Re: [RFC PATCH 1/3] RDMA/core: introduce rdma_restrict_node_type()

[Leon Romanovsky <leon@kernel.org>]

On Wed, Jan 21, 2026 at 09:07:11PM +0100, Stefan Metzmacher wrote:
> 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 designed to be called before calling any
> of rdma_bind_addr(), rdma_resolve_addr() or rdma_listen().
> 
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Leon Romanovsky <leon@kernel.org>
> Cc: Steve French <smfrench@gmail.com>
> Cc: Tom Talpey <tom@talpey.com>
> Cc: Long Li <longli@microsoft.com>
> Cc: Namjae Jeon <linkinjeon@kernel.org>
> Cc: linux-rdma@vger.kernel.org
> Cc: linux-cifs@vger.kernel.org
> Cc: samba-technical@lists.samba.org
> Signed-off-by: Stefan Metzmacher <metze@samba.org>
> ---
>  drivers/infiniband/core/cma.c      | 30 ++++++++++++++++++++++++++++++
>  drivers/infiniband/core/cma_priv.h |  1 +
>  include/rdma/rdma_cm.h             | 17 +++++++++++++++++
>  3 files changed, 48 insertions(+)

Thanks,
Acked-by: Leon Romanovsky <leon@kernel.org>