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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C575CC433F5 for ; Thu, 10 Mar 2022 15:51:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238022AbiCJPwY (ORCPT ); Thu, 10 Mar 2022 10:52:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232704AbiCJPwW (ORCPT ); Thu, 10 Mar 2022 10:52:22 -0500 Received: from mail-lj1-x235.google.com (mail-lj1-x235.google.com [IPv6:2a00:1450:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4D50182D89; Thu, 10 Mar 2022 07:51:20 -0800 (PST) Received: by mail-lj1-x235.google.com with SMTP id s25so8345447lji.5; Thu, 10 Mar 2022 07:51:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:in-reply-to:references:date:message-id :mime-version; bh=fqdAl6g8T5b8CCdXDXU4kRWnVjawXTgSM4gnCS0YVDA=; b=ZWEgd7vuurDAY2I1OnulI6eiSL8yCLgaJoxMpVzt5uZhruJGgevRtmuMUMEDF/HrhA JCzlSUE7nEOuEstZXK1itDK7t2VNObOx8xyy5uxT9r5FS17kwIYw3Cz0wsxWFFE0ybSb YvET/f3syD85/VklUOqtDB0b6zfJ17S2Y/MTUHsRfTcabLGRuStz8HvoQ7AgSTZdc1pT Nm3ce8YwJ94fV35BlYmiohPT04whu4tCW5+w4L4kcC7z4LX/1nm8ATMQceEk3Bm/Ea9D QWN0GR5dVwT5xUq055j/e4Ld2/PAoL4O/cNV6xu9daYhvQwfRzigDSX8GGgcemWmcc9s JaXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=fqdAl6g8T5b8CCdXDXU4kRWnVjawXTgSM4gnCS0YVDA=; b=EIjyVdv0lWh+3JEMbf1FxAEUx3zKWvHxZdJ7ihOtfSyI3H6OvSZQQOh6KK9OUjPO/C F5rz4Cr+cgogdz0qorhYTW0WJGW3/aeP0p49/38uxlKiGZ9trsz/OpDgZz2wazcFVUcX S8Zbm4rHmxpA+J3wthXYRPyYL08z9lBD7lnSS9OMufrIljMHm8Tfdj8JzNeuVXBZdTdA 5I1VUcNii7iuGpVmc4BEEe02V2EsTq+LxQfBjYlhIfCnVYbiQDbg4/TUD1nA3bCoiGyP sNNfWmflJnvMGsCE3t8AWkrs6+9yK2L1jUP57OPywhjmGE34+Ij7jKnYpkiiutDEwpr3 azMw== X-Gm-Message-State: AOAM532bSiCa1EAOpchzy/te1aey4Ys14XgLEsaacXKqDLngO08tJKvv EFcQ2M9TSFKSrcEb8JggyYc= X-Google-Smtp-Source: ABdhPJxA1m2GpjuOi6M2cRVlISGhS+trkh208Chi7ZhCdX+8Dd2aCE0bKm2WTunAi9Vtc2a9O1Bsjw== X-Received: by 2002:a05:651c:543:b0:247:e3b1:9ac3 with SMTP id q3-20020a05651c054300b00247e3b19ac3mr3439662ljp.438.1646927478958; Thu, 10 Mar 2022 07:51:18 -0800 (PST) Received: from wse-c0127 ([208.127.141.29]) by smtp.gmail.com with ESMTPSA id bq1-20020a056512150100b004481de98e5bsm1039808lfb.305.2022.03.10.07.51.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Mar 2022 07:51:18 -0800 (PST) From: Hans Schultz X-Google-Original-From: Hans Schultz To: Vladimir Oltean , Hans Schultz Cc: davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, Andrew Lunn , Vivien Didelot , Florian Fainelli , Jiri Pirko , Ivan Vecera , Roopa Prabhu , Nikolay Aleksandrov , Daniel Borkmann , Ido Schimmel , linux-kernel@vger.kernel.org, bridge@lists.linux-foundation.org Subject: Re: [PATCH net-next 3/3] net: dsa: mv88e6xxx: mac-auth/MAB implementation In-Reply-To: <20220310150717.h7gaxamvzv47e5zc@skbuf> References: <20220310142320.611738-1-schultz.hans+netdev@gmail.com> <20220310142320.611738-4-schultz.hans+netdev@gmail.com> <20220310142836.m5onuelv4jej5gvs@skbuf> <865yolg8d7.fsf@gmail.com> <20220310150717.h7gaxamvzv47e5zc@skbuf> Date: Thu, 10 Mar 2022 16:51:15 +0100 Message-ID: <86sfrpergs.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On tor, mar 10, 2022 at 17:07, Vladimir Oltean wrote: > On Thu, Mar 10, 2022 at 04:00:52PM +0100, Hans Schultz wrote: >> >> + brport = dsa_port_to_bridge_port(dp); >> > >> > Since this is threaded interrupt context, I suppose it could race with >> > dsa_port_bridge_leave(). So it is best to check whether "brport" is NULL >> > or not. >> > >> Would something like: >> if (dsa_is_unused_port(chip->ds, port)) >> return -ENODATA; >> >> be appropriate and sufficient for that? > > static inline > struct net_device *dsa_port_to_bridge_port(const struct dsa_port *dp) > { > if (!dp->bridge) > return NULL; > > if (dp->lag) > return dp->lag->dev; > else if (dp->hsr_dev) > return dp->hsr_dev; > > return dp->slave; > } > > Notice the "dp->bridge" check. The assignments are in dsa_port_bridge_create() > and in dsa_port_bridge_destroy(). These functions assume rtnl_mutex protection. > The question was how do you serialize with that, and why do you assume > that dsa_port_to_bridge_port() returns non-NULL. > > So no, dsa_is_unused_port() would do absolutely nothing to help. I was thinking in indirect terms (dangerous I know :-). But wrt the nl lock, I wonder when other threads could pull the carpet away under this, and so I might have to wait till after the last call (mv88e6xxx_g1_atu_loadpurge) to free the nl lock?