Commit 7b0b759b authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: combine duplicate code, courtesy of CONFIG_PREEMPT_RCU 



The CONFIG_PREEMPT_RCU kernel configuration parameter was recently
re-introduced, but as an indication of the type of RCU (preemptible
vs. non-preemptible) instead of as selecting a given implementation.
This commit uses CONFIG_PREEMPT_RCU to combine duplicate code
from include/linux/rcutiny.h and include/linux/rcutree.h into
include/linux/rcupdate.h.  This commit also combines a few other pieces
of duplicate code that have accumulated.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 73d4da4d

include/linux/rcupdate.h

+72 −3
Original line number Diff line number Diff line
@@ -61,16 +61,30 @@ struct rcu_head { 
};



/* Exported common interfaces */

extern void call_rcu_sched(struct rcu_head *head,

			   void (*func)(struct rcu_head *rcu));

extern void synchronize_sched(void);

extern void rcu_barrier_bh(void);

extern void rcu_barrier_sched(void);

extern void synchronize_sched_expedited(void);

extern int sched_expedited_torture_stats(char *page);



/* Internal to kernel */

extern void rcu_init(void);

static inline void __rcu_read_lock_bh(void)

{

	local_bh_disable();

}



static inline void __rcu_read_unlock_bh(void)

{

	local_bh_enable();

}



#ifdef CONFIG_PREEMPT_RCU



extern void __rcu_read_lock(void);

extern void __rcu_read_unlock(void);

void synchronize_rcu(void);



/*

 * Defined as a macro as it is a very low level header included from

 * areas that don't even know about current.  This gives the rcu_read_lock()
@@ -79,7 +93,53 @@ extern void rcu_init(void); 
 */

#define rcu_preempt_depth() (current->rcu_read_lock_nesting)



#endif /* #ifdef CONFIG_PREEMPT_RCU */

#else /* #ifdef CONFIG_PREEMPT_RCU */



static inline void __rcu_read_lock(void)

{

	preempt_disable();

}



static inline void __rcu_read_unlock(void)

{

	preempt_enable();

}



static inline void synchronize_rcu(void)

{

	synchronize_sched();

}



static inline int rcu_preempt_depth(void)

{

	return 0;

}



#endif /* #else #ifdef CONFIG_PREEMPT_RCU */



/* Internal to kernel */

extern void rcu_init(void);

extern void rcu_sched_qs(int cpu);

extern void rcu_bh_qs(int cpu);

extern void rcu_check_callbacks(int cpu, int user);

struct notifier_block;



#ifdef CONFIG_NO_HZ



extern void rcu_enter_nohz(void);

extern void rcu_exit_nohz(void);



#else /* #ifdef CONFIG_NO_HZ */



static inline void rcu_enter_nohz(void)

{

}



static inline void rcu_exit_nohz(void)

{

}



#endif /* #else #ifdef CONFIG_NO_HZ */



#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)

#include <linux/rcutree.h>
@@ -626,6 +686,8 @@ struct rcu_synchronize { 


extern void wakeme_after_rcu(struct rcu_head  *head);



#ifdef CONFIG_PREEMPT_RCU



/**

 * call_rcu() - Queue an RCU callback for invocation after a grace period.

 * @head: structure to be used for queueing the RCU updates.
@@ -642,6 +704,13 @@ extern void wakeme_after_rcu(struct rcu_head *head); 
extern void call_rcu(struct rcu_head *head,

			      void (*func)(struct rcu_head *head));



#else /* #ifdef CONFIG_PREEMPT_RCU */



/* In classic RCU, call_rcu() is just call_rcu_sched(). */

#define	call_rcu	call_rcu_sched



#endif /* #else #ifdef CONFIG_PREEMPT_RCU */



/**

 * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.

 * @head: structure to be used for queueing the RCU updates.

include/linux/rcutiny.h

+0 −51
Original line number Diff line number Diff line
@@ -27,34 +27,10 @@ 


#include <linux/cache.h>



void rcu_sched_qs(int cpu);

void rcu_bh_qs(int cpu);



#ifdef CONFIG_TINY_RCU

#define __rcu_read_lock()	preempt_disable()

#define __rcu_read_unlock()	preempt_enable()

#else /* #ifdef CONFIG_TINY_RCU */

void __rcu_read_lock(void);

void __rcu_read_unlock(void);

#endif /* #else #ifdef CONFIG_TINY_RCU */

#define __rcu_read_lock_bh()	local_bh_disable()

#define __rcu_read_unlock_bh()	local_bh_enable()

extern void call_rcu_sched(struct rcu_head *head,

			   void (*func)(struct rcu_head *rcu));



#define rcu_init_sched()	do { } while (0)



extern void synchronize_sched(void);



#ifdef CONFIG_TINY_RCU



#define call_rcu		call_rcu_sched



static inline void synchronize_rcu(void)

{

	synchronize_sched();

}



static inline void synchronize_rcu_expedited(void)

{

	synchronize_sched();	/* Only one CPU, so pretty fast anyway!!! */
@@ -67,7 +43,6 @@ static inline void rcu_barrier(void) 


#else /* #ifdef CONFIG_TINY_RCU */



void synchronize_rcu(void);

void rcu_barrier(void);

void synchronize_rcu_expedited(void);
@@ -83,25 +58,6 @@ static inline void synchronize_rcu_bh_expedited(void) 
	synchronize_sched();

}



struct notifier_block;



#ifdef CONFIG_NO_HZ



extern void rcu_enter_nohz(void);

extern void rcu_exit_nohz(void);



#else /* #ifdef CONFIG_NO_HZ */



static inline void rcu_enter_nohz(void)

{

}



static inline void rcu_exit_nohz(void)

{

}



#endif /* #else #ifdef CONFIG_NO_HZ */



#ifdef CONFIG_TINY_RCU



static inline void rcu_preempt_note_context_switch(void)
@@ -117,11 +73,6 @@ static inline int rcu_needs_cpu(int cpu) 
	return 0;

}



static inline int rcu_preempt_depth(void)

{

	return 0;

}



#else /* #ifdef CONFIG_TINY_RCU */



void rcu_preempt_note_context_switch(void);
@@ -141,8 +92,6 @@ static inline void rcu_note_context_switch(int cpu) 
	rcu_preempt_note_context_switch();

}



extern void rcu_check_callbacks(int cpu, int user);



/*

 * Return the number of grace periods.

 */

include/linux/rcutree.h

+0 −50
Original line number Diff line number Diff line
@@ -30,59 +30,23 @@ 
#ifndef __LINUX_RCUTREE_H

#define __LINUX_RCUTREE_H



struct notifier_block;



extern void rcu_sched_qs(int cpu);

extern void rcu_bh_qs(int cpu);

extern void rcu_note_context_switch(int cpu);

extern int rcu_needs_cpu(int cpu);

extern void rcu_cpu_stall_reset(void);



#ifdef CONFIG_TREE_PREEMPT_RCU



extern void __rcu_read_lock(void);

extern void __rcu_read_unlock(void);

extern void synchronize_rcu(void);

extern void exit_rcu(void);



#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */



static inline void __rcu_read_lock(void)

{

	preempt_disable();

}



static inline void __rcu_read_unlock(void)

{

	preempt_enable();

}



#define synchronize_rcu synchronize_sched



static inline void exit_rcu(void)

{

}



static inline int rcu_preempt_depth(void)

{

	return 0;

}



#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */



static inline void __rcu_read_lock_bh(void)

{

	local_bh_disable();

}

static inline void __rcu_read_unlock_bh(void)

{

	local_bh_enable();

}



extern void call_rcu_sched(struct rcu_head *head,

			   void (*func)(struct rcu_head *rcu));

extern void synchronize_rcu_bh(void);

extern void synchronize_sched(void);

extern void synchronize_rcu_expedited(void);



static inline void synchronize_rcu_bh_expedited(void)
@@ -92,8 +56,6 @@ static inline void synchronize_rcu_bh_expedited(void) 


extern void rcu_barrier(void);



extern void rcu_check_callbacks(int cpu, int user);



extern long rcu_batches_completed(void);

extern long rcu_batches_completed_bh(void);

extern long rcu_batches_completed_sched(void);
@@ -101,18 +63,6 @@ extern void rcu_force_quiescent_state(void); 
extern void rcu_bh_force_quiescent_state(void);

extern void rcu_sched_force_quiescent_state(void);



#ifdef CONFIG_NO_HZ

void rcu_enter_nohz(void);

void rcu_exit_nohz(void);

#else /* CONFIG_NO_HZ */

static inline void rcu_enter_nohz(void)

{

}

static inline void rcu_exit_nohz(void)

{

}

#endif /* CONFIG_NO_HZ */



/* A context switch is a grace period for RCU-sched and RCU-bh. */

static inline int rcu_blocking_is_gp(void)

{

kernel/rcutree_plugin.h

+0 −9
Original line number Diff line number Diff line
@@ -938,15 +938,6 @@ static void rcu_preempt_process_callbacks(void) 
{

}



/*

 * In classic RCU, call_rcu() is just call_rcu_sched().

 */

void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu))

{

	call_rcu_sched(head, func);

}

EXPORT_SYMBOL_GPL(call_rcu);



/*

 * Wait for an rcu-preempt grace period, but make it happen quickly.

 * But because preemptable RCU does not exist, map to rcu-sched.

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