[RFC PATCH 2/3] smb: client: make use of rdma_restrict_node_type()

[Stefan Metzmacher]

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).

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.

Cc: Jason Gunthorpe <jgg at ziepe.ca>
Cc: Leon Romanovsky <leon at kernel.org>
Cc: Steve French <smfrench at gmail.com>
Cc: Tom Talpey <tom at talpey.com>
Cc: Long Li <longli at microsoft.com>
Cc: Namjae Jeon <linkinjeon at kernel.org>
Cc: linux-rdma at vger.kernel.org
Cc: linux-cifs at vger.kernel.org
Cc: samba-technical at lists.samba.org
Signed-off-by: Stefan Metzmacher <metze at samba.org>
---
 fs/smb/client/smbdirect.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c
index 2900b02f90cd..e69bce88cc9c 100644
--- a/fs/smb/client/smbdirect.c
+++ b/fs/smb/client/smbdirect.c
@@ -903,6 +903,7 @@ static struct rdma_cm_id *smbd_create_id(
 {
 	struct smbdirect_socket_parameters *sp = &sc->parameters;
 	struct rdma_cm_id *id;
+	u8 node_type = RDMA_NODE_UNSPECIFIED;
 	int rc;
 	__be16 *sport;
 
@@ -914,6 +915,31 @@ static struct rdma_cm_id *smbd_create_id(
 		return id;
 	}
 
+	switch (port) {
+	case SMBD_PORT:
+		/*
+		 * only allow iWarp devices
+		 * for port 5445.
+		 */
+		node_type = RDMA_NODE_RNIC;
+		break;
+	case SMB_PORT:
+		/*
+		 * only allow InfiniBand, RoCEv1 or RoCEv2
+		 * devices for port 445.
+		 *
+		 * (Basically don't allow iWarp devices)
+		 */
+		node_type = RDMA_NODE_IB_CA;
+		break;
+	}
+	rc = rdma_restrict_node_type(id, node_type);
+	if (rc) {
+		log_rdma_event(ERR, "rdma_restrict_node_type(%u) failed %i\n",
+			       node_type, rc);
+		goto out;
+	}
+
 	if (dstaddr->sa_family == AF_INET6)
 		sport = &((struct sockaddr_in6 *)dstaddr)->sin6_port;
 	else
-- 
2.43.0