From patchwork Tue Apr 12 12:15:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakob Koschel X-Patchwork-Id: 12810727 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 02AEFC43219 for ; Tue, 12 Apr 2022 12:47:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352123AbiDLMuD (ORCPT ); Tue, 12 Apr 2022 08:50:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355272AbiDLMsJ (ORCPT ); Tue, 12 Apr 2022 08:48:09 -0400 Received: from mail-ej1-x62b.google.com (mail-ej1-x62b.google.com [IPv6:2a00:1450:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 19CD51AA; Tue, 12 Apr 2022 05:16:27 -0700 (PDT) Received: by mail-ej1-x62b.google.com with SMTP id r13so36972813ejd.5; Tue, 12 Apr 2022 05:16:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=SauRrPtkvH++wq5kM/ENmKVywKLBbnGlq4WrfqqSV+A=; b=KMMgTD4eqHSocfjUAX9sOYUKbAccfIdzUX7Y/cKXBZaA3DdYKoxaDEkMTRpY15o4Pp LEFDk2i7uYe0t8MnS99DWhcmH+n3krrsHjMfb/I9AeIsI7boJcVxlx6SSr3LxEFaO10s E+dBacnWczSHi6Vv6AnA0AFsgkjnfCuvnjTVH0BbxhhbuNqE4UFa+48BgViG/28eaG4b NZ2UlhPW2IbUHdjPVlGa6lA+1bTtbP/b9QYneqAekedYypLIIGTSjCsrCIUhJyEnNBmX FE6NJWukEY4Gyqss5WRrieAK/t7AiE0doun7ScIXJIEFBdGzgs0avwpahmiPVU8aR1Vm oAvQ== 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:date:message-id:mime-version :content-transfer-encoding; bh=SauRrPtkvH++wq5kM/ENmKVywKLBbnGlq4WrfqqSV+A=; b=4PbbPCtQ+0o0AMjvBnJU3fHhDynChtypLs/tfoxD5SwvfyCkjoW8s+bPdhPSAvOBn3 F9Bu/BJpCDHINqBjRwBF1Z+IqGFxobaOjOWWTWuGTyu8ZU4YsM+fo+euEsBEsFIY+iIk rbqBgCmdz+0yGAlo0+HnWXdiVWoX83GrbLtgCEGINxD/ha9+79KZu2V24E8jqIUrAY7Q MkZlDyEdhE7EXHGJeZ53JYWagS0orrI2HtywJh4l5Xw6lGEMmjmppb2o2oUY7aOfoxbp Egg/+zC9PCrkvoEr8gtD++2BpXtwAKBQxsF8xxjtgh7f0Fj4l5JEoIb5+U0VDvZtji1P 0Zmw== X-Gm-Message-State: AOAM533ctt5iwr+kjpXvLZaG/V4SNVwPV4ha4didb8pxO0g43ufexlxE UgKqEXWbAKLkhpXKbUjn9sk= X-Google-Smtp-Source: ABdhPJwaLV9WCXwPNDN9XsaLWYamOBWtMxnQwfCpN462OFM8kyd9vvvxbB2FB9m9bGxFmOH6VZCyVA== X-Received: by 2002:a17:906:2991:b0:6cd:ac19:ce34 with SMTP id x17-20020a170906299100b006cdac19ce34mr34558940eje.746.1649765780565; Tue, 12 Apr 2022 05:16:20 -0700 (PDT) Received: from localhost.localdomain (i130160.upc-i.chello.nl. [62.195.130.160]) by smtp.googlemail.com with ESMTPSA id b5-20020a17090630c500b006e8044fa76bsm8827900ejb.143.2022.04.12.05.16.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Apr 2022 05:16:20 -0700 (PDT) From: Jakob Koschel To: "David S. Miller" Cc: Jakub Kicinski , Paolo Abeni , Andrew Lunn , Vivien Didelot , Florian Fainelli , Vladimir Oltean , Lars Povlsen , Steen Hegelund , UNGLinuxDriver@microchip.com, Ariel Elior , Manish Chopra , Edward Cree , Martin Habets , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Jiri Pirko , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Casper Andersson , Bjarni Jonasson , Jakob Koschel , Christophe JAILLET , Michael Walle , Jason Gunthorpe , Colin Ian King , Arnd Bergmann , Eric Dumazet , Di Zhu , Xu Wang , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, bpf@vger.kernel.org, Mike Rapoport , "Brian Johannesmeyer" , Cristiano Giuffrida , "Bos, H.J." Subject: [PATCH net-next v3 00/18] Remove use of list iterator after loop body Date: Tue, 12 Apr 2022 14:15:39 +0200 Message-Id: <20220412121557.3553555-1-jakobkoschel@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When the list iterator loop does not exit early the list iterator variable contains a type-confused pointer to a 'bogus' list element computed based on the head [1]. Often a 'found' variable is used to ensure the list iterator variable is only accessed after the loop body if the loop did exit early (using a break or goto). In other cases that list iterator variable is used in combination to access the list member which reverses the invocation of container_of() and brings back a "safe" pointer to the head of the list. Since, due to this code patten, there were quite a few bugs discovered [2], Linus concluded that the rule should be to never use the list iterator after the loop and introduce a dedicated pointer for that [3]. With the new gnu11 standard, it will now be possible to limit the scope of the list iterator variable to the traversal loop itself by defining the variable within the for loop. This, however, requires to remove all uses of the list iterator after the loop. Based on input from Paolo Abeni [4], Vinicius Costa Gomes [5], and Jakub Kicinski [6], I've splitted all the net-next related changes into two patch sets, where this is part 1. v2->v3: - fix commit authors and signed-off order regarding Vladimir's patches (Sorry about that, wasn't intentional.) v1->v2: - Fixed commit message for PATCH 14/18 and used dedicated variable pointing to the position (Edward Cree) - Removed redundant check in mv88e6xxx_port_vlan() (Vladimir Oltean) - Refactor mv88e6xxx_port_vlan() using separate list iterator functions (Vladimir Oltean) - Refactor sja1105_insert_gate_entry() to use separate list iterator functions (Vladimir Oltean) - Allow early return in sja1105_insert_gate_entry() if sja1105_first_entry_longer_than() didn't find any element (Vladimir Oltean) - Use list_add_tail() instead of list_add() in sja1105_insert_gate_entry() (Jakub Kicinski) - net: netcp: also use separate 'pos' variable instead of duplicating list_add() Link: https://lwn.net/Articles/887097/ [1] Link: https://lore.kernel.org/linux-kernel/20220217184829.1991035-4-jakobkoschel@gmail.com/ [2] Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [3] Link: https://lore.kernel.org/linux-kernel/7393b673c626fd75f2b4f8509faa5459254fb87c.camel@redhat.com/ [4] Link: https://lore.kernel.org/linux-kernel/877d8a3sww.fsf@intel.com/ [5] Link: https://lore.kernel.org/linux-kernel/20220403205502.1b34415d@kernel.org/ [6]