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