rtc: test before subtraction on unsigned
authorRoel Kluin <roel.kluin@gmail.com>
Tue, 31 Mar 2009 22:25:00 +0000 (15:25 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 Apr 2009 15:59:26 +0000 (08:59 -0700)
new_alarm is unsigned so test before the subtraction.

[akpm@linux-foundation.org: time-wrapping fix]
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/rtc-ds1374.c

index a5b0fc09f0c673976720b10eca2cc3ecf8ff03bb..4d32e328f6cd6b7bb2e9cf9e72748b6031f30ef6 100644 (file)
@@ -222,16 +222,16 @@ static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
        rtc_tm_to_time(&alarm->time, &new_alarm);
        rtc_tm_to_time(&now, &itime);
 
-       new_alarm -= itime;
-
        /* This can happen due to races, in addition to dates that are
         * truly in the past.  To avoid requiring the caller to check for
         * races, dates in the past are assumed to be in the recent past
         * (i.e. not something that we'd rather the caller know about via
         * an error), and the alarm is set to go off as soon as possible.
         */
-       if (new_alarm <= 0)
+       if (time_before_eq(new_alarm, itime))
                new_alarm = 1;
+       else
+               new_alarm -= itime;
 
        mutex_lock(&ds1374->mutex);