From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967081AbdADRgy (ORCPT ); Wed, 4 Jan 2017 12:36:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32920 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934114AbdADRfY (ORCPT ); Wed, 4 Jan 2017 12:35:24 -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 , Stephen Hemminger Subject: [PATCH v2 4/4] hv_util: improve time adjustment accuracy by disabling interrupts Date: Wed, 4 Jan 2017 18:24:39 +0100 Message-Id: <20170104172439.19683-5-vkuznets@redhat.com> In-Reply-To: <20170104172439.19683-1-vkuznets@redhat.com> References: <20170104172439.19683-1-vkuznets@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 04 Jan 2017 17:24:51 +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 7e97231..4e50a42 100644 --- a/drivers/hv/hv_util.c +++ b/drivers/hv/hv_util.c @@ -187,6 +187,9 @@ static void hv_set_host_time(struct work_struct *work) struct timespec64 host_ts, our_ts; struct timex txc = {0}; int ret; + unsigned long flags; + + local_irq_save(flags); wrk = container_of(work, struct adj_time_work, work); @@ -218,6 +221,7 @@ static void hv_set_host_time(struct work_struct *work) * ordered to sync our time by the host. */ if (abs(delta) > MAXPHASE || wrk->flags & ICTIMESYNCFLAG_SYNC) { + local_irq_restore(flags); do_settimeofday64(&host_ts); return; } @@ -232,6 +236,8 @@ static void hv_set_host_time(struct work_struct *work) ret = do_adjtimex(&txc); if (ret) pr_debug("Failed to adjust system time: %d\n", ret); + + local_irq_restore(flags); } /* -- 2.9.3