Received-SPF: pass (google.com: domain of linux-kernel+bounces-129377-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Feedback-ID: i56a14606:Fastmail
User-Agent: Cyrus-JMAP/3.11.0-alpha0-333-gbfea15422e-fm-20240327.001-gbfea1542
Precedence: bulk
MIME-Version: 1.0
Message-Id: <bdcabb75-f9a5-4905-90b4-2c9c2cf0588a@app.fastmail.com>
In-Reply-To: <66a1d5f1-d9b2-402c-826d-955370288037@csgroup.eu>
References: <20240403080702.3509288-1-arnd@kernel.org>
 <20240403080702.3509288-19-arnd@kernel.org>
 <66a1d5f1-d9b2-402c-826d-955370288037@csgroup.eu>
Date: Wed, 03 Apr 2024 10:58:00 +0200
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Christophe Leroy" <christophe.leroy@csgroup.eu>,
 "Arnd Bergmann" <arnd@kernel.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 "Andrew Morton" <akpm@linux-foundation.org>,
 "Palmer Dabbelt" <palmer@rivosinc.com>
Cc: "Dave Hansen" <dave.hansen@linux.intel.com>,
 "Noah Goldstein" <goldstein.w.n@gmail.com>,
 "Charlie Jenkins" <charlie@rivosinc.com>
Subject: Re: [PATCH 18/34] lib: checksum: hide unused expected_csum_ipv6_magic[]
Content-Type: text/plain;charset=utf-8
Content-Transfer-Encoding: quoted-printable

On Wed, Apr 3, 2024, at 10:41, Christophe Leroy wrote:
> Le 03/04/2024 =C3=A0 10:06, Arnd Bergmann a =C3=A9crit=C2=A0:
>> From: Arnd Bergmann <arnd@arndb.de>
>>=20
>> When CONFIG_NET is disabled, an extra warning shows up for this
>> unused variable:
>>=20
>> lib/checksum_kunit.c:218:18: error: 'expected_csum_ipv6_magic' define=
d but not used [-Werror=3Dunused-const-variable=3D]
>>=20
>> Hide it under the same #ifdef as the reference to it.
>>=20
>> Fixes: f24a70106dc1 ("lib: checksum: Fix build with CONFIG_NET=3Dn")
>
> I think that commit introduced unjustified #ifdef in a C file.

> Refer=20
> https://docs.kernel.org/process/coding-style.html#conditional-compilat=
ion
>
> The fix should be:
>
> +	if (!IS_ENABLED(CONFIG_NET))
> +		return;
> +
>   	for (int i =3D 0; i < NUM_IPv6_TESTS; i++) {
>   		saddr =3D (const struct in6_addr *)(random_buf + i);
>   		daddr =3D (const struct in6_addr *)(random_buf + i +
> @@ -618,7 +620,6 @@ static void test_csum_ipv6_magic(struct kunit *tes=
t)
>   		CHECK_EQ(to_sum16(expected_csum_ipv6_magic[i]),
>   			 csum_ipv6_magic(saddr, daddr, len, proto, csum));
>   	}
> -#endif /* !CONFIG_NET */

Yes, I usually prefer that approach, and I think I tried it first
but ran into compile-time problems because csum_ipv6_magic()
is declared conditionally. Let me try again, maybe I misremember
what I did or I can remove some more #ifdef checks for this.

       Arnd