There is no need to mark this device node to use Giant. The only
architectures that use io(4) (i386 and amd64) only change a flag in
td->td_frame, which is only accessed by curthread.
Apart from this change, I think some fishy things may happen when using
/dev/io in multithreaded applications. I haven't tested, but looking at
the code, the flag doesn't get cleared when close() is called from
another thread, but this may not be this important.
I'm not removing D_NEEDGIANT from mem(4), because this driver isn't
Giant safe at all (it calls GIANT_REQUIRED).
Now that st_rdev is being automatically generated by the kernel, there
is no need to define static major/minor numbers for the iodev and
memdev. We still need the minor numbers for the memdev, however, to
distinguish between /dev/mem and /dev/kmem.
Approved by: philip (mentor)
their own directory and module, leaving the MD parts in the MD
area (the MD parts _are_ part of the modules). /dev/mem and /dev/io
are now loadable modules, thus taking us one step further towards
a kernel created entirely out of modules. Of course, there is nothing
preventing the kernel from having these statically compiled.
