[PATCH 1/3] alarmtimer: Replace the spinlock rtcdev_lock with mutex

From: Chuansheng Liu
Date: Wed Oct 31 2012 - 03:20:24 EST



When do code reviewing, found no special requirement to
use spin_lock_irqsave/spin_unlock_irqrestore, because
alarmtimer_get_rtcdev() is called by posix clock interface.
So would like to use mutex to replace it.

Signed-off-by: liu chuansheng <chuansheng.liu@xxxxxxxxx>
---
kernel/time/alarmtimer.c | 12 +++++-------
1 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index f11d83b..4fc17cb 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -51,7 +51,7 @@ static struct wakeup_source *ws;
/* rtc timer and device for setting alarm wakeups at suspend */
static struct rtc_timer rtctimer;
static struct rtc_device *rtcdev;
-static DEFINE_SPINLOCK(rtcdev_lock);
+static DEFINE_MUTEX(rtcdev_mutex);

/**
* alarmtimer_get_rtcdev - Return selected rtcdevice
@@ -62,12 +62,11 @@ static DEFINE_SPINLOCK(rtcdev_lock);
*/
struct rtc_device *alarmtimer_get_rtcdev(void)
{
- unsigned long flags;
struct rtc_device *ret;

- spin_lock_irqsave(&rtcdev_lock, flags);
+ mutex_lock(&rtcdev_mutex);
ret = rtcdev;
- spin_unlock_irqrestore(&rtcdev_lock, flags);
+ mutex_unlock(&rtcdev_mutex);

return ret;
}
@@ -76,7 +75,6 @@ struct rtc_device *alarmtimer_get_rtcdev(void)
static int alarmtimer_rtc_add_device(struct device *dev,
struct class_interface *class_intf)
{
- unsigned long flags;
struct rtc_device *rtc = to_rtc_device(dev);

if (rtcdev)
@@ -87,13 +85,13 @@ static int alarmtimer_rtc_add_device(struct device *dev,
if (!device_may_wakeup(rtc->dev.parent))
return -1;

- spin_lock_irqsave(&rtcdev_lock, flags);
+ mutex_lock(&rtcdev_mutex);
if (!rtcdev) {
rtcdev = rtc;
/* hold a reference so it doesn't go away */
get_device(dev);
}
- spin_unlock_irqrestore(&rtcdev_lock, flags);
+ mutex_unlock(&rtcdev_mutex);
return 0;
}

--
1.7.0.4



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