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Subject[PATCH tip/core/rcu 2/2] rcu: eliminate unneeded function wrapping
Date
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

The functions rcu_init() is a wrapper for __rcu_init(), and also sets
up the CPU-hotplug notifier for rcu_barrier_cpu_hotplug(). But TINY_RCU
doesn't need CPU-hotplug notification, and the rcu_barrier_cpu_hotplug()
is a simple wrapper for rcu_cpu_notify(). So push rcu_init() out to
kernel/rcutree.c and kernel/rcutiny.c and get rid of the wrapper function
rcu_barrier_cpu_hotplug().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/rcutiny.h | 2 --
include/linux/rcutree.h | 3 ---
kernel/rcupdate.c | 22 ----------------------
kernel/rcutiny.c | 11 +----------
kernel/rcutree.c | 17 ++++++++++++++---
5 files changed, 15 insertions(+), 40 deletions(-)

diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 2c1fe83..a3b6272 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -38,7 +38,6 @@ void rcu_bh_qs(int cpu);

#define rcu_init_sched() do { } while (0)
extern void rcu_check_callbacks(int cpu, int user);
-extern void __rcu_init(void);

/*
* Return the number of grace periods.
@@ -69,7 +68,6 @@ static inline void synchronize_rcu_bh_expedited(void)
}

struct notifier_block;
-extern int rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu);

#ifdef CONFIG_NO_HZ

diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 9642c6b..111a652 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -34,8 +34,6 @@ struct notifier_block;

extern void rcu_sched_qs(int cpu);
extern void rcu_bh_qs(int cpu);
-extern int rcu_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu);
extern int rcu_needs_cpu(int cpu);
extern int rcu_expedited_torture_stats(char *page);

@@ -83,7 +81,6 @@ static inline void synchronize_rcu_bh_expedited(void)
synchronize_sched_expedited();
}

-extern void __rcu_init(void);
extern void rcu_check_callbacks(int cpu, int user);

extern long rcu_batches_completed(void);
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 7625f20..eb6b534 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -161,28 +161,6 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_bh);

#endif /* #ifndef CONFIG_TINY_RCU */

-static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- return rcu_cpu_notify(self, action, hcpu);
-}
-
-void __init rcu_init(void)
-{
- int i;
-
- __rcu_init();
- cpu_notifier(rcu_barrier_cpu_hotplug, 0);
-
- /*
- * We don't need protection against CPU-hotplug here because
- * this is called early in boot, before either interrupts
- * or the scheduler are operational.
- */
- for_each_online_cpu(i)
- rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i);
-}
-
void rcu_scheduler_starting(void)
{
WARN_ON(num_online_cpus() != 1);
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index b33ec3a..9f6d9ff 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -178,15 +178,6 @@ static void rcu_process_callbacks(struct softirq_action *unused)
}

/*
- * Null function to handle CPU being onlined. Longer term, we want to
- * make TINY_RCU avoid using rcupdate.c, but later...
- */
-int rcu_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
-{
- return NOTIFY_OK;
-}
-
-/*
* Wait for a grace period to elapse. But it is illegal to invoke
* synchronize_sched() from within an RCU read-side critical section.
* Therefore, any legal call to synchronize_sched() is a quiescent
@@ -285,7 +276,7 @@ void rcu_barrier_sched(void)
}
EXPORT_SYMBOL_GPL(rcu_barrier_sched);

-void __rcu_init(void)
+void __init rcu_init(void)
{
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index b79bfcd..e3d3bbd 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1644,8 +1644,8 @@ static void __cpuinit rcu_online_cpu(int cpu)
/*
* Handle CPU online/offline notification events.
*/
-int __cpuinit rcu_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;

@@ -1781,8 +1781,10 @@ do { \
} \
} while (0)

-void __init __rcu_init(void)
+void __init rcu_init(void)
{
+ int i;
+
rcu_bootup_announce();
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
@@ -1791,6 +1793,15 @@ void __init __rcu_init(void)
RCU_INIT_FLAVOR(&rcu_bh_state, rcu_bh_data);
__rcu_init_preempt();
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+
+ /*
+ * We don't need protection against CPU-hotplug here because
+ * this is called early in boot, before either interrupts
+ * or the scheduler are operational.
+ */
+ cpu_notifier(rcu_cpu_notify, 0);
+ for_each_online_cpu(i)
+ rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)i);
}

#include "rcutree_plugin.h"
--
1.5.2.5


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