Subject: [net PATCH 2/2] ice: Do not skip not enabled queues in ice_vc_dis_qs_msg

From: Alice Michael <[email-masked]>
Date: Fri, 1 Apr 2022 05:14:53 -0700

From: Anatolii Gerasymenko <[email-masked]>

Disable check for queue being enabled in ice_vc_dis_qs_msg, because
there could be a case when queues were created, but were not enabled.
We still need to delete those queues.

Normal workflow for VF looks like:
Enable path:
VIRTCHNL_OP_ADD_ETH_ADDR (opcode 10)
VIRTCHNL_OP_CONFIG_VSI_QUEUES (opcode 6)
VIRTCHNL_OP_ENABLE_QUEUES (opcode 8)

Disable path:
VIRTCHNL_OP_DISABLE_QUEUES (opcode 9)
VIRTCHNL_OP_DEL_ETH_ADDR (opcode 11)

The issue appears only in stress conditions when VF is enabled and
disabled very fast.
Eventually there will be a case, when queues are created by
VIRTCHNL_OP_CONFIG_VSI_QUEUES, but are not enabled by
VIRTCHNL_OP_ENABLE_QUEUES.
In turn, these queues are not deleted by VIRTCHNL_OP_DISABLE_QUEUES,
because there is a check whether queues are enabled in
ice_vc_dis_qs_msg.

When we bring up the VF again, we will see the "Failed to set LAN Tx queue
context" error during VIRTCHNL_OP_CONFIG_VSI_QUEUES step. This
happens because old 16 queues were not deleted and VF requests to create
16 more, but ice_sched_get_free_qparent in ice_ena_vsi_txq would fail to
find a parent node for first newly requested queue (because all nodes
are allocated to 16 old queues).

Testing Hints:

Just enable and disable VF fast enough, so it would be disabled before
reaching VIRTCHNL_OP_ENABLE_QUEUES.

while true; do
        ip link set dev ens785f0v0 up
        sleep 0.065 # adjust delay value for your machine
        ip link set dev ens785f0v0 down
done

Fixes: 77ca27c41705 ("ice: add support for virtchnl_queue_select.[tx|rx]_queues bitmap")

Signed-off-by: Anatolii Gerasymenko <[email-masked]>
Tested-by: Konrad Jankowski <[email-masked]>
Signed-off-by: Alice Michael <[email-masked]>
---
 drivers/net/ethernet/intel/ice/ice_virtchnl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_virtchnl.c b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
index 3f1a63815bac..69ff4b929772 100644
--- a/drivers/net/ethernet/intel/ice/ice_virtchnl.c
+++ b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
@@ -1358,9 +1358,9 @@ static int ice_vc_dis_qs_msg(struct ice_vf *vf, u8 *msg)
 				goto error_param;
 			}
 
-			/* Skip queue if not enabled */
 			if (!test_bit(vf_q_id, vf->txq_ena))
-				continue;
+				dev_dbg(ice_pf_to_dev(vsi->back), "Queue %u on VSI %u is not enabled, but stopping it anyway\n",
+					vf_q_id, vsi->vsi_num);
 
 			ice_fill_txq_meta(vsi, ring, &txq_meta);
 
-- 
2.31.1