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 <anemo@mba.ocn.ne.jp>
Cc: David Brownell <david-b@pacbell.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 35dcc06eb3e2..f118252f3a9f 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -403,11 +403,14 @@ static long rtc_dev_ioctl(struct file *file,
 
 #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;