Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v3 01/11] checkpatch: check for nested (un)?likely() calls
To:     Denis Efremov <efremov@linux.com>, 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>,
        =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <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,
        =?UTF-8?Q?Pali_Roh=c3=a1r?= <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>
References: <20190829165025.15750-1-efremov@linux.com>
 <0d9345ed-f16a-de0b-6125-1f663765eb46@web.de>
 <689c8baf-2298-f086-3461-5cd1cdd191c6@linux.com>
From:   Markus Elfring <Markus.Elfring@web.de>
Autocrypt: addr=Markus.Elfring@web.de; prefer-encrypt=mutual; keydata=
 mQINBFg2+xABEADBJW2hoUoFXVFWTeKbqqif8VjszdMkriilx90WB5c0ddWQX14h6w5bT/A8
 +v43YoGpDNyhgA0w9CEhuwfZrE91GocMtjLO67TAc2i2nxMc/FJRDI0OemO4VJ9RwID6ltwt
 mpVJgXGKkNJ1ey+QOXouzlErVvE2fRh+KXXN1Q7fSmTJlAW9XJYHS3BDHb0uRpymRSX3O+E2
 lA87C7R8qAigPDZi6Z7UmwIA83ZMKXQ5stA0lhPyYgQcM7fh7V4ZYhnR0I5/qkUoxKpqaYLp
 YHBczVP+Zx/zHOM0KQphOMbU7X3c1pmMruoe6ti9uZzqZSLsF+NKXFEPBS665tQr66HJvZvY
 GMDlntZFAZ6xQvCC1r3MGoxEC1tuEa24vPCC9RZ9wk2sY5Csbva0WwYv3WKRZZBv8eIhGMxs
 rcpeGShRFyZ/0BYO53wZAPV1pEhGLLxd8eLN/nEWjJE0ejakPC1H/mt5F+yQBJAzz9JzbToU
 5jKLu0SugNI18MspJut8AiA1M44CIWrNHXvWsQ+nnBKHDHHYZu7MoXlOmB32ndsfPthR3GSv
 jN7YD4Ad724H8fhRijmC1+RpuSce7w2JLj5cYj4MlccmNb8YUxsE8brY2WkXQYS8Ivse39MX
 BE66MQN0r5DQ6oqgoJ4gHIVBUv/ZwgcmUNS5gQkNCFA0dWXznQARAQABtCZNYXJrdXMgRWxm
 cmluZyA8TWFya3VzLkVsZnJpbmdAd2ViLmRlPokCVAQTAQgAPhYhBHDP0hzibeXjwQ/ITuU9
 Figxg9azBQJYNvsQAhsjBQkJZgGABQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEOU9Figx
 g9azcyMP/iVihZkZ4VyH3/wlV3nRiXvSreqg+pGPI3c8J6DjP9zvz7QHN35zWM++1yNek7Ar
 OVXwuKBo18ASlYzZPTFJZwQQdkZSV+atwIzG3US50ZZ4p7VyUuDuQQVVqFlaf6qZOkwHSnk+
 CeGxlDz1POSHY17VbJG2CzPuqMfgBtqIU1dODFLpFq4oIAwEOG6fxRa59qbsTLXxyw+PzRaR
 LIjVOit28raM83Efk07JKow8URb4u1n7k9RGAcnsM5/WMLRbDYjWTx0lJ2WO9zYwPgRykhn2
 sOyJVXk9xVESGTwEPbTtfHM+4x0n0gC6GzfTMvwvZ9G6xoM0S4/+lgbaaa9t5tT/PrsvJiob
 kfqDrPbmSwr2G5mHnSM9M7B+w8odjmQFOwAjfcxoVIHxC4Cl/GAAKsX3KNKTspCHR0Yag78w
 i8duH/eEd4tB8twcqCi3aCgWoIrhjNS0myusmuA89kAWFFW5z26qNCOefovCx8drdMXQfMYv
 g5lRk821ZCNBosfRUvcMXoY6lTwHLIDrEfkJQtjxfdTlWQdwr0mM5ye7vd83AManSQwutgpI
 q+wE8CNY2VN9xAlE7OhcmWXlnAw3MJLW863SXdGlnkA3N+U4BoKQSIToGuXARQ14IMNvfeKX
 NphLPpUUnUNdfxAHu/S3tPTc/E/oePbHo794dnEm57LuuQINBFg2+xABEADZg/T+4o5qj4cw
 nd0G5pFy7ACxk28mSrLuva9tyzqPgRZ2bdPiwNXJUvBg1es2u81urekeUvGvnERB/TKekp25
 4wU3I2lEhIXj5NVdLc6eU5czZQs4YEZbu1U5iqhhZmKhlLrhLlZv2whLOXRlLwi4jAzXIZAu
 76mT813jbczl2dwxFxcT8XRzk9+dwzNTdOg75683uinMgskiiul+dzd6sumdOhRZR7YBT+xC
 wzfykOgBKnzfFscMwKR0iuHNB+VdEnZw80XGZi4N1ku81DHxmo2HG3icg7CwO1ih2jx8ik0r
 riIyMhJrTXgR1hF6kQnX7p2mXe6K0s8tQFK0ZZmYpZuGYYsV05OvU8yqrRVL/GYvy4Xgplm3
 DuMuC7/A9/BfmxZVEPAS1gW6QQ8vSO4zf60zREKoSNYeiv+tURM2KOEj8tCMZN3k3sNASfoG
 fMvTvOjT0yzMbJsI1jwLwy5uA2JVdSLoWzBD8awZ2X/eCU9YDZeGuWmxzIHvkuMj8FfX8cK/
 2m437UA877eqmcgiEy/3B7XeHUipOL83gjfq4ETzVmxVswkVvZvR6j2blQVr+MhCZPq83Ota
 xNB7QptPxJuNRZ49gtT6uQkyGI+2daXqkj/Mot5tKxNKtM1Vbr/3b+AEMA7qLz7QjhgGJcie
 qp4b0gELjY1Oe9dBAXMiDwARAQABiQI8BBgBCAAmFiEEcM/SHOJt5ePBD8hO5T0WKDGD1rMF
 Alg2+xACGwwFCQlmAYAACgkQ5T0WKDGD1rOYSw/+P6fYSZjTJDAl9XNfXRjRRyJSfaw6N1pA
 Ahuu0MIa3djFRuFCrAHUaaFZf5V2iW5xhGnrhDwE1Ksf7tlstSne/G0a+Ef7vhUyeTn6U/0m
 +/BrsCsBUXhqeNuraGUtaleatQijXfuemUwgB+mE3B0SobE601XLo6MYIhPh8MG32MKO5kOY
 hB5jzyor7WoN3ETVNQoGgMzPVWIRElwpcXr+yGoTLAOpG7nkAUBBj9n9TPpSdt/npfok9ZfL
 /Q+ranrxb2Cy4tvOPxeVfR58XveX85ICrW9VHPVq9sJf/a24bMm6+qEg1V/G7u/AM3fM8U2m
 tdrTqOrfxklZ7beppGKzC1/WLrcr072vrdiN0icyOHQlfWmaPv0pUnW3AwtiMYngT96BevfA
 qlwaymjPTvH+cTXScnbydfOQW8220JQwykUe+sHRZfAF5TS2YCkQvsyf7vIpSqo/ttDk4+xc
 Z/wsLiWTgKlih2QYULvW61XU+mWsK8+ZlYUrRMpkauN4CJ5yTpvp+Orcz5KixHQmc5tbkLWf
 x0n1QFc1xxJhbzN+r9djSGGN/5IBDfUqSANC8cWzHpWaHmSuU3JSAMB/N+yQjIad2ztTckZY
 pwT6oxng29LzZspTYUEzMz3wK2jQHw+U66qBFk8whA7B2uAU1QdGyPgahLYSOa4XAEGb6wbI FEE=
Message-ID: <493a7377-2de9-1d44-cd8f-c658793d15db@web.de>
Date:   Sat, 31 Aug 2019 18:45:45 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.0
MIME-Version: 1.0
In-Reply-To: <689c8baf-2298-f086-3461-5cd1cdd191c6@linux.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

>>> +# nested likely/unlikely calls
>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if ($line =3D~ /\b(?:(?:un=
)?likely)\s*\(\s*!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?|WARN)/) {
>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 WA=
RN("LIKELY_MISUSE",
>>
>> How do you think about to use the specification =E2=80=9C(?:IS_ERR(?:_(=
?:OR_NULL|VALUE))?|WARN)=E2=80=9D
>> in this regular expression?
=E2=80=A6
>    IS_ERR
>    (?:_ <- Another atomic group just to show that '_' is a common prefix=
?

Yes. - I hope that this specification detail can help a bit.


>            Usually, Perl interpreter is very good at optimizing such thi=
ngs.

Would you like to help this software component by omitting a pair of
non-capturing parentheses at the beginning?

\b(?:un)?likely\s*


Regards,
Markus