The modernization of PCIe hotplug in Linux

It is still not too hard to imagine deadlocking your machine due to the "Big PCI Lock", accessed through pci_lock_rescan_remove(). Various removal scenarios end up with circular lock dependencies. Ultimately I'd like to replace this coarse locking and with something more fine grain, or even move to lockless enumerations. This is proving very difficult as much of the pci bus driver's internal states are public, and many arch specific code access them directly, and without reference counting the devices they're using. But I think it's a worthwhile long-term goal.