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Commit a19423b9 authored by Gautham R. Shenoy's avatar Gautham R. Shenoy Committed by Rafael J. Wysocki
Browse files

CPU hotplug: Add lockdep annotations to get/put_online_cpus() 



Add lockdep annotations for get/put_online_cpus() and
cpu_hotplug_begin()/cpu_hotplug_end().

Cc: Ingo Molnar <mingo@kernel.org>
Reviewed-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: default avatarSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent dcb99fd9

kernel/cpu.c

+17 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/mutex.h>

#include <linux/gfp.h>

#include <linux/suspend.h>

#include <linux/lockdep.h>



#include "smpboot.h"
@@ -57,17 +58,30 @@ static struct { 
	 * an ongoing cpu hotplug operation.

	 */

	int refcount;



#ifdef CONFIG_DEBUG_LOCK_ALLOC

	struct lockdep_map dep_map;

#endif

} cpu_hotplug = {

	.active_writer = NULL,

	.lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),

	.refcount = 0,

#ifdef CONFIG_DEBUG_LOCK_ALLOC

	.dep_map = {.name = "cpu_hotplug.lock" },

#endif

};



/* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */

#define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)

#define cpuhp_lock_acquire()      lock_map_acquire(&cpu_hotplug.dep_map)

#define cpuhp_lock_release()      lock_map_release(&cpu_hotplug.dep_map)



void get_online_cpus(void)

{

	might_sleep();

	if (cpu_hotplug.active_writer == current)

		return;

	cpuhp_lock_acquire_read();

	mutex_lock(&cpu_hotplug.lock);

	cpu_hotplug.refcount++;

	mutex_unlock(&cpu_hotplug.lock);
@@ -87,6 +101,7 @@ void put_online_cpus(void) 
	if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))

		wake_up_process(cpu_hotplug.active_writer);

	mutex_unlock(&cpu_hotplug.lock);

	cpuhp_lock_release();



}

EXPORT_SYMBOL_GPL(put_online_cpus);
@@ -117,6 +132,7 @@ void cpu_hotplug_begin(void) 
{

	cpu_hotplug.active_writer = current;



	cpuhp_lock_acquire();

	for (;;) {

		mutex_lock(&cpu_hotplug.lock);

		if (likely(!cpu_hotplug.refcount))
@@ -131,6 +147,7 @@ void cpu_hotplug_done(void) 
{

	cpu_hotplug.active_writer = NULL;

	mutex_unlock(&cpu_hotplug.lock);

	cpuhp_lock_release();

}



/*