driver/rtc/class.c: check the error after rtc_read_time()

In rtc_suspend() and rtc_resume(), the error after rtc_read_time() is not
checked.  If rtc device fail to read time, we cannot guarantee the
following process.

Add the verification code for returned rtc_read_time() error.

Signed-off-by: Hyogi Gim <hyogi.gim@lge.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 589351ef75d0..38e26be705be 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -53,6 +53,7 @@ static int rtc_suspend(struct device *dev)
         struct rtc_device       *rtc = to_rtc_device(dev);
         struct rtc_time         tm;
         struct timespec         delta, delta_delta;
+        int err;
 
         if (has_persistent_clock())
                 return 0;
@@ -61,7 +62,12 @@ static int rtc_suspend(struct device *dev)
                 return 0;
 
         /* snapshot the current RTC and system time at suspend*/
-        rtc_read_time(rtc, &tm);
+        err = rtc_read_time(rtc, &tm);
+        if (err < 0) {
+                pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));
+                return 0;
+        }
+
         getnstimeofday(&old_system);
         rtc_tm_to_time(&tm, &old_rtc.tv_sec);
 
@@ -94,6 +100,7 @@ static int rtc_resume(struct device *dev)
         struct rtc_time         tm;
         struct timespec         new_system, new_rtc;
         struct timespec         sleep_time;
+        int err;
 
         if (has_persistent_clock())
                 return 0;
@@ -104,7 +111,12 @@ static int rtc_resume(struct device *dev)
 
         /* snapshot the current rtc and system time at resume */
         getnstimeofday(&new_system);
-        rtc_read_time(rtc, &tm);
+        err = rtc_read_time(rtc, &tm);
+        if (err < 0) {
+                pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));
+                return 0;
+        }
+
         if (rtc_valid_tm(&tm) != 0) {
                 pr_debug("%s:  bogus resume time\n", dev_name(&rtc->dev));
                 return 0;