rtc: cdev lock_kernel() pushdown

Signed-off-by: NJonathan Corbet <corbet@lwn.net>

drivers/rtc/rtc-dev.c

@@ -13,6 +13,7 @@
 
 #include <linux/module.h>
 #include <linux/rtc.h>
+#include <linux/smp_lock.h>
 #include "rtc-core.h"
 
 static dev_t rtc_devt;
@@ -26,8 +27,11 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
 					struct rtc_device, char_dev);
 	const struct rtc_class_ops *ops = rtc->ops;
 
-	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
-		return -EBUSY;
+	lock_kernel();
+	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) {
+		err = -EBUSY;
+		goto out;
+	}
 
 	file->private_data = rtc;
 
@@ -37,11 +41,13 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
 		rtc->irq_data = 0;
 		spin_unlock_irq(&rtc->irq_lock);
 
-		return 0;
+		goto out;
 	}
 
 	/* something has gone wrong */
 	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
+out:
+	unlock_kernel();
 	return err;
 }