[RFC PATCH v2 2/9] time: Provide y2106 safe get_seconds() replacement

[Xunlei Pang <xlpang@126.com>]

From: Xunlei Pang <pang.xunlei@linaro.org>

As part of addressing "y2038 problem" for in-kernel uses, this
patch adds safe get_seconds64() using time64_t.

After this patch, get_seconds() is deprecated and all its call sites
will be fixed using get_seconds64(), after that it can be removed.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
---
 include/linux/timekeeping.h | 10 +++++++++-
 kernel/time/timekeeping.c   |  4 ++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 9b63d13..384d101 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -17,7 +17,7 @@ extern int do_sys_settimeofday(const struct timespec *tv,
 /*
  * Kernel time accessors
  */
-unsigned long get_seconds(void);
+extern time64_t get_seconds64(void);
 struct timespec current_kernel_time(void);
 /* does not take xtime_lock */
 struct timespec __current_kernel_time(void);
@@ -34,6 +34,14 @@ extern time64_t ktime_get_real_seconds(void);
 extern int __getnstimeofday64(struct timespec64 *tv);
 extern void getnstimeofday64(struct timespec64 *tv);
 
+/**
+ * Deprecated. Use get_seconds64().
+ */
+static inline unsigned long get_seconds(void)
+{
+	return (unsigned long)get_seconds64();
+}
+
 #if BITS_PER_LONG == 64
 /**
  * Deprecated. Use do_settimeofday64().
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 6a93185..ab021a3 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1678,13 +1678,13 @@ void getboottime(struct timespec *ts)
 }
 EXPORT_SYMBOL_GPL(getboottime);
 
-unsigned long get_seconds(void)
+time64_t get_seconds64(void)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 
 	return tk->xtime_sec;
 }
-EXPORT_SYMBOL(get_seconds);
+EXPORT_SYMBOL(get_seconds64);
 
 struct timespec __current_kernel_time(void)
 {
-- 
1.9.1