2 files changed, 38 insertions, 13 deletions

diff --git a/kernel/itimer.c b/kernel/itimer.c
index 379be2f8c84c..a2dc375927d8 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -226,6 +226,43 @@ again:
 	return 0;
 }
 
+/**
+ * alarm_setitimer - set alarm in seconds
+ *
+ * @seconds:	number of seconds until alarm
+ *		0 disables the alarm
+ *
+ * Returns the remaining time in seconds of a pending timer or 0 when
+ * the timer is not active.
+ *
+ * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
+ * negative timeval settings which would cause immediate expiry.
+ */
+unsigned int alarm_setitimer(unsigned int seconds)
+{
+	struct itimerval it_new, it_old;
+
+#if BITS_PER_LONG < 64
+	if (seconds > INT_MAX)
+		seconds = INT_MAX;
+#endif
+	it_new.it_value.tv_sec = seconds;
+	it_new.it_value.tv_usec = 0;
+	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
+
+	do_setitimer(ITIMER_REAL, &it_new, &it_old);
+
+	/*
+	 * We can't return 0 if we have an alarm pending ...  And we'd
+	 * better return too much than too little anyway
+	 */
+	if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
+	      it_old.it_value.tv_usec >= 500000)
+		it_old.it_value.tv_sec++;
+
+	return it_old.it_value.tv_sec;
+}
+
 asmlinkage long sys_setitimer(int which,
 			      struct itimerval __user *value,
 			      struct itimerval __user *ovalue)
diff --git a/kernel/timer.c b/kernel/timer.c
index 17d956cebcb9..13fa72cac7d8 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -956,19 +956,7 @@ void do_timer(struct pt_regs *regs)
  */
 asmlinkage unsigned long sys_alarm(unsigned int seconds)
 {
-	struct itimerval it_new, it_old;
-	unsigned int oldalarm;
-
-	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
-	it_new.it_value.tv_sec = seconds;
-	it_new.it_value.tv_usec = 0;
-	do_setitimer(ITIMER_REAL, &it_new, &it_old);
-	oldalarm = it_old.it_value.tv_sec;
-	/* ehhh.. We can't return 0 if we have an alarm pending.. */
-	/* And we'd better return too much than too little anyway */
-	if ((!oldalarm && it_old.it_value.tv_usec) || it_old.it_value.tv_usec >= 500000)
-		oldalarm++;
-	return oldalarm;
+	return alarm_setitimer(seconds);
 }
 
 #endif