Re: [PATCH net] net/smc: Fix lookup of netdev by using ib_device_get_netdev()

[Leon Romanovsky <leon@kernel.org>]

On Fri, Nov 08, 2024 at 08:40:40AM +0900, Namjae Jeon wrote:
> On Thu, Nov 7, 2024 at 9:00 PM Halil Pasic <pasic@linux.ibm.com> wrote:
> >
> > On Wed, 6 Nov 2024 15:59:10 +0200
> > Leon Romanovsky <leon@kernel.org> wrote:
> >
> > > > Does  fs/smb/server/transport_rdma.c qualify as inside of RDMA core code?
> > >
> > > RDMA core code is drivers/infiniband/core/*.
> >
> > Understood. So this is a violation of the no direct access to the
> > callbacks rule.
> >
> > >
> > > > I would guess it is not, and I would not actually mind sending a patch
> > > > but I have trouble figuring out the logic behind  commit ecce70cf17d9
> > > > ("ksmbd: fix missing RDMA-capable flag for IPoIB device in
> > > > ksmbd_rdma_capable_netdev()").
> > >
> > > It is strange version of RDMA-CM. All other ULPs use RDMA-CM to avoid
> > > GID, netdev and fabric complexity.
> >
> > I'm not familiar enough with either of the subsystems. Based on your
> > answer my guess is that it ain't outright bugous but still a layering
> > violation. Copying linux-cifs@vger.kernel.org so that
> > the smb are aware.
> Could you please elaborate what the violation is ?

There are many, but the most screaming is that ksmbd has logic to
differentiate IPoIB devices. These devices are pure netdev devices
and should be treated like that. ULPs should treat them exactly
as they treat netdev devices.

> I would also appreciate it if you could suggest to me how to fix this.
> 
> Thanks.
> >
> > Thank you very much for all the explanations!
> >
> > Regards,
> > Halil
> >