[PATCH 3.11 038/121] timekeeping: Fix lost updates to tai adjustment

[Luis Henriques]

3.11.10.5 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: John Stultz <john.stultz at linaro.org>

commit f55c07607a38f84b5c7e6066ee1cfe433fa5643c upstream.

Since 48cdc135d4840 (Implement a shadow timekeeper), we have to
call timekeeping_update() after any adjustment to the timekeeping
structure in order to make sure that any adjustments to the structure
persist.

Unfortunately, the updates to the tai offset via adjtimex do not
trigger this update, causing adjustments to the tai offset to be
made and then over-written by the previous value at the next
update_wall_time() call.

This patch resovles the issue by calling timekeeping_update()
right after setting the tai offset.

Cc: Sasha Levin <sasha.levin at oracle.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Prarit Bhargava <prarit at redhat.com>
Cc: Richard Cochran <richardcochran at gmail.com>
Cc: Ingo Molnar <mingo at kernel.org>
Signed-off-by: John Stultz <john.stultz at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 kernel/time/timekeeping.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5cf6c70..22f3ae2 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -610,6 +610,7 @@ void timekeeping_set_tai_offset(s32 tai_offset)
 	raw_spin_lock_irqsave(&timekeeper_lock, flags);
 	write_seqcount_begin(&timekeeper_seq);
 	__timekeeping_set_tai_offset(tk, tai_offset);
+	timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
 	write_seqcount_end(&timekeeper_seq);
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 	clock_was_set();
@@ -1697,7 +1698,7 @@ int do_adjtimex(struct timex *txc)
 
 	if (tai != orig_tai) {
 		__timekeeping_set_tai_offset(tk, tai);
-		update_pvclock_gtod(tk, true);
+		timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
 		clock_was_set_delayed();
 	}
 	write_seqcount_end(&timekeeper_seq);
-- 
1.9.0