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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 8836AC3F2D1 for ; Tue, 3 Mar 2020 17:54:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 636D020870 for ; Tue, 3 Mar 2020 17:54:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258069; bh=2k1Uh2+g4UIU3FTUqMeqDDj6AHc8elwxBX5WMs5PIzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=I2sH633uJSbr4KDmMQ8u5T8XhfUEN7b/6qVe2ciIxmEK+/AfySA9Ob1mR88P8xoxi PEjQTpshBKKH2jLo5pemTGXmzYX2Lzq95L5bF6yo3v5tgBRL/ru6rmPn/E4QXdsKJ1 PxJe8HqMhvM4trMAMnHgqLIWot9HuWg/okcJOcG4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732518AbgCCRy1 (ORCPT ); Tue, 3 Mar 2020 12:54:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:35520 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732314AbgCCRyZ (ORCPT ); Tue, 3 Mar 2020 12:54:25 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3DF19206D5; Tue, 3 Mar 2020 17:54:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583258064; bh=2k1Uh2+g4UIU3FTUqMeqDDj6AHc8elwxBX5WMs5PIzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U1E0sPnY2VXvnV78tbciVvjkXWYDgiQWT/+efjT0UmUm77n4ESAuiV4+cd1nm43FK 207bOXacfQRoodMvsNxBmOIHxvZwmQaBPTX5idFTKSdgyKGHwL3bjuSzCTonNeGcEN 7g/50gBAv+8fnQOehDG3GNow/PVuDX1ffBoD8RwY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arthur Kiyanovski , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 050/152] net: ena: fix uses of round_jiffies() Date: Tue, 3 Mar 2020 18:42:28 +0100 Message-Id: <20200303174308.103154883@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200303174302.523080016@linuxfoundation.org> References: <20200303174302.523080016@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arthur Kiyanovski [ Upstream commit 2a6e5fa2f4c25b66c763428a3e65363214946931 ] >>From the documentation of round_jiffies(): "Rounds a time delta in the future (in jiffies) up or down to (approximately) full seconds. This is useful for timers for which the exact time they fire does not matter too much, as long as they fire approximately every X seconds. By rounding these timers to whole seconds, all such timers will fire at the same time, rather than at various times spread out. The goal of this is to have the CPU wake up less, which saves power." There are 2 parts to this patch: ================================ Part 1: ------- In our case we need timer_service to be called approximately every X=1 seconds, and the exact time does not matter, so using round_jiffies() is the right way to go. Therefore we add round_jiffies() to the mod_timer() in ena_timer_service(). Part 2: ------- round_jiffies() is used in check_for_missing_keep_alive() when getting the jiffies of the expiration of the keep_alive timeout. Here it is actually a mistake to use round_jiffies() because we want the exact time when keep_alive should expire and not an approximate rounded time, which can cause early, false positive, timeouts. Therefore we remove round_jiffies() in the calculation of keep_alive_expired() in check_for_missing_keep_alive(). Fixes: 82ef30f13be0 ("net: ena: add hardware hints capability to the driver") Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Arthur Kiyanovski Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index b4a145220abae..f0cddf250cfd5 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -3035,8 +3035,8 @@ static void check_for_missing_keep_alive(struct ena_adapter *adapter) if (adapter->keep_alive_timeout == ENA_HW_HINTS_NO_TIMEOUT) return; - keep_alive_expired = round_jiffies(adapter->last_keep_alive_jiffies + - adapter->keep_alive_timeout); + keep_alive_expired = adapter->last_keep_alive_jiffies + + adapter->keep_alive_timeout; if (unlikely(time_is_before_jiffies(keep_alive_expired))) { netif_err(adapter, drv, adapter->netdev, "Keep alive watchdog timeout.\n"); @@ -3138,7 +3138,7 @@ static void ena_timer_service(struct timer_list *t) } /* Reset the timer */ - mod_timer(&adapter->timer_service, jiffies + HZ); + mod_timer(&adapter->timer_service, round_jiffies(jiffies + HZ)); } static int ena_calc_io_queue_num(struct pci_dev *pdev, -- 2.20.1