locking/rwsem: Remove rwsem_wake() wakeup optimization

	lockevent_cond_inc(rwsem_opt_fail, !taken);

	return taken;

}

/*

 * Return true if the rwsem has active spinner

 */

static inline bool rwsem_has_spinner(struct rw_semaphore *sem)

{

	return osq_is_locked(&sem->osq);

}

#else

static bool rwsem_optimistic_spin(struct rw_semaphore *sem)

{

	return false;

}

static inline bool rwsem_has_spinner(struct rw_semaphore *sem)

{

	return false;

}

#endif

/*

	unsigned long flags;

	DEFINE_WAKE_Q(wake_q);

	/*

	* __rwsem_down_write_failed_common(sem)

	*   rwsem_optimistic_spin(sem)

	*     osq_unlock(sem->osq)

	*   ...

	*   atomic_long_add_return(&sem->count)

	*

	*      - VS -

	*

	*              __up_write()

	*                if (atomic_long_sub_return_release(&sem->count) < 0)

	*                  rwsem_wake(sem)

	*                    osq_is_locked(&sem->osq)

	*

	* And __up_write() must observe !osq_is_locked() when it observes the

	* atomic_long_add_return() in order to not miss a wakeup.

	*

	* This boils down to:

	*

	* [S.rel] X = 1                [RmW] r0 = (Y += 0)

	*         MB                         RMB

	* [RmW]   Y += 1               [L]   r1 = X

	*

	* exists (r0=1 /\ r1=0)

	*/

	smp_rmb();

	/*

	 * If a spinner is present, it is not necessary to do the wakeup.

	 * Try to do wakeup only if the trylock succeeds to minimize

	 * spinlock contention which may introduce too much delay in the

	 * unlock operation.

	 *

	 *    spinning writer		up_write/up_read caller

	 *    ---------------		-----------------------

	 * [S]   osq_unlock()		[L]   osq

	 *	 MB			      RMB

	 * [RmW] rwsem_try_write_lock() [RmW] spin_trylock(wait_lock)

	 *

	 * Here, it is important to make sure that there won't be a missed

	 * wakeup while the rwsem is free and the only spinning writer goes

	 * to sleep without taking the rwsem. Even when the spinning writer

	 * is just going to break out of the waiting loop, it will still do

	 * a trylock in rwsem_down_write_failed() before sleeping. IOW, if

	 * rwsem_has_spinner() is true, it will guarantee at least one

	 * trylock attempt on the rwsem later on.

	 */

	if (rwsem_has_spinner(sem)) {

		/*

		 * The smp_rmb() here is to make sure that the spinner

		 * state is consulted before reading the wait_lock.

		 */

		smp_rmb();

		if (!raw_spin_trylock_irqsave(&sem->wait_lock, flags))

			return sem;

		goto locked;

	}

	raw_spin_lock_irqsave(&sem->wait_lock, flags);

locked:

	if (!list_empty(&sem->wait_list))

		__rwsem_mark_wake(sem, RWSEM_WAKE_ANY, &wake_q);