diff options
Diffstat (limited to 'spin.c')
| -rw-r--r-- | spin.c | 281 |
1 files changed, 6 insertions, 275 deletions
@@ -38,279 +38,10 @@ #include "implement.h" -static INLINE int -ptw32_spinlock_check_need_init(pthread_spinlock_t *lock) -{ - int result = 0; +#include "ptw32_spinlock_check_need_init.c" +#include "pthread_spin_init.c" +#include "pthread_spin_destroy.c" +#include "pthread_spin_lock.c" +#include "pthread_spin_unlock.c" +#include "pthread_spin_trylock.c" - /* - * The following guarded test is specifically for statically - * initialised spinlocks (via PTHREAD_SPINLOCK_INITIALIZER). - * - * Note that by not providing this synchronisation we risk - * introducing race conditions into applications which are - * correctly written. - */ - EnterCriticalSection(&ptw32_spinlock_test_init_lock); - - /* - * We got here possibly under race - * conditions. Check again inside the critical section - * and only initialise if the spinlock is valid (not been destroyed). - * If a static spinlock has been destroyed, the application can - * re-initialise it only by calling pthread_spin_init() - * explicitly. - */ - if (*lock == PTHREAD_SPINLOCK_INITIALIZER) - { - result = pthread_spin_init(lock, PTHREAD_PROCESS_PRIVATE); - } - else if (*lock == NULL) - { - /* - * The spinlock has been destroyed while we were waiting to - * initialise it, so the operation that caused the - * auto-initialisation should fail. - */ - result = EINVAL; - } - - LeaveCriticalSection(&ptw32_spinlock_test_init_lock); - - return(result); -} - - -int -pthread_spin_init(pthread_spinlock_t *lock, int pshared) -{ - pthread_spinlock_t s; - int cpus = 0; - int result = 0; - - if (lock == NULL) - { - return EINVAL; - } - - if (0 != ptw32_getprocessors(&cpus)) - { - cpus = 1; - } - - if (cpus > 1) - { - if (pshared == PTHREAD_PROCESS_SHARED) - { - /* - * Creating spinlock that can be shared between - * processes. - */ -#if _POSIX_THREAD_PROCESS_SHARED - - /* - * Not implemented yet. - */ - -#error ERROR [__FILE__, line __LINE__]: Process shared spin locks are not supported yet. - -#else - - return ENOSYS; - -#endif /* _POSIX_THREAD_PROCESS_SHARED */ - - } - } - - s = (pthread_spinlock_t) calloc(1, sizeof(*s)); - - if (s == NULL) - { - return ENOMEM; - } - - if (cpus > 1) - { - s->u.cpus = cpus; - s->interlock = PTW32_SPIN_UNLOCKED; - } - else - { - pthread_mutexattr_t ma; - result = pthread_mutexattr_init(&ma); - - if (0 == result) - { - ma->pshared = pshared; - result = pthread_mutex_init(&(s->u.mutex), &ma); - if (0 == result) - { - s->interlock = PTW32_SPIN_USE_MUTEX; - } - } - (void) pthread_mutexattr_destroy(&ma); - } - - if (0 == result) - { - *lock = s; - } - else - { - (void) free(s); - *lock = NULL; - } - - return(result); -} - -int -pthread_spin_destroy(pthread_spinlock_t *lock) -{ - register pthread_spinlock_t s; - - if (lock == NULL || *lock == NULL) - { - return EINVAL; - } - - if ((s = *lock) != PTHREAD_SPINLOCK_INITIALIZER) - { - if (s->interlock == PTW32_SPIN_USE_MUTEX) - { - return pthread_mutex_destroy(&(s->u.mutex)); - } - - if ( (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED == - ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &(s->interlock), - (PTW32_INTERLOCKED_LONG) PTW32_OBJECT_INVALID, - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED)) - { - return 0; - } - - return EINVAL; - } - else - { - int result = 0; - - /* - * See notes in ptw32_spinlock_check_need_init() above also. - */ - EnterCriticalSection(&ptw32_spinlock_test_init_lock); - - /* - * Check again. - */ - if (*lock == PTHREAD_SPINLOCK_INITIALIZER) - { - /* - * This is all we need to do to destroy a statically - * initialised spinlock that has not yet been used (initialised). - * If we get to here, another thread - * waiting to initialise this mutex will get an EINVAL. - */ - *lock = NULL; - } - else - { - /* - * The spinlock has been initialised while we were waiting - * so assume it's in use. - */ - result = EBUSY; - } - - LeaveCriticalSection(&ptw32_spinlock_test_init_lock); - return(result); - } -} - -/* - * NOTE: For speed, these routines don't check if "lock" is valid. - */ -int -pthread_spin_lock(pthread_spinlock_t *lock) -{ - register pthread_spinlock_t s; - - if (*lock == PTHREAD_SPINLOCK_INITIALIZER) - { - int result; - - if ((result = ptw32_spinlock_check_need_init(lock)) != 0) - { - return(result); - } - } - - s = *lock; - - while ( (PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED == - ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &(s->interlock), - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED, - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED) ) - {} - - if (s->interlock == PTW32_SPIN_LOCKED) - { - return 0; - } - else if (s->interlock == PTW32_SPIN_USE_MUTEX) - { - return pthread_mutex_lock(&(s->u.mutex)); - } - - return EINVAL; -} - -int -pthread_spin_unlock(pthread_spinlock_t *lock) -{ - register pthread_spinlock_t s = *lock; - - if (s == PTHREAD_SPINLOCK_INITIALIZER) - { - return EPERM; - } - - switch ((long) ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &(s->interlock), - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED, - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED )) - { - case PTW32_SPIN_LOCKED: return 0; - case PTW32_SPIN_UNLOCKED: return EPERM; - case PTW32_SPIN_USE_MUTEX: return pthread_mutex_unlock(&(s->u.mutex)); - } - - return EINVAL; -} - -int -pthread_spin_trylock(pthread_spinlock_t *lock) -{ - pthread_spinlock_t s = *lock; - - if (s == PTHREAD_SPINLOCK_INITIALIZER) - { - int result; - - if ((result = ptw32_spinlock_check_need_init(lock)) != 0) - { - return(result); - } - } - - switch ((long) ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &(s->interlock), - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED, - (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED )) - { - case PTW32_SPIN_UNLOCKED: return 0; - case PTW32_SPIN_LOCKED: return EBUSY; - case PTW32_SPIN_USE_MUTEX: return pthread_mutex_trylock(&(s->u.mutex)); - } - - return EINVAL; -} |