On Tue, Feb 01, 2022 at 02:20:48PM +0100, Christian Brauner wrote:
> On Mon, Jan 31, 2022 at 05:33:29PM -0800, Luis Chamberlain wrote:
> > It would seem we keep tacking on things with ioctls for the block
> > layer and filesystems. Even for new trendy things like io_uring [0].
> > For a few years I have found this odd, and have slowly started
> > asking folks why we don't consider alternatives like a generic
> > netlink family. I've at least been told that this is desirable
> > but no one has worked on it. *If* we do want this I think we just
> > not only need to commit to do this, but also provide a target. LSFMM
> > seems like a good place to do this.
> >
> > Possible issues? Kernels without CONFIG_NET. Is that a deal breaker?
> > We already have a few filesystems with their own generic netlink
> > families, so not sure if this is a good argument against this.
> >
> > mcgrof@fulton ~/linux-next (git::master)$ git grep genl_register_family fs
> > fs/cifs/netlink.c: ret = genl_register_family(&cifs_genl_family);
> > fs/dlm/netlink.c: return genl_register_family(&family);
> > fs/ksmbd/transport_ipc.c: ret = genl_register_family(&ksmbd_genl_family);
> > fs/quota/netlink.c: if (genl_register_family("a_genl_family) != 0)
> > mcgrof@fulton ~/linux-next (git::master)$ git grep genl_register_family drivers/block
> > drivers/block/nbd.c: if (genl_register_family(&nbd_genl_family)) {
> >
> > Are there other reasons to *not* use generic netlink for new features?
> > For folks with experience using generic netlink on the block layer and
> > their own fs, any issues or pain points observed so far?
>
> Netlink is a giant pain to use for userspace tbh. ioctl()s aren't great
> but they are way easier to add and use.
We trade ease-of use for sloppiness. We must accept that at least.
Luis
