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1 /*****************************************************************************\
2 * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
3 * Copyright (C) 2007 The Regents of the University of California.
4 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
5 * Written by Brian Behlendorf <behlendorf1@llnl.gov>.
8 * This file is part of the SPL, Solaris Porting Layer.
9 * For details, see <http://zfsonlinux.org/>.
11 * The SPL is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
16 * The SPL is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 * You should have received a copy of the GNU General Public License along
22 * with the SPL. If not, see <http://www.gnu.org/licenses/>.
23 \*****************************************************************************/
25 #ifndef _SPL_RWSEM_COMPAT_H
26 #define _SPL_RWSEM_COMPAT_H
28 #include <linux/rwsem.h>
30 #if defined(RWSEM_SPINLOCK_IS_RAW)
31 #define spl_rwsem_lock_irqsave(lk, fl) raw_spin_lock_irqsave(lk, fl)
32 #define spl_rwsem_unlock_irqrestore(lk, fl) raw_spin_unlock_irqrestore(lk, fl)
33 #define spl_rwsem_trylock_irqsave(lk, fl) raw_spin_trylock_irqsave(lk, fl)
35 #define spl_rwsem_lock_irqsave(lk, fl) spin_lock_irqsave(lk, fl)
36 #define spl_rwsem_unlock_irqrestore(lk, fl) spin_unlock_irqrestore(lk, fl)
37 #define spl_rwsem_trylock_irqsave(lk, fl) spin_trylock_irqsave(lk, fl)
38 #endif /* RWSEM_SPINLOCK_IS_RAW */
41 * Prior to Linux 2.6.33 there existed a race condition in rwsem_is_locked().
42 * The semaphore's activity was checked outside of the wait_lock which
43 * could result in some readers getting the incorrect activity value.
45 * When a kernel without this fix is detected the SPL takes responsibility
46 * for acquiring the wait_lock to avoid this race.
48 #if defined(RWSEM_IS_LOCKED_TAKES_WAIT_LOCK)
49 #define spl_rwsem_is_locked(rwsem) rwsem_is_locked(rwsem)
52 spl_rwsem_is_locked(struct rw_semaphore
*rwsem
)
57 if (spl_rwsem_trylock_irqsave(&rwsem
->wait_lock
, flags
)) {
58 rc
= rwsem_is_locked(rwsem
);
59 spl_rwsem_unlock_irqrestore(&rwsem
->wait_lock
, flags
);
64 #endif /* RWSEM_IS_LOCKED_TAKES_WAIT_LOCK */
66 #endif /* _SPL_RWSEM_COMPAT_H */