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716154c592
Updated AUTHORS, COPYING, DISCLAIMER, and INSTALL files. Added standardized headers to all source file to clearly indicate the copyright, license, and to give credit where credit is due.
226 lines
8.7 KiB
C
226 lines
8.7 KiB
C
/*****************************************************************************\
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* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
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* Copyright (C) 2007 The Regents of the University of California.
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* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
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* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
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* UCRL-CODE-235197
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*
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* This file is part of the SPL, Solaris Porting Layer.
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* For details, see <http://github.com/behlendorf/spl/>.
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*
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* The SPL is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* The SPL 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
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with the SPL. If not, see <http://www.gnu.org/licenses/>.
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\*****************************************************************************/
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#ifndef _SPL_MUTEX_H
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#define _SPL_MUTEX_H
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#include <sys/types.h>
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#include <linux/mutex.h>
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typedef enum {
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MUTEX_DEFAULT = 0,
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MUTEX_SPIN = 1,
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MUTEX_ADAPTIVE = 2
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} kmutex_type_t;
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#ifdef HAVE_MUTEX_OWNER
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typedef struct mutex kmutex_t;
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static inline kthread_t *
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mutex_owner(kmutex_t *mp)
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{
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if (mp->owner)
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return (mp->owner)->task;
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return NULL;
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}
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#define mutex_owned(mp) (mutex_owner(mp) == current)
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#define MUTEX_HELD(mp) mutex_owned(mp)
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#undef mutex_init
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#define mutex_init(mp, name, type, ibc) \
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({ \
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static struct lock_class_key __key; \
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ASSERT(type == MUTEX_DEFAULT); \
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\
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__mutex_init((mp), #mp, &__key); \
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})
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#undef mutex_destroy
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#define mutex_destroy(mp) \
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({ \
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VERIFY(!MUTEX_HELD(mp)); \
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})
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#define mutex_tryenter(mp) mutex_trylock(mp)
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#define mutex_enter(mp) mutex_lock(mp)
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#define mutex_exit(mp) mutex_unlock(mp)
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#ifdef HAVE_GPL_ONLY_SYMBOLS
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# define mutex_enter_nested(mp, sc) mutex_lock_nested(mp, sc)
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#else
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# define mutex_enter_nested(mp, sc) mutex_enter(mp)
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#endif /* HAVE_GPL_ONLY_SYMBOLS */
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#else /* HAVE_MUTEX_OWNER */
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typedef struct {
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struct mutex m_mutex;
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kthread_t *m_owner;
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} kmutex_t;
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#ifdef HAVE_TASK_CURR
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extern int spl_mutex_spin_max(void);
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#else /* HAVE_TASK_CURR */
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# define task_curr(owner) 0
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# define spl_mutex_spin_max() 0
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#endif /* HAVE_TASK_CURR */
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#define MUTEX(mp) ((struct mutex *)(mp))
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static inline kthread_t *
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spl_mutex_get_owner(kmutex_t *mp)
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{
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return mp->m_owner;
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}
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static inline void
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spl_mutex_set_owner(kmutex_t *mp)
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{
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unsigned long flags;
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spin_lock_irqsave(&MUTEX(mp)->wait_lock, flags);
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mp->m_owner = current;
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spin_unlock_irqrestore(&MUTEX(mp)->wait_lock, flags);
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}
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static inline void
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spl_mutex_clear_owner(kmutex_t *mp)
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{
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unsigned long flags;
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spin_lock_irqsave(&MUTEX(mp)->wait_lock, flags);
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mp->m_owner = NULL;
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spin_unlock_irqrestore(&MUTEX(mp)->wait_lock, flags);
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}
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static inline kthread_t *
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mutex_owner(kmutex_t *mp)
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{
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unsigned long flags;
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kthread_t *owner;
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spin_lock_irqsave(&MUTEX(mp)->wait_lock, flags);
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owner = spl_mutex_get_owner(mp);
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spin_unlock_irqrestore(&MUTEX(mp)->wait_lock, flags);
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return owner;
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}
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#define mutex_owned(mp) (mutex_owner(mp) == current)
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#define MUTEX_HELD(mp) mutex_owned(mp)
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/*
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* The following functions must be a #define and not static inline.
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* This ensures that the native linux mutex functions (lock/unlock)
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* will be correctly located in the users code which is important
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* for the built in kernel lock analysis tools
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*/
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#undef mutex_init
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#define mutex_init(mp, name, type, ibc) \
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({ \
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static struct lock_class_key __key; \
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ASSERT(type == MUTEX_DEFAULT); \
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\
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__mutex_init(MUTEX(mp), #mp, &__key); \
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spl_mutex_clear_owner(mp); \
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})
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#undef mutex_destroy
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#define mutex_destroy(mp) \
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({ \
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VERIFY(!MUTEX_HELD(mp)); \
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})
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#define mutex_tryenter(mp) \
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({ \
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int _rc_; \
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\
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if ((_rc_ = mutex_trylock(MUTEX(mp))) == 1) \
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spl_mutex_set_owner(mp); \
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\
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_rc_; \
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})
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/*
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* Adaptive mutexs assume that the lock may be held by a task running
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* on a different cpu. The expectation is that the task will drop the
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* lock before leaving the head of the run queue. So the ideal thing
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* to do is spin until we acquire the lock and avoid a context switch.
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* However it is also possible the task holding the lock yields the
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* processor with out dropping lock. In this case, we know it's going
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* to be a while so we stop spinning and go to sleep waiting for the
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* lock to be available. This should strike the optimum balance
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* between spinning and sleeping waiting for a lock.
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*/
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#define mutex_enter(mp) \
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({ \
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kthread_t *_owner_; \
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int _rc_, _count_; \
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\
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_rc_ = 0; \
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_count_ = 0; \
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_owner_ = mutex_owner(mp); \
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\
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while (_owner_ && task_curr(_owner_) && \
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_count_ <= spl_mutex_spin_max()) { \
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if ((_rc_ = mutex_trylock(MUTEX(mp)))) \
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break; \
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\
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_count_++; \
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} \
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\
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if (!_rc_) \
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mutex_lock(MUTEX(mp)); \
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\
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spl_mutex_set_owner(mp); \
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})
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#define mutex_exit(mp) \
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({ \
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spl_mutex_clear_owner(mp); \
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mutex_unlock(MUTEX(mp)); \
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})
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#ifdef HAVE_GPL_ONLY_SYMBOLS
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# define mutex_enter_nested(mp, sc) \
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({ \
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mutex_lock_nested(MUTEX(mp, sc)); \
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spl_mutex_set_owner(mp); \
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})
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#else
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# define mutex_enter_nested(mp, sc) \
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({ \
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mutex_enter(mp); \
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})
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#endif
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#endif /* HAVE_MUTEX_OWNER */
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int spl_mutex_init(void);
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void spl_mutex_fini(void);
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#endif /* _SPL_MUTEX_H */
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