nfsd: Update NFS server comments related to RDMA support

The server does indeed now support NFSv4.1 on RDMA transports. It
does not support shifting an RDMA-capable TCP transport (such as
iWARP) to RDMA mode.
Reported-by: Shirley Ma <shirley.ma@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -2711,10 +2711,9 @@ nfsd4_create_session(struct svc_rqst *rqstp,
 		goto out_free_conn;
 	}
 	status = nfs_ok;
-	/*
-	 * We do not support RDMA or persistent sessions
-	 */
+	/* Persistent sessions are not supported */
 	cr_ses->flags &= ~SESSION4_PERSIST;
+	/* Upshifting from TCP to RDMA is not supported */
 	cr_ses->flags &= ~SESSION4_RDMA;
 
 	init_session(rqstp, new, conf, cr_ses);

fs/nfsd/nfs4xdr.c

@@ -3063,7 +3063,7 @@ static __be32 nfsd4_encode_bind_conn_to_session(struct nfsd4_compoundres *resp,
 		p = xdr_encode_opaque_fixed(p, bcts->sessionid.data,
 						NFS4_MAX_SESSIONID_LEN);
 		*p++ = cpu_to_be32(bcts->dir);
-		/* Sorry, we do not yet support RDMA over 4.1: */
+		/* Upshifting from TCP to RDMA is not supported */
 		*p++ = cpu_to_be32(0);
 	}
 	return nfserr;