Re: [PATCH 15/15] vfio: Add struct device to vfio_device

[Jason Gunthorpe <jgg@ziepe.ca>]

On Sun, Aug 28, 2022 at 01:10:37AM +0800, Kevin Tian wrote:
> From: Yi Liu <yi.l.liu@intel.com>
> 
> and replace kref. With it a 'vfio-dev/vfioX' node is created under the
> sysfs path of the parent, indicating the device is bound to a vfio
> driver, e.g.:
> 
> /sys/devices/pci0000\:6f/0000\:6f\:01.0/vfio-dev/vfio0
> 
> It is also a preparatory step toward adding cdev for supporting future
> device-oriented uAPI.
> 
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Kevin Tian <kevin.tian@intel.com>
> ---
>  drivers/vfio/vfio_main.c | 70 +++++++++++++++++++++++++++++++++-------
>  include/linux/vfio.h     |  6 ++--
>  2 files changed, 61 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index 0c5d120aeced..9ad0cbb83f1c 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -46,6 +46,8 @@ static struct vfio {
>  	struct mutex			group_lock; /* locks group_list */
>  	struct ida			group_ida;
>  	dev_t				group_devt;
> +	struct class			*device_class;
> +	struct ida			device_ida;
>  } vfio;
>  
>  struct vfio_iommu_driver {
> @@ -524,11 +526,19 @@ EXPORT_SYMBOL_GPL(_vfio_alloc_device);
>   *
>   * Only vfio-ccw driver should call this interface.
>   */
> +static void vfio_device_release(struct device *dev);

Since you added this new function in patch 1, it would be nice to
place it in a way that avoids this forward reference in this patch

>  	ret = alloc_chrdev_region(&vfio.group_devt, 0, MINORMASK + 1, "vfio");

I think we should change this "vfio" string at this point, it is
really the group fd, so "vfio_group" ?

It only shows in procfs.

Jason