Re: [PATCH 1/3] checkpatch.pl: add missing memory barriers - Russell King

From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Joe Perches <joe@perches.com>
Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	virtualization@lists.linux-foundation.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	sparclinux@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	linux-arch@vger.kernel.org, linux-s390@vger.kernel.org,
	Arnd Bergmann <arnd@arndb.de>,
	linux-sh@vger.kernel.org, x86@kernel.org,
	Tony Lindgren <tony@atomide.com>,
	xen-devel@lists.xenproject.org, Ingo Molnar <mingo@elte.hu>,
	linux-xtensa@linux-xtensa.org,
	user-mode-linux-devel@lists.sourceforge.net,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	adi-buildroot-devel@lists.sourceforge.net,
	"Cc : Andy Whitcroft" <apw@canonical.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-metag@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, Andrew Cooper <andrew>
Subject: Re: [PATCH 1/3] checkpatch.pl: add missing memory barriers
Date: Mon, 4 Jan 2016 16:11:23 +0000	[thread overview]
Message-ID: <20160104161123.GJ19062__18062.4388311573$1451924019$gmane$org@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1451923660.4334.83.camel@perches.com>

On Mon, Jan 04, 2016 at 08:07:40AM -0800, Joe Perches wrote:
> On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> > +		my $all_barriers = join('|', (@barriers, @smp_barriers));
> > +
> > +		if ($line =~ /\b($all_barriers)\(/) {
> 
> It would be better to use /\b$all_barriers\s*\(/
> as there's no reason for the capture and there
> could be a space between the function and the
> open parenthesis.

I think you mean

	/\b(?:$all_barriers)\s*\(/

as 'all_barriers' will be:

	mb|wmb|rmb|smp_mb|smp_wmb|smp_rmb

and putting that into your suggestion results in:

	/\bmb|wmb|rmb|smp_mb|smp_wmb|smp_rmb\s*\(/

which is clearly wrong - the \b only applies to 'mb' and the \s*\( only
applies to smp_rmb.

-- 
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
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