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

Alex Williamson
2023-04-04T20:32:21Z

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