Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 14 Jun 2023 15:33:33 +0100
From:   Conor Dooley <conor@kernel.org>
To:     Wang Ming <machel@vivo.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        linux-kernel@vger.kernel.org, opensource.kernel@vivo.com
Subject: Re: [PATCH v1] drivers:base:Fix unsigned compared with less than zero
Message-ID: <20230614-passcode-stimulate-70eecb6d81d2@spud>
References: <20230614133549.3774-1-machel@vivo.com>
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Hey,

On Wed, Jun 14, 2023 at 09:35:36PM +0800, Wang Ming wrote:
> The return value of the of_count_cache_leaves() is long.
> However, the return value is being assigned to an unsigned
> long variable 'leaves',so making 'leaves' to long.

But you actually made it an int?

> silence the warning:
> ./drivers/base/cacheinfo.c:300:5-11: WARNING: Unsigned expression
> compared with zero: leaves > 0

I'm dumb, why is comparing an unsigned value with zero a problem in and
of itself? Zero is a valid value for an unsigned type, no?

If you actually look at the function, it only returns positive, non-zero
values anyway, so returning an int is a bit pointless, as are the
checks, no?

>=20
> Signed-off-by: Wang Ming <machel@vivo.com>
> ---
>  drivers/base/cacheinfo.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index cbae8be1f..7280d5cb3 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -289,7 +289,8 @@ int init_of_cache_level(unsigned int cpu)
>         struct cpu_cacheinfo *this_cpu_ci =3D get_cpu_cacheinfo(cpu);
>         struct device_node *np =3D of_cpu_device_node_get(cpu);
>         struct device_node *prev =3D NULL;
> -       unsigned int levels =3D 0, leaves, level;
> +       unsigned int levels =3D 0, level;
> +       int leaves;
>=20
>         if (!of_check_cache_nodes(np)) {
>                 of_node_put(np);
> --
> 2.25.1
>=20
>=20
> ________________________________
> =E6=9C=AC=E9=82=AE=E4=BB=B6=E5=8F=8A=E5=85=B6=E9=99=84=E4=BB=B6=E5=86=85=
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=E5=88=A0=E9=99=A4=E3=80=82=E8=B0=A2=E8=B0=A2=E3=80=82
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^^^
Gotta sort this out chief, I should probably be deleting this, not
replying to it...

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