On Mon, Oct 26, 2020 at 09:13:23AM +0000, David Laight wrote:
From: Stefano Garzarella
Sent: 26 October 2020 08:43
...
>Isn't the canonical error for unknown ioctl codes -ENOTTY?
>
Oh, thanks for pointing that out!
I had not paid attention to the error returned, but looking at it I
noticed that perhaps the most appropriate would be -ENOIOCTLCMD.
In the ioctl syscall we return -ENOTTY, if the callback returns
-ENOIOCTLCMD.
What do you think?
It is 729 v 443 in favour of ENOTTY (based on grep).
Under net/ it is 6 vs 83 in favour of ENOIOCTLCMD.
No idea where ENOIOCTLCMD comes from, but ENOTTY probably
goes back to the early 1970s.
Me too.
The fact that the ioctl wrapper converts the value is a good
hint that userspace expects ENOTTY.
Agree on that, but since we are not interfacing directly with userspace,
I think it is better to return the more specific error (ENOIOCTLCMD).
Thanks,
Stefano
