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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 7727FC433E9 for ; Wed, 20 Jan 2021 23:42:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31BB223603 for ; Wed, 20 Jan 2021 23:42:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725910AbhATVom (ORCPT ); Wed, 20 Jan 2021 16:44:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:46762 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389788AbhATUxB (ORCPT ); Wed, 20 Jan 2021 15:53:01 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 10B9A233FC; Wed, 20 Jan 2021 20:52:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611175938; bh=8jBF67VISxuT/xu2rcoO5YE2FU88OFticdYf54+neO8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=N5+QPs/+DlLJt3MClwur9O+wbKTIHuhCZO1VVEg8KCi0KUGwZU0XaVmJBd/K8SOdz cEzlwRbPCzeRUL92LOaLG3+3089C3zNhwSfg9YkO9sJ70ZNsc3OXJjUzdq6Cv+skzI uQ+DIRkP//QC6bZTLNu6zeypikx0R1XyPDBuKUmj7JfObyOYNU2C5ebQ5Aoa7GYsPg 07E5RfDaVTnJIS3588nJV65f3gpv3VlcZ+3ItM3EcpYFKZReSNI8z9r19FnQwTFCJp p8VUIwhGYO2M00l1IuVVUkLQXOCs80dksUXtNmGbDSIgYqCI5cgFQNfisGIh2UQfND 5oJ72HvNobAzg== Date: Wed, 20 Jan 2021 12:52:17 -0800 From: Jakub Kicinski To: Lukasz Stelmach Cc: Andrew Lunn , jim.cromie@gmail.com, Heiner Kallweit , "David S. Miller" , Rob Herring , Kukjin Kim , Krzysztof Kozlowski , Russell King , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, =?UTF-8?B?QmFydMWCb21pZWogxbtvbG5pZXJr?= =?UTF-8?B?aWV3aWN6?= , Marek Szyprowski Subject: Re: [PATCH v10 3/3] net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver Message-ID: <20210120125217.6394e6a4@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: References: <20210115172722.516468bb@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org On Wed, 20 Jan 2021 20:30:14 +0100 Lukasz Stelmach wrote: > > You need to use 64 bit stats, like struct rtnl_link_stats64. > > On a 32bit system at 100Mbps ulong can wrap in minutes. > > > > Let me see. At first glance > > git grep -l ndo_get_stats\\\> drivers/net/ethernet/ | xargs grep -li SPEED_100\\\> > > quite a number of Fast Ethernet drivers use net_device_stats. Let me > calculate. > > - bytes > 100Mbps is ~10MiB/s > sending 4GiB at 10MiB/s takes 27 minutes > > - packets > minimum frame size is 84 bytes (840 bits on the wire) on 100Mbps means > 119048 pps at this speed it takse 10 hours to transmit 2^32 packets > > Anyway, I switched to rtnl_link_stats64. Tell me, is it OK to just > memcpy() in .ndo_get_stats64? Yup, you can just memcpy() your local copy over the one you get as an argument of ndo_get_stats64 > >> + struct work_struct ax_work; > > > > I don't see you ever canceling / flushing this work. > > You should do that at least on driver remove if not close. > > Done. > > Does it mean most drivers do it wrong? > > git grep INIT_WORK drivers/net/ethernet/ | \ > sed -e 's/\(^[^:]*\):[^>]*->\([^,]*\),.*/\1 \2/' | \ > while read file var; do \ > grep -H $var $file; > done | grep INIT_WORK\\\|cancel_work Some may use flush, but I wouldn't be surprised if there were bugs like this out there.