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/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://zfsonlinux.org/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL 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 General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
\*****************************************************************************/
#ifndef _SPL_RWSEM_COMPAT_H
#define _SPL_RWSEM_COMPAT_H
#include <linux/rwsem.h>
#if defined(RWSEM_SPINLOCK_IS_RAW)
#define spl_rwsem_lock_irqsave(lk, fl) raw_spin_lock_irqsave(lk, fl)
#define spl_rwsem_unlock_irqrestore(lk, fl) raw_spin_unlock_irqrestore(lk, fl)
#define spl_rwsem_trylock_irqsave(lk, fl) raw_spin_trylock_irqsave(lk, fl)
#else
#define spl_rwsem_lock_irqsave(lk, fl) spin_lock_irqsave(lk, fl)
#define spl_rwsem_unlock_irqrestore(lk, fl) spin_unlock_irqrestore(lk, fl)
#define spl_rwsem_trylock_irqsave(lk, fl) spin_trylock_irqsave(lk, fl)
#endif /* RWSEM_SPINLOCK_IS_RAW */
/*
* Prior to Linux 2.6.33 there existed a race condition in rwsem_is_locked().
* The semaphore's activity was checked outside of the wait_lock which
* could result in some readers getting the incorrect activity value.
*
* When a kernel without this fix is detected the SPL takes responsibility
* for acquiring the wait_lock to avoid this race.
*/
#if defined(RWSEM_IS_LOCKED_TAKES_WAIT_LOCK)
#define spl_rwsem_is_locked(rwsem) rwsem_is_locked(rwsem)
#else
static inline int
spl_rwsem_is_locked(struct rw_semaphore *rwsem)
{
unsigned long flags;
int rc = 1;
if (spl_rwsem_trylock_irqsave(&rwsem->wait_lock, flags)) {
rc = rwsem_is_locked(rwsem);
spl_rwsem_unlock_irqrestore(&rwsem->wait_lock, flags);
}
return (rc);
}
#endif /* RWSEM_IS_LOCKED_TAKES_WAIT_LOCK */
#endif /* _SPL_RWSEM_COMPAT_H */
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