1// SPDX-License-Identifier: GPL-2.0-only
2#ifndef _LINUX_RWBASE_RT_H
3#define _LINUX_RWBASE_RT_H
4
5#include <linux/rtmutex.h>
6#include <linux/atomic.h>
7
8#define READER_BIAS		(1U << 31)
9#define WRITER_BIAS		(1U << 30)
10
11struct rwbase_rt {
12	atomic_t		readers;
13	struct rt_mutex_base	rtmutex;
14};
15
16#define __RWBASE_INITIALIZER(name)				\
17{								\
18	.readers = ATOMIC_INIT(READER_BIAS),			\
19	.rtmutex = __RT_MUTEX_BASE_INITIALIZER(name.rtmutex),	\
20}
21
22#define init_rwbase_rt(rwbase)					\
23	do {							\
24		rt_mutex_base_init(&(rwbase)->rtmutex);		\
25		atomic_set(&(rwbase)->readers, READER_BIAS);	\
26	} while (0)
27
28
29static __always_inline bool rw_base_is_locked(struct rwbase_rt *rwb)
30{
31	return atomic_read(&rwb->readers) != READER_BIAS;
32}
33
34static __always_inline bool rw_base_is_contended(struct rwbase_rt *rwb)
35{
36	return atomic_read(&rwb->readers) > 0;
37}
38
39#endif /* _LINUX_RWBASE_RT_H */
40