Re: [PATCH] rfkill: return ENOTTY on invalid ioctl

[Przemek Kitszel]

On 11/2/23 20:14, Thomas Weißschuh wrote:
> Hi!
>
> On 2023-11-02 09:57:45+0100, Przemek Kitszel wrote:
> > 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?
>
> "break" would mean that some user application worked correctly before
> but does not do so anymore with this change.
>
> This seems highly unlikely and I was not able to find such an
> application via Debian code search.
>
> In general I did *not* mark this change for stable so if some
> application would indeed break it gets detected before the patch hits
> a release.
>
> > > ENOSYS as returned before should only be used to indicate that a syscall
> > > is not available at all.
> > >
> > > Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
> > > ---
> > >    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,

Thanks!

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@xxxxxxxxx>