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posix: Avoid Giant lock in sem_getvalue()

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Update #2555.
This commit is contained in:
Sebastian Huber
2016-04-20 06:15:07 +02:00
parent cca2d8abc4
commit b5a21bf139
1 changed files with 11 additions and 2 deletions
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13
cpukit/posix/src/semgetvalue.c
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@@ -37,13 +37,22 @@ int sem_getvalue(
{ {
POSIX_Semaphore_Control *the_semaphore; POSIX_Semaphore_Control *the_semaphore;
Objects_Locations location; Objects_Locations location;
ISR_lock_Context lock_context;
the_semaphore = _POSIX_Semaphore_Get( sem, &location ); the_semaphore = _POSIX_Semaphore_Get_interrupt_disable(
sem,
&location,
&lock_context
);
switch ( location ) { switch ( location ) {
case OBJECTS_LOCAL: case OBJECTS_LOCAL:
/*
* Assume a relaxed atomic load of the value on SMP configurations.
* Thus, there is no need to acquire a lock.
*/
*sval = _CORE_semaphore_Get_count( &the_semaphore->Semaphore ); *sval = _CORE_semaphore_Get_count( &the_semaphore->Semaphore );
_Objects_Put( &the_semaphore->Object ); _ISR_lock_ISR_enable( &lock_context );
return 0; return 0;
#if defined(RTEMS_MULTIPROCESSING) #if defined(RTEMS_MULTIPROCESSING)