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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2005-2020 Junjiro R. Okajima
*
* This program, aufs 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* simple read-write semaphore wrappers
*/
#ifndef __AUFS_RWSEM_H__
#define __AUFS_RWSEM_H__
#ifdef __KERNEL__
#include "debug.h"
/* in the future, the name 'au_rwsem' will be totally gone */
#define au_rwsem rw_semaphore
/* to debug easier, do not make them inlined functions */
#define AuRwMustNoWaiters(rw) AuDebugOn(rwsem_is_contended(rw))
/* rwsem_is_locked() is unusable */
#define AuRwMustReadLock(rw) AuDebugOn(!lockdep_recursing(current) \
&& debug_locks \
&& !lockdep_is_held_type(rw, 1))
#define AuRwMustWriteLock(rw) AuDebugOn(!lockdep_recursing(current) \
&& debug_locks \
&& !lockdep_is_held_type(rw, 0))
#define AuRwMustAnyLock(rw) AuDebugOn(!lockdep_recursing(current) \
&& debug_locks \
&& !lockdep_is_held(rw))
#define AuRwDestroy(rw) AuDebugOn(!lockdep_recursing(current) \
&& debug_locks \
&& lockdep_is_held(rw))
#define au_rw_init(rw) init_rwsem(rw)
#define au_rw_init_wlock(rw) do { \
au_rw_init(rw); \
down_write(rw); \
} while (0)
#define au_rw_init_wlock_nested(rw, lsc) do { \
au_rw_init(rw); \
down_write_nested(rw, lsc); \
} while (0)
#define au_rw_read_lock(rw) down_read(rw)
#define au_rw_read_lock_nested(rw, lsc) down_read_nested(rw, lsc)
#define au_rw_read_unlock(rw) up_read(rw)
#define au_rw_dgrade_lock(rw) downgrade_write(rw)
#define au_rw_write_lock(rw) down_write(rw)
#define au_rw_write_lock_nested(rw, lsc) down_write_nested(rw, lsc)
#define au_rw_write_unlock(rw) up_write(rw)
/* why is not _nested version defined? */
#define au_rw_read_trylock(rw) down_read_trylock(rw)
#define au_rw_write_trylock(rw) down_write_trylock(rw)
#endif /* __KERNEL__ */
#endif /* __AUFS_RWSEM_H__ */
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