64 lines
2.2 KiB
C
64 lines
2.2 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_RWSEM_COMPAT_H
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#define _SPL_RWSEM_COMPAT_H
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#include <linux/rwsem.h>
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#ifdef RWSEM_IS_LOCKED_TAKES_WAIT_LOCK
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/*
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* A race condition in rwsem_is_locked() was fixed in Linux 2.6.33 and the fix
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* was backported to RHEL5 as of kernel 2.6.18-190.el5. Details can be found
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* here:
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*
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* https://bugzilla.redhat.com/show_bug.cgi?id=526092
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* The race condition was fixed in the kernel by acquiring the semaphore's
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* wait_lock inside rwsem_is_locked(). The SPL worked around the race
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* condition by acquiring the wait_lock before calling that function, but
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* with the fix in place we must not do that.
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*/
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#define spl_rwsem_is_locked(rwsem) \
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({ \
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rwsem_is_locked(rwsem); \
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})
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#else
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#define spl_rwsem_is_locked(rwsem) \
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({ \
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unsigned long _flags_; \
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int _rc_; \
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spin_lock_irqsave(&rwsem->wait_lock, _flags_); \
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_rc_ = rwsem_is_locked(rwsem); \
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spin_unlock_irqrestore(&rwsem->wait_lock, _flags_); \
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_rc_; \
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})
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#endif /* RWSEM_IS_LOCKED_TAKES_WAIT_LOCK */
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#endif /* _SPL_RWSEM_COMPAT_H */
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