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Subject[PATCH 10/12] rtc/lib: Provide y2038 safe rtc_tm_to_time()/rtc_time_to_tm() replacement
Date
From: "pang.xunlei" <pang.xunlei@linaro.org>

As part of addressing "y2038 problem" for in-kernel uses, this patch
adds safe rtc_tm_to_time64()/rtc_time64_to_tm() respectively using
time64_t.

After this patch, rtc_tm_to_time() is deprecated and all its call
sites will be fixed using corresponding safe versions, it can be
removed when having no users. Also change rtc_tm_to_time64() to
return time64_t directly instead of just as a parameter like
rtc_tm_to_time() does.

After this patch, rtc_time_to_tm() is deprecated and all its call
sites will be fixed using corresponding safe versions, it can be
removed when having no users.

In addition, change rtc_tm_to_ktime() and rtc_ktime_to_tm() to use
the safe version in passing.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnd Bergmann <arnd.bergmann@linaro.org>
Cc: pang.xunlei <pang.xunlei@linaro.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: pang.xunlei <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/rtc/rtc-lib.c | 38 ++++++++++++++++++++------------------
include/linux/rtc.h | 21 +++++++++++++++++++--
2 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index c4cf057..e6bfb9c 100644
--- a/drivers/rtc/rtc-lib.c
+++ b/drivers/rtc/rtc-lib.c
@@ -45,16 +45,20 @@ int rtc_year_days(unsigned int day, unsigned int month, unsigned int year)
}
EXPORT_SYMBOL(rtc_year_days);

+
/*
+ * rtc_time_to_tm64 - Converts time64_t to rtc_time.
* Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
*/
-void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
+void rtc_time64_to_tm(time64_t time, struct rtc_time *tm)
{
unsigned int month, year;
+ unsigned long secs;
int days;

- days = time / 86400;
- time -= (unsigned int) days * 86400;
+ /* time must be positive */
+ days = div_s64(time, 86400);
+ secs = time - (unsigned int) days * 86400;

/* day of the week, 1970-01-01 was a Thursday */
tm->tm_wday = (days + 4) % 7;
@@ -81,14 +85,14 @@ void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
tm->tm_mon = month;
tm->tm_mday = days + 1;

- tm->tm_hour = time / 3600;
- time -= tm->tm_hour * 3600;
- tm->tm_min = time / 60;
- tm->tm_sec = time - tm->tm_min * 60;
+ tm->tm_hour = secs / 3600;
+ secs -= tm->tm_hour * 3600;
+ tm->tm_min = secs / 60;
+ tm->tm_sec = secs - tm->tm_min * 60;

tm->tm_isdst = 0;
}
-EXPORT_SYMBOL(rtc_time_to_tm);
+EXPORT_SYMBOL(rtc_time64_to_tm);

/*
* Does the rtc_time represent a valid date/time?
@@ -109,24 +113,22 @@ int rtc_valid_tm(struct rtc_time *tm)
EXPORT_SYMBOL(rtc_valid_tm);

/*
+ * rtc_tm_to_time64 - Converts rtc_time to time64_t.
* Convert Gregorian date to seconds since 01-01-1970 00:00:00.
*/
-int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
+time64_t rtc_tm_to_time64(struct rtc_time *tm)
{
- *time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
+ return mktime64(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
- return 0;
}
-EXPORT_SYMBOL(rtc_tm_to_time);
+EXPORT_SYMBOL(rtc_tm_to_time64);

/*
* Convert rtc_time to ktime
*/
ktime_t rtc_tm_to_ktime(struct rtc_time tm)
{
- time_t time;
- rtc_tm_to_time(&tm, &time);
- return ktime_set(time, 0);
+ return ktime_set(rtc_tm_to_time64(&tm), 0);
}
EXPORT_SYMBOL_GPL(rtc_tm_to_ktime);

@@ -135,14 +137,14 @@ EXPORT_SYMBOL_GPL(rtc_tm_to_ktime);
*/
struct rtc_time rtc_ktime_to_tm(ktime_t kt)
{
- struct timespec ts;
+ struct timespec64 ts;
struct rtc_time ret;

- ts = ktime_to_timespec(kt);
+ ts = ktime_to_timespec64(kt);
/* Round up any ns */
if (ts.tv_nsec)
ts.tv_sec++;
- rtc_time_to_tm(ts.tv_sec, &ret);
+ rtc_time64_to_tm(ts.tv_sec, &ret);
return ret;
}
EXPORT_SYMBOL_GPL(rtc_ktime_to_tm);
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index c2c2897..6d6be09 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -19,11 +19,28 @@
extern int rtc_month_days(unsigned int month, unsigned int year);
extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
extern int rtc_valid_tm(struct rtc_time *tm);
-extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time);
-extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
+extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
+extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
ktime_t rtc_tm_to_ktime(struct rtc_time tm);
struct rtc_time rtc_ktime_to_tm(ktime_t kt);

+/**
+ * Deprecated. Use rtc_time64_to_tm().
+ */
+static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
+{
+ rtc_time64_to_tm(time, tm);
+}
+
+/**
+ * Deprecated. Use rtc_tm_to_time64().
+ */
+static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
+{
+ *time = rtc_tm_to_time64(tm);
+
+ return 0;
+}

#include <linux/device.h>
#include <linux/seq_file.h>
--
1.9.1


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