linux-kernel - [PATCH] rtc: fix rtc_time64_to

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Message-Id: <20180228215053.17498-1-alexandre.belloni@bootlin.com>
Date:   Wed, 28 Feb 2018 22:50:53 +0100
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     linux-rtc@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Subject: [PATCH] rtc: fix rtc_time64_to_tm for 3477

The current correction for leap years will fail in 3477. 3476-12-31 being
3477-01-00 because this is 366 leap years after 1970 and 3477 isn't a leap
year.

Fix that by looping over until days is positive or zero.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/rtc/rtc-lib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index ad5bb21908e5..4a3c0f3aab14 100644
--- a/drivers/rtc/rtc-lib.c
+++ b/drivers/rtc/rtc-lib.c
@@ -65,7 +65,7 @@ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm)
 	days -= (year - 1970) * 365
 		+ LEAPS_THRU_END_OF(year - 1)
 		- LEAPS_THRU_END_OF(1970 - 1);
-	if (days < 0) {
+	while (days < 0) {
 		year -= 1;
 		days += 365 + is_leap_year(year);
 	}
-- 
2.16.2