mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-27 05:00:15 +00:00
08970190fc
The symbol was moved using scripts/move-symbol-to-libc.py. The __pthread_mutex_trylock@@GLIBC_2.34 symbol version is no longer needed because the call is now internal to libc, so remove it with this commit. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
465 lines
14 KiB
C
465 lines
14 KiB
C
/* Copyright (C) 2002-2021 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include "pthreadP.h"
|
|
#include <lowlevellock.h>
|
|
#include <futex-internal.h>
|
|
|
|
int
|
|
___pthread_mutex_trylock (pthread_mutex_t *mutex)
|
|
{
|
|
int oldval;
|
|
pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
|
|
|
|
/* See concurrency notes regarding mutex type which is loaded from __kind
|
|
in struct __pthread_mutex_s in sysdeps/nptl/bits/thread-shared-types.h. */
|
|
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);
|
|
/* We need to set op_pending before starting the operation. Also
|
|
see comments at ENQUEUE_MUTEX. */
|
|
__asm ("" ::: "memory");
|
|
|
|
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;
|
|
|
|
/* We must not enqueue the mutex before we have acquired it.
|
|
Also see comments at ENQUEUE_MUTEX. */
|
|
__asm ("" ::: "memory");
|
|
ENQUEUE_MUTEX (mutex);
|
|
/* We need to clear op_pending after we enqueue the mutex. */
|
|
__asm ("" ::: "memory");
|
|
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;
|
|
}
|
|
|
|
/* 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)
|
|
{
|
|
/* We do not need to ensure ordering wrt another memory
|
|
access. Also see comments at ENQUEUE_MUTEX. */
|
|
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending,
|
|
NULL);
|
|
return EDEADLK;
|
|
}
|
|
|
|
if (kind == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP)
|
|
{
|
|
/* We do not need to ensure ordering wrt another memory
|
|
access. */
|
|
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)
|
|
{
|
|
/* We haven't acquired the lock as it is already acquired by
|
|
another owner. We do not need to ensure ordering wrt another
|
|
memory access. */
|
|
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));
|
|
/* FIXME This violates the mutex destruction requirements. See
|
|
__pthread_mutex_unlock_full. */
|
|
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
|
|
return ENOTRECOVERABLE;
|
|
}
|
|
}
|
|
while ((oldval & FUTEX_OWNER_DIED) != 0);
|
|
|
|
/* We must not enqueue the mutex before we have acquired it.
|
|
Also see comments at ENQUEUE_MUTEX. */
|
|
__asm ("" ::: "memory");
|
|
ENQUEUE_MUTEX (mutex);
|
|
/* We need to clear op_pending after we enqueue the mutex. */
|
|
__asm ("" ::: "memory");
|
|
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, robust;
|
|
{
|
|
/* See concurrency notes regarding __kind in struct __pthread_mutex_s
|
|
in sysdeps/nptl/bits/thread-shared-types.h. */
|
|
int mutex_kind = atomic_load_relaxed (&(mutex->__data.__kind));
|
|
kind = mutex_kind & PTHREAD_MUTEX_KIND_MASK_NP;
|
|
robust = mutex_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));
|
|
/* We need to set op_pending before starting the operation. Also
|
|
see comments at ENQUEUE_MUTEX. */
|
|
__asm ("" ::: "memory");
|
|
}
|
|
|
|
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)
|
|
{
|
|
/* We do not need to ensure ordering wrt another memory
|
|
access. */
|
|
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
|
|
return EDEADLK;
|
|
}
|
|
|
|
if (kind == PTHREAD_MUTEX_RECURSIVE_NP)
|
|
{
|
|
/* We do not need to ensure ordering wrt another memory
|
|
access. */
|
|
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)
|
|
{
|
|
/* We haven't acquired the lock as it is already acquired by
|
|
another owner. We do not need to ensure ordering wrt another
|
|
memory access. */
|
|
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));
|
|
int e = INTERNAL_SYSCALL_CALL (futex, &mutex->__data.__lock,
|
|
__lll_private_flag (FUTEX_TRYLOCK_PI,
|
|
private), 0, 0);
|
|
|
|
if (INTERNAL_SYSCALL_ERROR_P (e)
|
|
&& INTERNAL_SYSCALL_ERRNO (e) == EWOULDBLOCK)
|
|
{
|
|
/* The kernel has not yet finished the mutex owner death.
|
|
We do not need to ensure ordering wrt another memory
|
|
access. */
|
|
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;
|
|
|
|
/* We must not enqueue the mutex before we have acquired it.
|
|
Also see comments at ENQUEUE_MUTEX. */
|
|
__asm ("" ::: "memory");
|
|
ENQUEUE_MUTEX (mutex);
|
|
/* We need to clear op_pending after we enqueue the mutex. */
|
|
__asm ("" ::: "memory");
|
|
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;
|
|
|
|
futex_unlock_pi ((unsigned int *) &mutex->__data.__lock,
|
|
PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
|
|
|
|
/* To the kernel, this will be visible after the kernel has
|
|
acquired the mutex in the syscall. */
|
|
THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
|
|
return ENOTRECOVERABLE;
|
|
}
|
|
|
|
if (robust)
|
|
{
|
|
/* We must not enqueue the mutex before we have acquired it.
|
|
Also see comments at ENQUEUE_MUTEX. */
|
|
__asm ("" ::: "memory");
|
|
ENQUEUE_MUTEX_PI (mutex);
|
|
/* We need to clear op_pending after we enqueue the mutex. */
|
|
__asm ("" ::: "memory");
|
|
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:
|
|
{
|
|
/* See concurrency notes regarding __kind in struct __pthread_mutex_s
|
|
in sysdeps/nptl/bits/thread-shared-types.h. */
|
|
int kind = atomic_load_relaxed (&(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;
|
|
}
|
|
versioned_symbol (libc, ___pthread_mutex_trylock,
|
|
pthread_mutex_trylock, GLIBC_2_34);
|
|
libc_hidden_ver (___pthread_mutex_trylock, __pthread_mutex_trylock)
|
|
#ifndef SHARED
|
|
strong_alias (___pthread_mutex_trylock, __pthread_mutex_trylock)
|
|
#endif
|
|
|
|
#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_34)
|
|
compat_symbol (libpthread, ___pthread_mutex_trylock,
|
|
pthread_mutex_trylock, GLIBC_2_0);
|
|
compat_symbol (libpthread, ___pthread_mutex_trylock,
|
|
__pthread_mutex_trylock, GLIBC_2_0);
|
|
#endif
|