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- /* Copyright (C) 2002-2007, 2008, 2009 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 <unistd.h>
- #include <not-cancel.h>
- #include "pthreadP.h"
- #include <lowlevellock.h>
- #ifndef LLL_MUTEX_LOCK
- # define LLL_MUTEX_LOCK(mutex) \
- lll_lock ((mutex)->__data.__lock, PTHREAD_MUTEX_PSHARED (mutex))
- # define LLL_MUTEX_TRYLOCK(mutex) \
- lll_trylock ((mutex)->__data.__lock)
- # define LLL_ROBUST_MUTEX_LOCK(mutex, id) \
- lll_robust_lock ((mutex)->__data.__lock, id, \
- PTHREAD_ROBUST_MUTEX_PSHARED (mutex))
- #endif
- static int __pthread_mutex_lock_full (pthread_mutex_t *mutex)
- __attribute_noinline__;
- int
- #ifdef NO_INCR
- attribute_hidden internal_function
- #else
- attribute_protected
- #endif
- __pthread_mutex_lock (
- pthread_mutex_t *mutex)
- {
- assert (sizeof (mutex->__size) >= sizeof (mutex->__data));
- unsigned int type = PTHREAD_MUTEX_TYPE (mutex);
- if (__builtin_expect (type & ~PTHREAD_MUTEX_KIND_MASK_NP, 0))
- return __pthread_mutex_lock_full (mutex);
- pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
- if (__builtin_expect (type, PTHREAD_MUTEX_TIMED_NP)
- == PTHREAD_MUTEX_TIMED_NP)
- {
- simple:
- /* Normal mutex. */
- LLL_MUTEX_LOCK (mutex);
- assert (mutex->__data.__owner == 0);
- }
- else if (__builtin_expect (type == PTHREAD_MUTEX_RECURSIVE_NP, 1))
- {
- /* Recursive mutex. */
- /* Check whether we already hold the mutex. */
- if (mutex->__data.__owner == id)
- {
- /* Just bump the counter. */
- if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
- /* Overflow of the counter. */
- return EAGAIN;
- ++mutex->__data.__count;
- return 0;
- }
- /* We have to get the mutex. */
- LLL_MUTEX_LOCK (mutex);
- assert (mutex->__data.__owner == 0);
- mutex->__data.__count = 1;
- }
- else if (__builtin_expect (type == PTHREAD_MUTEX_ADAPTIVE_NP, 1))
- {
- if (! __is_smp)
- goto simple;
- if (LLL_MUTEX_TRYLOCK (mutex) != 0)
- {
- int cnt = 0;
- int max_cnt = MIN (MAX_ADAPTIVE_COUNT,
- mutex->__data.__spins * 2 + 10);
- do
- {
- if (cnt++ >= max_cnt)
- {
- LLL_MUTEX_LOCK (mutex);
- break;
- }
- #ifdef BUSY_WAIT_NOP
- BUSY_WAIT_NOP;
- #endif
- }
- while (LLL_MUTEX_TRYLOCK (mutex) != 0);
- mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8;
- }
- assert (mutex->__data.__owner == 0);
- }
- else
- {
- assert (type == PTHREAD_MUTEX_ERRORCHECK_NP);
- /* Check whether we already hold the mutex. */
- if (__builtin_expect (mutex->__data.__owner == id, 0))
- return EDEADLK;
- goto simple;
- }
- /* Record the ownership. */
- mutex->__data.__owner = id;
- #ifndef NO_INCR
- ++mutex->__data.__nusers;
- #endif
- return 0;
- }
- static int
- __pthread_mutex_lock_full (pthread_mutex_t *mutex)
- {
- int oldval;
- pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
- switch (PTHREAD_MUTEX_TYPE (mutex))
- {
- 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;
- #ifdef NO_INCR
- newval |= FUTEX_WAITERS;
- #else
- newval |= (oldval & FUTEX_WAITERS);
- #endif
- 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 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. If we are not supposed
- to increment __nusers we actually have to decrement
- it here. */
- #ifdef NO_INCR
- --mutex->__data.__nusers;
- #endif
- return EOWNERDEAD;
- }
- /* Check whether we already hold the mutex. */
- if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0))
- {
- 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 (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
- /* Overflow of the counter. */
- return EAGAIN;
- ++mutex->__data.__count;
- return 0;
- }
- }
- oldval = LLL_ROBUST_MUTEX_LOCK (mutex, id);
- if (__builtin_expect (mutex->__data.__owner
- == PTHREAD_MUTEX_NOTRECOVERABLE, 0))
- {
- /* This mutex is now not recoverable. */
- mutex->__data.__count = 0;
- 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);
- mutex->__data.__count = 1;
- ENQUEUE_MUTEX (mutex);
- THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
- break;
- 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 (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0))
- {
- 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 (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
- /* Overflow of the counter. */
- return EAGAIN;
- ++mutex->__data.__count;
- return 0;
- }
- }
- int newval = id;
- #ifdef NO_INCR
- newval |= FUTEX_WAITERS;
- #endif
- oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
- newval, 0);
- if (oldval != 0)
- {
- /* The mutex is locked. 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_LOCK_PI,
- private), 1, 0);
- if (INTERNAL_SYSCALL_ERROR_P (e, __err)
- && (INTERNAL_SYSCALL_ERRNO (e, __err) == ESRCH
- || INTERNAL_SYSCALL_ERRNO (e, __err) == EDEADLK))
- {
- assert (INTERNAL_SYSCALL_ERRNO (e, __err) != EDEADLK
- || (kind != PTHREAD_MUTEX_ERRORCHECK_NP
- && kind != PTHREAD_MUTEX_RECURSIVE_NP));
- /* ESRCH can happen only for non-robust PI mutexes where
- the owner of the lock died. */
- assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust);
- /* Delay the thread indefinitely. */
- while (1)
- pause_not_cancel ();
- }
- oldval = mutex->__data.__lock;
- assert (robust || (oldval & FUTEX_OWNER_DIED) == 0);
- }
- if (__builtin_expect (oldval & FUTEX_OWNER_DIED, 0))
- {
- 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_PI (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. If we are not supposed to
- increment __nusers we actually have to decrement it here. */
- #ifdef NO_INCR
- --mutex->__data.__nusers;
- #endif
- 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;
- }
- mutex->__data.__count = 1;
- if (robust)
- {
- ENQUEUE_MUTEX_PI (mutex);
- THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL);
- }
- }
- break;
- 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 (__builtin_expect (mutex->__data.__count + 1 == 0, 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,
- #ifdef NO_INCR
- ceilval | 2,
- #else
- ceilval | 1,
- #endif
- 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,
- PTHREAD_MUTEX_PSHARED (mutex));
- }
- while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock,
- ceilval | 2, ceilval)
- != ceilval);
- }
- while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval);
- assert (mutex->__data.__owner == 0);
- mutex->__data.__count = 1;
- }
- break;
- default:
- /* Correct code cannot set any other type. */
- return EINVAL;
- }
- /* Record the ownership. */
- mutex->__data.__owner = id;
- #ifndef NO_INCR
- ++mutex->__data.__nusers;
- #endif
- return 0;
- }
- #ifndef __pthread_mutex_lock
- strong_alias (__pthread_mutex_lock, pthread_mutex_lock)
- strong_alias (__pthread_mutex_lock, __pthread_mutex_lock_internal)
- #endif
- #ifdef NO_INCR
- void
- attribute_hidden internal_function
- __pthread_mutex_cond_lock_adjust (
- pthread_mutex_t *mutex)
- {
- assert ((mutex->__data.__kind & PTHREAD_MUTEX_PRIO_INHERIT_NP) != 0);
- assert ((mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP) == 0);
- assert ((mutex->__data.__kind & PTHREAD_MUTEX_PSHARED_BIT) == 0);
- /* Record the ownership. */
- pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
- mutex->__data.__owner = id;
- if (mutex->__data.__kind == PTHREAD_MUTEX_PI_RECURSIVE_NP)
- ++mutex->__data.__count;
- }
- #endif
|