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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 2C1B7C433E6 for ; Fri, 12 Mar 2021 00:29:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F035664F91 for ; Fri, 12 Mar 2021 00:29:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231299AbhCLA3S (ORCPT ); Thu, 11 Mar 2021 19:29:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbhCLA26 (ORCPT ); Thu, 11 Mar 2021 19:28:58 -0500 Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DB57C061574; Thu, 11 Mar 2021 16:28:58 -0800 (PST) Received: by mail-pj1-x102b.google.com with SMTP id t18so4297068pjs.3; Thu, 11 Mar 2021 16:28:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=15VUT7DJn+pnOXHgIaEAd3HHArwp6lQ8zP41QSI3bfY=; b=ZJYo+PRkcpG5ShjLmsQYOvjCuPMVFH0KciMv3hf7amMitAnW72Lya1SpEg8moGGCO8 4Zatez7ckGwdpCRP7Fwcb5AswfegpMyRGq8q7EMCw19jrdPwJP6Ov2HTB0ZeIiQwdXmT 6cHBEEHriwAJEmND5WFStO8DZ8VWXeOOuM8XutlV3JyfU5V5nodVWNiH9XVmiyeKMXaL WLiyIQnzTjZ2qs+pYHfLG+U4JFXrCxjCQ+ajORSjlcRjlOisZkdL3W4+yBXb9cjkNoDw 3MzF8TqudjqdXK9VEAvdvZgrgEuuNNg2vTCakN6y8GCBJb3ijJQjgqM8GklTd8/eLmcQ 5KLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=15VUT7DJn+pnOXHgIaEAd3HHArwp6lQ8zP41QSI3bfY=; b=KjHsKAtFQ7yWaDBPUu+zzFE7WmgIMybu2IvSbAbBoLpCXChLtUnREqzG5yHOY3fFcR QYSXzI8jF2LGWcSbGRF1pRfP+rBwNwd4RJpmq+29mkQj4ED1PlRMSh6d1uXNDEJ2P8LK xjOLZ2Ew073xOYWg94LPbR72vPVnrQ6Ot3JSZ730CS7dnnKz8udK4Js2dQ7KBc72zxc2 L5jbwv/5dQfqCsPCPGhOSMRujHQcKk9EUby4NG3mNt4HDQva8XxHDtapLRBe+T9rSxX8 iHZ+z7kHKwx+DZ/eEeYrNISxbqklxl1sUVK4ocD0ml3iVKa87uUenk6KOjAkFADZQvaU 8ljg== X-Gm-Message-State: AOAM532G4iEbDxwCiucHHEDedsl4PViBUCEUYudjnCPDVwNCI/1+qfJV 72bda0DZW2G1LeEFiCmWCpQo69WO3l+Apo5j5Cc= X-Google-Smtp-Source: ABdhPJyc5WkdWAbCbtxeh2tlXfG8byRG+AjnQvX7WPwURgiCF7SmTF1Eg1JOolxh4qyVRiFg3NpeyeVwB+db2ENUW5c= X-Received: by 2002:a17:90a:ea91:: with SMTP id h17mr11386538pjz.66.1615508937868; Thu, 11 Mar 2021 16:28:57 -0800 (PST) MIME-Version: 1.0 References: <20210311072311.2969-1-xie.he.0141@gmail.com> <20210311124309.5ee0ef02@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210311145230.5f368151@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210311161030.5ed11805@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210311161030.5ed11805@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Xie He Date: Thu, 11 Mar 2021 16:28:47 -0800 Message-ID: Subject: Re: [PATCH net] net: lapbether: Prevent racing when checking whether the netif is running To: Jakub Kicinski Cc: Martin Schiller , "David S. Miller" , Linux X25 , Linux Kernel Network Developers , LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 11, 2021 at 4:10 PM Jakub Kicinski wrote: > > And the "noqueue" queue is there because it's on top of hdlc_fr.c > somehow or some out of tree driver? Or do you install it manually? No, this driver is not related to "hdlc_fr.c" or any out-of-tree driver. The default qdisc is "noqueue" for this driver because this driver doesn't set "tx_queue_len". This means the value of "tx_queue_len" would be 0. In this case, "alloc_netdev_mqs" will automatically add the "IFF_NO_QUEUE" flag to the device, then "attach_one_default_qdisc" in "net/sched/sch_generic.c" will attach the "noqueue" qdisc for devices with the "IFF_NO_QUEUE" flag.