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