101 lines
2.0 KiB
C
101 lines
2.0 KiB
C
/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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/**
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* @file spinlock.c - Spinlock operations for the SkySQL Gateway
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*
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* @verbatim
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* Revision History
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*
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* Date Who Description
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* 10/06/13 Mark Riddoch Initial implementation
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*
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* @endverbatim
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*/
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#include <spinlock.h>
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#include <atomic.h>
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/**
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* Initialise a spinlock.
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*
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* @param lock The spinlock to initialise.
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*/
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void
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spinlock_init(SPINLOCK *lock)
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{
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lock->lock = 0;
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#ifdef DEBUG
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lock->spins = 0;
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lock->acquired = 0;
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#endif
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}
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/**
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* Acquire a spinlock.
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*
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* @param lock The spinlock to acquire
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*/
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void
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spinlock_acquire(SPINLOCK *lock)
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{
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while (atomic_add(&(lock->lock), 1) != 0)
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{
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atomic_add(&(lock->lock), -1);
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#ifdef DEBUG
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atomic_add(&(lock->spins), 1);
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#endif
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}
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#ifdef DEBUG
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lock->acquired++;
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lock->owner = THREAD_SHELF();
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#endif
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}
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/**
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* Acquire a spinlock if it is not already locked.
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*
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* @param lock The spinlock to acquire
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* @return True ifthe spinlock was acquired, otherwise false
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*/
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int
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spinlock_acquire_nowait(SPINLOCK *lock)
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{
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if (atomic_add(&(lock->lock), 1) != 0)
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{
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atomic_add(&(lock->lock), -1);
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return FALSE;
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}
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#ifdef DEBUG
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lock->acquired++;
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lock->owner = THREAD_SHELF();
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#endif
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return TRUE;
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}
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/*
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* Release a spinlock.
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*
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* @param lock The spinlock to release
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*/
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void
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spinlock_release(SPINLOCK *lock)
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{
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atomic_add(&(lock->lock), -1);
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}
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