serialize attach and detach of device sub-trees -- only one device

sub-tree may attach or detach at a time.  attach and detach will sleep
against each other.
this is fixing (working around?) some bizzare corner cases that have
been seen (but not fully diagnosed) where the device trees, disk registration
subsystem, and other things could get messed up.  one could argue though
that this serialization is a very good thing; it is easier than adding piles
of locks in various other places.
ok matthew jsing

0 files changed, 0 insertions, 0 deletions