Re: [PATCH v2] vdpa: regist vhost-vdpa dev class

[Jason Wang <jasowang@redhat.com>]

On Fri, Dec 24, 2021 at 3:13 PM Yi Wang <wang.yi59@zte.com.cn> wrote:
>
> From: Zhang Min <zhang.min9@zte.com.cn>
>
> Some applications like kata-containers need to acquire MAJOR/MINOR/DEVNAME
> for devInfo [1], so regist vhost-vdpa dev class to expose uevent.

Hi:

I think we need to be more verbose here e.g:

1) why can't we get major/minor with the current interface
2) what kind of the uevent is required and not supported currently

Thanks

>
> 1. https://github.com/kata-containers/kata-containers/blob/main/src/runtime/virtcontainers/device/config/config.go
>
> Signed-off-by: Zhang Min <zhang.min9@zte.com.cn>
> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
> ---
> v2: remove redundant vhost_vdpa_class reset and pr_warn, adjust location
>     of *vhost_vdpa_class impl and class_destroy.
>
>  drivers/vhost/vdpa.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index e3c4f059b21a..55e966c508c8 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -53,6 +53,7 @@ struct vhost_vdpa {
>  static DEFINE_IDA(vhost_vdpa_ida);
>
>  static dev_t vhost_vdpa_major;
> +static struct class *vhost_vdpa_class;
>
>  static void handle_vq_kick(struct vhost_work *work)
>  {
> @@ -1140,6 +1141,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
>         v->dev.release = vhost_vdpa_release_dev;
>         v->dev.parent = &vdpa->dev;
>         v->dev.devt = MKDEV(MAJOR(vhost_vdpa_major), minor);
> +       v->dev.class = vhost_vdpa_class;
>         v->vqs = kmalloc_array(v->nvqs, sizeof(struct vhost_virtqueue),
>                                GFP_KERNEL);
>         if (!v->vqs) {
> @@ -1197,6 +1199,10 @@ static int __init vhost_vdpa_init(void)
>  {
>         int r;
>
> +       vhost_vdpa_class = class_create(THIS_MODULE, "vhost-vdpa");
> +       if (IS_ERR(vhost_vdpa_class))
> +               return PTR_ERR(vhost_vdpa_class);
> +
>         r = alloc_chrdev_region(&vhost_vdpa_major, 0, VHOST_VDPA_DEV_MAX,
>                                 "vhost-vdpa");
>         if (r)
> @@ -1211,6 +1217,7 @@ static int __init vhost_vdpa_init(void)
>  err_vdpa_register_driver:
>         unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
>  err_alloc_chrdev:
> +       class_destroy(vhost_vdpa_class);
>         return r;
>  }
>  module_init(vhost_vdpa_init);
> @@ -1219,6 +1226,7 @@ static void __exit vhost_vdpa_exit(void)
>  {
>         vdpa_unregister_driver(&vhost_vdpa_driver);
>         unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
> +       class_destroy(vhost_vdpa_class);
>  }
>  module_exit(vhost_vdpa_exit);
>
> --
> 2.27.0
>