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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 6F163C43331 for ; Mon, 11 Nov 2019 21:30:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33F7C2084F for ; Mon, 11 Nov 2019 21:30:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="CGijAHat" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727233AbfKKVau (ORCPT ); Mon, 11 Nov 2019 16:30:50 -0500 Received: from mout.web.de ([212.227.15.4]:35193 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726964AbfKKVat (ORCPT ); Mon, 11 Nov 2019 16:30:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1573507844; bh=fxVlF1Zgg15ZCrFLhofu+Bts3rxSUammJp/efUAaH9I=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=CGijAHat0Gz2UxRVgC9zkfNqnN1rxRhksN7bzFsks6ITVMvgEmSxVdOigxDZZdUnz Y1jNQxJL3tQXfIA5bn0ys6iTuWhqQM9DZ1reMnilh4hm6Zi8Ltzt0bOr6MQp6MVHer Cs5l4sRk7zD6EISrQWpJS2cnYxrnvTff/xD91tuo= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.3] ([78.49.55.229]) by smtp.web.de (mrweb004 [213.165.67.108]) with ESMTPSA (Nemesis) id 0MN87U-1iWT8N3YVc-006hmr; Mon, 11 Nov 2019 22:30:43 +0100 Subject: Re: [PATCH 2/4] pwm: omap-dmtimer: simplify error handling To: =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= , linux-pwm@vger.kernel.org Cc: Neil Armstrong , Neil Brown , kernel-janitors@vger.kernel.org, LKML , Thierry Reding , kernel@pengutronix.de References: <20191111071952.6pbswbboqreen6im@pengutronix.de> <20191111090357.13903-1-u.kleine-koenig@pengutronix.de> <20191111090357.13903-2-u.kleine-koenig@pengutronix.de> <20191111200800.7njfdz7w3offt6we@pengutronix.de> From: Markus Elfring Autocrypt: addr=Markus.Elfring@web.de; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20191111200800.7njfdz7w3offt6we@pengutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:iNXGVR4sAfwA4nVSeSOdAnYXCwXNfH56QeO2rBJcwvdE9XTdrvS p7VqmMxHXhuaby7Qy2W7pkCm7j9dnZPY4pWB4DYixNMjc9kbCSv5O8MdDPdikfAKhkKGKhx WUqbIqHRdGJ5s2HS9WbQcTKbiboJ5ZhFMGUcGkDMYgeI7qcOPfOIIlER2h18GpseTiGZNIo +1xi5qTJEbo3T05HJZ9jw== X-UI-Out-Filterresults: notjunk:1;V03:K0:ORNKvg2W+C0=:ULIALGlmb/7YDVc9+OZx5x nGwshEqQkV2Gp/Ao0dZd6B7elzJ1g30cgaTwbWpxHmlvwbbAMwzIVxsXNeiijWLyNabADvV+J lEX4x4RHUAnzwl5yevjwC4oTecdnPR5zTmVfrmuFVP82VTha/eSZHyCUnuwtVgM9NS2c4thlS AWpkYDePz8myqkRrxn7T/22UiqAMU18Vb39sAoTQ1Oze+LQs9Q6fv4Au4gsLHBXwpGgZPBjGB Bfg2d1tk4iq5yvFuB8ZIKVsGwlvSSEPmtYs5GecSV/iUQBHC6y0moYrFF0nn+3HadG1f42QaM IJmQX/oTSowoqxUHi4wpye5OiKzw6tVK2211MNyLhTJwLblpiX35BdBUnKhXvoyfRzz27zCow Fy7ONNs5sEbneoAMpp0tu26/Vk3ne1MCEXFFC4XjGf9R1jWrRZS5//WOByYa8ch+3D6F1OlFq PmYcLjpiZKdhCGnbBVP1MH6IZoEVEU5FtvIiKV4axLpPnnegMTddvF82Cqmt4C+XxG/4eE63R FaseZp5lhN0BWVBkNomn23oE6dePnA8OW4oMCzTr3mhRtmlXpUdtl/XzqQApFhCIZ2u+96rnF +drd3iMhGe1JCoOk+5bVOVHckAYbfq1yz0OyHImHfZs17MQ7fNk48VrQtaagnlz9YkhZCKV8b XSSml+780SnkGUAYMLaJtgSOymX3yPYmyOCNuwXQye2jo/mxSoN7w+vYDyNGbdW37pDTCc+36 xG081oUY98CKMdfs9f06NAnHHAb0c7/6QnrNQY/ev1cXMgpNizn9LQuG52N8A/TK41JDmYia+ 4v2kwbOOHbVw9STAf2RU943v0VNC3hdWizBshqinKChBWcmBGlRQhScChw+GkfgFIk9H/Umdm T0n7iGSWIkbNRhGrHolJNButUxpkK6WrxINVeSx6Pio0Utl406WPPnwFXni9gb+nhHalvDuoB ldd6QDpj+mRhrmzZbxmnYpdI7QeRn47iLUTHGEBFBShGv8Q0Arpi2h2zUXrtCyxa/TH1eRI9Q iGvk62E5unH3WQFikNsv0xdPxzaM0VrzjORoZCVizGduu09Jtyn25CQJ/xZ8tNW8OieFuJTgH ECClUJiB0BcIusbRvdKkEZIlL2WoF/6X2sXgVS74a0j8M3u6R4UfeuXtexWIKkzpaxOQtpgkL SpGK7atustKarCz/x+OEesIgwGnl+XHL2FVQ6WsA7alexKijUpesa3QzZEwVnT8/E4xCcjmtV Mph/30eukqyrzvKRwUJFRRifif7tLWNzO19VJeQwc75VBzz/SIREbElMfxvE= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Archived-At: List-Archive: List-Post: >> Do you really want to call the function =E2=80=9Cof_node_put=E2=80=9D a= t two places now? > > Yes, this is in my eyes more sensible. Thanks for this explanation. > Either you have the expected path and the error path interwinded, > and the error path interwinded, This is also reasonable then. This design approach provides the possibility to release a few resources earlier before using additional functionality. > or you have to duplicate some cleanup. * This can be required. * I imagine that specific software infrastructures can help to avoid such duplication, can't they? > IMHO the latter variant is the one that is easier to understand and the > one where it's less likely to oversee a needed cleanup. I am curious on how the clarification will be continued. >>> +++ b/drivers/pwm/pwm-omap-dmtimer.c >> =E2=80=A6 >>> omap =3D devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL); >>> if (!omap) { >>> - pdata->free(dm_timer); >>> - return -ENOMEM; >>> + ret =3D -ENOMEM; >>> + goto err_alloc_omap; >>> } >> =E2=80=A6 >> >> I suggest to reconsider your label name selection according to >> the Linux coding style. > > Documentation/process/coding-style.rst states: "Choose label names which > say what the goto does or why the goto exists." So I'd say my names are > perfectly fine. The guidance from the example after this quotation might be still too ters= e so far, isn't it? >>> @@ -339,13 +334,28 @@ static int pwm_omap_dmtimer_probe(struct platfor= m_device *pdev) >> =E2=80=A6 >>> +err_pwmchip_add: >>> + >>> + /* >>> + * *omap is allocated using devm_kzalloc, >>> + * so no free necessary here >>> + */ >>> +err_alloc_omap: >>> + >>> + pdata->free(dm_timer); >> >> Would the use of the label =E2=80=9Cfree_dm_timer=E2=80=9D be more appr= opriate? > > Either you name your labels after what the code at the label does > (then "free_dm_timer" is good) I got used to this approach. > you name it after why you are here (and then err_alloc_omap is fine). This choice can trigger special software design consequences. > I prefer the latter style and then the label > name always has to correspond to the action just above it (if any). > That's why I grouped the "err_alloc_omap" label to a comment saying that > *omap doesn't need to be freed. I am also curious if any other contributors would like to share more views around this choice. >>> +put: >>> + of_node_put(timer); >> =E2=80=A6 >> >> Can the label =E2=80=9Cput_node=E2=80=9D be nicer? > > I agree that the label name is bad. I find your agreement on this aspect interesting then. > I kept the name here and after the 3rd patch the label names are consist= ent. Can such an evolution be questionable? Regards, Markus