RDMA/ucma: Mask QPN to be 24 bits according to IBTA

IBTA declares QPN as 24bits, mask input to ensure that kernel
doesn't get higher bits and ensure by adding WANR_ONCE() that
other CM users do the same.

Link: https://lore.kernel.org/r/20200212072635.682689-2-leon@kernel.orgSigned-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/cm.c

@@ -2188,6 +2188,9 @@ int ib_send_cm_rep(struct ib_cm_id *cm_id,
 	cm_id_priv->initiator_depth = param->initiator_depth;
 	cm_id_priv->responder_resources = param->responder_resources;
 	cm_id_priv->rq_psn = cpu_to_be32(IBA_GET(CM_REP_STARTING_PSN, rep_msg));
+	WARN_ONCE(param->qp_num & 0xFF000000,
+		  "IBTA declares QPN to be 24 bits, but it is 0x%X\n",
+		  param->qp_num);
 	cm_id_priv->local_qpn = cpu_to_be32(param->qp_num & 0xFFFFFF);
 
 out:	spin_unlock_irqrestore(&cm_id_priv->lock, flags);

drivers/infiniband/core/ucma.c

@@ -1045,7 +1045,7 @@ static void ucma_copy_conn_param(struct rdma_cm_id *id,
 	dst->retry_count = src->retry_count;
 	dst->rnr_retry_count = src->rnr_retry_count;
 	dst->srq = src->srq;
-	dst->qp_num = src->qp_num;
+	dst->qp_num = src->qp_num & 0xFFFFFF;
 	dst->qkey = (id->route.addr.src_addr.ss_family == AF_IB) ? src->qkey : 0;
 }