rtc: fix double lock on UIE emulation

With commit 5ad31a575157147b43fa84ef1e21471661653878 ("rtc: remove BKL
for ioctl()"), RTC_UIE_ON ioctl cause double lock on rtc->ops_lock.
The ops_lock must not be held while set_uie() calls rtc_read_time()
which takes the lock. Also clear_uie() does not need ops_lock. This
patch fixes return value of RTC_UIE_OFF ioctl too.

Signed-off-by: Atsushi Nemoto <[e-mail]>
Cc: David Brownell <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Alessandro Zummo <[e-mail]>
Cc: "Rafael J. Wysocki" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/rtc/rtc-dev.c

···
 
 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
 	case RTC_UIE_OFF:
+		mutex_unlock(&rtc->ops_lock);
 		clear_uie(rtc);
-		break;
+		return 0;
 
 	case RTC_UIE_ON:
+		mutex_unlock(&rtc->ops_lock);
 		err = set_uie(rtc);
+		return err;
 #endif
 	default:
 		err = -ENOTTY;