Re: [PATCH v3 01/11] checkpatch: check for nested (un)?likely() calls

From: Denis Efremov <efremov@linux.com>
To: Markus Elfring <Markus.Elfring@web.de>, Joe Perches <joe@perches.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Anton Altaparmakov" <anton@tuxera.com>,
	"Andy Whitcroft" <apw@canonical.com>,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
	"Boris Pismenny" <borisp@mellanox.com>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Dennis Dalessandro" <dennis.dalessandro@intel.com>,
	"Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
	dri-devel@lists.freedesktop.org,
	"Inaky Perez-Gonzalez" <inaky.perez-gonzalez@intel.com>,
	"Jürgen Groß" <jgross@suse.com>,
	"Leon Romanovsky" <leon@kernel.org>,
	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" <mike.marciniszyn@intel.com>,
	netdev@vger.kernel.org, "Pali Rohár" <pali.rohar@gmail.com>,
	"Rob Clark" <robdclark@gmail.com>,
	"Saeed Mahameed" <saeedm@mellanox.com>,
	"Sean Paul" <sean@poorly.run>,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	xen-devel@lists.xenproject.org, "Enrico Weigelt" <lkml@metux.net>
Subject: Re: [PATCH v3 01/11] checkpatch: check for nested (un)?likely() calls
Date: Sat, 31 Aug 2019 18:54:12 +0300	[thread overview]
Message-ID: <689c8baf-2298-f086-3461-5cd1cdd191c6@linux.com> (raw)
In-Reply-To: <0d9345ed-f16a-de0b-6125-1f663765eb46@web.de>


On 31.08.2019 12:15, 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?

Hmm, 
(?:   <- Catch group is required here, since it is used in diagnostic message,
         see $1
   IS_ERR
   (?:_ <- Another atomic group just to show that '_' is a common prefix?
           I'm not sure about this. Usually, Perl interpreter is very good at optimizing such things.
           You could see this optimization if you run perl with -Mre=debug.
     (?:OR_NULL|VALUE))?|WARN)

Regards,
Denis