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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C0C49C56201 for ; Wed, 25 Nov 2020 21:49:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6589A20857 for ; Wed, 25 Nov 2020 21:49:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="PGGCjpps" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732960AbgKYVt2 (ORCPT ); Wed, 25 Nov 2020 16:49:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:40600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732851AbgKYVt1 (ORCPT ); Wed, 25 Nov 2020 16:49:27 -0500 Received: from kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com (unknown [163.114.132.4]) (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 ACE602083E; Wed, 25 Nov 2020 21:49:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606340967; bh=kwlAvwQ9x4w4c8oPPCfGpynB2t32g0wSKIXIqjXmwR0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=PGGCjppsUSg6q4yK+aIE7KQ6BZ9kyOUsHKRuYbcXLJDZGDAiKEpBmcb3HjyiyyBZU eCitBdLNVcCUyna8/Orrjfup3rjcaA/Uvyw30grsZzBBVPulXev50u1Eeleh1oSVNC ji3JZFhFt5YHwE8STfvw6Y4jUKFTmD92pmSFwIwM= Date: Wed, 25 Nov 2020 13:49:25 -0800 From: Jakub Kicinski To: Martin Schiller Cc: andrew.hendry@gmail.com, davem@davemloft.net, xie.he.0141@gmail.com, linux-x25@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v6 2/5] net/lapb: support netdev events Message-ID: <20201125134925.26d851f7@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20201124093938.22012-3-ms@dev.tdt.de> References: <20201124093938.22012-1-ms@dev.tdt.de> <20201124093938.22012-3-ms@dev.tdt.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 24 Nov 2020 10:39:35 +0100 Martin Schiller wrote: > This patch allows layer2 (LAPB) to react to netdev events itself and > avoids the detour via layer3 (X.25). > > 1. Establish layer2 on NETDEV_UP events, if the carrier is already up. > > 2. Call lapb_disconnect_request() on NETDEV_GOING_DOWN events to signal > the peer that the connection will go down. > (Only when the carrier is up.) > > 3. When a NETDEV_DOWN event occur, clear all queues, enter state > LAPB_STATE_0 and stop all timers. > > 4. The NETDEV_CHANGE event makes it possible to handle carrier loss and > detection. > > In case of Carrier Loss, clear all queues, enter state LAPB_STATE_0 > and stop all timers. > > In case of Carrier Detection, we start timer t1 on a DCE interface, > and on a DTE interface we change to state LAPB_STATE_1 and start > sending SABM(E). > > Signed-off-by: Martin Schiller > +/* Handle device status changes. */ > +static int lapb_device_event(struct notifier_block *this, unsigned long event, > + void *ptr) > +{ > + struct net_device *dev = netdev_notifier_info_to_dev(ptr); > + struct lapb_cb *lapb; > + > + if (!net_eq(dev_net(dev), &init_net)) > + return NOTIFY_DONE; > + > + if (dev->type == ARPHRD_X25) { Flip condition, save indentation. if (dev->type != ARPHRD_X25) return NOTIFY_DONE; You can also pull out of all the cases: lapb = lapb_devtostruct(dev); if (!lapb) return NOTIFY_DONE; right? > + switch (event) { > + case NETDEV_UP: > + lapb_dbg(0, "(%p) Interface up: %s\n", dev, > + dev->name); > + > + if (netif_carrier_ok(dev)) { > + lapb = lapb_devtostruct(dev); > + if (!lapb) > + break; > static int __init lapb_init(void) > { > + register_netdevice_notifier(&lapb_dev_notifier); This can fail, so: return register_netdevice_notifier(&lapb_dev_notifier); > return 0; > } > > static void __exit lapb_exit(void) > { > WARN_ON(!list_empty(&lapb_list)); > + > + unregister_netdevice_notifier(&lapb_dev_notifier); > } > > MODULE_AUTHOR("Jonathan Naylor ");