Re: [PATCH v1 5/7] vdpa/mlx5: Support configuring max data virtqueue pairs

---
v0->v1:
1. Remove requirement to configure power of two virtqueue pairs
2. Fix cleanup if kcalloc failed

 drivers/vdpa/mlx5/net/mlx5_vnet.c | 43 +++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 1ec29879fc2c..4f0b8bba8b58 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -131,11 +131,6 @@ struct mlx5_vdpa_virtqueue {
        struct mlx5_vq_restore_info ri;
 };

-/* We will remove this limitation once mlx5_vdpa_alloc_resources()
- * provides for driver space allocation
- */
-#define MLX5_MAX_SUPPORTED_VQS 16
-
 static bool is_index_valid(struct mlx5_vdpa_dev *mvdev, u16 idx)
 {
        if (unlikely(idx > mvdev->max_idx))

@@ -148,8 +143,8 @@ struct mlx5_vdpa_net {
        struct mlx5_vdpa_dev mvdev;
        struct mlx5_vdpa_net_resources res;
        struct virtio_net_config config;
-       struct mlx5_vdpa_virtqueue vqs[MLX5_MAX_SUPPORTED_VQS];
-       struct vdpa_callback event_cbs[MLX5_MAX_SUPPORTED_VQS + 1];
+       struct mlx5_vdpa_virtqueue *vqs;
+       struct vdpa_callback *event_cbs;

        /* Serialize vq resources creation and destruction. This is required
         * since memory map might change and we need to destroy and create

@@ -1218,7 +1213,7 @@ static void suspend_vqs(struct mlx5_vdpa_net *ndev)
 {
        int i;

-       for (i = 0; i < MLX5_MAX_SUPPORTED_VQS; i++)
+       for (i = 0; i < ndev->mvdev.max_vqs; i++)
                suspend_vq(ndev, &ndev->vqs[i]);
 }

@@ -1245,7 +1240,7 @@ static int create_rqt(struct mlx5_vdpa_net *ndev)
        int i, j;
        int err;

-       max_rqt = min_t(int, MLX5_MAX_SUPPORTED_VQS / 2,
+       max_rqt = min_t(int, roundup_pow_of_two(ndev->mvdev.max_vqs  / 2),
                        1 << MLX5_CAP_GEN(ndev->mvdev.mdev, log_max_rqt_size));
        if (max_rqt < 1)
                return -EOPNOTSUPP;

@@ -2219,7 +2214,7 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
        clear_vqs_ready(ndev);
        mlx5_vdpa_destroy_mr(&ndev->mvdev);
        ndev->mvdev.status = 0;
-       memset(ndev->event_cbs, 0, sizeof(ndev->event_cbs));
+       memset(ndev->event_cbs, 0, sizeof(*ndev->event_cbs) * (mvdev->max_vqs + 1));
        ndev->mvdev.actual_features = 0;
        ++mvdev->generation;
        if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {

@@ -2292,6 +2287,8 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev)
        }
        mlx5_vdpa_free_resources(&ndev->mvdev);
        mutex_destroy(&ndev->reslock);
+       kfree(ndev->event_cbs);
+       kfree(ndev->vqs);
 }

 static struct vdpa_notification_area mlx5_get_vq_notification(struct vdpa_device *vdev, u16 idx)

@@ -2537,15 +2534,33 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
                return -EOPNOTSUPP;
        }

-       /* we save one virtqueue for control virtqueue should we require it */
        max_vqs = MLX5_CAP_DEV_VDPA_EMULATION(mdev, max_num_virtio_queues);
-       max_vqs = min_t(u32, max_vqs, MLX5_MAX_SUPPORTED_VQS);
+       if (max_vqs < 2) {
+               dev_warn(mdev->device,
+                        "%d virtqueues are supported. At least 2 are required\n",
+                        max_vqs);
+               return -EAGAIN;
+       }
+
+       if (add_config->mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP)) {
+               if (add_config->net.max_vq_pairs > max_vqs / 2)
+                       return -EINVAL;
+               max_vqs = min_t(u32, max_vqs, 2 * add_config->net.max_vq_pairs);
+       } else {
+               max_vqs = 2;
+       }

        ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
                                 name, false);
        if (IS_ERR(ndev))
                return PTR_ERR(ndev);

+       ndev->vqs = kcalloc(max_vqs, sizeof(*ndev->vqs), GFP_KERNEL);
+       ndev->event_cbs = kcalloc(max_vqs + 1, sizeof(*ndev->event_cbs), GFP_KERNEL);
+       if (!ndev->vqs || !ndev->event_cbs) {
+               err = -ENOMEM;
+               goto err_alloc;
+       }
        ndev->mvdev.max_vqs = max_vqs;
        mvdev = &ndev->mvdev;
        mvdev->mdev = mdev;

@@ -2626,6 +2641,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
                mlx5_mpfs_del_mac(pfmdev, config->mac);
 err_mtu:
        mutex_destroy(&ndev->reslock);
+err_alloc:
        put_device(&mvdev->vdev.dev);
        return err;
 }

@@ -2668,7 +2684,8 @@ static int mlx5v_probe(struct auxiliary_device *adev,
        mgtdev->mgtdev.ops = &mdev_ops;
        mgtdev->mgtdev.device = mdev->device;
        mgtdev->mgtdev.id_table = id_table;
-       mgtdev->mgtdev.config_attr_mask = BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR);
+       mgtdev->mgtdev.config_attr_mask = BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR) |
+                                         BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP);
        mgtdev->madev = madev;

        err = vdpa_mgmtdev_register(&mgtdev->mgtdev);
--

2.33.1