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Commit 791875d1 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Eliminate the unused __rcu_is_watching() function 



The __rcu_is_watching() function is currently not used, aside from
to implement the rcu_is_watching() function.  This commit therefore
eliminates __rcu_is_watching(), which has the beneficial side-effect
of shrinking include/linux/rcupdate.h a bit.

Reported-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent d0df7a34

include/linux/rcupdate.h

+0 −4
Original line number Diff line number Diff line
@@ -204,10 +204,6 @@ do { \ 
		rcu_note_voluntary_context_switch(current); \

} while (0)



#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP)

bool __rcu_is_watching(void);

#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */



/*

 * Infrastructure to implement the synchronize_() primitives in

 * TREE_RCU and rcu_barrier_() primitives in TINY_RCU.

include/linux/rcutiny.h

+0 −11
Original line number Diff line number Diff line
@@ -232,22 +232,11 @@ static inline void rcu_scheduler_starting(void) 
}

#endif /* #else #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */



#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)



static inline bool rcu_is_watching(void)

{

	return __rcu_is_watching();

}



#else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */



static inline bool rcu_is_watching(void)

{

	return true;

}



#endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */



static inline void rcu_request_urgent_qs_task(struct task_struct *t)

{

}

kernel/rcu/tiny.c

+0 −13
Original line number Diff line number Diff line
@@ -59,19 +59,6 @@ void rcu_barrier_sched(void) 
}

EXPORT_SYMBOL(rcu_barrier_sched);



#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)



/*

 * Test whether RCU thinks that the current CPU is idle.

 */

bool notrace __rcu_is_watching(void)

{

	return true;

}

EXPORT_SYMBOL(__rcu_is_watching);



#endif /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */



/*

 * Helper function for rcu_sched_qs() and rcu_bh_qs().

 * Also irqs are disabled to avoid confusion due to interrupt handlers

kernel/rcu/tree.c

+4 −15
Original line number Diff line number Diff line
@@ -1138,23 +1138,12 @@ void rcu_nmi_exit(void) 
	rcu_dynticks_eqs_enter();

}



/**

 * __rcu_is_watching - are RCU read-side critical sections safe?

 *

 * Return true if RCU is watching the running CPU, which means that

 * this CPU can safely enter RCU read-side critical sections.  Unlike

 * rcu_is_watching(), the caller of __rcu_is_watching() must have at

 * least disabled preemption.

 */

bool notrace __rcu_is_watching(void)

{

	return !rcu_dynticks_curr_cpu_in_eqs();

}



/**

 * rcu_is_watching - see if RCU thinks that the current CPU is idle

 *

 * If the current CPU is in its idle loop and is neither in an interrupt

 * Return true if RCU is watching the running CPU, which means that this

 * CPU can safely enter RCU read-side critical sections.  In other words,

 * if the current CPU is in its idle loop and is neither in an interrupt

 * or NMI handler, return true.

 */

bool notrace rcu_is_watching(void)
@@ -1162,7 +1151,7 @@ bool notrace rcu_is_watching(void) 
	bool ret;



	preempt_disable_notrace();

	ret = __rcu_is_watching();

	ret = !rcu_dynticks_curr_cpu_in_eqs();

	preempt_enable_notrace();

	return ret;

}