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Diffstat (limited to 'nptl/pthread_mutex_trylock.c')
| -rw-r--r-- | nptl/pthread_mutex_trylock.c | 408 |
1 files changed, 0 insertions, 408 deletions
diff --git a/nptl/pthread_mutex_trylock.c b/nptl/pthread_mutex_trylock.c deleted file mode 100644 index e514997be8..0000000000 --- a/nptl/pthread_mutex_trylock.c +++ /dev/null @@ -1,408 +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> - -#ifndef lll_trylock_elision -#define lll_trylock_elision(a,t) lll_trylock(a) -#endif - -#ifndef FORCE_ELISION -#define FORCE_ELISION(m, s) -#endif - -int -__pthread_mutex_trylock (pthread_mutex_t *mutex) -{ - int oldval; - pid_t id = THREAD_GETMEM (THREAD_SELF, tid); - - switch (__builtin_expect (PTHREAD_MUTEX_TYPE_ELISION (mutex), - PTHREAD_MUTEX_TIMED_NP)) - { - /* Recursive mutex. */ - case PTHREAD_MUTEX_RECURSIVE_NP|PTHREAD_MUTEX_ELISION_NP: - case PTHREAD_MUTEX_RECURSIVE_NP: - /* Check whether we already hold the mutex. */ - if (mutex->__data.__owner == id) - { - /* Just bump the counter. */ - if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) - /* Overflow of the counter. */ - return EAGAIN; - - ++mutex->__data.__count; - return 0; - } - - if (lll_trylock (mutex->__data.__lock) == 0) - { - /* Record the ownership. */ - mutex->__data.__owner = id; - mutex->__data.__count = 1; - ++mutex->__data.__nusers; - return 0; - } - break; - - case PTHREAD_MUTEX_TIMED_ELISION_NP: - elision: __attribute__((unused)) - if (lll_trylock_elision (mutex->__data.__lock, - mutex->__data.__elision) != 0) - break; - /* Don't record the ownership. */ - return 0; - - case PTHREAD_MUTEX_TIMED_NP: - FORCE_ELISION (mutex, goto elision); - /*FALL THROUGH*/ - case PTHREAD_MUTEX_ADAPTIVE_NP: - case PTHREAD_MUTEX_ERRORCHECK_NP: - if (lll_trylock (mutex->__data.__lock) != 0) - break; - - /* Record the ownership. */ - mutex->__data.__owner = id; - ++mutex->__data.__nusers; - - return 0; - - case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP: - case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: - case PTHREAD_MUTEX_ROBUST_NORMAL_NP: - case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, - &mutex->__data.__list.__next); - - oldval = mutex->__data.__lock; - do - { - again: - if ((oldval & FUTEX_OWNER_DIED) != 0) - { - /* The previous owner died. Try locking the mutex. */ - int newval = id | (oldval & FUTEX_WAITERS); - - newval - = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, - newval, oldval); - - if (newval != oldval) - { - oldval = newval; - goto again; - } - - /* We got the mutex. */ - mutex->__data.__count = 1; - /* But it is inconsistent unless marked otherwise. */ - mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; - - ENQUEUE_MUTEX (mutex); - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - /* Note that we deliberately exist here. If we fall - through to the end of the function __nusers would be - incremented which is not correct because the old - owner has to be discounted. */ - return EOWNERDEAD; - } - - /* Check whether we already hold the mutex. */ - if (__glibc_unlikely ((oldval & FUTEX_TID_MASK) == id)) - { - int kind = PTHREAD_MUTEX_TYPE (mutex); - if (kind == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, - NULL); - return EDEADLK; - } - - if (kind == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, - NULL); - - /* Just bump the counter. */ - if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) - /* Overflow of the counter. */ - return EAGAIN; - - ++mutex->__data.__count; - - return 0; - } - } - - oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, - id, 0); - if (oldval != 0 && (oldval & FUTEX_OWNER_DIED) == 0) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - return EBUSY; - } - - if (__builtin_expect (mutex->__data.__owner - == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) - { - /* This mutex is now not recoverable. */ - mutex->__data.__count = 0; - if (oldval == id) - lll_unlock (mutex->__data.__lock, - PTHREAD_ROBUST_MUTEX_PSHARED (mutex)); - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - return ENOTRECOVERABLE; - } - } - while ((oldval & FUTEX_OWNER_DIED) != 0); - - ENQUEUE_MUTEX (mutex); - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - mutex->__data.__owner = id; - ++mutex->__data.__nusers; - mutex->__data.__count = 1; - - return 0; - - /* 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: - case PTHREAD_MUTEX_PI_ERRORCHECK_NP: - case PTHREAD_MUTEX_PI_NORMAL_NP: - case PTHREAD_MUTEX_PI_ADAPTIVE_NP: - case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP: - case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP: - case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP: - case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP: - { - int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; - int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP; - - if (robust) - /* 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)); - - oldval = mutex->__data.__lock; - - /* Check whether we already hold the mutex. */ - if (__glibc_unlikely ((oldval & FUTEX_TID_MASK) == id)) - { - if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - return EDEADLK; - } - - if (kind == PTHREAD_MUTEX_RECURSIVE_NP) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - /* Just bump the counter. */ - if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) - /* Overflow of the counter. */ - return EAGAIN; - - ++mutex->__data.__count; - - return 0; - } - } - - oldval - = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, - id, 0); - - if (oldval != 0) - { - if ((oldval & FUTEX_OWNER_DIED) == 0) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - return EBUSY; - } - - assert (robust); - - /* The mutex owner died. The kernel will now take care of - everything. */ - int private = (robust - ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex) - : PTHREAD_MUTEX_PSHARED (mutex)); - INTERNAL_SYSCALL_DECL (__err); - int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, - __lll_private_flag (FUTEX_TRYLOCK_PI, - private), 0, 0); - - if (INTERNAL_SYSCALL_ERROR_P (e, __err) - && INTERNAL_SYSCALL_ERRNO (e, __err) == EWOULDBLOCK) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - return EBUSY; - } - - oldval = mutex->__data.__lock; - } - - if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED)) - { - atomic_and (&mutex->__data.__lock, ~FUTEX_OWNER_DIED); - - /* We got the mutex. */ - mutex->__data.__count = 1; - /* But it is inconsistent unless marked otherwise. */ - mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; - - ENQUEUE_MUTEX (mutex); - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - - /* Note that we deliberately exit here. If we fall - through to the end of the function __nusers would be - incremented which is not correct because the old owner - has to be discounted. */ - return EOWNERDEAD; - } - - if (robust - && __builtin_expect (mutex->__data.__owner - == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) - { - /* This mutex is now not recoverable. */ - mutex->__data.__count = 0; - - INTERNAL_SYSCALL_DECL (__err); - INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, - __lll_private_flag (FUTEX_UNLOCK_PI, - PTHREAD_ROBUST_MUTEX_PSHARED (mutex)), - 0, 0); - - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - return ENOTRECOVERABLE; - } - - if (robust) - { - ENQUEUE_MUTEX_PI (mutex); - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); - } - - mutex->__data.__owner = id; - ++mutex->__data.__nusers; - mutex->__data.__count = 1; - - return 0; - } -#endif /* __NR_futex. */ - - case PTHREAD_MUTEX_PP_RECURSIVE_NP: - case PTHREAD_MUTEX_PP_ERRORCHECK_NP: - case PTHREAD_MUTEX_PP_NORMAL_NP: - case PTHREAD_MUTEX_PP_ADAPTIVE_NP: - { - int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; - - oldval = mutex->__data.__lock; - - /* Check whether we already hold the mutex. */ - if (mutex->__data.__owner == id) - { - if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) - return EDEADLK; - - if (kind == PTHREAD_MUTEX_RECURSIVE_NP) - { - /* Just bump the counter. */ - if (__glibc_unlikely (mutex->__data.__count + 1 == 0)) - /* Overflow of the counter. */ - return EAGAIN; - - ++mutex->__data.__count; - - return 0; - } - } - - int oldprio = -1, ceilval; - do - { - int ceiling = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) - >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT; - - if (__pthread_current_priority () > ceiling) - { - if (oldprio != -1) - __pthread_tpp_change_priority (oldprio, -1); - return EINVAL; - } - - int retval = __pthread_tpp_change_priority (oldprio, ceiling); - if (retval) - return retval; - - ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT; - oldprio = ceiling; - - oldval - = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, - ceilval | 1, ceilval); - - if (oldval == ceilval) - break; - } - while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval); - - if (oldval != ceilval) - { - __pthread_tpp_change_priority (oldprio, -1); - break; - } - - assert (mutex->__data.__owner == 0); - /* Record the ownership. */ - mutex->__data.__owner = id; - ++mutex->__data.__nusers; - mutex->__data.__count = 1; - - return 0; - } - break; - - default: - /* Correct code cannot set any other type. */ - return EINVAL; - } - - return EBUSY; -} - -#ifndef __pthread_mutex_trylock -#ifndef pthread_mutex_trylock -strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock) -#endif -#endif |