diff options
Diffstat (limited to 'nptl/pthread_mutex_unlock.c')
| -rw-r--r-- | nptl/pthread_mutex_unlock.c | 350 |
1 files changed, 0 insertions, 350 deletions
diff --git a/nptl/pthread_mutex_unlock.c b/nptl/pthread_mutex_unlock.c deleted file mode 100644 index f701d4e274..0000000000 --- a/nptl/pthread_mutex_unlock.c +++ /dev/null @@ -1,350 +0,0 @@ -/* Copyright (C) 2002-2017 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,c) ({ lll_unlock (a,c); 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 (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 (__glibc_likely (type == PTHREAD_MUTEX_TIMED_ELISION_NP)) - { - /* Don't reset the owner/users fields for elision. */ - return lll_unlock_elision (mutex->__data.__lock, mutex->__data.__elision, - 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; - int private; - - 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); - /* We must set op_pending before we dequeue the mutex. Also see - comments at ENQUEUE_MUTEX. */ - __asm ("" ::: "memory"); - DEQUEUE_MUTEX (mutex); - - mutex->__data.__owner = newowner; - if (decr) - /* One less user. */ - --mutex->__data.__nusers; - - /* Unlock by setting the lock to 0 (not acquired); if the lock had - FUTEX_WAITERS set previously, then wake any waiters. - The unlock operation must be the last access to the mutex to not - violate the mutex destruction requirements (see __lll_unlock). */ - private = PTHREAD_ROBUST_MUTEX_PSHARED (mutex); - if (__glibc_unlikely ((atomic_exchange_rel (&mutex->__data.__lock, 0) - & FUTEX_WAITERS) != 0)) - lll_futex_wake (&mutex->__data.__lock, 1, private); - - /* We must clear op_pending after we release the mutex. - FIXME However, this violates the mutex destruction requirements - because another thread could acquire the mutex, destroy it, and - reuse the memory for something else; then, if this thread crashes, - and the memory happens to have a value equal to the TID, the kernel - will believe it is still related to the mutex (which has been - destroyed already) and will modify some other random object. */ - __asm ("" ::: "memory"); - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - break; - - /* The PI support requires the Linux futex system call. If that's not - available, pthread_mutex_init should never have allowed the type to - be set. So it will get the default case for an invalid type. */ -#ifdef __NR_futex - 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)); - /* We must set op_pending before we dequeue the mutex. Also see - comments at ENQUEUE_MUTEX. */ - __asm ("" ::: "memory"); - DEQUEUE_MUTEX (mutex); - } - - continue_pi_non_robust: - mutex->__data.__owner = newowner; - if (decr) - /* One less user. */ - --mutex->__data.__nusers; - - /* Unlock. Load all necessary mutex data before releasing the mutex - to not violate the mutex destruction requirements (see - lll_unlock). */ - int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP; - private = (robust - ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex) - : PTHREAD_MUTEX_PSHARED (mutex)); - /* Unlock the mutex using a CAS unless there are futex waiters or our - TID is not the value of __lock anymore, in which case we let the - kernel take care of the situation. Use release MO in the CAS to - synchronize with acquire MO in lock acquisitions. */ - int l = atomic_load_relaxed (&mutex->__data.__lock); - do - { - if (((l & FUTEX_WAITERS) != 0) - || (l != THREAD_GETMEM (THREAD_SELF, tid))) - { - INTERNAL_SYSCALL_DECL (__err); - INTERNAL_SYSCALL (futex, __err, 2, &mutex->__data.__lock, - __lll_private_flag (FUTEX_UNLOCK_PI, private)); - break; - } - } - while (!atomic_compare_exchange_weak_release (&mutex->__data.__lock, - &l, 0)); - - /* This happens after the kernel releases the mutex but violates the - mutex destruction requirements; see comments in the code handling - PTHREAD_MUTEX_ROBUST_NORMAL_NP. */ - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - break; -#endif /* __NR_futex. */ - - 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. Use release MO in the CAS to synchronize with acquire MO in - lock acquisitions. */ - int newval; - int oldval = atomic_load_relaxed (&mutex->__data.__lock); - do - { - newval = oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK; - } - while (!atomic_compare_exchange_weak_release (&mutex->__data.__lock, - &oldval, newval)); - - 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 (pthread_mutex_t *mutex) -{ - return __pthread_mutex_unlock_usercnt (mutex, 1); -} -strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock) -hidden_def (__pthread_mutex_unlock) |