RDMA/core: introduce rdma_restrict_node_type()

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: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: linux-rdma@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Acked-by: Leon Romanovsky <leon@kernel.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h
index 9bd930a83e6e..6de6fd8bd15e 100644
--- a/include/rdma/rdma_cm.h
+++ b/include/rdma/rdma_cm.h
@@ -169,6 +169,23 @@ struct rdma_cm_id *rdma_create_user_id(rdma_cm_event_handler event_handler,
 void rdma_destroy_id(struct rdma_cm_id *id);
 
 /**
+ * rdma_restrict_node_type - Restrict an RDMA identifier to specific
+ *   RDMA device node type.
+ *
+ * @id: RDMA identifier.
+ * @node_type: The device node type. Only RDMA_NODE_UNSPECIFIED (default),
+ *   RDMA_NODE_RNIC and RDMA_NODE_IB_CA are allowed
+ *
+ * This allows the caller to restrict the possible devices
+ * used to iWarp (RDMA_NODE_RNIC) or InfiniBand/RoCEv1/RoCEv2 (RDMA_NODE_IB_CA).
+ *
+ * It needs to be called before the RDMA identifier is bound
+ * to an device, which mean it should be called before
+ * rdma_bind_addr(), rdma_bind_addr() and rdma_listen().
+ */
+int rdma_restrict_node_type(struct rdma_cm_id *id, u8 node_type);
+
+/**
  * rdma_bind_addr - Bind an RDMA identifier to a source address and
  *   associated RDMA device, if needed.
  *