From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756302AbdABTmf (ORCPT ); Mon, 2 Jan 2017 14:42:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41932 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933999AbdABTlZ (ORCPT ); Mon, 2 Jan 2017 14:41:25 -0500 From: Vitaly Kuznetsov To: devel@linuxdriverproject.org Cc: linux-kernel@vger.kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , John Stultz , Thomas Gleixner , Alex Ng Subject: [PATCH 4/4] hv_util: improve time adjustment accuracy by disabling interrupts Date: Mon, 2 Jan 2017 20:41:14 +0100 Message-Id: <20170102194114.657-5-vkuznets@redhat.com> In-Reply-To: <20170102194114.657-1-vkuznets@redhat.com> References: <20170102194114.657-1-vkuznets@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 02 Jan 2017 19:41:25 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we happen to receive interrupts during hv_set_host_time() execution our adjustments may get inaccurate. Make the whole function atomic. Unfortunately, we can's call do_settimeofday64() with interrupts disabled as some cross-CPU work is being done but this call happens very rarely. Signed-off-by: Vitaly Kuznetsov --- drivers/hv/hv_util.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c index 4c0fbb0..233d5cb 100644 --- a/drivers/hv/hv_util.c +++ b/drivers/hv/hv_util.c @@ -186,6 +186,9 @@ static void hv_set_host_time(struct work_struct *work) u64 newtime; struct timespec64 host_ts, our_ts; struct timex txc = {0}; + unsigned long flags; + + local_irq_save(flags); wrk = container_of(work, struct adj_time_work, work); @@ -214,6 +217,7 @@ static void hv_set_host_time(struct work_struct *work) /* Try adjusting time by using phase adjustment if possible */ if (abs(delta) > MAXPHASE) { + local_irq_restore(flags); do_settimeofday64(&host_ts); return; } @@ -225,6 +229,8 @@ static void hv_set_host_time(struct work_struct *work) txc.status = STA_PLL; txc.offset = delta; do_adjtimex(&txc); + + local_irq_restore(flags); } /* -- 2.9.3