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Subject[patch 17/42] rtc_time_to_tm: fix signed/unsigned arithmetic
2.6.26-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Jan Altenberg <jan.altenberg@linutronix.de>

commit 73442daf2ea85e2a779396b76b1a39b10188ecb5 upstream

commit 945185a69daa457c4c5e46e47f4afad7dcea734f ("rtc: rtc_time_to_tm: use
unsigned arithmetic") 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.

Signed-off-by: Jan Altenberg <jan.altenberg@linutronix.de>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/rtc/rtc-lib.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- 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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