[src/trunk]: src/sys/kern Remove charade dancing around now-dead RCU patent.

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

details:   https://anonhg.NetBSD.org/src/rev/d694d96ab08b
branches:  trunk
changeset: 847196:d694d96ab08b
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Dec 14 16:58:25 2019 +0000

description:
Remove charade dancing around now-dead RCU patent.

diffstat:

 sys/kern/kern_ras.c |  22 ++--------------------
 1 files changed, 2 insertions(+), 20 deletions(-)

diffs (44 lines):

diff -r 49e7955e4a2a -r d694d96ab08b sys/kern/kern_ras.c
--- a/sys/kern/kern_ras.c       Sat Dec 14 16:57:48 2019 +0000
+++ b/sys/kern/kern_ras.c       Sat Dec 14 16:58:25 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_ras.c,v 1.39 2019/10/06 15:11:17 uwe Exp $        */
+/*     $NetBSD: kern_ras.c,v 1.40 2019/12/14 16:58:25 riastradh Exp $  */
 
 /*-
  * Copyright (c) 2002, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_ras.c,v 1.39 2019/10/06 15:11:17 uwe Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_ras.c,v 1.40 2019/12/14 16:58:25 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -65,25 +65,7 @@
 
        /* No need to sync if exiting or single threaded. */
        if (curproc->p_nlwps > 1 && ncpu > 1) {
-#ifdef NO_SOFTWARE_PATENTS
                xc_barrier(0);
-#else
-               /*
-                * Assumptions:
-                *
-                * o preemption is disabled by the thread in
-                *   ras_lookup().
-                * o proc::p_raslist is only inspected with
-                *   preemption disabled.
-                * o ras_lookup() plus loads reordered in advance
-                *   will take no longer than 1/8s to complete.
-                */
-               const int delta = hz >> 3;
-               int target = hardclock_ticks + delta;
-               do {
-                       kpause("ras", false, delta, NULL);
-               } while (hardclock_ticks < target);
-#endif
        }
 }