[RFC][PATCH] sysinfo: Use timespec64 accessors for calculating uptime

[John Stultz <john.stultz@linaro.org>]

As part of the y2038 effort, convert sysinfo's uptime calculation
to use the timespec64 based accessor.

Uptime isn't likely to ever exceed a s32, so this doesn't actually
bring much in the way of change, but it is done for consistency
sake as we deprecate 32bit internal interfaces.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: "vishnu.ps" <vishnu.ps@samsung.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/sys.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index a03d9cd..6d2d700 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2260,12 +2260,16 @@ static int do_sysinfo(struct sysinfo *info)
 {
 	unsigned long mem_total, sav_total;
 	unsigned int mem_unit, bitcount;
-	struct timespec tp;
+	struct timespec64 tp;
 
 	memset(info, 0, sizeof(struct sysinfo));
 
-	get_monotonic_boottime(&tp);
-	info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
+	get_monotonic_boottime64(&tp);
+	/*
+	 * y2038: uptime is unlikely to ever grow beyond an s32
+	 * so this cast to a long shouldn't be an issue.
+	 */
+	info->uptime = (long)tp.tv_sec + (tp.tv_nsec ? 1 : 0);
 
 	get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
 
-- 
1.9.1