Jason Gunthorpe wrote: > On Mon, Aug 12, 2024 at 10:41:20PM -0700, Christoph Hellwig wrote: > > On Mon, Aug 12, 2024 at 08:12:49PM -0300, Jason Gunthorpe wrote: > > > > This is unfortunately not really minor unless we have a well documented > > > > way to force this :( > > > > > > It is not that different from blocking driver unbind while FDs are > > > open which a lot of places do in various ways? > > > > Where do we block driver unbind with an open resource? > > I keep seeing it in different subsystems, safe driver unbind is really > hard. :\ eg I think VFIO has some waits in it > > > The whole concept is that open resources will pin the in-memory > > object (and modulo for a modular driver), but never an unbind or > > hardware unplug, of which unbind really just is a simulation. > > Yes, ideally, but not every part of the kernel hits that ideal in my > experience. It is alot of work and some places don't have any good > solutions, like here. ...but there is a distinction between transient and permanent waits, right? The difficult aspect of FOLL_LONGTERM is the holder has no idea someone is trying to cleanup and may never drop its pin.
