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Message-ID: <25b5f2297c98500ed91971a61ccc4bfa5921035e.camel@redhat.com>
Subject: Re: [PATCH 6/9] nilfs2: fix out-of-range warning
From: Philipp Stanner <pstanner@redhat.com>
To: Arnd Bergmann <arnd@kernel.org>, linux-kernel@vger.kernel.org, Ryusuke
	Konishi <konishi.ryusuke@gmail.com>, Nathan Chancellor <nathan@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>, Nick Desaulniers
 <ndesaulniers@google.com>,  Bill Wendling <morbo@google.com>, Justin Stitt
 <justinstitt@google.com>, Andrew Morton <akpm@linux-foundation.org>,
 Christian Brauner <brauner@kernel.org>, Jeff Layton <jlayton@kernel.org>,
 Thorsten Blum <thorsten.blum@toblux.com>,  linux-nilfs@vger.kernel.org,
 llvm@lists.linux.dev, pstanner@redhat.com
Date: Thu, 28 Mar 2024 16:21:38 +0100
In-Reply-To: <20240328143051.1069575-7-arnd@kernel.org>
References: <20240328143051.1069575-1-arnd@kernel.org>
	 <20240328143051.1069575-7-arnd@kernel.org>
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On Thu, 2024-03-28 at 15:30 +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>=20
> clang-14 points out that v_size is always smaller than a 64KB
> page size if that is configured by the CPU architecture:
>=20
> fs/nilfs2/ioctl.c:63:19: error: result of comparison of constant
> 65536 with expression of type '__u16' (aka 'unsigned short') is
> always false [-Werror,-Wtautological-constant-out-of-range-compare]
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (argv->v_size > PAGE_SIZE)
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ~~~~~~=
~~~~~~ ^ ~~~~~~~~~
>=20
> This is ok, so just shut up that warning with a cast.

nit:
It's not a warning, but actually a compile error, right?

(no idea why they make that an error btw. Warning would be perfectly
fine)

>=20
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Should / could that be backported to stable kernels in case people
start building those with clang-14?

Regards,
P.

> ---
> =C2=A0fs/nilfs2/ioctl.c | 2 +-
> =C2=A01 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
> index f1a01c191cf5..8be471ce4f19 100644
> --- a/fs/nilfs2/ioctl.c
> +++ b/fs/nilfs2/ioctl.c
> @@ -60,7 +60,7 @@ static int nilfs_ioctl_wrap_copy(struct the_nilfs
> *nilfs,
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (argv->v_nmembs =3D=3D=
 0)
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0return 0;
> =C2=A0
> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (argv->v_size > PAGE_SIZE)
> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if ((size_t)argv->v_size > PAG=
E_SIZE)
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0return -EINVAL;
> =C2=A0
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0/*