.
+       */
+
+      sched_lock();
+
+      /* Does the calling thread own the semaphore? */
+
+      if (mutex->pid != (int)getpid())
+        {
+          /* No... return an error (default behavior is like PTHREAD_MUTEX_ERRORCHECK) */
+
+          sdbg("Holder=%d returning EPERM\n", mutex->pid);
+          ret = EPERM;
+        }
+        
+
+      /* Yes, the caller owns the semaphore.. Is this a recursive mutex? */
+
+#ifdef CONFIG_MUTEX_TYPES
+      else if (mutex->type == PTHREAD_MUTEX_RECURSIVE && mutex->nlocks > 1)
+        {
+          /* This is a recursive mutex and we there are multiple locks held. Retain
+           * the mutex lock, just decrement the count of locks held, and return
+           * success.
+           */
+          mutex->nlocks--;
+        }
+#endif
+
+      /* This is either a non-recursive mutex or is the outermost unlock of
+       * a recursive mutex.
+       */
+
+      else
+        {
+          /* Nullify the pid and lock count then post the semaphore */
+
+          mutex->pid    = 0;
+#ifdef CONFIG_MUTEX_TYPES
+          mutex->nlocks = 0;
+#endif
+          ret = pthread_givesemaphore((sem_t*)&mutex->sem);
+        }
+      sched_unlock();
+    }
+
+  sdbg("Returning %d\n", ret);
+  return ret;
+}
+
+