Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751382AbeAEAHN (ORCPT + 1 other); Thu, 4 Jan 2018 19:07:13 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:55762 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166AbeAEAHM (ORCPT ); Thu, 4 Jan 2018 19:07:12 -0500 Date: Thu, 4 Jan 2018 16:07:07 -0800 From: Matthew Wilcox To: "Paul E. McKenney" Cc: Joe Perches , Rao Shoaib , Boqun Feng , linux-kernel@vger.kernel.org, brouer@redhat.com, linux-mm@kvack.org Subject: Re: [PATCH 1/2] Move kfree_call_rcu() to slab_common.c Message-ID: <20180105000707.GA22237@bombadil.infradead.org> References: <1514923898-2495-1-git-send-email-rao.shoaib@oracle.com> <20180102222341.GB20405@bombadil.infradead.org> <3be609d4-800e-a89e-f885-7e0f5d288862@oracle.com> <20180104013807.GA31392@tardis> <64ca3929-4044-9393-a6ca-70c0a2589a35@oracle.com> <20180104214658.GA20740@bombadil.infradead.org> <3e4ea0b9-686f-7e36-d80c-8577401517e2@oracle.com> <20180104231307.GA794@bombadil.infradead.org> <20180104234732.GM9671@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180104234732.GM9671@linux.vnet.ibm.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Thu, Jan 04, 2018 at 03:47:32PM -0800, Paul E. McKenney wrote: > I was under the impression that typeof did not actually evaluate its > argument, but rather only returned its type. And there are a few macros > with this pattern in mainline. > > Or am I confused about what typeof does? I think checkpatch is confused by the '*' in the typeof argument: $ git diff |./scripts/checkpatch.pl --strict CHECK: Macro argument reuse 'ptr' - possible side-effects? #29: FILE: include/linux/rcupdate.h:896: +#define kfree_rcu(ptr, rcu_head) \ + __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head)) If one removes the '*', the warning goes away. I'm no perlista, but Joe, would this regexp modification make sense? +++ b/scripts/checkpatch.pl @@ -4957,7 +4957,7 @@ sub process { next if ($arg =~ /\.\.\./); next if ($arg =~ /^type$/i); my $tmp_stmt = $define_stmt; - $tmp_stmt =~ s/\b(typeof|__typeof__|__builtin\w+|typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\s*$arg\s*\)*\b//g; + $tmp_stmt =~ s/\b(typeof|__typeof__|__builtin\w+|typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\**\(*\s*$arg\s*\)*\b//g; $tmp_stmt =~ s/\#+\s*$arg\b//g; $tmp_stmt =~ s/\b$arg\s*\#\#//g; my $use_cnt = $tmp_stmt =~ s/\b$arg\b//g;