[PATCH 2/6] timekeeping: Use syscore_ops instead of sysdev class and sysdev

From: Rafael J. Wysocki
Date: Mon Mar 21 2011 - 19:39:10 EST


From: Rafael J. Wysocki <rjw@xxxxxxx>

The timekeeping subsystem uses a sysdev class and a sysdev for
executing timekeeping_suspend() after interrupts have been turned off
on the boot CPU (during system suspend) and for executing
timekeeping_resume() before turning on interrupts on the boot CPU
(during system resume). However, since both of these functions
ignore their arguments, the entire mechanism may be replaced with a
struct syscore_ops object which is simpler.

Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/timekeeping.c | 27 ++++++++-------------------
1 file changed, 8 insertions(+), 19 deletions(-)

Index: linux-2.6/kernel/time/timekeeping.c
===================================================================
--- linux-2.6.orig/kernel/time/timekeeping.c
+++ linux-2.6/kernel/time/timekeeping.c
@@ -14,7 +14,7 @@
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/sched.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
#include <linux/clocksource.h>
#include <linux/jiffies.h>
#include <linux/time.h>
@@ -597,13 +597,12 @@ static struct timespec timekeeping_suspe

/**
* timekeeping_resume - Resumes the generic timekeeping subsystem.
- * @dev: unused
*
* This is for the generic clocksource timekeeping.
* xtime/wall_to_monotonic/jiffies/etc are
* still managed by arch specific suspend/resume code.
*/
-static int timekeeping_resume(struct sys_device *dev)
+static void timekeeping_resume(void)
{
unsigned long flags;
struct timespec ts;
@@ -632,11 +631,9 @@ static int timekeeping_resume(struct sys

/* Resume hrtimers */
hres_timers_resume();
-
- return 0;
}

-static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
+static int timekeeping_suspend(void)
{
unsigned long flags;

@@ -654,26 +651,18 @@ static int timekeeping_suspend(struct sy
}

/* sysfs resume/suspend bits for timekeeping */
-static struct sysdev_class timekeeping_sysclass = {
- .name = "timekeeping",
+static struct syscore_ops timekeeping_syscore_ops = {
.resume = timekeeping_resume,
.suspend = timekeeping_suspend,
};

-static struct sys_device device_timer = {
- .id = 0,
- .cls = &timekeeping_sysclass,
-};
-
-static int __init timekeeping_init_device(void)
+static int __init timekeeping_init_ops(void)
{
- int error = sysdev_class_register(&timekeeping_sysclass);
- if (!error)
- error = sysdev_register(&device_timer);
- return error;
+ register_syscore_ops(&timekeeping_syscore_ops);
+ return 0;
}

-device_initcall(timekeeping_init_device);
+device_initcall(timekeeping_init_ops);

/*
* If the error is already larger, we look ahead even further

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