On Wed, Feb 25, 2026 at 3:15 PM David Matlack <[email protected]> wrote: > > On 2026-02-25 02:33 PM, Alex Williamson wrote: > > On Thu, 29 Jan 2026 21:24:51 +0000 > > David Matlack <[email protected]> wrote: > > > > +int __init vfio_pci_liveupdate_init(void) > > > +{ > > > + if (!liveupdate_enabled()) > > > + return 0; > > > + > > > + return liveupdate_register_file_handler(&vfio_pci_liveupdate_fh); > > > +} > > > > liveupdate_register_file_handler() "pins" vfio-pci with a > > try_module_get(). Since this is done in our module_init function and > > unregister occurs in our module_exit function, rather than relative > > to any actual device binding or usage, this means vfio-pci CANNOT be > > unloaded. That seems bad. Thanks, > > Good point. So a better approach that would allow vfio-pci to be > unloaded would be to register the file handler when the number of > devices bound to vfio-pci goes from 0->1 and then unregister on 1->0.
Yeah maybe a kref that gets inc/dec in probe/remove. I have a similar problem with iommufd preservation, but I think I can handle it based on the number of iommufd open. I am wondering whether this file handler registration kref stuff can be moved into LUO by adding it to LUO file_handler and the modules only call get/put?
