On Thu, Jun 02, 2022 at 10:16:10AM -0600, Logan Gunthorpe wrote: > > Just stuff the pages into the mmap, and your driver unprobe will > > automatically block until all the mmaps are closed - no different than > > having an open file descriptor or something. > > Oh is that what we want? Yes, it is the typical case - eg if you have a sysfs file open unbind hangs indefinitely. Many drivers can't unbind while they have open file descriptors/etc. A couple drivers go out of their way to allow unbinding while a live userspace exists but this can get complicated. Usually there should be a good reason. The module will already be refcounted anyhow because the mmap points to a char file which holds a module reference - meaning a simple rmmod of the driver shouldn't work already.. Jason
