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// SPDX-License-Identifier: GPL-2.0-only
#ifndef _LINUX_RWBASE_RT_H
#define _LINUX_RWBASE_RT_H
#include <linux/rtmutex.h>
#include <linux/atomic.h>
#define READER_BIAS (1U << 31)
#define WRITER_BIAS (1U << 30)
struct rwbase_rt {
atomic_t readers;
struct rt_mutex_base rtmutex;
};
#define __RWBASE_INITIALIZER(name) \
{ \
.readers = ATOMIC_INIT(READER_BIAS), \
.rtmutex = __RT_MUTEX_BASE_INITIALIZER(name.rtmutex), \
}
#define init_rwbase_rt(rwbase) \
do { \
rt_mutex_base_init(&(rwbase)->rtmutex); \
atomic_set(&(rwbase)->readers, READER_BIAS); \
} while (0)
static __always_inline bool rw_base_is_locked(const struct rwbase_rt *rwb)
{
return atomic_read(&rwb->readers) != READER_BIAS;
}
static __always_inline bool rw_base_is_write_locked(const struct rwbase_rt *rwb)
{
return atomic_read(&rwb->readers) == WRITER_BIAS;
}
static __always_inline bool rw_base_is_contended(const struct rwbase_rt *rwb)
{
return atomic_read(&rwb->readers) > 0;
}
#endif /* _LINUX_RWBASE_RT_H */
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