the stack, and remove the no-longer-necessary PHOLD()/PRELE() calls
in fdformat().
(This eliminates 1/3 of the instances of PHOLD()/PRELE() in the kernel code.)
XXX We still have too many mostly-redundant floppy drivers.
This work is based on code written by Scott D. Telford, the IBM
Token Ring card attachment was written by Gregory McGarry.
XXX this is still very experimental and development version; use at your
XXX own risk
where the floppy driver would wedge because a motor-on timeout would
be cancelled by another I/O operation cancelling a motor-off timeout.
From enami tsugutomo <enami@sm.sony.co.jp>.
nathanw