1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/rwbase_rt.h b/include/linux/rwbase_rt.h
new file mode 100644
index 000000000000..1d264dd08625
--- /dev/null
+++ b/include/linux/rwbase_rt.h
@@ -0,0 +1,39 @@
+// 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(struct rwbase_rt *rwb)
+{
+	return atomic_read(&rwb->readers) != READER_BIAS;
+}
+
+static __always_inline bool rw_base_is_contended(struct rwbase_rt *rwb)
+{
+	return atomic_read(&rwb->readers) > 0;
+}
+
+#endif /* _LINUX_RWBASE_RT_H */