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=-2.3 required=3.0 tests=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 AE025C3A5A6 for ; Sat, 31 Aug 2019 17:07:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C41622D37 for ; Sat, 31 Aug 2019 17:07:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728423AbfHaRHl (ORCPT ); Sat, 31 Aug 2019 13:07:41 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:44855 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728119AbfHaRHl (ORCPT ); Sat, 31 Aug 2019 13:07:41 -0400 Received: by mail-ed1-f66.google.com with SMTP id a21so11559656edt.11; Sat, 31 Aug 2019 10:07:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Lik2TQFtm24ZeMK7lbOS3RM+iMDhKtG/DlU1Hn/vZvk=; b=IzJRNCSwoQaaawnqH5JdQhmrYzO19Ll6eYto0R1OjvO+dLU0rqEfq9SHnOBHM4ZJmd PZVOH6es77IXwL9eQS9AS45/VuyjnKGEcSuFCpbTWMU8OqPgXZSrUdAN0ze+MSfUGe4h UD8jfnSbkTUK+oALMnqQff0HvXr9w5bYf0Q4aBZH4x6D+BojR3LeEtdPFbQphnskvAPR RFjb49+o+9L+N1BF6gyKlTMlODxDbg77UnIEdTQnUwbFJWTp1jkHJZG1h49eX8qgICpJ Lnk+zEtSzCNjLeOlun606LVo6Zj4C/hyVR096kFtvgw5ptdfD+ph+r2roCxu+wTA4qLE IQ4A== X-Gm-Message-State: APjAAAWnzPTprPpd4yAextydYr/KFliZwBLSAjicJFr7z5c+QVebLtpV W5aUKwVNipYyFRQKWJQSdsE= X-Google-Smtp-Source: APXvYqwYiVn+T/jnXqHdTksQFpnl6eq02sfkOXYISHWm5GobK2D0xg22AxYic/zL89Sp0zVPu8fsxw== X-Received: by 2002:a50:88c5:: with SMTP id d63mr21674654edd.122.1567271258673; Sat, 31 Aug 2019 10:07:38 -0700 (PDT) Received: from [10.68.32.192] (broadband-188-32-48-208.ip.moscow.rt.ru. [188.32.48.208]) by smtp.gmail.com with ESMTPSA id i23sm1739594edv.11.2019.08.31.10.07.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 31 Aug 2019 10:07:38 -0700 (PDT) Subject: Re: [PATCH v3 01/11] checkpatch: check for nested (un)?likely() calls To: Markus Elfring , Joe Perches Cc: Andrew Morton , Anton Altaparmakov , Andy Whitcroft , Boris Ostrovsky , Boris Pismenny , "Darrick J. Wong" , "David S. Miller" , Dennis Dalessandro , Dmitry Torokhov , dri-devel@lists.freedesktop.org, Inaky Perez-Gonzalez , =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , Leon Romanovsky , linux-arm-msm@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, linux-rdma@vger.kernel.org, linux-wimax@intel.com, linux-xfs@vger.kernel.org, Mike Marciniszyn , netdev@vger.kernel.org, =?UTF-8?Q?Pali_Roh=c3=a1r?= , Rob Clark , Saeed Mahameed , Sean Paul , Alexander Viro , xen-devel@lists.xenproject.org, Enrico Weigelt References: <20190829165025.15750-1-efremov@linux.com> <0d9345ed-f16a-de0b-6125-1f663765eb46@web.de> <689c8baf-2298-f086-3461-5cd1cdd191c6@linux.com> <493a7377-2de9-1d44-cd8f-c658793d15db@web.de> From: Denis Efremov Message-ID: Date: Sat, 31 Aug 2019 20:07:34 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <493a7377-2de9-1d44-cd8f-c658793d15db@web.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 31.08.2019 19:45, Markus Elfring wrote: >>>> +# nested likely/unlikely calls >>>> +        if ($line =~ /\b(?:(?:un)?likely)\s*\(\s*!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?|WARN)/) { >>>> +            WARN("LIKELY_MISUSE", >>> >>> How do you think about to use the specification “(?:IS_ERR(?:_(?:OR_NULL|VALUE))?|WARN)” >>> in this regular expression? > … >> IS_ERR >> (?:_ <- Another atomic group just to show that '_' is a common prefix? > > Yes. - I hope that this specification detail can help a bit. I'm not sure that another pair of brackets for a single char worth it. >> Usually, Perl interpreter is very good at optimizing such things. The interpreter optimizes it internally: echo 'IS_ERR_OR_NULL' | perl -Mre=debug -ne '/IS_ERR(?:_OR_NULL|_VALUE)?/ && print' Compiling REx "IS_ERR(?:_OR_NULL|_VALUE)?" Final program: 1: EXACT (4) 4: CURLYX[0]{0,1} (16) 6: EXACT <_> (8) <-- common prefix 8: TRIE-EXACT[OV] (15) ... > > Would you like to help this software component by omitting a pair of > non-capturing parentheses at the beginning? > > \b(?:un)?likely\s* This pair of brackets is required to match "unlikely" and it's optional in order to match "likely". Regards, Denis