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rtc_time_to_tm: fix signed/unsigned arithmetic

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commit 945185a69d ("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>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Altenberg 2008-09-02 14:36:05 -07:00 committed by Linus Torvalds
parent b4a49b12e8
commit 73442daf2e
1 changed files with 3 additions and 2 deletions
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5
drivers/rtc/rtc-lib.c
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@ -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;