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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 D7486C41514 for ; Wed, 31 Jul 2019 22:53:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8F25206A2 for ; Wed, 31 Jul 2019 22:53:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=networkplumber-org.20150623.gappssmtp.com header.i=@networkplumber-org.20150623.gappssmtp.com header.b="jcvbyeO2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730409AbfGaWxr (ORCPT ); Wed, 31 Jul 2019 18:53:47 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:32830 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726232AbfGaWxq (ORCPT ); Wed, 31 Jul 2019 18:53:46 -0400 Received: by mail-pf1-f193.google.com with SMTP id g2so32680996pfq.0 for ; Wed, 31 Jul 2019 15:53:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=J5fdy7Wd9FHVlBYpOs7Z6b4FYMlCutBaVHd3ZTvQnx8=; b=jcvbyeO2Rb27mNd8+lNcStEOaoRfSBfIecOdeOrvehK1UDI3XXjVpnaSL1Y5VbgW0o S43AF7PCzFEJIzJb7T9OY8rvM6899WR8raNH7Q1x+ulDZXGVgvvBio39kalP+YHLuWWX 9fFavIJ3A1Upf0jJXLMFN6P/tCRtAc+4DZDVsEm0eQ5TDR78H73gh/rbMhAEU6bfxNTg grHUKYAFHED5LCNQSvcLQTDqwBygF07HXRgwjJqDJRUw9xXVBvZsDBeKVGK/o94BfIb7 ZkSAS3k+LQqjoxBxsKIk5YWLFT5xTrWE117kWcnAxP/Mah8wyBd32ATujwmACKDQoKh+ 8NZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=J5fdy7Wd9FHVlBYpOs7Z6b4FYMlCutBaVHd3ZTvQnx8=; b=EiB4bjh9Sakz9L/kyOHpVSDzftLyGUy8Sh2x3QbmOrekNB+rLgBEDh+0ZNnyaQq6/Z yJl8T62E2UWd01byTueiTt8NYb7nxxvsIpUbUyvJijpDC87gsg8oHn9+Tc6qgVQSPVWw qy4JKT3xQvd/zxbHr//HsKcR+Dx8vmrEe+R5BLwNL2tZ07T0SbZKhISQnpJzKIdPi25A jvg7lOFuPfEOSLoKo+c1bOghK6NXRY0jjs1jHn0HI4zNBovniK4nWVdBxPJZEvtuy/EV 232iCpEYNFQYsMp3MF9lLDVe0D3wH+xrBTUfCL5Ii1cajnEoF+9CoBTGU3emM9qJQ4y3 dmjQ== X-Gm-Message-State: APjAAAWnmf2CJ7tEpN/VgOsQlYvrxQ3hurMTAmpTfi14rp8PiAdbllJG U3kF/z0kvqikAHnMp8kjp6ngC9cL X-Google-Smtp-Source: APXvYqw2iGgfavbMtasargiQy6HXHinRozneVKQp1jvdntL0M9Ibd5QpMWPBFGHiCtK48lDQdqdGFw== X-Received: by 2002:a17:90a:9bca:: with SMTP id b10mr5142192pjw.90.1564613625545; Wed, 31 Jul 2019 15:53:45 -0700 (PDT) Received: from hermes.lan (204-195-22-127.wavecable.com. [204.195.22.127]) by smtp.gmail.com with ESMTPSA id h70sm64404924pgc.36.2019.07.31.15.53.45 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 31 Jul 2019 15:53:45 -0700 (PDT) Date: Wed, 31 Jul 2019 15:53:38 -0700 From: Stephen Hemminger To: Nikolay Aleksandrov Cc: netdev@vger.kernel.org, roopa@cumulusnetworks.com, davem@davemloft.net, bridge@lists.linux-foundation.org, michael-dev Subject: Re: [PATCH net v3] net: bridge: move vlan init/deinit to NETDEV_REGISTER/UNREGISTER Message-ID: <20190731155338.15ff34cb@hermes.lan> In-Reply-To: <20190731224955.10908-1-nikolay@cumulusnetworks.com> References: <319fda43-195d-2b92-7f62-7e273c084a29@cumulusnetworks.com> <20190731224955.10908-1-nikolay@cumulusnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > -int br_vlan_init(struct net_bridge *br) > +static int br_vlan_init(struct net_bridge *br) > { > struct net_bridge_vlan_group *vg; > int ret = -ENOMEM; > @@ -1083,6 +1085,8 @@ int br_vlan_init(struct net_bridge *br) > return ret; > > err_vlan_add: > + RCU_INIT_POINTER(br->vlgrp, NULL); > + synchronize_rcu(); Calling sychronize_rcu is expensive. And the callback for notifier is always called with rtnl_head. Why not just keep the pointer initialization back in the code where bridge is created, it was safe there.