Re: [PATCH v3 07/12] vfio: Accpet device file from vfio PCI hot reset path

[Alex Williamson <alex.williamson@redhat.com>]

On Sat,  1 Apr 2023 07:44:24 -0700
Yi Liu <yi.l.liu@intel.com> wrote:

> This extends both vfio_file_is_valid() and vfio_file_has_dev() to accept
> device file from the vfio PCI hot reset.
> 
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Tested-by: Yanting Jiang <yanting.jiang@intel.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
>  drivers/vfio/vfio_main.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index fe7446805afd..ebbb6b91a498 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -1154,13 +1154,23 @@ const struct file_operations vfio_device_fops = {
>  	.mmap		= vfio_device_fops_mmap,
>  };
>  
> +static struct vfio_device *vfio_device_from_file(struct file *file)
> +{
> +	struct vfio_device *device = file->private_data;
> +
> +	if (file->f_op != &vfio_device_fops)
> +		return NULL;
> +	return device;
> +}
> +
>  /**
>   * vfio_file_is_valid - True if the file is valid vfio file
>   * @file: VFIO group file or VFIO device file
>   */
>  bool vfio_file_is_valid(struct file *file)
>  {
> -	return vfio_group_from_file(file);
> +	return vfio_group_from_file(file) ||
> +	       vfio_device_from_file(file);
>  }
>  EXPORT_SYMBOL_GPL(vfio_file_is_valid);
>  
> @@ -1174,12 +1184,17 @@ EXPORT_SYMBOL_GPL(vfio_file_is_valid);
>  bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
>  {
>  	struct vfio_group *group;
> +	struct vfio_device *vdev;
>  
>  	group = vfio_group_from_file(file);
> -	if (!group)
> -		return false;
> +	if (group)
> +		return vfio_group_has_dev(group, device);
> +
> +	vdev = vfio_device_from_file(file);
> +	if (vdev)
> +		return vdev == device;
>  
> -	return vfio_group_has_dev(group, device);
> +	return false;

Nit, unless we expect to be testing against NULL devices, this could
just be:

	return device == vfio_device_from_file(file);

Thanks,
Alex