projects / mirror_spl.git / blame
| Commit | Line | Data |
|---|---|---|
| 46aa7b39 NB |
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>. | |
| 6 | * UCRL-CODE-235197 | |
| 7 | * | |
| 8 | * This file is part of the SPL, Solaris Porting Layer. | |
| 3d6af2dd | 9 | * For details, see <http://zfsonlinux.org/>. |
| 46aa7b39 NB |
10 | * |
| 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. | |
| 15 | * | |
| 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 | |
| 19 | * for more details. | |
| 20 | * | |
| 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 | \*****************************************************************************/ | |
| 24 | ||
| 25 | #ifndef _SPL_RWSEM_COMPAT_H | |
| 26 | #define _SPL_RWSEM_COMPAT_H | |
| 27 | ||
| 28 | #include <linux/rwsem.h> | |
| 29 | ||
| d503b971 BB |
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) | |
| 588d9004 | 34 | #else |
| d503b971 BB |
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) | |
| 588d9004 DH |
38 | #endif /* RWSEM_SPINLOCK_IS_RAW */ |
| 39 | ||
| 46aa7b39 | 40 | /* |
| d503b971 BB |
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. | |
| 46aa7b39 | 44 | * |
| d503b971 BB |
45 | * When a kernel without this fix is detected the SPL takes responsibility |
| 46 | * for acquiring the wait_lock to avoid this race. | |
| 46aa7b39 | 47 | */ |
| d503b971 BB |
48 | #if defined(RWSEM_IS_LOCKED_TAKES_WAIT_LOCK) |
| 49 | #define spl_rwsem_is_locked(rwsem) rwsem_is_locked(rwsem) | |
| 46aa7b39 | 50 | #else |
| d503b971 BB |
51 | static inline int |
| 52 | spl_rwsem_is_locked(struct rw_semaphore *rwsem) | |
| 53 | { | |
| 54 | unsigned long flags; | |
| 55 | int rc = 1; | |
| 46aa7b39 | 56 | |
| d503b971 BB |
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); | |
| 60 | } | |
| 46aa7b39 | 61 | |
| d503b971 BB |
62 | return (rc); |
| 63 | } | |
| 46aa7b39 NB |
64 | #endif /* RWSEM_IS_LOCKED_TAKES_WAIT_LOCK */ |
| 65 | ||
| 66 | #endif /* _SPL_RWSEM_COMPAT_H */ |