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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 09F8BC64E7D for ; Sat, 28 Nov 2020 21:59:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD5F022267 for ; Sat, 28 Nov 2020 21:59:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390809AbgK1Vvg (ORCPT ); Sat, 28 Nov 2020 16:51:36 -0500 Received: from smtprelay0197.hostedemail.com ([216.40.44.197]:38522 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731051AbgK1Sre (ORCPT ); Sat, 28 Nov 2020 13:47:34 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay05.hostedemail.com (Postfix) with ESMTP id 37034180206ED; Sat, 28 Nov 2020 18:46:52 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: board30_171438327392 X-Filterd-Recvd-Size: 4846 Received: from XPS-9350.home (unknown [47.151.128.180]) (Authenticated sender: joe@perches.com) by omf02.hostedemail.com (Postfix) with ESMTPA; Sat, 28 Nov 2020 18:46:51 +0000 (UTC) Message-ID: <55d38c770a3316a3c67f5380ffb8ed37540900da.camel@perches.com> Subject: Re: [PATCH v3] checkpatch: add warning for unnecessary use of %h[xudi] and %hh[xudi] From: Joe Perches To: Dwaipayan Ray Cc: linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org, lukas.bulwahn@gmail.com Date: Sat, 28 Nov 2020 10:46:50 -0800 In-Reply-To: <20201128173850.66509-1-dwaipayanray1@gmail.com> References: <20201128173850.66509-1-dwaipayanray1@gmail.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2020-11-28 at 23:08 +0530, Dwaipayan Ray wrote: > 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. > > Also add a fix option to the check. > > Link: https://lore.kernel.org/lkml/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.camel@perches.com/ > > Suggested-by: Joe Perches > Suggested-by: Lukas Bulwahn > Signed-off-by: Dwaipayan Ray > --- > Changes in v3: > - Change warning message > - Fix regex match to include capture group > - Warn on every unnecesary use of %h on a line > - Add fix option when the format line matches current line > > Changes in v2: > - Use $logFunctions instead of the manual list. > - Relocate the check to after logging continuations check. > - Remove perl_version_ok check > >  scripts/checkpatch.pl | 16 ++++++++++++++++ >  1 file changed, 16 insertions(+) > > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl > index 7dc094445d83..dc25d32f0c5f 100755 > --- a/scripts/checkpatch.pl > +++ b/scripts/checkpatch.pl > @@ -6027,6 +6027,22 @@ sub process { >   "Avoid logging continuation uses where feasible\n" . $herecurr); >   } >   > > +# check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions > + if (defined $stat && > + $line =~ /\b$logFunctions\s*\(/) { > + my $lc = $stat =~ tr@\n@@; > + for (my $cur_ln = $linenr; $cur_ln <= $linenr + $lc; $cur_ln++) { > + my $cur_rawline = raw_line($cur_ln, 0); > + while ($cur_rawline =~ /^\+.*\"[^\"]*(%[\d\.\*\-]*h+[idux])/g) { > + if (WARN("INTEGER_PROMOTION", > + "Using 'h' in $1 is unnecessary\n" . "$cur_rawline\n") && > + $fix && ($cur_ln == $linenr)) { > + $fixed[$fixlinenr] =~ s/(\"[^\"]*%[\d\.\*\-]*)h+([idux])/$1$2/; > + } > + } > + } > + } > + Here was what I tried: There are uses like %#06hh", so # was addedto the format block and multiple line uses were also inspected. scripts/checkpatch.pl | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 7dc094445d83..b985b6b37ba8 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6027,6 +6027,29 @@ sub process { "Avoid logging continuation uses where feasible\n" . $herecurr); } +# check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions + if (defined $stat && + $line =~ /\b$logFunctions\s*\(/ && + index($stat, '"') >= 0) { + my $lc = $stat =~ tr@\n@@; + $lc = $lc + $linenr; + my $stat_real = get_stat_real($linenr, $lc); + pos($stat_real) = index($stat_real, '"'); + my $lineoff = substr($stat_real, 0, pos($stat_real)) =~ tr/\n//; + while ($stat_real =~ /[^"%]*(%[#\d\.\*\-]*(h+)[idux])/g) { + my $pspec = $1; + my $h = $2; + if (WARN("UNNECESSARY_MODIFIER", + "Integer promotion: '$h' use in '$pspec' is unnecessary\n" . "$here\n$stat_real\n") && + $fix && + $fixed[$fixlinenr + $lineoff] =~ /^\+/) { + my $nspec = $pspec; + $nspec =~ s/h//g; + $fixed[$fixlinenr + $lineoff] =~ s/\Q$pspec\E/$nspec/; + } + } + } + # check for mask then right shift without a parentheses if ($perl_version_ok && $line =~ /$LvalOrFunc\s*\&\s*($LvalOrFunc)\s*>>/ &&