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Subject[PATCH] rtc_time_to_tm: Fix signed / unsigned arithmetic
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Hi all,

commit 945185a69daa457c4c5e46e47f4afad7dcea734f changed the some types
in rtc_time_to_tm() to unsigned:

void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
{
- register int days, month, year;
+ unsigned int days, month, year;

This doesn't work for all cases, because days is checked for < 0 later
on:

if (days < 0) {
year -= 1;
days += 365 + LEAP_YEAR(year);
}

I think the correct fix would be to keep days signed and do an
appropriate cast later on. See attached patch.

Signed-off-by: Jan Altenberg <jan.altenberg@linutronix.de>

---
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index 9f996ec..dd70bf7 100644
--- a/drivers/rtc/rtc-lib.c
+++ b/drivers/rtc/rtc-lib.c
@@ -51,10 +51,11 @@ EXPORT_SYMBOL(rtc_year_days);
*/
void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
{
- unsigned int days, month, year;
+ unsigned int month, year;
+ int days;

days = time / 86400;
- time -= days * 86400;
+ time -= (unsigned int) days * 86400;

/* day of the week, 1970-01-01 was a Thursday */
tm->tm_wday = (days + 4) % 7;



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