From: Dragos Tatulea <dtatulea@nvidia.com>
Date: Wed, 26 Jun 2024 10:26:56 +0000 (+0300)
Subject: vdpa/mlx5: Use suspend/resume during VQP change
X-Git-Tag: v6.11-rc1~110^2~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3b3adb3bbfce275400b21f7a0d54db0ba0a46cc9;p=thirdparty%2Flinux.git

vdpa/mlx5: Use suspend/resume during VQP change

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.

Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-20-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index ce1f6a1f36cd1..324604b16b911 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;
 		}