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=-3.8 required=3.0 tests=BAYES_00, 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 572AEC4361B for ; Sat, 12 Dec 2020 18:49:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF79F207C7 for ; Sat, 12 Dec 2020 18:49:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404822AbgLLStm (ORCPT ); Sat, 12 Dec 2020 13:49:42 -0500 Received: from smtprelay0132.hostedemail.com ([216.40.44.132]:42224 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726167AbgLLStj (ORCPT ); Sat, 12 Dec 2020 13:49:39 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay04.hostedemail.com (Postfix) with ESMTP id B983F180A7FE4; Sat, 12 Dec 2020 18:48:58 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: hour92_2d166912740b X-Filterd-Recvd-Size: 2591 Received: from XPS-9350.home (unknown [47.151.137.21]) (Authenticated sender: joe@perches.com) by omf04.hostedemail.com (Postfix) with ESMTPA; Sat, 12 Dec 2020 18:48:56 +0000 (UTC) Message-ID: <03bb4d4436ca7022effbf23551ada24ff9eeb4c6.camel@perches.com> Subject: Re: mmc: atmel-mci: Reduce scope for the variable =?UTF-8?Q?=E2=80=9Cslot=E2=80=9D?= in atmci_request_end() From: Joe Perches To: Alexandre Belloni Cc: Markus Elfring , linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ludovic Desroches , Nicolas Ferre , Ulf Hansson , LKML , kernel-janitors@vger.kernel.org, Colin Ian King , Dan Carpenter Date: Sat, 12 Dec 2020 10:48:55 -0800 In-Reply-To: <20201212131727.GL1781038@piout.net> References: <466b4c6d-032f-fbcc-58ac-75f6f39d734f@web.de> <20201210151035.GC1578121@piout.net> <20201210170723.GD1578121@piout.net> <2667790c-fad2-aaa9-36e8-6be66949ac8d@web.de> <20201210182150.GE1578121@piout.net> <4c0d8efe-de25-f168-8b8d-b7f1ede6c6b1@web.de> <20201211080301.GC1781038@piout.net> <031a64e4261e1543a136d737436abefd63dbaee1.camel@perches.com> <20201212131727.GL1781038@piout.net> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2020-12-12 at 14:17 +0100, Alexandre Belloni wrote: > On 12/12/2020 01:16:39-0800, Joe Perches wrote: > > In this case Alexandre it seems true, but in the generic case > > it may be false. It may depend on stack size and location. > > > > For instance, with large structs declared either at the top > > of a function or in separate branches within the function: > > I think you realize your example is way more complicated than > initializing basic type variable to 0 or NULL which has probably been > optimized forever. Maybe. Markus does a lot of what most (or perhaps some) consider thoughtless. A generic point might be maximizing the local scope of declarations. Maximizing the local scope can make reading easier as the type of an automatic used for a temporary purpose can be found closer to the code that uses it. This is especially true for long line-count functions. IMO: it's a reasonable goal though in this instance perhaps unnecessary. cheers, Joe