> From: Liu, Yi L <[email protected]> > Sent: Monday, February 6, 2023 5:05 PM > > struct vfio_device_file * > -vfio_allocate_device_file(struct vfio_device *device) > +vfio_allocate_device_file(struct vfio_device *device, bool is_cdev_device) > { > struct vfio_device_file *df; > > @@ -407,6 +407,7 @@ vfio_allocate_device_file(struct vfio_device *device) > return ERR_PTR(-ENOMEM); > > df->device = device; > + df->is_cdev_device = is_cdev_device;
You missed Alex's comment that the one caller can open code the assignment instead of introducing an unmemorable Boolean arg here. > > + /* > + * 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->is_cdev_device || device->single_open)) > + return -EINVAL; > + If we are gonna handle the exclusive open via dma ownership, then here we don't need a new single_open flag inside vfio_device since only one interface (cdev or group) could be used to open this device. Just preventing multi-open in cdev is sufficient here.
