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path: root/drivers/char/ip27-rtc.c
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Diffstat (limited to 'drivers/char/ip27-rtc.c')
-rw-r--r--drivers/char/ip27-rtc.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/char/ip27-rtc.c b/drivers/char/ip27-rtc.c
index 86e6538a77b..ec9d0443d92 100644
--- a/drivers/char/ip27-rtc.c
+++ b/drivers/char/ip27-rtc.c
@@ -27,6 +27,7 @@
#include <linux/bcd.h>
#include <linux/module.h>
#include <linux/kernel.h>
+#include <linux/smp_lock.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
@@ -163,15 +164,18 @@ static long rtc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
static int rtc_open(struct inode *inode, struct file *file)
{
+ lock_kernel();
spin_lock_irq(&rtc_lock);
if (rtc_status & RTC_IS_OPEN) {
spin_unlock_irq(&rtc_lock);
+ unlock_kernel();
return -EBUSY;
}
rtc_status |= RTC_IS_OPEN;
spin_unlock_irq(&rtc_lock);
+ unlock_kernel();
return 0;
}