locking/mutex: Move MCS related comments to proper location

It serves much better if the comments are right before the osq_lock() call.
Also delete a useless comment.

Signed-off-by: Davidlohr Bueso <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: "Paul E. McKenney" <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

kernel/locking/mutex.c

···
 
 
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-/*
- * In order to avoid a stampede of mutex spinners from acquiring the mutex
- * more or less simultaneously, the spinners need to acquire a MCS lock
- * first before spinning on the owner field.
- *
- */
-
-/*
- * Mutex spinning code migrated from kernel/sched/core.c
- */
-
 static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
 {
 	if (lock->owner != owner)
···
 	if (!mutex_can_spin_on_owner(lock))
 		goto done;
 
+	/*
+	 * In order to avoid a stampede of mutex spinners trying to
+	 * acquire the mutex all at once, the spinners need to take a
+	 * MCS (queued) lock first before spinning on the owner field.
+	 */
 	if (!osq_lock(&lock->osq))
 		goto done;