> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Tuesday, January 17, 2023 9:50 PM
>
> @@ -17,7 +17,11 @@ struct vfio_device;
> struct vfio_container;
>
> struct vfio_device_file {
> + /* static fields, init per allocation */
> struct vfio_device *device;
> + bool single_open;
I wonder whether the readability is better by renaming this
to 'cdev', e.g.:
/*
* Device cdev path cannot support multiple device open since
* it doesn't have a secure way for it. So a second device
* open attempt should be failed if the caller is from a cdev
* path or the device has already been opened by a cdev path.
*/
if (device->open_count != 0 &&
(df->cdev || device->single_open))
return -EINVAL;
/*
* group path supports multiple device open, while cdev doesn't.
* So use vfio_device_group_close() for !singel_open case.
*/
if (!df->cdev)
vfio_device_group_close(df);
because from device file p.o.v we just want to differentiate cdev
vs. group interface. With this change we even don't need the
comment for the last condition check.
it's fine to have device->single_open as it's kind of a status bit
set in the cdev path to prevent more opens on this device.
