Update callout_halt() to match src/sys/sys/callout.h

branches: 1.28.16; 1.28.18;
Make it clear that we should use not callout_stop but callout_halt before callout_destroy

branches: 1.27.2;
callout_ack returns void, not bool.

branches: 1.26.6;
Note that a callout should be stopped before being destroyed.

branches: 1.25.8; 1.25.10; 1.25.14;
Relate interfaces by updating "see also" section.

Add missing word.

Add a CONCURRENCY section with some food for thought.

Document callout_halt.

No space between dot and macro name.

branches: 1.20.2;
Add callout_pending to NAME section.

Convert TNF licenses to new 2 clause variant

branches: 1.18.4; 1.18.6;
Document CALLOUT_MPSAFE. Bump date.

Sync callout(9) man page with bool changes.

branches: 1.16.4;
Bump date.

Sync with reality.

Document callout_active().

- Change callout_setfunc() to require that the callout handle is already
initialized. Update the txp(4) to compensate.
- Statically initialize the TCP timer callout handles in the tcpcb
template. We still use callout_setfunc(), but that call is now much
less expensive. Add a comment that the compiler is likely to unroll
the loop (so don't sweat that it's there).

Make the documentation match the source, and excise instances of
the RUNNING flag which existed in an earlier draft implementation.
Also, now that callout_stop() no longer clears INVOKING, reflect
that as well.

Bump date for callout_invoking; fix macro usage; remove superfluous "The".

Temporarily introduce CALLOUT_INVOKING, callout_invoking() and callout_ack()
to make users of the callout facility able to cooperate to work around the
race caused by the callout code lowering interrupt priority level when
invoking callout handlers, something which allows other code to run before
the callout handler gets to it's spl*() call.

This is to enable the workaround for the TCP code found in PR#20390 to be
applied.

This should be backed out once a more comprehensive fix can be put in
place.

Use
.In header.h
instead of
.Fd #include \*[Lt]header.h\*[Gt]
Much easier to read and write, and supported by groff for ages.
Okayed by ross.

Update for new callout(9) implemenatation.

New sentence, new line.

branches: 1.6.2;
Generate <>& symbolically. I'm avoiding .../dist/... directories for now.

Xref hz(9), now that it exists.

Fix typos, punctuation and whitespace.

Comment out references to hz(9) and hardclock(9). It'd be nice
if someone wrote them, but let's not reference them until they are
written. Addresses PR kern/4901.

Add an include statement to SYNOPSIS sections. Fixes kern/9685.

Documentation for new callout interfaces.