diff options
Diffstat (limited to 'nptl/sem_getvalue.c')
| -rw-r--r-- | nptl/sem_getvalue.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/nptl/sem_getvalue.c b/nptl/sem_getvalue.c index c3c91e1f33..1432cc795e 100644 --- a/nptl/sem_getvalue.c +++ b/nptl/sem_getvalue.c @@ -19,23 +19,37 @@ #include <semaphore.h> #include <shlib-compat.h> #include "semaphoreP.h" +#include <atomic.h> int -__new_sem_getvalue (sem, sval) - sem_t *sem; - int *sval; +__new_sem_getvalue (sem_t *sem, int *sval) { struct new_sem *isem = (struct new_sem *) sem; /* XXX Check for valid SEM parameter. */ - - *sval = isem->value; + /* FIXME This uses relaxed MO, even though POSIX specifies that this function + should be linearizable. However, its debatable whether linearizability + is the right requirement. We need to follow up with POSIX and, if + necessary, use a stronger MO here and elsewhere (e.g., potentially + release MO in all places where we consume a token). */ + +#if __HAVE_64B_ATOMICS + *sval = atomic_load_relaxed (&isem->data) & SEM_VALUE_MASK; +#else + *sval = atomic_load_relaxed (&isem->value) >> SEM_VALUE_SHIFT; +#endif return 0; } versioned_symbol (libpthread, __new_sem_getvalue, sem_getvalue, GLIBC_2_1); #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1) -strong_alias (__new_sem_getvalue, __old_sem_getvalue) +int +__old_sem_getvalue (sem_t *sem, int *sval) +{ + struct old_sem *isem = (struct old_sem *) sem; + *sval = isem->value; + return 0; +} compat_symbol (libpthread, __old_sem_getvalue, sem_getvalue, GLIBC_2_0); #endif |