Re: [RFC PATCH 0/3] RDMA/smbdirect: introduce and use rdma_restrict_node_type()

[Leon Romanovsky <leon@kernel.org>]

On Tue, Feb 03, 2026 at 04:25:35PM +0100, Stefan Metzmacher wrote:
> Am 28.01.26 um 15:11 schrieb Leon Romanovsky:
> > On Wed, Jan 21, 2026 at 09:07:10PM +0100, Stefan Metzmacher wrote:
> > > Hi,
> > > 
> > > for smbdirect it required to use different ports depending
> > > on the RDMA protocol. E.g. for iWarp 5445 is needed
> > > (as tcp port 445 already used by the raw tcp transport for SMB),
> > > while InfiniBand, RoCEv1 and RoCEv2 use port 445, as they
> > > use an independent port range (even for RoCEv2, which uses udp
> > > port 4791 itself).
> > > 
> > > Currently ksmbd is not able to function correctly at
> > > all if the system has iWarp (RDMA_NODE_RNIC) interface(s)
> > > and any InfiniBand, RoCEv1 and/or RoCEv2 interface(s)
> > > at the same time.
> > > 
> > > And cifs.ko uses 5445 with a fallback to 445, which
> > > means depending on the available interfaces, it tries
> > > 5445 in the RoCE range or may tries iWarp with 445
> > > as a fallback. This leads to strange error messages
> > > and strange network captures.
> > > 
> > > To avoid these problems they will be able to
> > > use rdma_restrict_node_type(RDMA_NODE_RNIC) before
> > > trying port 5445 and rdma_restrict_node_type(RDMA_NODE_IB_CA)
> > > before trying port 445. It means we'll get early
> > > -ENODEV early from rdma_resolve_addr() without any
> > > network traffic and timeouts.
> > > 
> > > This is marked as RFC as I want to get feedback
> > > if the rdma_restrict_node_type() function is acceptable
> > > for the RDMA layer. And because the current form of
> > > the smb patches are not tested, I only tested the
> > > rdma part with my branch the prepares IPPROTO_SMBDIRECT
> > > sockets.
> > > 
> > > I'm not sure if this would be acceptable for 6.19
> > > in order to avoid the smb layer problems, if the
> > > RDMA layer change is only acceptable for 7.0 that's
> > > also fine.
> > > 
> > > This is based on the following fix applied:
> > > smb: server: reset smb_direct_port = SMB_DIRECT_PORT_INFINIBAND on init
> > > https://lore.kernel.org/linux-cifs/20251208154919.934760-1-metze@samba.org/
> > > It's not yet in Linus' tree, so if this gets ready
> > > before it's merged we can squash it.
> > > 
> > > Stefan Metzmacher (3):
> > >    RDMA/core: introduce rdma_restrict_node_type()
> > >    smb: client: make use of rdma_restrict_node_type()
> > >    smb: server: make use of rdma_restrict_node_type()
> > 
> > The approach looks reasonable.
> 
> Thanks!
> 
> > Do you want me to take it through RDMA
> > tree?
> 
> As I also have other smb patches on top changing/using
> it I guess it would be easier if Steve would take them.
> 
> Steve, Leon what do you think?

I'm ok with that, let's me add my Acked-by on first patch.

Thanks

> 
> Thanks!
> metze