void _ump_osu_lock_term( _ump_osu_lock_t *lock )
{
int call_result;
UMP_DEBUG_ASSERT_POINTER( lock );
/** Debug lock checking: */
/* Lock is signalled on terminate - not a guarantee, since we could be locked immediately beforehand */
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_UNDEF == lock->locked_as,
("cannot terminate held lock\n") );
call_result = pthread_mutex_destroy( &lock->mutex );
UMP_DEBUG_ASSERT( 0 == call_result,
("Incorrect mutex use detected: pthread_mutex_destroy call failed with error code %d\n", call_result) );
/* Destroy extra state for ANY_UNLOCK type osu_locks */
if ( lock->flags & _UMP_OSU_LOCKFLAG_ANYUNLOCK )
{
UMP_DEBUG_ASSERT( UMP_FALSE == lock->state, ("terminate called on locked object %p\n", lock));
call_result = pthread_cond_destroy(&lock->condition);
UMP_DEBUG_ASSERT( 0 == call_result,
("Incorrect condition-variable use detected: pthread_cond_destroy call failed with error code %d\n", call_result) );
}
UMP_IGNORE(call_result);
_ump_osu_free( lock );
}
_ump_osu_errcode_t _ump_osu_lock_wait( _ump_osu_lock_t *lock, _ump_osu_lock_mode_t mode)
{
/* Parameter validation */
UMP_DEBUG_ASSERT_POINTER( lock );
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_RW == mode,
("unrecognised mode, %.8X\n", mode) );
/** @note since only one flag can be set, we use a switch statement here.
* Otherwise, MUST add an enum into the _ump_osu_lock_t to store the
* implemented lock type */
switch ( lock->flags )
{
case _UMP_OSU_LOCKFLAG_STATIC:
case _UMP_OSU_LOCKFLAG_DEFAULT:
/* Usual Mutex type */
{
int call_result;
call_result = pthread_mutex_lock( &lock->mutex );
UMP_DEBUG_ASSERT( 0 == call_result,
("pthread_mutex_lock call failed with error code %d\n", call_result));
UMP_IGNORE( call_result );
}
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_UNDEF == lock->locked_as,
("This lock was already locked\n") );
UMP_DEBUG_CODE( lock->locked_as = mode );
break;
case _UMP_OSU_LOCKFLAG_ANYUNLOCK:
/** @note Use of bitflags in a case statement ONLY works because this
* is the ONLY flag that is supported */
/* lock the mutex protecting access to the state field */
pthread_mutex_lock( &lock->mutex );
/* loop while locked (state is UMP_TRUE) */
/* pthread_cond_wait unlocks the mutex, wait, and locks the mutex once unblocked */
while ( UMP_TRUE == lock->state ) pthread_cond_wait( &lock->condition, &lock->mutex );
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_UNDEF == lock->locked_as,
("This lock was already locked\n") );
UMP_DEBUG_CODE( lock->locked_as = mode );
/* the state is UMP_FALSE (unlocked), so we set it to UMP_TRUE to indicate that it's locked and can return knowing that we own the lock */
lock->state = UMP_TRUE;
/* final unlock of the mutex */
pthread_mutex_unlock(&lock->mutex);
break;
default:
UMP_DEBUG_ERROR( ("lock has incorrect flags==%.8X\n", lock->flags) );
break;
}
return _UMP_OSU_ERR_OK;
}
void _ump_osu_lock_signal( _ump_osu_lock_t *lock, _ump_osu_lock_mode_t mode )
{
/* Parameter validation */
UMP_DEBUG_ASSERT_POINTER( lock );
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_RW == mode,
("unrecognised mode, %.8X\n", mode) );
/** @note since only one flag can be set, we use a switch statement here.
* Otherwise, MUST add an enum into the _ump_osu_lock_t to store the
* implemented lock type */
switch ( lock->flags )
{
case _UMP_OSU_LOCKFLAG_STATIC:
case _UMP_OSU_LOCKFLAG_DEFAULT:
/* Usual Mutex type */
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
UMP_DEBUG_ASSERT( mode == lock->locked_as,
("This lock was locked as==%.8X, but tried to unlock as mode==%.8X\n", lock->locked_as, mode));
UMP_DEBUG_CODE( lock->locked_as = _UMP_OSU_LOCKMODE_UNDEF );
{
int call_result;
call_result = pthread_mutex_unlock( &lock->mutex );
UMP_DEBUG_ASSERT( 0 == call_result,
("pthread_mutex_lock call failed with error code %d\n", call_result));
UMP_IGNORE( call_result );
}
break;
case _UMP_OSU_LOCKFLAG_ANYUNLOCK:
/** @note Use of bitflags in a case statement ONLY works because this
* is the ONLY flag that is supported */
pthread_mutex_lock(&lock->mutex);
UMP_DEBUG_ASSERT( UMP_TRUE == lock->state, ("Unlocking a _ump_osu_lock_t %p which is not locked\n", lock));
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
UMP_DEBUG_ASSERT( mode == lock->locked_as,
("This lock was locked as==%.8X, but tried to unlock as %.8X\n", lock->locked_as, mode ));
UMP_DEBUG_CODE( lock->locked_as = _UMP_OSU_LOCKMODE_UNDEF );
/* mark as unlocked */
lock->state = UMP_FALSE;
/* signal the condition, only wake a single thread */
pthread_cond_signal(&lock->condition);
pthread_mutex_unlock(&lock->mutex);
break;
default:
UMP_DEBUG_ERROR( ("lock has incorrect flags==%.8X\n", lock->flags) );
break;
}
}
_ump_osu_errcode_t _ump_osu_lock_auto_init( _ump_osu_lock_t **pplock, _ump_osu_lock_flags_t flags, u32 initial, u32 order )
{
int call_result;
/* Validate parameters: */
UMP_DEBUG_ASSERT_POINTER( pplock );
/** @opt We don't lock the Critical Section or do anything if this is already non-null */
if ( NULL != *pplock)
{
return _UMP_OSU_ERR_OK;
}
/* We MIGHT need to initialize it, lock the Critical Section and check again */
call_result = pthread_mutex_lock(&static_auto_init_mutex);
/* It would be a programming error for this to fail: */
UMP_DEBUG_ASSERT( 0 == call_result,
("failed to lock critical section\n") );
if ( NULL != *pplock )
{
/*
We caught a race condition to initialize this osu_lock.
The other thread won the race, so the osu_lock is now initialized.
*/
call_result = pthread_mutex_unlock(&static_auto_init_mutex);
UMP_DEBUG_ASSERT(0 == call_result,
("failed to unlock critical section\n"));
return _UMP_OSU_ERR_OK;
}
/* We're the first thread in: initialize the osu_lock */
*pplock = _ump_osu_lock_init( flags, initial, order );
if ( NULL == *pplock )
{
/* osu_lock creation failed */
call_result = pthread_mutex_unlock(&static_auto_init_mutex);
UMP_DEBUG_ASSERT(0 == call_result,
("failed to unlock critical section\n"));
return _UMP_OSU_ERR_FAULT;
}
/* osu_lock created OK */
call_result = pthread_mutex_unlock(&static_auto_init_mutex);
UMP_DEBUG_ASSERT(0 == call_result,
("failed to unlock critical section\n"));
UMP_IGNORE( call_result );
return _UMP_OSU_ERR_OK;
}
_ump_osu_errcode_t _ump_osu_lock_trywait( _ump_osu_lock_t *lock, _ump_osu_lock_mode_t mode)
{
_ump_osu_errcode_t err = _UMP_OSU_ERR_FAULT;
/* Parameter validation */
UMP_DEBUG_ASSERT_POINTER( lock );
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_RW == mode,
("unrecognised mode, %.8X\n", mode) );
/** @note since only one flag can be set, we use a switch statement here.
* Otherwise, MUST add an enum into the _ump_osu_lock_t to store the
* implemented lock type */
switch ( lock->flags )
{
case _UMP_OSU_LOCKFLAG_STATIC:
case _UMP_OSU_LOCKFLAG_DEFAULT:
/* Usual Mutex type */
{
/* This is not subject to UMP_CHECK - overriding the result would cause a programming error */
if ( 0 == pthread_mutex_trylock( &lock->mutex ) )
{
err = _UMP_OSU_ERR_OK;
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_UNDEF == lock->locked_as
|| mode == lock->locked_as,
("tried as mode==%.8X, but was locked as %.8X\n", mode, lock->locked_as) );
UMP_DEBUG_CODE( lock->locked_as = mode );
}
}
break;
case _UMP_OSU_LOCKFLAG_ANYUNLOCK:
/** @note Use of bitflags in a case statement ONLY works because this
* is the ONLY flag that is supported */
/* lock the mutex protecting access to the state field */
pthread_mutex_lock(&lock->mutex);
if ( UMP_FALSE == lock->state)
{
/* unlocked, take the lock */
lock->state = UMP_TRUE;
err = _UMP_OSU_ERR_OK;
}
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
/* Can do this regardless of whether we obtained ANYUNLOCK: */
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_UNDEF == lock->locked_as
|| mode == lock->locked_as,
("tried as mode==%.8X, but was locked as %.8X\n", mode, lock->locked_as) );
/* If we were already locked, this does no harm, because of the above assert: */
UMP_DEBUG_CODE( lock->locked_as = mode );
pthread_mutex_unlock(&lock->mutex);
break;
default:
UMP_DEBUG_ERROR( ("lock has incorrect flags==%.8X\n", lock->flags) );
break;
}
return err;
}
_ump_osu_errcode_t _ump_osu_lock_timed_wait( _ump_osu_lock_t *lock, _ump_osu_lock_mode_t mode, u64 timeout)
{
/* absolute time specifier */
struct timespec ts;
struct timeval tv;
/* Parameter validation */
UMP_DEBUG_ASSERT_POINTER( lock );
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_RW == mode,
("unrecognised mode, %.8X\n", mode) );
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKFLAG_ANYUNLOCK == lock->flags, ("Timed operations only implemented for ANYUNLOCK type locks"));
/* calculate the realtime timeout value */
if (0 != gettimeofday(&tv, NULL))
{
UMP_DEBUG_PRINT(1,("Could not get the current realtime value to calculate the absolute value for a timed mutex lock with a timeout"));
return _UMP_OSU_ERR_FAULT;
}
tv.tv_usec += timeout;
#define UMP_USECS_PER_SECOND 1000000LL
#define UMP_NANOSECS_PER_USEC 1000LL
/* did we overflow a second in the usec part? */
while (tv.tv_usec >= UMP_USECS_PER_SECOND)
{
tv.tv_usec -= UMP_USECS_PER_SECOND;
tv.tv_sec++;
}
/* copy to the correct struct */
ts.tv_sec = tv.tv_sec;
ts.tv_nsec = (tv.tv_usec * UMP_NANOSECS_PER_USEC);
#undef UMP_USECS_PER_SECOND
#undef UMP_NANOSECS_PER_USEC
/* lock the mutex protecting access to the state field */
pthread_mutex_lock( &lock->mutex );
/* loop while locked (state is UMP_TRUE) */
/* pthread_cond_timedwait unlocks the mutex, wait, and locks the mutex once unblocked (either due to the event or the timeout) */
while ( UMP_TRUE == lock->state )
{
int res;
res = pthread_cond_timedwait( &lock->condition, &lock->mutex, &ts );
if (0 == res) continue; /* test the state variable again (loop condition) */
else if (ETIMEDOUT == res)
{
/* timeout, need to clean up and return the correct error code */
pthread_mutex_unlock(&lock->mutex);
return _UMP_OSU_ERR_TIMEOUT;
}
else
{
UMP_DEBUG_PRINT(1, ("Unexpected return from pthread_cond_timedwait 0x%08X\n", res));
pthread_mutex_unlock(&lock->mutex);
return _UMP_OSU_ERR_FAULT;
}
}
/* DEBUG tracking of previously locked state - occurs while lock is obtained */
UMP_DEBUG_ASSERT( _UMP_OSU_LOCKMODE_UNDEF == lock->locked_as,
("This lock was already locked\n") );
UMP_DEBUG_CODE( lock->locked_as = mode );
/* the state is UMP_FALSE (unlocked), so we set it to UMP_TRUE to indicate that it's locked and can return knowing that we own the lock */
lock->state = UMP_TRUE;
/* final unlock of the mutex */
pthread_mutex_unlock(&lock->mutex);
return _UMP_OSU_ERR_OK;
}
