diff options
Diffstat (limited to 'nptl/pthread_mutex_lock.c')
| -rw-r--r-- | nptl/pthread_mutex_lock.c | 333 |
1 files changed, 6 insertions, 327 deletions
diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index 1c3ee4fe25..ee39f20820 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2002,2003,2004,2005,2006,2007 Free Software Foundation, Inc. +/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -19,9 +19,6 @@ #include <assert.h> #include <errno.h> -#include <stdlib.h> -#include <unistd.h> -#include <not-cancel.h> #include "pthreadP.h" #include <lowlevellock.h> @@ -29,7 +26,6 @@ #ifndef LLL_MUTEX_LOCK # define LLL_MUTEX_LOCK(mutex) lll_mutex_lock (mutex) # define LLL_MUTEX_TRYLOCK(mutex) lll_mutex_trylock (mutex) -# define LLL_ROBUST_MUTEX_LOCK(mutex, id) lll_robust_mutex_lock (mutex, id) #endif @@ -39,10 +35,8 @@ __pthread_mutex_lock (mutex) { assert (sizeof (mutex->__size) >= sizeof (mutex->__data)); - int oldval; pid_t id = THREAD_GETMEM (THREAD_SELF, tid); - int retval = 0; switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP)) { /* Recursive mutex. */ @@ -63,23 +57,23 @@ __pthread_mutex_lock (mutex) /* We have to get the mutex. */ LLL_MUTEX_LOCK (mutex->__data.__lock); - assert (mutex->__data.__owner == 0); mutex->__data.__count = 1; break; /* Error checking mutex. */ case PTHREAD_MUTEX_ERRORCHECK_NP: /* Check whether we already hold the mutex. */ - if (__builtin_expect (mutex->__data.__owner == id, 0)) + if (mutex->__data.__owner == id) return EDEADLK; /* FALLTHROUGH */ + default: + /* Correct code cannot set any other type. */ case PTHREAD_MUTEX_TIMED_NP: simple: /* Normal mutex. */ LLL_MUTEX_LOCK (mutex->__data.__lock); - assert (mutex->__data.__owner == 0); break; case PTHREAD_MUTEX_ADAPTIVE_NP: @@ -107,332 +101,17 @@ __pthread_mutex_lock (mutex) mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8; } - assert (mutex->__data.__owner == 0); break; - - 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)) - { - if (mutex->__data.__kind - == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP) - { - THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, - NULL); - return EDEADLK; - } - - if (mutex->__data.__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->__data.__lock, id); - - if (__builtin_expect (mutex->__data.__owner - == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) - { - /* This mutex is now not recoverable. */ - mutex->__data.__count = 0; - lll_mutex_unlock (mutex->__data.__lock); - 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. */ - INTERNAL_SYSCALL_DECL (__err); - int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, - FUTEX_LOCK_PI, 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, - FUTEX_UNLOCK_PI, 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; - } - - 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); - } - 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. */ + assert (mutex->__data.__owner == 0); mutex->__data.__owner = id; #ifndef NO_INCR ++mutex->__data.__nusers; #endif - return retval; + return 0; } #ifndef __pthread_mutex_lock strong_alias (__pthread_mutex_lock, pthread_mutex_lock) |