[src/trunk]: src/share/man/man9 rnd(9): Document the serial use of rndsource ...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b25ffbb4e9db
branches:  trunk
changeset: 364363:b25ffbb4e9db
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Mar 19 11:54:53 2022 +0000

description:
rnd(9): Document the serial use of rndsource callbacks.

This simplifies the rndsource API -- no need to lock, unless you're
also coordinating with other driver logic like concurrent
opencrypto(4) requests that share device requests.

diffstat:

 share/man/man9/rnd.9 |  8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diffs (22 lines):

diff -r 1e99a7df7daa -r b25ffbb4e9db share/man/man9/rnd.9
--- a/share/man/man9/rnd.9      Sat Mar 19 11:37:17 2022 +0000
+++ b/share/man/man9/rnd.9      Sat Mar 19 11:54:53 2022 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: rnd.9,v 1.29 2020/05/04 15:13:45 wiz Exp $
+.\"    $NetBSD: rnd.9,v 1.30 2022/03/19 11:54:53 riastradh Exp $
 .\"
 .\" Copyright (c) 1997 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -165,6 +165,12 @@
 or
 .Fn rnd_add_uint32 .
 .El
+.Pp
+.Nm
+issues calls to each source's
+.Fa callback
+in serial \(em it never issues two calls to the same source's callback
+at the same time in two differen threads or on two different CPUs.
 .It Fn rnd_attach_source "rnd_source" "devname" "type" "flags"
 Makes
 .Fa rnd_source