/* TimedWait
* block until a count becomes available
*
* "lock" [ IN ] - externally acquired lock
*
* "tm" [ IN, NULL OKAY ] - optional timeout where
* NULL means timeout value of 0
*/
LIB_EXPORT rc_t CC KSemaphoreTimedWait ( KSemaphore *self,
struct KLock *lock, struct timeout_t *tm )
{
if ( self == NULL )
return RC ( rcPS, rcSemaphore, rcWaiting, rcSelf, rcNull );
if ( self -> avail == 0 )
{
SMSG ( "%s[%p]: avail == 0\n", __func__, self );
if ( tm == NULL )
{
SMSG ( "%s[%p]: non-blocking mode - return timeout exhausted\n", __func__, self );
return RC ( rcPS, rcSemaphore, rcWaiting, rcTimeout, rcExhausted );
}
if ( ++ self -> waiting == 1 )
{
SMSG ( "%s[%p]: first waiter\n", __func__, self );
self -> requested = self -> min_requested = 1;
self -> uniform = true;
}
else if ( self -> requested != 1 )
{
SMSG ( "%s[%p]: multiple waiters ( %u )\n", __func__, self, self -> waiting );
self -> min_requested = 1;
self -> uniform = false;
}
do
{
rc_t rc;
SMSG ( "%s[%p]: wait on condition...\n", __func__, self );
rc = KConditionTimedWait ( self -> cond, lock, tm );
SMSG ( "%s[%p]:...done, rc = %R\n", __func__, self, rc );
if ( rc != 0 )
{
SMSG ( "%s[%p]: timed out - decrementing wait count\n", __func__, self );
-- self -> waiting;
return ResetRCContext ( rc, rcPS, rcSemaphore, rcWaiting );
}
SMSG ( "%s[%p]: condition signaled - avail = %lu\n", __func__, self, self -> avail );
}
while ( self -> avail == 0 );
SMSG ( "%s[%p]: finished waiting\n", __func__, self );
-- self -> waiting;
}
SMSG ( "%s[%p]: decrementing count from %lu\n", __func__, self, self -> avail );
-- self -> avail;
return 0;
}
/* TimedAlloc
* allocate a count
* used for resource metering
*
* "lock" [ IN ] - externally acquired lock
*
* "count" [ IN ] - the resource count
*
* "tm" [ IN, NULL OKAY ] - optional timeout where
* NULL means timeout value of 0
*/
LIB_EXPORT rc_t CC KSemaphoreTimedAlloc ( KSemaphore *self,
struct KLock *lock, uint64_t count, struct timeout_t *tm )
{
if ( self == NULL )
return RC ( rcPS, rcSemaphore, rcWaiting, rcSelf, rcNull );
if ( self -> avail < count )
{
if ( tm == NULL )
return RC ( rcPS, rcSemaphore, rcWaiting, rcTimeout, rcExhausted );
if ( ++ self -> waiting == 1 )
{
self -> requested = self -> min_requested = count;
self -> uniform = true;
}
else if ( self -> requested != count )
{
if ( self -> min_requested > count )
self -> min_requested = count;
self -> uniform = false;
}
do
{
rc_t rc;
if ( self -> canceled )
{
-- self -> waiting;
return RC ( rcPS, rcSemaphore, rcWaiting, rcSemaphore, rcCanceled );
}
rc = KConditionTimedWait ( self -> cond, lock, tm );
if ( rc != 0 )
{
-- self -> waiting;
return ResetRCContext ( rc, rcPS, rcSemaphore, rcWaiting );
}
}
while ( self -> avail < count );
-- self -> waiting;
}
self -> avail -= count;
return 0;
}
