[PATCH vhost 19/23] vdpa/mlx5: Use suspend/resume during VQP change

Dragos Tatulea
2024-06-17T15:09:19Z

Resume a VQ if it is already created when the number of VQ pairs
increases. This is done in preparation for VQ pre-creation which is
coming in a later patch. It is necessary because calling setup_vq() on
an already created VQ will return early and will not enable the queue.

For symmetry, suspend a VQ instead of tearing it down when the number of
VQ pairs decreases. But only if the resume operation is supported.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 0e1c1b7ff297..249b5afbe34a 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2130,14 +2130,22 @@ static int change_num_qps(struct mlx5_vdpa_dev *mvdev, int newqps)
if (err)
return err;

- for (i = ndev->cur_num_vqs - 1; i >= 2 * newqps; i--)
- teardown_vq(ndev, &ndev->vqs[i]);
+ for (i = ndev->cur_num_vqs - 1; i >= 2 * newqps; i--) {
+ struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[i];
+
+ if (is_resumable(ndev))
+ suspend_vq(ndev, mvq);
+ else
+ teardown_vq(ndev, mvq);
+ }

ndev->cur_num_vqs = 2 * newqps;
} else {
ndev->cur_num_vqs = 2 * newqps;
for (i = cur_qps * 2; i < 2 * newqps; i++) {
- err = setup_vq(ndev, &ndev->vqs[i], true);
+ struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[i];
+
+ err = mvq->initialized ? resume_vq(ndev, mvq) : setup_vq(ndev, mvq, true);
if (err)
goto clean_added;
}

--
2.45.1