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Commit bf32c765 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Convert rnp->lock wrappers to macros for SRCU use 



Use of smp_mb__after_unlock_lock() would allow SRCU to omit a full
memory barrier during callback execution, so this commit converts
raw_spin_lock_rcu_node() from inline functions to type-generic macros
to allow them to handle locks in srcu_node structures as well as
rcu_node structures.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 5f192ab0

kernel/rcu/tree.h

+21 −26
Original line number Diff line number Diff line
@@ -580,27 +580,22 @@ static inline void rcu_nocb_q_lengths(struct rcu_data *rdp, long *ql, long *qll) 
 * As ->lock of struct rcu_node is a __private field, therefore one should use

 * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.

 */

static inline void raw_spin_lock_rcu_node(struct rcu_node *rnp)

{

	raw_spin_lock(&ACCESS_PRIVATE(rnp, lock));

	smp_mb__after_unlock_lock();

}

#define raw_spin_lock_rcu_node(p)					\

do {									\

	raw_spin_lock(&ACCESS_PRIVATE(p, lock));			\

	smp_mb__after_unlock_lock();					\

} while (0)



static inline void raw_spin_unlock_rcu_node(struct rcu_node *rnp)

{

	raw_spin_unlock(&ACCESS_PRIVATE(rnp, lock));

}

#define raw_spin_unlock_rcu_node(p) raw_spin_unlock(&ACCESS_PRIVATE(p, lock))



static inline void raw_spin_lock_irq_rcu_node(struct rcu_node *rnp)

{

	raw_spin_lock_irq(&ACCESS_PRIVATE(rnp, lock));

	smp_mb__after_unlock_lock();

}

#define raw_spin_lock_irq_rcu_node(p)					\

do {									\

	raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock));			\

	smp_mb__after_unlock_lock();					\

} while (0)



static inline void raw_spin_unlock_irq_rcu_node(struct rcu_node *rnp)

{

	raw_spin_unlock_irq(&ACCESS_PRIVATE(rnp, lock));

}

#define raw_spin_unlock_irq_rcu_node(p)					\

	raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock))



#define raw_spin_lock_irqsave_rcu_node(rnp, flags)			\

do {									\
@@ -615,11 +610,11 @@ do { \ 
	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(rnp, lock), flags);	\

} while (0)



static inline bool raw_spin_trylock_rcu_node(struct rcu_node *rnp)

{

	bool locked = raw_spin_trylock(&ACCESS_PRIVATE(rnp, lock));



	if (locked)

		smp_mb__after_unlock_lock();

	return locked;

}
 
#define raw_spin_trylock_rcu_node(p)					\

({									\

	bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock));	\

									\

	if (___locked)							\

		smp_mb__after_unlock_lock();				\

	___locked;							\

})