devfs patch, please test.

[Poul-Henning Kamp]

http://phk.freebsd.dk/patch/devfs.patch

Please test and report.


Back when devfs was first introduced, it was necessary to isolate the
device driver context(s) from the filesystem context(s) and a lot of
atomic instructions went into that.

Now that SMPng and various cleanups have simplified the world a bit,
this patch eliminates all the atomic fireworks and does away with the
"overflow" table and other nastyness.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.