locking/rtmutex: Provide rt_mutex_base_is_locked()

Provide rt_mutex_base_is_locked(), which will be used for various wrapped
locking primitives for RT.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211302.899572818@linutronix.de

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 8527402..174419e 100644 (file)
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -13,6 +13,7 @@
 #ifndef __LINUX_RT_MUTEX_H
 #define __LINUX_RT_MUTEX_H
 
+#include <linux/compiler.h>
 #include <linux/linkage.h>
 #include <linux/rbtree.h>
 #include <linux/spinlock_types.h>
@@ -32,6 +33,17 @@ struct rt_mutex_base {
        .owner = NULL                                                   \
 }
 
+/**
+ * rt_mutex_base_is_locked - is the rtmutex locked
+ * @lock: the mutex to be queried
+ *
+ * Returns true if the mutex is locked, false if unlocked.
+ */
+static inline bool rt_mutex_base_is_locked(struct rt_mutex_base *lock)
+{
+       return READ_ONCE(lock->owner) != NULL;
+}
+
 extern void rt_mutex_base_init(struct rt_mutex_base *rtb);
 
 /**