Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Song Liu <songliubraving@fb.com>
To:     Joe Perches <joe@perches.com>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
        Andy Whitcroft <apw@canonical.com>
Subject: Re: [PATCH v3] checkpatch: do not apply "initialise globals to 0"
 check to BPF progs
Thread-Topic: [PATCH v3] checkpatch: do not apply "initialise globals to 0"
 check to BPF progs
Thread-Index: AQHW/xIkjCL+hhYrfku+4kePe6r7yqpQLT8AgAAMdgA=
Date:   Tue, 9 Feb 2021 19:44:07 +0000
Message-ID: <4D649CDF-A738-468E-AD00-8A64DDB11D1D@fb.com>
References: <20210209183343.3929160-1-songliubraving@fb.com>
 <2b41e46fcf909bd67a578524107214fe4b1eeede.camel@perches.com>
In-Reply-To: <2b41e46fcf909bd67a578524107214fe4b1eeede.camel@perches.com>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-ID: <665CA15C19C9A947A26EF12B2F496439@namprd15.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 6cbb6e7b-a15f-4368-3259-08d8cd33109a
X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Feb 2021 19:44:07.7382
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: QtgHv4ilCKifkCqSxGyNzwtAuf6H6FxWvSftjVQ2XmHv9nlPVHYUUqDmq1CCXY5eK/cIrYKd9qmFBjgBsOArzg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2999
X-OriginatorOrg: fb.com
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369,18.0.737
 definitions=2021-02-09_06:2021-02-09,2021-02-09 signatures=0
X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015
 impostorscore=0 mlxscore=0 adultscore=0 mlxlogscore=999 lowpriorityscore=0
 phishscore=0 spamscore=0 suspectscore=0 malwarescore=0 priorityscore=1501
 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2009150000 definitions=main-2102090096
X-FB-Internal: deliver
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> On Feb 9, 2021, at 10:59 AM, Joe Perches <joe@perches.com> wrote:
>=20
> On Tue, 2021-02-09 at 10:33 -0800, Song Liu wrote:
>> BPF programs explicitly initialise global variables to 0 to make sure
>> clang (v10 or older) do not put the variables in the common section.
>> Skip "initialise globals to 0" check for BPF programs to elimiate error
>> messages like:
>>=20
>>     ERROR: do not initialise globals to 0
>>     #19: FILE: samples/bpf/tracex1_kern.c:21:
>>=20
>> Cc: Andy Whitcroft <apw@canonical.com>
>> Cc: Joe Perches <joe@perches.com>
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>>=20
>> ---
>> Changes v2 =3D> v3:
>>   1. Fix regex.
>=20
> Unfortunately, this has broken regexes...
>=20
>> Changes v1 =3D> v2:
>>   1. Add function exclude_global_initialisers() to keep the code clean.
>> ---
>>  scripts/checkpatch.pl | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>=20
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> []
>> @@ -2428,6 +2428,15 @@ sub get_raw_comment {
>>  	return $comment;
>>  }
>> =20
>> +sub exclude_global_initialisers {
>> +	my ($realfile) =3D @_;
>> +
>> +	# Do not check for BPF programs (tools/testing/selftests/bpf/progs/*.c=
, samples/bpf/*_kern.c, *.bpf.c).
>> +	return $realfile =3D~ m@/^tools\/testing\/selftests\/bpf\/progs\/.*\.c=
@ ||
>=20
> You don't need to escape the / when using m@@, and this doesn't work
> given the leading / after @, and it should use a trailing $
>=20
> 	return $realfile =3D~ m@^tools/testing/selftests/bpf/progs/.*\.c$@ ||
>=20
>> +		$realfile =3D~ m@^samples\/bpf\/.*_kern.c@ ||
>=20
> This is still missing an escape on the . before c@, and there's no
> trailing $ between c and @
>=20
> 		$realfile =3D~ m@^samples/bpf/.*_kern\.c$@ ||
>=20
>> +		$realfile =3D~ m@/bpf/.*\.bpf\.c$@;
>=20
> I believe I showed the correct regexes in my earlier reply.

Just to be sure I got everything correct, does the follow look right?

        return $realfile =3D~ m@^tools/testing/selftests/bpf/progs/.*\.c$@ =
||
                $realfile =3D~ m@^samples/bpf/.*_kern\.c$@ ||
                $realfile =3D~ m@/bpf/.*\.bpf\.c$@;

Thanks,
Song=