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,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 1A77CC10F27 for ; Tue, 10 Mar 2020 13:07:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC2EB20873 for ; Tue, 10 Mar 2020 13:07:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845666; bh=YUp+x46YJV3qWYuyFvqm+xktcZT6q3KY1sQikdYXYxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=b4E6M0IAlUXQDAZYXLqOJtfj48kYNkMofh5nJTCN50KEV5UfjuTZKUVfiKeg42LwN aSEnjQPUfnmbdaAOKRe3CDtiED3Z5TGu7Ma9P7AYbgidY7NEgFzmQttQq6PdB1fz0s RHafez7mybnKlbl0lC5dl4WOwQ19jYnEvhJUyuJQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730713AbgCJNHp (ORCPT ); Tue, 10 Mar 2020 09:07:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:53534 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730987AbgCJNHi (ORCPT ); Tue, 10 Mar 2020 09:07:38 -0400 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 4236E20873; Tue, 10 Mar 2020 13:07:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845657; bh=YUp+x46YJV3qWYuyFvqm+xktcZT6q3KY1sQikdYXYxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wGS6e656p0cfQ3aPv6h12yp4V1bDw1F/W4TaQ6e4+NOjALapyWSX3VckRfJ7LJwjl TV0nQng0nePYsuAgHPKgvJf34uIlvua6nMTBNlqLPq0c4dJATdi9ptLDExDcKiUOPW FaGti7Dm5TNfTjeSBdmxIVYBBbKkLDQ3fax2FeyI= 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 4.14 014/126] net: ena: fix uses of round_jiffies() Date: Tue, 10 Mar 2020 13:40:35 +0100 Message-Id: <20200310124205.027325354@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200310124203.704193207@linuxfoundation.org> References: <20200310124203.704193207@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 518ff393a026b..d9ece9ac6f53c 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -2803,8 +2803,8 @@ 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"); @@ -2906,7 +2906,7 @@ static void ena_timer_service(unsigned long data) } /* 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