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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 90AA3C43381 for ; Sun, 24 Feb 2019 20:43:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 483D420651 for ; Sun, 24 Feb 2019 20:43:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="XwnlnqdN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbfBXUnp (ORCPT ); Sun, 24 Feb 2019 15:43:45 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:37026 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726458AbfBXUnp (ORCPT ); Sun, 24 Feb 2019 15:43:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=qxi4BgPLMkFC/is26L0mhNdfTxVbY+7gAYF7h0ZsMf8=; b=XwnlnqdNDeT5MlHfOMRSLdA/Qz B9BIUHblxkX8XIN9mGLEC/DyKHrhfPnfSuhDGjfVnGtoC8dkoTxWQ9E9g9la4+RDddv+B/1QqTe63 xDrXmzY4tr6bdcvwwArH1reMB4wT+jXBVzAQAxZXLVgm9RneEzM2BwhjZYyxceYPtaNE=; Received: from andrew by vps0.lunn.ch with local (Exim 4.89) (envelope-from ) id 1gy0ca-0005t9-Da; Sun, 24 Feb 2019 21:43:36 +0100 Date: Sun, 24 Feb 2019 21:43:36 +0100 From: Andrew Lunn To: Michal Kubecek Cc: Tariq Toukan , "John W. Linville" , netdev@vger.kernel.org, Eran Ben Elisha , Aya Levin Subject: Re: [PATCH ethtool] ethtool: Add support for 200Gbps (50Gbps per lane) link mode Message-ID: <20190224204336.GC20855@lunn.ch> References: <1551020901-20257-1-git-send-email-tariqt@mellanox.com> <20190224164751.GG26626@lunn.ch> <20190224184046.GB1914@unicorn.suse.cz> <20190224194015.GM26626@lunn.ch> <20190224203333.GC1914@unicorn.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190224203333.GC1914@unicorn.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > > Hi Michal > > > > So are you doing a read/modify/write? In that case, off/on makes > > sense. For a pure write, i don't see the need for off/on. > > When using netlink interface, the read/modify/write cycle is limited to > kernel code and is done under rtnl_lock. The netlink interface allows > userspace to send only attributes it wants to change and for bit sets > (like link modes) to tell kernel which bits it wants to change so that > there is no need to read current values first (and open a race window). Nice. But it would still be good to get feedback from people who use this more often. I guess that is top of rack switches with all these odd link modes. Andrew