[tip:timers/urgent] time: Make settimeofday error checking work again

[tip-bot for John Stultz]

Commit-ID:  dfc2507b26af22b0bbc85251b8545b36d8bc5d72
Gitweb:     http://git.kernel.org/tip/dfc2507b26af22b0bbc85251b8545b36d8bc5d72
Author:     John Stultz <john.stultz@xxxxxxxxxx>
AuthorDate: Wed, 1 Jun 2016 11:53:26 -0700
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 1 Jun 2016 21:13:43 +0200

time: Make settimeofday error checking work again

In commit 86d3473224b0 some of the checking for a valid timeval
was subtley changed which caused -EINVAL to be returned whenever
the timeval was null.

However, it is possible to set the timezone data while specifying
a NULL timeval, which is usually done to handle systems where the
RTC keeps local time instead of UTC. Thus the patch causes such
systems to have the time incorrectly set.

This patch addresses the issue by handling the error conditionals
in the same way as was done previously.

Fixes: 86d3473224b0 "time: Introduce do_sys_settimeofday64()"
Reported-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Tested-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1464807207-16530-2-git-send-email-john.stultz@xxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
 include/linux/timekeeping.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 37dbacf..816b754 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -21,6 +21,9 @@ static inline int do_sys_settimeofday(const struct timespec *tv,
 	struct timespec64 ts64;
 
 	if (!tv)
+		return do_sys_settimeofday64(NULL, tz);
+
+	if (!timespec_valid(tv))
 		return -EINVAL;
 
 	ts64 = timespec_to_timespec64(*tv);