Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r227124: fifo_misc test: Fix swapped lseek arguments.

It worked regardless because SEEK_CUR happens to be 1.

PR: misc/160866

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

The devices that supported EVFILT_NETDEV kqueue filters were removed in
r195175. Remove all definitions, documentation, and usage.

fifo_misc.c:
Remove all kqueue tests as fifo_io.c performs all those that
would have remained.

Reviewed by: rwatson
MFC after: 3 weeks
X-MFC note: don't change vlan_link_state() function signature

o Test truncate(2) on fifo: it should ignore the request and
return success.

PR: kern/98064
Submitted by: Kirk Russell

Add two small tests to set and clear two file I/O flags using ioctl on
a fifo: FIONBIO, FIOASYNC.

Remove a debugging printf.

Comment test_lseek().

Add test_kqueue(), which registers and unregisters various kqueue filter
types on a fifo in order to make sure that EVFILT_READ, EVFILT_WRITE can
be registered, and that EVFILT_NETDEV can't be registered. For now, we
don't test that EVFILT_VNODE can be registered on fifos, as that has been
broken at some point.

Add fifo_misc, a regression test to hold misc. functional tests for fifos
that don't obviously fit into create, open, and io. For now, add only a
regression test to make sure that lseek() fails with ESPIPE (which it
doesn't).