diff options
Diffstat (limited to 'nptl/pthread_mutex_setprioceiling.c')
| -rw-r--r-- | nptl/pthread_mutex_setprioceiling.c | 81 |
1 files changed, 71 insertions, 10 deletions
diff --git a/nptl/pthread_mutex_setprioceiling.c b/nptl/pthread_mutex_setprioceiling.c index 3271f8833a..cd13d1c14c 100644 --- a/nptl/pthread_mutex_setprioceiling.c +++ b/nptl/pthread_mutex_setprioceiling.c @@ -18,6 +18,7 @@ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ +#include <stdbool.h> #include <errno.h> #include <pthreadP.h> @@ -33,23 +34,83 @@ pthread_mutex_setprioceiling (mutex, prioceiling, old_ceiling) if ((mutex->__data.__kind & PTHREAD_MUTEX_PRIO_PROTECT_NP) == 0) return EINVAL; - if (prioceiling < 0 || __builtin_expect (prioceiling > 255, 0)) + if (__sched_fifo_min_prio == -1) + __init_sched_fifo_prio (); + + if (__builtin_expect (prioceiling < __sched_fifo_min_prio, 0) + || __builtin_expect (prioceiling > __sched_fifo_max_prio, 0) + || __builtin_expect ((prioceiling + & (PTHREAD_MUTEXATTR_PRIO_CEILING_MASK + >> PTHREAD_MUTEXATTR_PRIO_CEILING_SHIFT)) + != prioceiling, 0)) return EINVAL; - /* XXX This needs to lock with TID, but shouldn't obey priority protect - protocol. */ - /* lll_xxx_mutex_lock (mutex->__data.__lock); */ + /* Check whether we already hold the mutex. */ + bool locked = false; + if (mutex->__data.__owner == THREAD_GETMEM (THREAD_SELF, tid)) + { + if (mutex->__data.__kind == PTHREAD_MUTEX_PP_ERRORCHECK_NP) + return EDEADLK; + + if (mutex->__data.__kind == PTHREAD_MUTEX_PP_RECURSIVE_NP) + locked = true; + } + + int oldval = mutex->__data.__lock; + if (! locked) + do + { + /* Need to lock the mutex, but without obeying the priority + protect protocol. */ + int ceilval = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK); + + oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 1, ceilval); + if (oldval == ceilval) + break; + + do + { + oldval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 2, + ceilval | 1); + + if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval) + break; + + if (oldval != ceilval) + lll_futex_wait (&mutex->__data.__lock, ceilval | 2); + } + while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 2, ceilval) + != ceilval); + + if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval) + continue; + } + while (0); + + int oldprio = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) + >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + if (locked) + { + int ret = __pthread_tpp_change_priority (oldprio, prioceiling); + if (ret) + return ret; + } if (old_ceiling != NULL) - *old_ceiling = (mutex->__data.__kind & PTHREAD_MUTEX_PRIO_CEILING_MASK) - >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + *old_ceiling = oldprio; - int newkind = (mutex->__data.__kind & ~PTHREAD_MUTEX_PRIO_CEILING_MASK); - mutex->__data.__kind = newkind + int newlock = 0; + if (locked) + newlock = (mutex->__data.__lock & ~PTHREAD_MUTEX_PRIO_CEILING_MASK); + mutex->__data.__lock = newlock | (prioceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT); + atomic_full_barrier (); - /* XXX This needs to unlock the above special kind of lock. */ - /* lll_xxx_mutex_unlock (mutex->__data.__lock); */ + lll_futex_wake (&mutex->__data.__lock, INT_MAX); return 0; } |