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rcu: combine duplicate code, courtesy of CONFIG_PREEMPT_RCU

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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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2010-08-17 14:18:46 -07:00
parent 73d4da4d36
commit 7b0b759b65
4 changed files with 72 additions and 113 deletions
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75
include/linux/rcupdate.h
View File

@ -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.

51
include/linux/rcutiny.h
View File

@ -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.
*/

50
include/linux/rcutree.h
View File

@ -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)
{

9
kernel/rcutree_plugin.h
View File

@ -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.