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From:   Austin Kim <austindh.kim@gmail.com>
Date:   Wed, 3 Nov 2021 17:15:13 +0900
Message-ID: <CADLLry4fgoj5CVeZ8M+QmzzvQ=GTj2AheBJA3eMeSTZT47scNA@mail.gmail.com>
Subject: Re: [PATCH] cachefiles: remove always false 'datalen < 0' expression
To:     dhowells@redhat.com
Cc:     linux-cachefs@redhat.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?6rmA64+Z7ZiE?= <austin.kim@lge.com>
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2021=EB=85=84 8=EC=9B=94 24=EC=9D=BC (=ED=99=94) =EC=98=A4=ED=9B=84 12:18, =
Austin Kim <austindh.kim@gmail.com>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> From: Austin Kim <austin.kim@lge.com>
>
> Since 'datalen' is declared as size_t, the 'datalen < 0' expression
> is always false. Where size_t is defined as below;
>
>    typedef unsigned long __kernel_ulong_t;
>    typedef __kernel_ulong_t __kernel_size_t;
>    typedef __kernel_size_t size_t;
>
> So it had better remove unnecessary 'always false' expression.
>
> Signed-off-by: Austin Kim <austin.kim@lge.com>
> ---
>  fs/cachefiles/daemon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
> index 752c1e43416f..1cfed9e0812a 100644
> --- a/fs/cachefiles/daemon.c
> +++ b/fs/cachefiles/daemon.c
> @@ -225,7 +225,7 @@ static ssize_t cachefiles_daemon_write(struct file *f=
ile,
>         if (test_bit(CACHEFILES_DEAD, &cache->flags))
>                 return -EIO;
>
> -       if (datalen < 0 || datalen > PAGE_SIZE - 1)
> +       if (datalen > PAGE_SIZE - 1)
>                 return -EOPNOTSUPP;
>
>         /* drag the command string into the kernel so we can parse it */
> --
> 2.20.1
>

If you are available, would you please review this patch?
It will not take long.

BR,
Austin Kim