// SPDX-License-Identifier: GPL-2.0-only
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#ifndef _LINUX_RWSEM_RT_H
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#define _LINUX_RWSEM_RT_H
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#ifndef _LINUX_RWSEM_H
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#error "Include rwsem.h"
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#endif
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#include <linux/rtmutex.h>
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#include <linux/swait.h>
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#define READER_BIAS (1U << 31)
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#define WRITER_BIAS (1U << 30)
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struct rw_semaphore {
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atomic_t readers;
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struct rt_mutex rtmutex;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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};
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#define __RWSEM_INITIALIZER(name) \
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{ \
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.readers = ATOMIC_INIT(READER_BIAS), \
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.rtmutex = __RT_MUTEX_INITIALIZER(name.rtmutex), \
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RW_DEP_MAP_INIT(name) \
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}
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#define DECLARE_RWSEM(lockname) \
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struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
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extern void __rwsem_init(struct rw_semaphore *rwsem, const char *name,
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struct lock_class_key *key);
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#define __init_rwsem(sem, name, key) \
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do { \
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rt_mutex_init(&(sem)->rtmutex); \
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__rwsem_init((sem), (name), (key)); \
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} while (0)
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#define init_rwsem(sem) \
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do { \
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static struct lock_class_key __key; \
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\
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__init_rwsem((sem), #sem, &__key); \
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} while (0)
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static inline int rwsem_is_locked(struct rw_semaphore *sem)
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{
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return atomic_read(&sem->readers) != READER_BIAS;
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}
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static inline int rwsem_is_contended(struct rw_semaphore *sem)
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{
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return atomic_read(&sem->readers) > 0;
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}
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extern void __down_read(struct rw_semaphore *sem);
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extern int __down_read_interruptible(struct rw_semaphore *sem);
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extern int __down_read_killable(struct rw_semaphore *sem);
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extern int __down_read_trylock(struct rw_semaphore *sem);
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extern void __down_write(struct rw_semaphore *sem);
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extern int __must_check __down_write_killable(struct rw_semaphore *sem);
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extern int __down_write_trylock(struct rw_semaphore *sem);
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extern void __up_read(struct rw_semaphore *sem);
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extern void __up_write(struct rw_semaphore *sem);
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extern void __downgrade_write(struct rw_semaphore *sem);
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#endif
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