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/**
* @file
*
* @brief Changes the Priority Ceiling of a Mutex and Releases it
* @ingroup POSIXAPI
*/
/*
* COPYRIGHT (c) 1989-2009.
* 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.org/license/LICENSE.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/posix/muteximpl.h>
#include <rtems/posix/priorityimpl.h>
/*
* 13.6.2 Change the Priority Ceiling of a Mutex, P1003.1c/Draft 10, p. 131
*/
int pthread_mutex_setprioceiling(
pthread_mutex_t *mutex,
int prioceiling,
int *old_ceiling
)
{
POSIX_Mutex_Control *the_mutex;
int error;
int unlock_error;
if ( old_ceiling == NULL ) {
return EINVAL;
}
/*
* Must acquire the mutex before we can change it's ceiling.
* POSIX says block until we acquire it.
*/
error = pthread_mutex_lock( mutex );
if ( error != 0 ) {
_Assert( error == EINVAL );
return EINVAL;
}
the_mutex = _POSIX_Mutex_Get( mutex );
if (
_POSIX_Mutex_Get_protocol( the_mutex->flags )
== POSIX_MUTEX_PRIORITY_CEILING
) {
const Scheduler_Control *scheduler;
bool valid;
Priority_Control new_priority;
Priority_Control old_priority;
scheduler = _POSIX_Mutex_Get_scheduler( the_mutex );
old_priority = _POSIX_Mutex_Get_priority( the_mutex );
*old_ceiling = _POSIX_Priority_From_core( scheduler, old_priority );
new_priority = _POSIX_Priority_To_core( scheduler, prioceiling, &valid );
if ( valid ) {
Thread_queue_Context queue_context;
Per_CPU_Control *cpu_self;
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Context_clear_priority_updates( &queue_context );
_POSIX_Mutex_Set_priority(
the_mutex,
new_priority,
&queue_context
);
cpu_self = _Thread_Dispatch_disable();
_Thread_Priority_update( &queue_context );
_Thread_Dispatch_enable( cpu_self );
error = 0;
} else {
error = EINVAL;
}
} else {
*old_ceiling = 0;
error = 0;
}
unlock_error = pthread_mutex_unlock( mutex );
_Assert( unlock_error == 0 );
(void) unlock_error;
return error;
}
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