s390/stp: Remove leap second support

With moving time steering to userspace, there's no need
to handle leap seconds inside the kernel. Remove it.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

Author: svens-s390

arch/s390/kernel/time.c

@@ -558,81 +558,6 @@ static int stp_sync_clock(void *data)
 	return 0;
 }
 
-static int stp_clear_leap(void)
-{
-	struct __kernel_timex txc;
-	int ret;
-
-	memset(&txc, 0, sizeof(txc));
-
-	ret = do_adjtimex(&txc);
-	if (ret < 0)
-		return ret;
-
-	txc.modes = ADJ_STATUS;
-	txc.status &= ~(STA_INS|STA_DEL);
-	return do_adjtimex(&txc);
-}
-
-static void stp_check_leap(void)
-{
-	struct stp_stzi stzi;
-	struct stp_lsoib *lsoib = &stzi.lsoib;
-	struct __kernel_timex txc;
-	int64_t timediff;
-	int leapdiff, ret;
-
-	if (!stp_info.lu || !check_sync_clock()) {
-		/*
-		 * Either a scheduled leap second was removed by the operator,
-		 * or STP is out of sync. In both cases, clear the leap second
-		 * kernel flags.
-		 */
-		if (stp_clear_leap() < 0)
-			pr_err("failed to clear leap second flags\n");
-		return;
-	}
-
-	if (chsc_stzi(stp_page, &stzi, sizeof(stzi))) {
-		pr_err("stzi failed\n");
-		return;
-	}
-
-	timediff = tod_to_ns(lsoib->nlsout - get_tod_clock()) / NSEC_PER_SEC;
-	leapdiff = lsoib->nlso - lsoib->also;
-
-	if (leapdiff != 1 && leapdiff != -1) {
-		pr_err("Cannot schedule %d leap seconds\n", leapdiff);
-		return;
-	}
-
-	if (timediff < 0) {
-		if (stp_clear_leap() < 0)
-			pr_err("failed to clear leap second flags\n");
-	} else if (timediff < 7200) {
-		memset(&txc, 0, sizeof(txc));
-		ret = do_adjtimex(&txc);
-		if (ret < 0)
-			return;
-
-		txc.modes = ADJ_STATUS;
-		if (leapdiff > 0)
-			txc.status |= STA_INS;
-		else
-			txc.status |= STA_DEL;
-		ret = do_adjtimex(&txc);
-		if (ret < 0)
-			pr_err("failed to set leap second flags\n");
-		/* arm Timer to clear leap second flags */
-		mod_timer(&stp_timer, jiffies + secs_to_jiffies(14400));
-	} else {
-		/* The day the leap second is scheduled for hasn't been reached. Retry
-		 * in one hour.
-		 */
-		mod_timer(&stp_timer, jiffies + secs_to_jiffies(3600));
-	}
-}
-
 /*
  * STP work. Check for the STP state and take over the clock
  * synchronization if the STP clock source is usable.
@@ -674,8 +599,6 @@ static void stp_work_fn(struct work_struct *work)
 		 * Retry after a second.
 		 */
 		mod_timer(&stp_timer, jiffies + msecs_to_jiffies(MSEC_PER_SEC));
-	else if (stp_info.lu)
-		stp_check_leap();
 
 out_unlock:
 	mutex_unlock(&stp_mutex);