locking/mutex: Define mutex_init() once

With CONFIG_PREEMPT_RT disabled __mutex_init() is a function. With
CONFIG_PREEMPT_RT enabled, __mutex_init() is a macro. I assume this is why
mutex_init() is defined twice as exactly the same macro.

Prepare for introducing a new macro for mutex initialization by combining
the two identical mutex_init() definitions into a single definition. This
patch does not change any functionality because the C preprocessor expands
macros when it encounters the macro name and not when a macro definition
is encountered. See also commit bb630f9f7a7d ("locking/rtmutex: Add mutex
variant for RT").

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240912223956.3554086-2-bvanassche@acm.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index a561c629d89f0fb7d1cb16ca867e503c4e2c99c2..ef617089db19921c0638583b4a31c7a6a1bb831c 100644 (file)
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -49,7 +49,6 @@ static inline void mutex_destroy(struct mutex *lock) {}
 
 #endif
 
-#ifndef CONFIG_PREEMPT_RT
 /**
  * mutex_init - initialize the mutex
  * @mutex: the mutex to be initialized
@@ -65,6 +64,7 @@ do {                                                                  \
        __mutex_init((mutex), #mutex, &__key);                          \
 } while (0)
 
+#ifndef CONFIG_PREEMPT_RT
 #define __MUTEX_INITIALIZER(lockname) \
                { .owner = ATOMIC_LONG_INIT(0) \
                , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
@@ -111,12 +111,6 @@ do {                                                       \
        __mutex_rt_init((mutex), name, key);            \
 } while (0)
 
-#define mutex_init(mutex)                              \
-do {                                                   \
-       static struct lock_class_key __key;             \
-                                                       \
-       __mutex_init((mutex), #mutex, &__key);          \
-} while (0)
 #endif /* CONFIG_PREEMPT_RT */
 
 #ifdef CONFIG_DEBUG_MUTEXES