On Wed, May 23, 2018 at 11:56:36AM -0400, David Miller wrote: > From: Guillaume Nault <g.nault@xxxxxxxxxxxx> > Date: Wed, 23 May 2018 15:57:08 +0200 > > > I'd rather add > > + if (cmd == PPPIOCDETACH) { > > + err = -EINVAL; > > + goto out; > > + } > > > > Making PPPIOCDETACH unknown to ppp_generic means that the ioctl would > > be handled by the underlying channel when pf->kind == CHANNEL (see the > > chan->ops->ioctl() call further down). That shouldn't be a problem per > > se, but even though PPPIOCDETACH is unsupported, I feel that it should > > remain a ppp_generic thing. I don't really want its value to be reused > > for other purposes in the future or have different behaviour depending > > on the underlying channel. > > > > Also PPPIOCDETACH can already fail with -EINVAL. Therefore, if ever > > there really were programs out there using this call, they'd already > > have to handle this case. Unconditionally returning -EINVAL would > > further minimise possibilities for breakage. > > I agree. Okay, I'll do that and leave the ioctl number reserved. I will add a pr_warn_once() too. Thanks, - Eric