On Tue, 9 Jul 2002, Roman Zippel wrote:
> Who is changing the use count? How do you ensure that someone doesn't
> cache a reference past that magic sync point?
> IMO the real problem is that cleanup_module() can't fail. If modules
> already do proper data acounting, it's not too difficult to detect if
> there still exists a reference. In the driverfs example the problem is
> that remove_driver() returns void instead of int, so it can't fail.
I tend to see this differently: cleanup_module() cannot fail, but it can
sleep. So it's perfectly fine to deregister, wait until all references are
gone, clean up and return. So a kind of two-stage unregister is already
happening.
It's different in that it does use explicit refcounting, but
when the right interfaces are provided, the driver author doesn't need to
care - the author should just call pci_unregister/netdev_unregister/..,
that'll sleep until all references are gone (which also means no one will
use callbacks into the module anymore) and be done.
--Kai
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This archive was generated by hypermail 2b29 : Mon Jul 15 2002 - 22:00:14 EST