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Message-ID: <a069393c-86b3-ef79-82dd-0b60caf2a907@intel.com>
Date:   Thu, 2 Nov 2023 09:57:45 +0100
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Subject: Re: [PATCH] rfkill: return ENOTTY on invalid ioctl
To:     =?UTF-8?Q?Thomas_Wei=c3=9fschuh?= <linux@weissschuh.net>,
        Johannes Berg <johannes@sipsolutions.net>,
        "David S. Miller" <davem@davemloft.net>,
        "Eric Dumazet" <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
CC:     <linux-wireless@vger.kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20231101-rfkill-ioctl-enosys-v1-1-5bf374fabffe@weissschuh.net>
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From:   Przemek Kitszel <przemyslaw.kitszel@intel.com>
In-Reply-To: <20231101-rfkill-ioctl-enosys-v1-1-5bf374fabffe@weissschuh.net>
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On 11/1/23 20:41, Thomas Weißschuh wrote:
> For unknown ioctls the correct error is
> ENOTTY "Inappropriate ioctl for device".

For sure!

I would like to learn more of why this is not an UAPI breaking change?

> 
> ENOSYS as returned before should only be used to indicate that a syscall
> is not available at all.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
>   net/rfkill/core.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/rfkill/core.c b/net/rfkill/core.c
> index 14cc8fe8584b..c3feb4f49d09 100644
> --- a/net/rfkill/core.c
> +++ b/net/rfkill/core.c
> @@ -1351,11 +1351,11 @@ static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
>   			     unsigned long arg)
>   {
>   	struct rfkill_data *data = file->private_data;
> -	int ret = -ENOSYS;
> +	int ret = -ENOTTY;
>   	u32 size;
>   
>   	if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
> -		return -ENOSYS;
> +		return -ENOTTY;
>   
>   	mutex_lock(&data->mtx);
>   	switch (_IOC_NR(cmd)) {
> 
> ---
> base-commit: 7d461b291e65938f15f56fe58da2303b07578a76
> change-id: 20231101-rfkill-ioctl-enosys-00a2bb0a4ab1
> 
> Best regards,