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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 54D39C56202 for ; Thu, 26 Nov 2020 07:29:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACF0C2173E for ; Thu, 26 Nov 2020 07:29:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DzLNjMcJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388459AbgKZH3J (ORCPT ); Thu, 26 Nov 2020 02:29:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729990AbgKZH3J (ORCPT ); Thu, 26 Nov 2020 02:29:09 -0500 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B98FC0613D4 for ; Wed, 25 Nov 2020 23:29:09 -0800 (PST) Received: by mail-pg1-x543.google.com with SMTP id l17so1002839pgk.1 for ; Wed, 25 Nov 2020 23:29:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=1pi9O3cyuNu1mNgsP919qLPV/NgB9Q3iHB4i+uum6yk=; b=DzLNjMcJmlfr82HmrsJXykti2GEhPMrG0SEg7zKdoGbGUVRum4GMN5MIJsTypxi/ao YNlUaUkr+ygnUlpsmUAxWN8I0yhtJb0msg7nVNQUaRz1XSSwrCIzhcRibOSkk08BFuZ3 IThSmYUZSNx3Lgg43FTfYi4zx4mHQp7W4dvgOlWE5oqjSMLE05uiXU88mcVBOig2/0Fd FFuZkDjSIiwHVtRA3J4tusKHawtaDG4D1tdvrQMKJayh6FZAYMeLbMKld6QqPPnAkFbY +ASb8Fd6Fp3HE1+NZX9/uJLUsQAGfpZW0k+PzjBtQpUadh624p48I1b58uv3PbGDexuC Ylpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=1pi9O3cyuNu1mNgsP919qLPV/NgB9Q3iHB4i+uum6yk=; b=rJFklGT/eef+b/Twpb0YTqFW8xz762WOV03dSCK/f3nAtjyEc4BqoB4kFd7u9Wv5wY XqarTOS3XlKoJ7M01366KQiMlrNyZY2a4YF/76bEq616+mcDGwRMgKbuBZqA3ioMomf3 IA0GVAQTMnmMnND6D1BfJ498CH2RiFg/RlPLfitBjDryIE7jw/VHCF8GO4VufVbaqiq7 JSuoJ8eXPFpz1dMR4VrhL7CxxtL9Vif5M2R44qnc+f17j9Y09R8ayV5c114coT6Ut9Aj XSk2FT4YW2dI0KqMX2Pr3mikVts6sbY2xwCNXeUTOJnh2kqWBuaWXrYLzqfvpOoKMblx qUqg== X-Gm-Message-State: AOAM532OfFRwOoBnsZVvL+fdYLd4Sr0LZyZPxPRTwosEk15mFLcQCKLx Bpm48UjkqWViAtB5y93CQik9luRHq2O2tL0+ X-Google-Smtp-Source: ABdhPJz4KICB0kuuy0BPKk/Hr7oanZ67ULP4kWWRn8saCecz2h3+3CZOjPt7Dh/PgMFCOokoAWNJOQ== X-Received: by 2002:a05:6a00:228a:b029:18b:212a:1af7 with SMTP id f10-20020a056a00228ab029018b212a1af7mr1697062pfe.55.1606375748924; Wed, 25 Nov 2020 23:29:08 -0800 (PST) Received: from localhost.localdomain ([2405:201:9004:6052:6026:75db:5ad2:e7b3]) by smtp.gmail.com with ESMTPSA id j74sm3805528pfd.43.2020.11.25.23.29.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Nov 2020 23:29:07 -0800 (PST) From: Dwaipayan Ray To: joe@perches.com Cc: linux-kernel-mentees@lists.linuxfoundation.org, dwaipayanray1@gmail.com, linux-kernel@vger.kernel.org, lukas.bulwahn@gmail.com Subject: [PATCH RFC] checkpatch: add warning for unnecessary use of %h[xudi] and %hh[xudi] Date: Thu, 26 Nov 2020 12:58:40 +0530 Message-Id: <20201126072840.32681-1-dwaipayanray1@gmail.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Modifiers %h and %hh should never be used. Commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]") specifies that: "Standard integer promotion is already done and %hx and %hhx is useless so do not encourage the use of %hh[xudi] or %h[xudi]." "The "h" and "hh" things should never be used. The only reason for them being used if you have an "int", but you want to print it out as a "char" (and honestly, that is a really bad reason, you'd be better off just using a proper cast to make the code more obvious)." Add a new check to emit a warning on finding an unneeded use of %h or %hh modifier. Link: https://lore.kernel.org/lkml/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.camel@perches.com/ Suggested-by: Lukas Bulwahn Signed-off-by: Dwaipayan Ray --- scripts/checkpatch.pl | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 7dc094445d83..47c1017a9973 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6570,6 +6570,19 @@ sub process { } } +# check for unnecessary use of %h[xudi] and %hh[xudi] + if ($perl_version_ok && + defined $stat && + $line =~ /(?:[sd]?print[kfd]|(?:pr_|drm_)(?:info|debug|warn|error))/i) { + my $lc = $stat =~ tr@\n@@; + $lc = $lc + $linenr; + my $stat_real = get_stat_real($linenr, $lc); + if ($stat_real =~ /\"[^\"]*%[\d\.\*\-]*h+[idux].*\"/i) { + WARN("UNNECESSARY_MODIFIER", + "Unnecessary use of length modifiers %h[xudi] or %hh[xudi]\n" . "$here\n$stat_real\n"); + } + } + # check for naked sscanf if ($perl_version_ok && defined $stat && -- 2.27.0