From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753356AbaABWYr (ORCPT ); Thu, 2 Jan 2014 17:24:47 -0500 Received: from mail-pa0-f49.google.com ([209.85.220.49]:61735 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752896AbaABWXj (ORCPT ); Thu, 2 Jan 2014 17:23:39 -0500 From: John Stultz To: LKML Cc: John Stultz , Sasha Levin , Thomas Gleixner , Prarit Bhargava , Richard Cochran , Ingo Molnar , stable Subject: [PATCH 5/9] timekeeping: Fix CLOCK_TAI timer/nanosleep delays Date: Thu, 2 Jan 2014 14:23:23 -0800 Message-Id: <1388701407-5029-5-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1388701407-5029-1-git-send-email-john.stultz@linaro.org> References: <52C5E6A0.7010507@linaro.org> <1388701407-5029-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A think-o in the calculation of the monotonic -> tai time offset results in CLOCK_TAI timers and nanosleeps to expire late (the latency is ~2x the tai offset). Fix this by adding the tai offset from the realtime offset instead of subtracting. Cc: Sasha Levin Cc: Thomas Gleixner Cc: Prarit Bhargava Cc: Richard Cochran Cc: Ingo Molnar Cc: stable #3.10+ Signed-off-by: John Stultz --- kernel/time/timekeeping.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 44b7e6b..3f6a827 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -77,7 +77,7 @@ static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm) tk->wall_to_monotonic = wtm; set_normalized_timespec(&tmp, -wtm.tv_sec, -wtm.tv_nsec); tk->offs_real = timespec_to_ktime(tmp); - tk->offs_tai = ktime_sub(tk->offs_real, ktime_set(tk->tai_offset, 0)); + tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0)); } static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t) @@ -595,7 +595,7 @@ s32 timekeeping_get_tai_offset(void) static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) { tk->tai_offset = tai_offset; - tk->offs_tai = ktime_sub(tk->offs_real, ktime_set(tai_offset, 0)); + tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0)); } /** -- 1.8.3.2