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/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include "pthreadP.h"
#include <lowlevellock.h>
#include <stap-probe.h>
#ifndef lll_unlock_elision
#define lll_unlock_elision(a,b) ({ lll_unlock (a,b); 0; })
#endif
static int
internal_function
__pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
__attribute_noinline__;
int
internal_function attribute_hidden
__pthread_mutex_unlock_usercnt (mutex, decr)
pthread_mutex_t *mutex;
int decr;
{
int type = PTHREAD_MUTEX_TYPE_ELISION (mutex);
if (__builtin_expect (type &
~(PTHREAD_MUTEX_KIND_MASK_NP|PTHREAD_MUTEX_ELISION_FLAGS_NP), 0))
return __pthread_mutex_unlock_full (mutex, decr);
if (__builtin_expect (type, PTHREAD_MUTEX_TIMED_NP)
== PTHREAD_MUTEX_TIMED_NP)
{
/* Always reset the owner field. */
normal:
mutex->__data.__owner = 0;
if (decr)
/* One less user. */
--mutex->__data.__nusers;
/* Unlock. */
lll_unlock (mutex->__data.__lock, PTHREAD_MUTEX_PSHARED (mutex));
LIBC_PROBE (mutex_release, 1, mutex);
return 0;
}
else if (__builtin_expect (type == PTHREAD_MUTEX_TIMED_ELISION_NP, 1))
{
/* Don't reset the owner/users fields for elision. */
return lll_unlock_elision (mutex->__data.__lock,
PTHREAD_MUTEX_PSHARED (mutex));
}
else if (__builtin_expect (PTHREAD_MUTEX_TYPE (mutex)
== PTHREAD_MUTEX_RECURSIVE_NP, 1))
{
/* Recursive mutex. */
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
return EPERM;
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return 0;
goto normal;
}
else if (__builtin_expect (PTHREAD_MUTEX_TYPE (mutex)
== PTHREAD_MUTEX_ADAPTIVE_NP, 1))
goto normal;
else
{
/* Error checking mutex. */
assert (type == PTHREAD_MUTEX_ERRORCHECK_NP);
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid)
|| ! lll_islocked (mutex->__data.__lock))
return EPERM;
goto normal;
}
}
static int
internal_function
__pthread_mutex_unlock_full (pthread_mutex_t *mutex, int decr)
{
int newowner = 0;
switch (PTHREAD_MUTEX_TYPE (mutex))
{
case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP:
/* Recursive mutex. */
if ((mutex->__data.__lock & FUTEX_TID_MASK)
== THREAD_GETMEM (THREAD_SELF, tid)
&& __builtin_expect (mutex->__data.__owner
== PTHREAD_MUTEX_INCONSISTENT, 0))
{
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return ENOTRECOVERABLE;
goto notrecoverable;
}
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
return EPERM;
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return 0;
goto robust;
case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP:
case PTHREAD_MUTEX_ROBUST_NORMAL_NP:
case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP:
if ((mutex->__data.__lock & FUTEX_TID_MASK)
!= THREAD_GETMEM (THREAD_SELF, tid)
|| ! lll_islocked (mutex->__data.__lock))
return EPERM;
/* If the previous owner died and the caller did not succeed in
making the state consistent, mark the mutex as unrecoverable
and make all waiters. */
if (__builtin_expect (mutex->__data.__owner
== PTHREAD_MUTEX_INCONSISTENT, 0))
notrecoverable:
newowner = PTHREAD_MUTEX_NOTRECOVERABLE;
robust:
/* Remove mutex from the list. */
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
&mutex->__data.__list.__next);
DEQUEUE_MUTEX (mutex);
mutex->__data.__owner = newowner;
if (decr)
/* One less user. */
--mutex->__data.__nusers;
/* Unlock. */
lll_robust_unlock (mutex->__data.__lock,
PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
break;
case PTHREAD_MUTEX_PI_RECURSIVE_NP:
/* Recursive mutex. */
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
return EPERM;
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return 0;
goto continue_pi_non_robust;
case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP:
/* Recursive mutex. */
if ((mutex->__data.__lock & FUTEX_TID_MASK)
== THREAD_GETMEM (THREAD_SELF, tid)
&& __builtin_expect (mutex->__data.__owner
== PTHREAD_MUTEX_INCONSISTENT, 0))
{
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return ENOTRECOVERABLE;
goto pi_notrecoverable;
}
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
return EPERM;
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return 0;
goto continue_pi_robust;
case PTHREAD_MUTEX_PI_ERRORCHECK_NP:
case PTHREAD_MUTEX_PI_NORMAL_NP:
case PTHREAD_MUTEX_PI_ADAPTIVE_NP:
case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP:
case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP:
case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP:
if ((mutex->__data.__lock & FUTEX_TID_MASK)
!= THREAD_GETMEM (THREAD_SELF, tid)
|| ! lll_islocked (mutex->__data.__lock))
return EPERM;
/* If the previous owner died and the caller did not succeed in
making the state consistent, mark the mutex as unrecoverable
and make all waiters. */
if ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) != 0
&& __builtin_expect (mutex->__data.__owner
== PTHREAD_MUTEX_INCONSISTENT, 0))
pi_notrecoverable:
newowner = PTHREAD_MUTEX_NOTRECOVERABLE;
if ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) != 0)
{
continue_pi_robust:
/* Remove mutex from the list.
Note: robust PI futexes are signaled by setting bit 0. */
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
(void *) (((uintptr_t) &mutex->__data.__list.__next)
| 1));
DEQUEUE_MUTEX (mutex);
}
continue_pi_non_robust:
mutex->__data.__owner = newowner;
if (decr)
/* One less user. */
--mutex->__data.__nusers;
/* Unlock. */
if ((mutex->__data.__lock & FUTEX_WAITERS) != 0
|| atomic_compare_and_exchange_bool_rel (&mutex->__data.__lock, 0,
THREAD_GETMEM (THREAD_SELF,
tid)))
{
int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP;
int private = (robust
? PTHREAD_ROBUST_MUTEX_PSHARED (mutex)
: PTHREAD_MUTEX_PSHARED (mutex));
INTERNAL_SYSCALL_DECL (__err);
INTERNAL_SYSCALL (futex, __err, 2, &mutex->__data.__lock,
__lll_private_flag (FUTEX_UNLOCK_PI, private));
}
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
break;
case PTHREAD_MUTEX_PP_RECURSIVE_NP:
/* Recursive mutex. */
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
return EPERM;
if (--mutex->__data.__count != 0)
/* We still hold the mutex. */
return 0;
goto pp;
case PTHREAD_MUTEX_PP_ERRORCHECK_NP:
/* Error checking mutex. */
if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid)
|| (mutex->__data.__lock & ~ PTHREAD_MUTEX_PRIO_CEILING_MASK) == 0)
return EPERM;
/* FALLTHROUGH */
case PTHREAD_MUTEX_PP_NORMAL_NP:
case PTHREAD_MUTEX_PP_ADAPTIVE_NP:
/* Always reset the owner field. */
pp:
mutex->__data.__owner = 0;
if (decr)
/* One less user. */
--mutex->__data.__nusers;
/* Unlock. */
int newval, oldval;
do
{
oldval = mutex->__data.__lock;
newval = oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK;
}
while (atomic_compare_and_exchange_bool_rel (&mutex->__data.__lock,
newval, oldval));
if ((oldval & ~PTHREAD_MUTEX_PRIO_CEILING_MASK) > 1)
lll_futex_wake (&mutex->__data.__lock, 1,
PTHREAD_MUTEX_PSHARED (mutex));
int oldprio = newval >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT;
LIBC_PROBE (mutex_release, 1, mutex);
return __pthread_tpp_change_priority (oldprio, -1);
default:
/* Correct code cannot set any other type. */
return EINVAL;
}
LIBC_PROBE (mutex_release, 1, mutex);
return 0;
}
int
__pthread_mutex_unlock (mutex)
pthread_mutex_t *mutex;
{
return __pthread_mutex_unlock_usercnt (mutex, 1);
}
strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock)
hidden_def (__pthread_mutex_unlock)
|
