[PATCH rdma-next v1] RDMA/ucma: Mask QPN to be 24 bits according to IBTA

[Leon Romanovsky <leon@kernel.org>]

From: Leon Romanovsky <leonro@mellanox.com>

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.

Fixes: 75216638572f ("RDMA/cma: Export rdma cm interface to userspace")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
 Changelog:
 v0 -> v1: https://lore.kernel.org/linux-rdma/20191031190504.GA5939@ziepe.ca
 * Squashed patch https://lore.kernel.org/linux-rdma/20191031190504.GA5939@ziepe.ca
   and https://lore.kernel.org/linux-rdma/20191020071559.9743-5-leon@kernel.org
---
 drivers/infiniband/core/cm.c   | 5 ++++-
 drivers/infiniband/core/ucma.c | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 33b384c7df42..acc1e1d80c42 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -2101,7 +2101,10 @@ 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 = cm_rep_get_starting_psn(rep_msg);
-	cm_id_priv->local_qpn = cpu_to_be32(param->qp_num & 0xFFFFFF);
+	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);

 out:	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 	return ret;
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 0274e9b704be..57e68491a2fd 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/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;
 }

--
2.20.1