From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABA75ECDFB3 for ; Mon, 16 Jul 2018 20:41:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA39020846 for ; Mon, 16 Jul 2018 20:41:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="ibsZRQEb"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="PrlVHa2j" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA39020846 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730375AbeGPVKG (ORCPT ); Mon, 16 Jul 2018 17:10:06 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:36476 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728075AbeGPVKG (ORCPT ); Mon, 16 Jul 2018 17:10:06 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 10AF5606DB; Mon, 16 Jul 2018 20:40:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1531773660; bh=KgL+wIxQK5AMHv2P4Rxxaxd9VaZ2aa+8yRz7fDg4om0=; h=From:To:Cc:Subject:Date:From; b=ibsZRQEb6sVkKKHIaVT2qpivoLOdmggNSkT/I1kvO53Tg48KmeMGb6e5eEDPUygWK SPGNNqReIYpEMazswx7XyXvPQ5RHgka5uIi0WfgRB7RkYCNWZOMlZCn9NHCYYQKQ3H kiWOQf/q2JrwaCLsjXlo4Sc0cuI0NeNB3EtyeiUI= Received: from mojha-linux.qualcomm.com (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: mojha@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 756A060541; Mon, 16 Jul 2018 20:40:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1531773659; bh=KgL+wIxQK5AMHv2P4Rxxaxd9VaZ2aa+8yRz7fDg4om0=; h=From:To:Cc:Subject:Date:From; b=PrlVHa2jn7AL4cjxIo4H/M96eMv0wb+DaSGSBtJn7b0LowfiWo7DQlE3BBQQ5gjKL KrSJMgiFNcuWwRCtgVHZFShjoaAwrkH4yxfTKo5YIX9LYZiogI2CCHFXeXy2y8g+DT HoFI79CQa48680iY6gCVDRuiqUD/JEx0zBn/SmoI= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 756A060541 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=mojha@codeaurora.org From: Mukesh Ojha To: john.stultz@linaro.org, tglx@linutronix.de, linux-kernel@vger.kernel.org Cc: gkohli@codeaurora.org, cpandya@codeaurora.org, neeraju@codeaurora.org, Mukesh Ojha Subject: [PATCH v4] time: Fix extra sleeptime injection when suspend fails Date: Tue, 17 Jul 2018 02:10:50 +0530 Message-Id: <1531773650-30424-1-git-send-email-mojha@codeaurora.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, there exists a corner case assuming when there is only one clocksource e.g RTC, and system failed to go to suspend mode. While resume rtc_resume() injects the sleeptime as timekeeping_rtc_skipresume() returned 'false' (default value of sleeptime_injected) due to which we can see mismatch in timestamps. This issue can also come in a system where more than one clocksource are present and very first suspend fails. Fix this by handling the sleeptime_injected flag properly. Success case: ------------ {sleeptime_injected=false} rtc_suspend() => timekeeping_suspend() => timekeeping_resume() => (sleeptime injected) rtc_resume() Failure case: ------------ {failure in sleep path} {sleeptime_injected=false} rtc_suspend() => rtc_resume() sleeptime injected again which was not required as the suspend failed) Originally-by: Thomas Gleixner Signed-off-by: Mukesh Ojha --- Changes in V4: * Changes as suggested by John - Changed the variable name from sleeptime_injected to suspend_timing_needed - Changed the boolean logic. Changes in v3: * Updated commit subject and description. * Updated the patch as per the fix given by Thomas Gleixner. Changes in v2: * Updated the commit text. * Removed extra variable and used the earlier static variable 'sleeptime_injected'. drivers/rtc/class.c | 2 +- kernel/time/timekeeping.c | 29 ++++++++++++++++++++++------- 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index d37588f..ee455cc 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -102,7 +102,7 @@ static int rtc_resume(struct device *dev) struct timespec64 sleep_time; int err; - if (timekeeping_rtc_skipresume()) + if (!timekeeping_rtc_skipresume()) return 0; rtc_hctosys_ret = -ENODEV; diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 4786df9..b25f771 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1510,8 +1510,20 @@ void __weak read_boot_clock64(struct timespec64 *ts) ts->tv_nsec = 0; } -/* Flag for if timekeeping_resume() has injected sleeptime */ -static bool sleeptime_injected; +/* + * Flag reflecting whether timekeeping_resume() has injected sleeptime. + * + * The flag starts of false and is only set when a suspend reaches + * timekeeping_suspend(), timekeeping_resume() sets it to false when the + * timekeeper clocksource is not stopping across suspend and has been + * used to update sleep time. If the timekeeper clocksource has stopped + * then the flag stays true and is used by the RTC resume code to decide + * whether sleeptime must be injected and if so the flag gets false then. + * + * If a suspend fails before reaching timekeeping_resume() then the flag + * stays false and prevents erroneous sleeptime injection. + */ +static bool suspend_timing_needed; /* Flag for if there is a persistent clock on this platform */ static bool persistent_clock_exists; @@ -1610,7 +1622,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, */ bool timekeeping_rtc_skipresume(void) { - return sleeptime_injected; + return suspend_timing_needed; } /** @@ -1646,6 +1658,8 @@ void timekeeping_inject_sleeptime64(struct timespec64 *delta) raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); + suspend_timing_needed = false; + timekeeping_forward_now(tk); __timekeeping_inject_sleeptime(tk, delta); @@ -1671,7 +1685,6 @@ void timekeeping_resume(void) struct timespec64 ts_new, ts_delta; u64 cycle_now; - sleeptime_injected = false; read_persistent_clock64(&ts_new); clockevents_resume(); @@ -1701,13 +1714,13 @@ void timekeeping_resume(void) tk->tkr_mono.mask); nsec = mul_u64_u32_shr(cyc_delta, clock->mult, clock->shift); ts_delta = ns_to_timespec64(nsec); - sleeptime_injected = true; + suspend_timing_needed = false; } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); - sleeptime_injected = true; + suspend_timing_needed = false; } - if (sleeptime_injected) + if (!suspend_timing_needed) __timekeeping_inject_sleeptime(tk, &ts_delta); /* Re-base the last cycle value */ @@ -1743,6 +1756,8 @@ int timekeeping_suspend(void) if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec) persistent_clock_exists = true; + suspend_timing_needed = true; + raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); timekeeping_forward_now(tk); -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project