From: Eli Cohen <elic@nvidia.com>
Date: Tue, 11 Jan 2022 20:34:00 +0200
Subject: vdpa/mlx5: Fix tracking of current number of VQs
Patch-mainline: v5.17-rc1
Git-commit: b03fc43e73877e180c1803a33aea3e7396642367
References: jsc#PED-1549

Modify the code such that ndev->cur_num_vqs better reflects the actual
number of data virtqueues. The value can be accurately realized after
features have been negotiated.

This is to prevent possible failures when modifying the RQT object if
the cur_num_vqs bears invalid value.

No issue was actually encountered but this also makes the code more
readable.

Fixes: c5a5cd3d3217 ("vdpa/mlx5: Support configuring max data virtqueue")
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20220111183400.38418-5-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Si-Wei Liu<si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1246,8 +1246,7 @@ static int create_rqt(struct mlx5_vdpa_n
 	if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_MQ)))
 		num = 1;
 	else
-		num = mlx5vdpa16_to_cpu(&ndev->mvdev,
-					ndev->config.max_virtqueue_pairs);
+		num = ndev->cur_num_vqs / 2;
 
 	max_rqt = min_t(int, roundup_pow_of_two(num),
 			1 << MLX5_CAP_GEN(ndev->mvdev.mdev, log_max_rqt_size));
@@ -1983,6 +1982,11 @@ static int mlx5_vdpa_set_driver_features
 		return err;
 
 	ndev->mvdev.actual_features = features & ndev->mvdev.mlx_features;
+	if (ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_MQ))
+		ndev->cur_num_vqs = 2 * mlx5vdpa16_to_cpu(mvdev, ndev->config.max_virtqueue_pairs);
+	else
+		ndev->cur_num_vqs = 2;
+
 	update_cvq_info(mvdev);
 	return err;
 }
@@ -2233,6 +2237,7 @@ static int mlx5_vdpa_reset(struct vdpa_d
 	clear_vqs_ready(ndev);
 	mlx5_vdpa_destroy_mr(&ndev->mvdev);
 	ndev->mvdev.status = 0;
+	ndev->cur_num_vqs = 0;
 	memset(ndev->event_cbs, 0, sizeof(*ndev->event_cbs) * (mvdev->max_vqs + 1));
 	ndev->mvdev.actual_features = 0;
 	++mvdev->generation;
@@ -2641,9 +2646,8 @@ static int mlx5_vdpa_dev_add(struct vdpa
 
 	ndev->nb.notifier_call = event_handler;
 	mlx5_notifier_register(mdev, &ndev->nb);
-	ndev->cur_num_vqs = 2 * mlx5_vdpa_max_qps(max_vqs);
 	mvdev->vdev.mdev = &mgtdev->mgtdev;
-	err = _vdpa_register_device(&mvdev->vdev, ndev->cur_num_vqs + 1);
+	err = _vdpa_register_device(&mvdev->vdev, 2 * mlx5_vdpa_max_qps(max_vqs) + 1);
 	if (err)
 		goto err_reg;