[PATCH 5.6 046/118] net/mlx5: DR, On creation set CQs arm_db member to right value

[Greg Kroah-Hartman]

From: Erez Shitrit <erezsh@xxxxxxxxxxxx>

[ Upstream commit 8075411d93b6efe143d9f606f6531077795b7fbf ]

In polling mode, set arm_db member to a value that will avoid CQ
event recovery by the HW.
Otherwise we might get event without completion function.
In addition,empty completion function to was added to protect from
unexpected events.

Fixes: 297cccebdc5a ("net/mlx5: DR, Expose an internal API to issue RDMA operations")
Signed-off-by: Erez Shitrit <erezsh@xxxxxxxxxxxx>
Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
Reviewed-by: Alex Vesker <valex@xxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/steering/dr_send.c |   14 ++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_send.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_send.c
@@ -689,6 +689,12 @@ static void dr_cq_event(struct mlx5_core
 	pr_info("CQ event %u on CQ #%u\n", event, mcq->cqn);
 }
 
+static void dr_cq_complete(struct mlx5_core_cq *mcq,
+			   struct mlx5_eqe *eqe)
+{
+	pr_err("CQ completion CQ: #%u\n", mcq->cqn);
+}
+
 static struct mlx5dr_cq *dr_create_cq(struct mlx5_core_dev *mdev,
 				      struct mlx5_uars_page *uar,
 				      size_t ncqe)
@@ -750,6 +756,7 @@ static struct mlx5dr_cq *dr_create_cq(st
 	mlx5_fill_page_frag_array(&cq->wq_ctrl.buf, pas);
 
 	cq->mcq.event = dr_cq_event;
+	cq->mcq.comp  = dr_cq_complete;
 
 	err = mlx5_core_create_cq(mdev, &cq->mcq, in, inlen, out, sizeof(out));
 	kvfree(in);
@@ -761,7 +768,12 @@ static struct mlx5dr_cq *dr_create_cq(st
 	cq->mcq.set_ci_db = cq->wq_ctrl.db.db;
 	cq->mcq.arm_db = cq->wq_ctrl.db.db + 1;
 	*cq->mcq.set_ci_db = 0;
-	*cq->mcq.arm_db = 0;
+
+	/* set no-zero value, in order to avoid the HW to run db-recovery on
+	 * CQ that used in polling mode.
+	 */
+	*cq->mcq.arm_db = cpu_to_be32(2 << 28);
+
 	cq->mcq.vector = 0;
 	cq->mcq.irqn = irqn;
 	cq->mcq.uar = uar;